ORCID Profile
0000-0002-0824-9682
Current Organisations
University of Western Australia
,
Griffith University Griffith Health
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biomedical Engineering | Biomaterials | Biomechanical Engineering | Biomedical Instrumentation | Medical Devices | Vertebrate Biology | Biomechanics | Biomedical Engineering not elsewhere classified | Composite and Hybrid Materials |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in Engineering | Education and Training Systems not elsewhere classified | Skeletal System and Disorders (incl. Arthritis) | Disability and Functional Capacity | Injury Control | Health not elsewhere classified | Expanding Knowledge in the Medical and Health Sciences
Related Links
Publications
Predicting Free Achilles Tendon Strain From Motion Capture Data Using Artificial Intelligence
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Muscle contributions to recovery from forward loss of balance by stepping
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.JBIOMECH.2013.11.047
Abstract: The purpose of this study was to determine the muscular contributions to the stepping phase of recovery from forward loss of balance in 5 young and 5 older adults that were able to recover balance in a single step, and 5 older adults that required multiple steps. Forward loss of balance was achieved by releasing participants from a static forward lean angle. All participants were instructed to attempt to recover balance by taking a rapid single step. A scalable anatomical model consisting of 36 degrees-of-freedom was used to compute kinematics and joint moments from motion capture and force plate data. Forces for 94 muscle actuators were computed using static optimisation and induced acceleration analysis was used to compute in idual muscle contributions to net lumbar spine joint, and stepping side hip joint and knee joint accelerations during recovery. Older adults that required multiple recovery steps used a significantly shorter and faster initial recovery step and adopted significantly more trunk flexion throughout recovery compared to the older single steppers. Older multiple steppers also produced significantly more force in the stance side hamstrings, which resulted in significantly higher hamstring induced flexion accelerations at the lumbar spine and extension accelerations at the hip. However since the net joint lumbar spine and hip accelerations remained similar between older multiple steppers and older single steppers, we suggest that the recovery strategy adopted by older multiple steppers was less efficient as well as less effective than for older single steppers.
Isokinetic knee extensor strength deficit following matrix-induced autologous chondrocyte implantation
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.CLINBIOMECH.2012.01.006
Abstract: Autologous chondrocyte implantation has become an established technique for addressing knee cartilage defects. Despite reported improvement in pain and regeneration of hyaline-like repair tissue, little has been reported on the recovery of knee strength. Knee strength assessment was undertaken in 60 patients at 5 years following autologous chondrocyte implantation. Using an isokinetic dynamometer, and during isokinetic knee extension and flexion angular velocities of 60°, 90° and 120°/s, the peak torque, torque at 45° of knee flexion and hamstrings/quadriceps ratio was obtained, in both the operated and non-operated limbs. Pain at the time of assessment was obtained. Independent s le t-tests were used to assess differences in the operated and non-operated sides. There were no significant differences (p>0.05) between the operated and non-operated legs in the peak knee flexor torque or knee flexor torque at a knee flexion angle of 45°, at all angular velocities (60°, 90° and 120°/s). While the peak knee extensor torque was less in the operated leg at all angular velocities, these differences were not significant (p>0.05). However, a significantly reduced (p<0.05) knee extensor torque at a knee flexion angle of 45°, was observed at all speeds. While patients had recovered their knee flexor strength, they still demonstrated a reduced knee extensor strength profile at 5 years. This demonstrates that the early supervised rehabilitation phase following autologous chondrocyte implantation is not sufficient to restore long-term knee strength, and ongoing patient advice and rehabilitation is required extending beyond this early period. It is unknown how this prolonged reduction in strength may affect long-term graft outcome.
The relationship between patellofemoral and tibiofemoral morphology and gait biomechanics following arthroscopic partial medial meniscectomy
Publisher: Springer Science and Business Media LLC
Date: 07-06-2012
DOI: 10.1007/S00167-012-2075-6
Abstract: To examine the relationship between tibiofemoral and patellofemoral joint articular cartilage and subchondral bone in the medial and gait biomechanics following partial medial meniscectomy. For this cross-sectional study, 122 patients aged 30-55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy, underwent gait analysis and MRI on the operated knee once for each sub-cohort of 3 months, 2 years, or 4 years post-surgery. Cartilage volume, cartilage defects, and bone size were assessed from the MRI using validated methods. The 1st peak in the knee adduction moment, knee adduction moment impulse, 1st peak in the knee flexion moment, knee extension range of motion, and the heel strike transient from the vertical ground reaction force trace were identified from the gait data. Increased knee stance phase range of motion was associated with decreased patella cartilage volume (B = -17.9 (95% CI -35.4, -0.4) p = 0.045) while knee adduction moment impulse was associated with increased medial tibial plateau area (B = 7.7 (95% CI 0.9, 13.3) p = 0.025). A number of other variables approached significance. Knee joint biomechanics exhibited by persons who had undergone arthroscopic partial meniscectomy gait may go some way to explaining the morphological degeneration observed at the patellofemoral and tibiofemoral compartments of the knee as patients progress from surgery. III.
Effect of ankle taping on knee and ankle joint biomechanics in sporting tasks
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2010
Coding OSICS sports injury diagnoses in epidemiological studies: Does the background of the coder matter?
Publisher: BMJ
Date: 23-08-2014
Do Moments and Strength Predict Cartilage Changes following Partial Meniscectomy?
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2014
Real-time inverse kinematics and inverse dynamics for lower limb applications using OpenSim
Publisher: Informa UK Limited
Date: 10-10-2016
Electromyography measurements of the deep hip muscles do not improve estimates of hip contact force
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.JBIOMECH.2022.111220
Abstract: The deep hip muscles are often omitted in studies investigating hip contact forces using neuromusculoskeletal modelling methods. However, recent evidence indicates the deep hip muscles have potential to change the direction of hip contact force and could have relevance for hip contact loading estimates. Further, it is not known whether deep hip muscle excitation patterns can be accurately estimated using neuromusculoskeletal modelling or require measurement (through invasive and time-consuming methods) to inform models used to estimate hip contact forces. We calculated hip contact forces during walking, squatting, and squat-jumping for 17 participants using electromyography (EMG)-informed neuromusculoskeletal modelling with (informed) and without (synthesized) intramuscular EMG for the deep hip muscles (piriformis, obturator internus, quadratus femoris). Hip contact force magnitude and direction, calculated as the angle between hip contact force and vector from femoral head to acetabular center, were compared between configurations using a paired t-test deployed through statistical parametric mapping (P < 0.05). Additionally, root mean square error, correlation coefficients (R
Individual muscle contributions to tibiofemoral compressive articular loading during walking, running and sidestepping
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.JBIOMECH.2018.08.022
Abstract: The tibiofemoral joint (TFJ) experiences large compressive articular contact loads during activities of daily living, caused by inertial, ligamentous, capsular, and most significantly musculotendon loads. Comparisons of relative contributions of in idual muscles to TFJ contact loading between walking and sporting movements have not been previously examined. The purpose of this study was to determine relative contributions of in idual lower-limb muscles to compressive articular loading of the medial and lateral TFJ during walking, running, and sidestepping. The medial and lateral compartments of the TFJ were loaded by a combination of medial and lateral muscles. During all gait tasks, the primary muscles loading the medial and lateral TFJ were the vastus medialis (VM) and vastus lateralis (VL) respectively during weight acceptance, while typically the medial gastrocnemii (MG) and lateral gastrocnemii (LG) dominated medial and lateral TFJ loading respectively during midstance and push off. Generally, the contribution of the quadriceps muscles were higher in running compared to walking, whereas gastrocnemii contributions were higher in walking compared to running. When comparing running and sidestepping, contributions to medial TFJ contact loading were generally higher during sidestepping while contributions to lateral TFJ contact loading were generally lower. These results suggests that after orthopaedic procedures, the VM, VL, MG and LG should be of particular rehabilitation focus to restore TFJ stability during dynamic gait tasks.
EMG-Driven Forward-Dynamic Estimation of Muscle Force and Joint Moment about Multiple Degrees of Freedom in the Human Lower Extremity
Publisher: Public Library of Science (PLoS)
Date: 26-12-2012
Subject-specific calibration of neuromuscular parameters enables neuromusculoskeletal models to estimate physiologically plausible hip joint contact forces in healthy adults
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.JBIOMECH.2018.08.023
Abstract: In-vivo hip joint contact forces (HJCF) can be estimated using computational neuromusculoskeletal (NMS) modelling. However, different neural solutions can result in different HJCF estimations. NMS model predictions are also influenced by the selection of neuromuscular parameters, which are either based on cadaveric data or calibrated to the in idual. To date, the best combination of neural solution and parameter calibration to obtain plausible estimations of HJCF have not been identified. The aim of this study was to determine the effect of three electromyography (EMG)-informed neural solution modes (EMG-driven, EMG-hybrid, and EMG-assisted) and static optimisation, each using three different parameter calibrations (uncalibrated, minimise joint moments error, and minimise joint moments error and peak HJCF), on the estimation of HJCF in a healthy population (n = 23) during walking. When compared to existing in-vivo data, the EMG-assisted mode and static optimisation produced the most physiologically plausible HJCF when using a NMS model calibrated to minimise joint moments error and peak HJCF. EMG-assisted mode produced first and second peaks of 3.55 times body weight (BW) and 3.97 BW during walking static optimisation produced 3.75 BW and 4.19 BW, respectively. However, compared to static optimisation, EMG-assisted mode generated muscle excitations closer to recorded EMG signals (average across hip muscles R
Towards a national sports safety strategy: addressing facilitators and barriers towards safety guideline uptake
Publisher: BMJ
Date: 22-02-2011
Abstract: Limited information exists about how best to conduct intervention implementation studies in community sport settings. Research should be directed towards understanding the context within which evidence-based injury prevention interventions are to be implemented, while continuing to build the evidence-base for the effectiveness of sports injury interventions. To identify factors that influence the translation of evidence-based injury prevention interventions into practice in community sport, and to provide specific evidence for the effectiveness of an evidence-based exercise training programme for lower limb injury prevention in community Australian football. Community-level Australian football clubs, teams and players. An exercise-based lower limb injury prevention programme will be developed and evaluated in terms of the implementation context, infrastructure and resources needed for its effective translation into community sport. Analysis of the community sports safety policy context will be undertaken to understand the barriers and facilitators to policy development and uptake. A randomised group-clustered ecological study will be conducted to compare the reach, effectiveness, adoption, implementation and maintenance (RE-AIM) of the intervention over 2 years. The primary outcome will be evidence-based prevention guidelines that are fully supported by a comprehensively evaluated dissemination plan. The plan will detail the support structures and add-ons necessary to ensure sustainability and subsequent national implementation. Research outcomes will include new knowledge about how sports safety policy is set, how consensus is reached among sports safety experts in the community setting and how evidence-based safety guidelines are best developed, packaged and disseminated to community sport.
Muscle Synergies May Improve Optimization Prediction of Knee Contact Forces During Walking
Publisher: ASME International
Date: 02-2014
DOI: 10.1115/1.4026428
Abstract: The ability to predict patient-specific joint contact and muscle forces accurately could improve the treatment of walking-related disorders. Muscle synergy analysis, which decomposes a large number of muscle electromyographic (EMG) signals into a small number of synergy control signals, could reduce the dimensionality and thus redundancy of the muscle and contact force prediction process. This study investigated whether use of subject-specific synergy controls can improve optimization prediction of knee contact forces during walking. To generate the predictions, we performed mixed dynamic muscle force optimizations (i.e., inverse skeletal dynamics with forward muscle activation and contraction dynamics) using data collected from a subject implanted with a force-measuring knee replacement. Twelve optimization problems (three cases with four subcases each) that minimized the sum of squares of muscle excitations were formulated to investigate how synergy controls affect knee contact force predictions. The three cases were: (1) Calibrate+Match where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously matched, (2) Precalibrate+Predict where experimental knee contact forces were predicted using precalibrated muscle model parameters values from the first case, and (3) Calibrate+Predict where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously predicted, all while matching inverse dynamic loads at the hip, knee, and ankle. The four subcases used either 44 independent controls or five synergy controls with and without EMG shape tracking. For the Calibrate+Match case, all four subcases closely reproduced the measured medial and lateral knee contact forces (R2 ≥ 0.94, root-mean-square (RMS) error 66 N), indicating sufficient model fidelity for contact force prediction. For the Precalibrate+Predict and Calibrate+Predict cases, synergy controls yielded better contact force predictions (0.61 R2 0.90, 83 N RMS error 161 N) than did independent controls (-0.15 R2 0.79, 124 N RMS error 343 N) for corresponding subcases. For independent controls, contact force predictions improved when precalibrated model parameter values or EMG shape tracking was used. For synergy controls, contact force predictions were relatively insensitive to how model parameter values were calibrated, while EMG shape tracking made lateral (but not medial) contact force predictions worse. For the subject and optimization cost function analyzed in this study, use of subject-specific synergy controls improved the accuracy of knee contact force predictions, especially for lateral contact force when EMG shape tracking was omitted, and reduced prediction sensitivity to uncertainties in muscle model parameter values.
Correlation between in vivo knee contact forces and external measures during gait
Publisher: American Society of Mechanical Engineers
Date: 20-06-2012
Abstract: Researchers have sought to explain the development and progression of knee osteoarthritis using in vivo estimates of knee contact forces. Unfortunately, it is not possible to measure knee contact forces in a clinical environment. Thus, studies often estimate knee contact forces using a variety of external measures. For ex le, inverse dynamics knee loads such as the adduction moment and superior force are frequently used as surrogate measures of medial and total knee contact force, respectively. Contraction of muscles spanning the knee is believed to increase knee contact force, and hence muscle electromyographic (EMG) signals are another external measure that may be indicative of internal contact force. The recent development of instrumented knee implants, such as the eTibia design [1], has provided access to in vivo knee contact force data during gait and other activities. However, few studies have correlated inverse dynamics loads, and none have correlated EMG signals, with total, medial, and lateral in vivo knee contact forces.
Biomechanical predictors of maximal balance recovery performance amongst community-dwelling older adults
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.EXGER.2015.04.006
Abstract: Falls are prevalent in older adults and are predicted by the maximum forward lean magnitude (MRLM) that can be recovered using a single step. The purpose of this study was to determine the relative contribution of selected neuromuscular and biomechanical variables associated with balance recovery to the MRLM. Forward loss of balance was induced by releasing participants (n=117 community-dwelling older adults) from a static forward lean angle. Participants were instructed to attempt to recover balance by taking a single step. A scalable anatomical model consisting of 36 degrees-of-freedom was used to compute kinematics and joint moments from motion capture and force plate data. Isometric muscle strength at the ankle, knee and hip joints was assessed using a dynamometer. A univariate analysis revealed that lower limb strength measures, step recovery kinematics, and stepping limb kinetics accounted for between 8 and 19%, 3 and 59%, and 3 and 61% of the variance in MRLM respectively. When all variables were entered into a stepwise multiple regression analysis, normalised step length, peak hip extension moment, trunk angle at foot contact, and peak hip flexion power during stepping together accounted for 69% of the variance in MRLM. These findings confirm that successful recovery from forward loss of balance is a whole body control task that requires adequate trunk control and generation of adequate lower limb moments and powers to generate a long and rapid step. Training programmes that specifically target these measures may be effective in improving balance recovery performance and thereby contribute to fall prevention amongst older adults.
Bioreactor design for tendon/ligament engineering
Publisher: Mary Ann Liebert Inc
Date: 04-2013
Toward modeling locomotion using electromyography‐informed 3D models: application to cerebral palsy
Publisher: Wiley
Date: 21-12-2016
DOI: 10.1002/WSBM.1368
Abstract: This position paper proposes a modeling pipeline to develop clinically relevant neuromusculoskeletal models to understand and treat complex neurological disorders. Although applicable to a variety of neurological conditions, we provide direct pipeline applicative ex les in the context of cerebral palsy ( CP ). This paper highlights technologies in: (1) patient‐specific segmental rigid body models developed from magnetic resonance imaging for use in inverse kinematics and inverse dynamics pipelines (2) efficient population‐based approaches to derive skeletal models and muscle origins/insertions that are useful for population statistics and consistent creation of continuum models (3) continuum muscle descriptions to account for complex muscle architecture including spatially varying material properties with muscle wrapping (4) muscle and tendon properties specific to CP and (5) neural‐based electromyography‐informed methods for muscle force prediction. This represents a novel modeling pipeline that couples for the first time electromyography extracted features of disrupted neuromuscular behavior with advanced numerical methods for modeling CP ‐specific musculoskeletal morphology and function. The translation of such pipeline to the clinical level will provide a new class of biomarkers that objectively describe the neuromusculoskeletal determinants of pathological locomotion and complement current clinical assessment techniques, which often rely on subjective judgment. WIREs Syst Biol Med 2017, 9:e1368. doi: 10.1002/wsbm.1368 This article is categorized under: Analytical and Computational Methods Computational Methods Models of Systems Properties and Processes Organ, Tissue, and Physiological Models
Knee strength and knee adduction moments following arthroscopic partial meniscectomy
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2008
Greater magnitude tibiofemoral contact forces are associated with reduced prevalence of osteochondral pathologies 2–3 years following anterior cruciate ligament reconstruction
Publisher: Springer Science and Business Media LLC
Date: 16-09-1970
DOI: 10.1007/S00167-018-5006-3
Abstract: External loading of osteoarthritic and healthy knees correlates with current and future osteochondral tissue state. These relationships have not been examined following anterior cruciate ligament reconstruction. We hypothesised greater magnitude tibiofemoral contact forces were related to increased prevalence of osteochondral pathologies, and these relationships were exacerbated by concomitant meniscal injury. This was a cross-sectional study of 100 in iduals (29.7 ± 6.5 years, 78.1 ± 14.4 kg) examined 2-3 years following hamstring tendon anterior cruciate ligament reconstruction. Thirty-eight participants had concurrent meniscal pathology (30.6 ± 6.6 years, 83.3 ± 14.3 kg), which included treated and untreated meniscal injury, and 62 participants (29.8 ± 6.4 years, 74.9 ± 13.3 kg) were free of meniscal pathology. Magnetic resonance imaging of reconstructed knees was used to assess prevalence of tibiofemoral osteochondral pathologies (i.e., cartilage defects and bone marrow lesions). A calibrated electromyogram-driven neuromusculoskeletal model was used to predict medial and lateral tibiofemoral compartment contact forces from gait analysis data. Relationships between contact forces and osteochondral pathology prevalence were assessed using logistic regression models. In patients with reconstructed knees free from meniscal pathology, greater medial contact forces were related to reduced prevalence of medial cartilage defects (odds ratio (OR) = 0.7, Wald χ In patients with reconstructed knees free from meniscal pathology, increased contact forces were associated with fewer cartilage defects and bone marrow lesions in medial, but not, lateral tibiofemoral compartments. No significant relationships were found between contact forces and osteochondral pathologies in reconstructed knees with meniscal pathology for any tibiofemoral compartment. Future studies should focus on determining longitudinal effects of contact forces and changes in osteochondral pathologies. IV.
Grand challenge competition to predict in vivo knee loads
Publisher: Wiley
Date: 12-12-2012
DOI: 10.1002/JOR.22023
Feasibility of using MRIs to create subject-specific parallel-mechanism joint models
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.JBIOMECH.2016.12.018
Abstract: Musculoskeletal models typically use generic 2D models for the tibiofemoral (TFJ) and patellofemoral (PFJ) joints, with a hinge talocrural joint (TCJ), which are scaled to each subject׳s bone dimensions. Alternatively joints' measured kinematics in cadavers are well-predicted using 3D cadaver-specific models. These employ mechanisms constrained by the articulations of geometric objects fitted to the joint׳s surfaces. In this study, we developed TFJ, PFJ and TCJ mechanism-based models off MRIs for fourteen participants and compared the estimated kinematics with those from published studies modified to be consistent with mechanisms models and subject-specific anatomical landmarks. The models' parameters were estimated by fitting spheres to segmented articular cartilage surfaces, while ligament attachment points were selected from their bony attachment regions. Each participant׳s kinematics were estimated by ensuring no length changes in ligaments and constant distances between spheres' centres. Two parameters' optimizations were performed both avoid singularities and one best matches the kinematic patterns off published studies. Sensitivity analysis determined which parameters the models were sensitive to. With both optimization methods, kinematics did not present singularities but correlation values were higher, exceeding 0.6, when matching the published studies. However, ranges of motion (ROM) were different between estimated and published studies. Across participants, models presented large parameter variation. Small variations were found between estimated- and optimized-parameters, and in the estimated-rotations and translations' means and ROM. Model results were sensitive to changes in distal tibia, talus and patella spheres' centres. These models can be implemented in subject-specific rigid-body musculoskeletal models to estimate joint moments and loads.
A Prospective, Randomized Comparison of Traditional and Accelerated Approaches to Postoperative Rehabilitation following Autologous Chondrocyte Implantation: 2-Year Clinical Outcomes
Publisher: SAGE Publications
Date: 24-03-2010
Abstract: Objective: To determine the safety and efficacy of “accelerated” postoperative load-bearing rehabilitation following matrix-induced autologous chondrocyte implantation (MACI). Design: A randomized controlled study design was used to investigate clinical outcomes in 70 patients following MACI, in conjunction with either accelerated or traditional approaches to postoperative weight-bearing (WB) rehabilitation. Both interventions sought to protect the implant for an initial period and then incrementally increase WB. Under the accelerated protocol, patients reached full WB at 8 weeks postsurgery, compared to 11 weeks for the traditional group. Clinical outcomes were assessed presurgery and at 3, 6, 12, and 24 months postsurgery. Results: A significant effect ( P 0.017) for time existed for all clinical measures, demonstrating improvement up to 24 months in both groups. A significant interaction effect (P 0.017) existed for pain severity and the 6-minute walk test, with accelerated group patients reporting significantly less severe pain and demonstrating superior 6-minute walk distance over the period. Although there was a significant group effect (P 0.017) for maximal active knee extension range in favor of the accelerated regime, no further significant differences existed. There was no incidence of graft delamination up to 24 months that resulted directly from the 3-month postoperative rehabilitation program. Conclusion: The accelerated load-bearing approach that reduced the length of time spent ambulating on crutches produced comparable if not superior clinical outcomes up to 24 months postsurgery in the accelerated rehabilitation group, without compromising graft integrity. This accelerated regime is safe and effective and demonstrates a faster return to normal function postsurgery.
Effect of exercise on knee joint contact forces in people following medial partial meniscectomy: A secondary analysis of a randomised controlled trial
Publisher: Elsevier BV
Date: 06-2020
High-resolution study of the 3D collagen fibrillary matrix of Achilles tendons without tissue labelling and dehydrating
Publisher: Wiley
Date: 02-03-2017
DOI: 10.1111/JMI.12537
Abstract: Knowledge of the collagen structure of an Achilles tendon is critical to comprehend the physiology, biomechanics, homeostasis and remodelling of the tissue. Despite intensive studies, there are still uncertainties regarding the microstructure. The majority of studies have examined the longitudinally arranged collagen fibrils as they are primarily attributed to the principal tensile strength of the tendon. Few studies have considered the structural integrity of the entire three-dimensional (3D) collagen meshwork, and how the longitudinal collagen fibrils are integrated as a strong unit in a 3D domain to provide the tendons with the essential tensile properties. Using second harmonic generation imaging, a 3D imaging technique was developed and used to study the 3D collagen matrix in the midportion of Achilles tendons without tissue labelling and dehydration. Therefore, the 3D collagen structure is presented in a condition closely representative of the in vivo status. Atomic force microscopy studies have confirmed that second harmonic generation reveals the internal collagen matrix of tendons in 3D at a fibril level. Achilles tendons primarily contain longitudinal collagen fibrils that braid spatially into a dense rope-like collagen meshwork and are encapsulated or wound tightly by the oblique collagen fibrils emanating from the epitenon region. The arrangement of the collagen fibrils provides the longitudinal fibrils with essential structural integrity and endows the tendon with the unique mechanical function for withstanding tensile stresses. A novel 3D microscopic method has been developed to examine the 3D collagen microstructure of tendons without tissue dehydrating and labelling. The study also provides new knowledge about the collagen microstructure in an Achilles tendon, which enables understanding of the function of the tissue. The knowledge may be important for applying surgical and tissue engineering techniques to tendon reconstruction.
Modelling the loading mechanics of anterior cruciate ligament
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.CMPB.2019.105098
Abstract: The anterior cruciate ligament (ACL) plays a crucial role in knee stability and is the most commonly injured knee ligament. Although ACL loading patterns have been investigated previously, the interactions between knee loadings transmitted to ACL remain elusive. Understanding the loading mechanism of ACL during dynamic tasks is essential to prevent ACL injuries. Therefore, we propose a computational model that predicts the force applied to ACL in response to knee loading in three planes of motion. First, a three-dimensional (3D) computational model was developed and validated using available cadaveric experimental data to predict ACL force. This 3D model was then combined with a neuromusculoskeletal model of lower limb and used to estimate in vivo ACL forces during a standardised drop-landing task. The neuromusculoskeletal model utilised movement data collected from female participants during a dynamic task and calculated lower limb joint kinematics and kinetics, as well as muscle forces. The total ACL force predicted by the 3D computational ACL force model was in good agreement with cadaveric data, as strong correlation (r The proposed computational model is the first validated model that can provide an accessible tool to develop and test knee ACL injury prevention programs for people with normal ACL. This method can be extended to study the abnormal ACL upon the availability of relevant experimental data.
Neuromuscular adaptations to eccentric strength training in children and adolescents with cerebral palsy
Publisher: Wiley
Date: 04-03-2010
DOI: 10.1111/J.1469-8749.2009.03409.X
Abstract: To determine the neuromuscular outcomes of an eccentric strength-training programme for children and adolescents with cerebral palsy (CP). In this randomised, parallel-group trial with waiting control, 14 participants with CP (six males, eight females mean age 11y, SD 2y range 9-15y), diagnosed with upper-limb spasticity were compared with 14 age- and sex-matched typically developing participants. Participants with CP completed a 6-week progressive resistance-strengthening programme, performing eccentric lengthening contractions of their upper limb three times a week. Data from dynamometer and surface electromyography (EMG) assessments included peak torque normalised to body mass (T/Bm), work normalised to body mass (W/Bm), angle at peak torque, curve width, and EMG activation. After training, children with CP had improved eccentric T/Bm (p=0.009) and W/Bm (p=0.009) to a level similar to that of the typically developing children. No change in angle of peak torque occurred, although curve width increased both concentrically (p=0.018) and eccentrically (p=0.015). EMG activity was elevated before training in children with CP but decreased with training to levels similar to those of the typically developing children. With eccentric strength training, children with CP increased torque throughout range of motion. Results suggest that eccentric exercises may decrease co-contraction, improving net torque development. Eccentric actions may be important in the maintenance of the torque-angle relationship. These results have significant implications for the prescription of strength-training programmes for people with CP.
A musculoskeletal model of human locomotion driven by a low dimensional set of impulsive excitation primitives
Publisher: Frontiers Media SA
Date: 2013
Bone remodelling in the natural acetabulum is influenced by muscle force-induced bone stress
Publisher: Wiley
Date: 25-08-2014
DOI: 10.1002/CNM.2586
Abstract: A modelling framework using the international Physiome Project is presented for evaluating the role of muscles on acetabular stress patterns in the natural hip. The novel developments include the following: (i) an efficient method for model generation with validation (ii) the inclusion of electromyography-estimated muscle forces from gait and (iii) the role that muscles play in the hip stress pattern. The 3D finite element hip model includes anatomically based muscle area attachments, material properties derived from Hounsfield units and validation against an Instron compression test. The primary outcome from this study is that hip loading applied as anatomically accurate muscle forces redistributes the stress pattern and reduces peak stress throughout the pelvis and within the acetabulum compared with applying the same net hip force without muscles through the femur. Muscle forces also increased stress where large muscles have small insertion sites. This has implications for the hip where bone stress and strain are key excitation variables used to initiate bone remodelling based on the strain-based bone remodelling theory. Inclusion of muscle forces reduces the predicted sites and degree of remodelling. The secondary outcome is that the key muscles that influenced remodelling in the acetabulum were the rectus femoris, adductor magnus and iliacus.
Free Achilles tendon strain during selected rehabilitation, locomotor, jumping, and landing tasks
Publisher: American Physiological Society
Date: 04-2022
DOI: 10.1152/JAPPLPHYSIOL.00662.2021
Abstract: Our work combines medical imaging and electromyogram-informed neuromusculoskeletal modeling data to estimate free Achilles tendon strain during selected rehabilitation, locomotor, jumping, and landing tasks in trained middle-distance runners. These data may potentially be used to inform Achilles tendon training and rehabilitation to maximize anabolic tendon remodeling.
Patellofemoral and tibiofemoral articular cartilage and subchondral bone health following arthroscopic partial medial meniscectomy
Publisher: Springer Science and Business Media LLC
Date: 24-09-2012
DOI: 10.1007/S00167-011-1681-Z
Abstract: To examine articular cartilage and subchondral bone changes in tibiofemoral and patellofemoral joints following partial medial meniscectomy. For this cross-sectional study, 158 patients aged 30-55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy (APMM), and 38 controls were recruited. MRI was performed once on the operated knee for each subcohort of 3 months, 2 or 4 years post-surgery, and the randomly assigned knee of the controls. Cartilage volume, cartilage defects, and bone size were assessed using validated methods. Compared with controls, APMM patients had more prevalent cartilage defects in medial tibiofemoral (OR = 3.17, 95%CI 1.24-8.11) and patellofemoral (OR = 13.76, 95%CI 1.52-124.80) compartments, and increased medial tibial plateau bone area (B = 143.8, 95%CI 57.4-230.2). Time from APMM was positively associated with cartilage defect prevalence in medial tibiofemoral (OR = 1.02, 95%CI 1.00-1.03) and patellofemoral (OR = 1.04, 95%CI 1.01-1.07) compartments, and medial tibial plateau area (B = 2.5, 95%CI 0.8-4.3), but negatively associated with lateral tibial cartilage volume (B = -4.9, 95%CI -8.4 to -1.5). The association of APMM and time from APMM with patellar cartilage defects was independent of tibial cartilage volume. Partial medial meniscectomy is associated with adverse effects on articular cartilage and subchondral bone, which are associated with subsequent osteoarthritis, in both tibiofemoral and patellofemoral compartments. III.
Muscle activity is different for humans performing static tasks which require force control and position control
Publisher: Elsevier BV
Date: 07-1995
DOI: 10.1016/0304-3940(95)11727-E
Abstract: Muscle activation levels in humans were examined during two different static tasks which required the same joint angles and the same joint moments. In the isometric case, joint angles were fixed and subjects were required to match forces. In the isoinertial case, a constant load was imposed across the joint and the subject was required to match position. It was observed that for a specified posture and for specified load conditions, EMG activity varied depending on whether the limb was loaded isometrically or isoinertially. That is, different co-activation relationships were observed for position control versus force control tasks during otherwise similar conditions. These results imply that the neural command for static tasks depends on more than joint angles and load magnitude.
A stiff tendon neuromusculoskeletal model of the knee
Publisher: IEEE
Date: 11-2009
Comments on Harkness‐Armstrong et al. (2021) ‘In vivo operating lengths of the gastrocnemius muscle during gait in children who idiopathically toe‐walk’
Publisher: Wiley
Date: 09-11-2022
DOI: 10.1113/EP090713
Evaluation of different analytical methods for subject-specific scaling of musculotendon parameters
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.JBIOMECH.2008.03.008
Abstract: Musculoskeletal models are often used to estimate internal muscle forces and the effects of those forces on the development of human movement. The Hill-type muscle model is an important component of many of these models, yet it requires specific knowledge of several muscle and tendon properties. These include the optimal muscle fibre length, the length at which the muscle can generate maximum force, and the tendon slack length, the length at which the tendon starts to generate a resistive force to stretch. Both of these parameters greatly influence the force-generating behaviour of a musculotendon unit and vary with the size of the person. However, these are difficult to measure directly and are often estimated using the results of cadaver studies, which do not account for differences in subject size. This paper examined several different techniques that can be used to scale the optimal muscle fibre length and tendon slack length of a musculotendon unit according to subject size. The techniques were ided into three categories corresponding to linear scaling, scaling by maintaining a constant tendon slack length throughout the range of joint motion, and scaling by maintaining muscle operating range throughout the range of joint motion. We suggest that a good rationale for scaling muscle properties should be to maintain the same force-generating characteristics of a musculotendon unit for all subjects, which is best achieved by scaling that preserves the muscle operating range when the muscle is maximally activated.
Is the soleus a sentinel muscle for impaired aerobic capacity in heart failure?
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2014
Hip Contact Force Magnitude and Regional Loading Patterns Are Altered in Those with Femoroacetabular Impingement Syndrome
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-06-2022
DOI: 10.1249/MSS.0000000000002971
Abstract: The magnitude and location of hip contact force influence the local mechanical environment of the articular tissue, driving remodeling. We used a neuromusculoskeletal model to investigate hip contact force magnitudes and their regional loading patterns on the articular surfaces in those with femoroacetabular impingement (FAI) syndrome and controls during walking. An EMG-assisted neuromusculoskeletal model was used to estimate hip contact forces in eligible participants with FAI syndrome ( n = 41) and controls ( n = 24), walking at self-selected speed. Hip contact forces were used to determine the average and spread of regional loading for femoral and acetabular articular surfaces. Hip contact force magnitude and region of loading were compared between groups using statistical parametric mapping and independent t -tests, respectively ( P 0.05). All of the following findings are reported compared with controls. Those with FAI syndrome walked with lower-magnitude hip contact forces (mean difference, −0.7 N·BW −1 P 0.001) during first and second halves of stance, and with lower anteroposterior, vertical, and mediolateral contact force vector components. Participants with FAI syndrome also had less between-participant variation in average regional loading, which was located more anteriorly (3.8°, P = 0.035) and laterally (2.2°, P = 0.01) on the acetabulum but more posteriorly (−4.8°, P = 0.01) on the femoral head. Participants with FAI syndrome had a smaller spread of regional loading across both the acetabulum (−1.9 mm, P = 0.049) and femoral head (1 mm, P 0.001) during stance. Compared with controls, participants with FAI syndrome walked with lower-magnitude hip contact forces that were constrained to smaller regions on the acetabulum and femoral head. Differences in regional loading patterns might contribute to the mechanobiological processes driving cartilage maladaptation in those with FAI syndrome.
Knee joint kinematics, kinetics and muscle co-contraction in knee osteoarthritis patient gait
Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1016/J.CLINBIOMECH.2009.08.005
Abstract: Compared to matched controls, knee osteoarthritis patients walk with altered, kinematics, kinetics and muscle activity. Studies of osteoarthritis patient gait have focused on in idual measures, and findings from these studies differ due to differences in patient levels of disability and age. Therefore, aims of this study were to examine kinematic, kinetic and muscle co-contraction gait variables within a single osteoarthritis patient group, and to determine if alterations in these variables are related to pain, symptom and function measures. Thirty asymptomatic controls and 54 patients with radiographic evidence of knee osteoarthritis participated. Self-perceived measures of pain and symptoms, and gait (knee joint angles, moments and muscle co-contraction) were analysed and compared. Osteoarthritis patients had greater self-perceived pain and symptoms on the questionnaires. Gait differences in the knee osteoarthritis patients were greater knee flexion at heel strike and during early stance along with reductions in the peak external knee extension moment in late stance. Co-contraction ratios highlighted greater lateral muscle activation in osteoarthritis patients, which were correlated with the magnitude of their adduction moments. Larger adduction moments were related to lower self-perceived pain and symptoms. Osteoarthritis patients use predominantly lateral muscle activation during stance which may aid in stabilising the external knee adduction moment. Kinematic alterations in knee osteoarthritis patient gait occur without alterations in knee joint moments. Our results also suggest that adduction moments are lowered to reduce the patients' pain and symptoms.
Machine learning methods to support personalized neuromusculoskeletal modelling.
Publisher: Springer Science and Business Media LLC
Date: 16-07-2020
An anterior cruciate ligament injury prevention framework: Incorporating the recent evidence
Publisher: Informa UK Limited
Date: 28-06-2012
DOI: 10.1080/15438627.2012.680989
Abstract: Anterior cruciate ligament (ACL) injury rates have increased by ∼50% over the last 10 years. These figures suggest that ACL focused research has not been effective in reducing injury rates among community level athletes. Training protocols designed to reduce ACL injury rates have been both effective (n = 3) and ineffective (n = 7). Although a rationale for the use of exercise to reduce ACL injuries is established, the mechanisms by which they act are relatively unknown. This article provides an injury prevention framework specific to noncontact ACL injuries and the design of prophylactic training protocols. It is also apparent that feedback within this framework is needed to determine how biomechanically relevant risk factors like peak joint loading and muscular support are influenced following training. It is by identifying these links that more effective ACL injury prevention training programs can be developed, and, in turn, lead to reduced ACL injury rates in the future.
The evolution of multiagency partnerships for safety over the course of research engagement: experiences from the NoGAPS project
Publisher: BMJ
Date: 25-03-2016
Development of 18 Quality Control Gates for Additive Manufacturing of Error Free Patient-Specific Implants
Publisher: MDPI AG
Date: 24-09-2019
DOI: 10.3390/MA12193110
Abstract: Unlike subtractive manufacturing technologies, additive manufacturing (AM) can fabricate complex shapes from the macro to the micro scale, thereby allowing the design of patient-specific implants following a biomimetic approach for the reconstruction of complex bone configurations. Nevertheless, factors such as high design variability and changeable customer needs are re-shaping current medical standards and quality control strategies in this sector. Such factors necessitate the urgent formulation of comprehensive AM quality control procedures. To address this need, this study explored and reported on a variety of aspects related to the production and the quality control of additively manufactured patient-specific implants in three different AM companies. The research goal was to develop an integrated quality control procedure based on the synthesis and the adaptation of the best quality control practices with the three examined companies and/or reported in literature. The study resulted in the development of an integrated quality control procedure consisting of 18 distinct gates based on the best identified industry practices and reported literature such as the Food and Drug Administration (FDA) guideline for AM medical devices and American Society for Testing and Materials (ASTM) standards, to name a few. This integrated quality control procedure for patient-specific implants seeks to prepare the AM industry for the inevitable future tightening in related medical regulations. Moreover, this study revealed some critical success factors for companies developing additively manufactured patient-specific implants, including ongoing research and development (R& D) investment, investment in advanced technologies for controlling quality, and fostering a quality improvement organizational culture.
Bridging the Gap Between Content and Context
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2015
Cancellous bone and theropod dinosaur locomotion. Part II—a new approach to inferring posture and locomotor biomechanics in extinct tetrapod vertebrates
Publisher: PeerJ
Date: 31-10-2018
DOI: 10.7717/PEERJ.5779
Abstract: This paper is the second of a three-part series that investigates the architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is widely known to be highly sensitive to its mechanical environment, and therefore has the potential to provide insight into locomotor biomechanics in extinct tetrapod vertebrates such as dinosaurs. Here in Part II, a new biomechanical modelling approach is outlined, one which mechanistically links cancellous bone architectural patterns with three-dimensional musculoskeletal and finite element modelling of the hindlimb. In particular, the architecture of cancellous bone is used to derive a single ‘characteristic posture’ for a given species—one in which bone continuum-level principal stresses best align with cancellous bone fabric—and thereby clarify hindlimb locomotor biomechanics. The quasi-static approach was validated for an extant theropod, the chicken, and is shown to provide a good estimate of limb posture at around mid-stance. It also provides reasonable predictions of bone loading mechanics, especially for the proximal hindlimb, and also provides a broadly accurate assessment of muscle recruitment insofar as limb stabilization is concerned. In addition to being useful for better understanding locomotor biomechanics in extant species, the approach hence provides a new avenue by which to analyse, test and refine palaeobiomechanical hypotheses, not just for extinct theropods, but potentially many other extinct tetrapod groups as well.
Cancellous bone and theropod dinosaur locomotion. Part III—Inferring posture and locomotor biomechanics in extinct theropods, and its evolution on the line to birds
Publisher: PeerJ
Date: 31-10-2018
DOI: 10.7717/PEERJ.5777
Abstract: This paper is the last of a three-part series that investigates the architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is highly sensitive to its prevailing mechanical environment, and may therefore help further understanding of locomotor biomechanics in extinct tetrapod vertebrates such as dinosaurs. Here in Part III, the biomechanical modelling approach derived previously was applied to two species of extinct, non-avian theropods, Daspletosaurus torosus and Troodon formosus . Observed cancellous bone architectural patterns were linked with quasi-static, three-dimensional musculoskeletal and finite element models of the hindlimb of both species, and used to derive characteristic postures that best aligned continuum-level principal stresses with cancellous bone fabric. The posture identified for Daspletosaurus was largely upright, with a subvertical femoral orientation, whilst that identified for Troodon was more crouched, but not to the degree observed in extant birds. In addition to providing new insight on posture and limb articulation, this study also tested previous hypotheses of limb bone loading mechanics and muscular control strategies in non-avian theropods, and how these aspects evolved on the line to birds. The results support the hypothesis that an upright femoral posture is correlated with bending-dominant bone loading and abduction-based muscular support of the hip, whereas a crouched femoral posture is correlated with torsion-dominant bone loading and long-axis rotation-based muscular support. Moreover, the results of this study also support the inference that hindlimb posture, bone loading mechanics and muscular support strategies evolved in a gradual fashion along the line to extant birds.
Cancellous bone and theropod dinosaur locomotion. Part I—an examination of cancellous bone architecture in the hindlimb bones of theropods
Publisher: PeerJ
Date: 31-10-2018
DOI: 10.7717/PEERJ.5778
Abstract: This paper is the first of a three-part series that investigates the architecture of cancellous (‘spongy’) bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is widely known to be highly sensitive to its mechanical environment, and has previously been used to infer locomotor biomechanics in extinct tetrapod vertebrates, especially primates. Despite great promise, cancellous bone architecture has remained little utilized for investigating locomotion in many other extinct vertebrate groups, such as dinosaurs. Documentation and quantification of architectural patterns across a whole bone, and across multiple bones, can provide much information on cancellous bone architectural patterns and variation across species. Additionally, this also lends itself to analysis of the musculoskeletal biomechanical factors involved in a direct, mechanistic fashion. On this premise, computed tomographic and image analysis techniques were used to describe and analyse the three-dimensional architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs for the first time. A comprehensive survey across many extant and extinct species is produced, identifying several patterns of similarity and contrast between groups. For instance, more stemward non-avian theropods (e.g. ceratosaurs and tyrannosaurids) exhibit cancellous bone architectures more comparable to that present in humans, whereas species more closely related to birds (e.g. paravians) exhibit architectural patterns bearing greater similarity to those of extant birds. Many of the observed patterns may be linked to particular aspects of locomotor biomechanics, such as the degree of hip or knee flexion during stance and gait. A further important observation is the abundance of markedly oblique trabeculae in the diaphyses of the femur and tibia of birds, which in large species produces spiralling patterns along the endosteal surface. Not only do these observations provide new insight into theropod anatomy and behaviour, they also provide the foundation for mechanistic testing of locomotor hypotheses via musculoskeletal biomechanical modelling.
A hypothesis for the function of braking forces during running turns
Publisher: Elsevier BV
Date: 2006
DOI: 10.1016/J.JBIOMECH.2005.05.007
Abstract: We examined the functional role of braking forces observed when humans execute turning maneuvers. Deceleration caused by braking forces contributes to changing the movement direction of the center of mass (COM) and maintaining constant velocity. We argue that braking forces also prevent over-rotation of the body about the vertical axis during maneuvers. We analyzed data from sidestep and crossover cuts at average initial running velocities of 3 m s(-1). Absent braking, lateral forces would result in body rotations 1.4-3 times the change in COM movement direction, causing the orientation of the body to be substantially mis-aligned with the direction of movement at the end of the step. A simple model based on the hypothesis that body rotation should match COM deflection can explain 70% of the variance in braking forces employed during running turns.
Establishing outcome measures in early knee osteoarthritis
Publisher: Springer Science and Business Media LLC
Date: 14-06-2019
DOI: 10.1038/S41584-019-0237-3
Abstract: The classification and monitoring of in iduals with early knee osteoarthritis (OA) are important considerations for the design and evaluation of therapeutic interventions and require the identification of appropriate outcome measures. Potential outcome domains to assess for early OA include patient-reported outcomes (such as pain, function and quality of life), features of clinical examination (such as joint line tenderness and crepitus), objective measures of physical function, levels of physical activity, features of imaging modalities (such as of magnetic resonance imaging) and biochemical markers in body fluid. Patient characteristics such as adiposity and biomechanics of the knee could also have relevance to the assessment of early OA. Importantly, research is needed to enable the selection of outcome measures that are feasible, reliable and validated in in iduals at risk of knee OA or with early knee OA. In this Perspectives article, potential outcome measures for early symptomatic knee OA are discussed, including those measures that could be of use in clinical practice and/or the research setting.
A flexible architecture to enhance wearable robots: Integration of EMG-informed models
Publisher: IEEE
Date: 09-2015
A real-time EMG-driven virtual arm
Publisher: Elsevier BV
Date: 2002
DOI: 10.1016/S0010-4825(01)00024-5
Abstract: An EMG-driven virtual arm is being developed in our laboratories for the purposes of studying neuromuscular control of arm movements. The virtual arm incorporates the major muscles spanning the elbow joint and is used to estimate tension developed by in idual muscles based on recorded electromyograms (EMGs). It is able to estimate joint moments and the corresponding virtual movements, which are displayed in real-time on a computer screen. In addition, the virtual arm offers artificial control over a variety of physiological and environmental conditions. The virtual arm can be used to examine how the neuromuscular system compensates for the partial or total loss of a muscle's ability to generate force as might result from trauma or pathology. The purpose of this paper is to describe the design objectives, fundamental components and implementation of our real-time, EMG-driven virtual arm.
National Osteoarthritis Strategy brief report: Prevention of osteoarthritis
Publisher: The Royal Australian College of General Practitioners
Date: 05-2020
Estimation of the hip joint centre in human motion analysis: a systematic review.
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.CLINBIOMECH.2015.02.005
Abstract: Inaccuracies in locating the three-dimensional position of the hip joint centre affect the calculated hip and knee kinematics, force- and moment-generating capacity of muscles and hip joint mechanics, which can lead to incorrect interpretations and recommendations in gait analysis. Several functional and predictive methods have been developed to estimate the hip joint centre location, and the International Society of Biomechanics recommends a functional approach for use with participants that have adequate range of motion at the hip, and predictive methods in those with insufficient range of motion. The purpose of the current systematic review was to substantiate the International Society of Biomechanics recommendations. This included identifying the most accurate functional and predictive methods, and defining 'adequate' range of motion. A systematic search with broad search terms was performed including five databases. The systematic search yielded to 801 articles, of which 34 papers were included. Eleven different predictive and 13 different functional methods were identified. The results showed that the geometric sphere fit method and Harrington equations are the most accurate functional and predictive approaches respectively that have been evaluated in vivo. In regard to the International Society of Biomechanics recommendations, the geometric sphere fit method should be used in people with sufficient active hip range of motion and the Harrington equations should be used in patients without sufficient hip range of motion. Multi-plane movement trials with at least 60° of flexion-extension and 30° of ab-adduction range of motion are suggested when using functional methods.
Changes in muscle activation following balance and technique training and a season of Australian football
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.JSAMS.2014.04.012
Abstract: Determine if balance and technique training implemented adjunct to 1001 male Australian football players' training influenced the activation/strength of the muscles crossing the knee during pre-planned and unplanned sidestepping. Randomized Control Trial. Each Australian football player participated in either 28 weeks of balance and technique training or 'sham' training. Twenty-eight Australian football players (balance and technique training, n=12 'sham' training, n=16) completed biomechanical testing pre-to-post training. Peak knee moments and directed co-contraction ratios in three degrees of freedom, as well as total muscle activation were calculated during pre-planned and unplanned sidestepping. No significant differences in muscle activation/strength were observed between the 'sham' training and balance and technique training groups. Following a season of Australian football, knee extensor (p=0.023) and semimembranosus (p=0.006) muscle activation increased during both pre-planned sidestepping and unplanned sidestepping. Following a season of Australian football, total muscle activation was 30% lower and peak valgus knee moments 80% greater (p=0.022) during unplanned sidestepping when compared with pre-planned sidestepping. When implemented in a community level training environment, balance and technique training was not effective in changing the activation of the muscles crossing the knee during sidestepping. Following a season of Australian football, players are better able to support both frontal and sagittal plane knee moments. When compared to pre-planned sidestepping, Australian football players may be at increased risk of anterior cruciate ligament injury during unplanned sidestepping in the latter half of an Australian football season.
Tibiofemoral contact forces during walking, running and sidestepping
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.GAITPOST.2016.06.014
Abstract: We explored the tibiofemoral contact forces and the relative contributions of muscles and external loads to those contact forces during various gait tasks. Second, we assessed the relationships between external gait measures and contact forces. A calibrated electromyography-driven neuromusculoskeletal model estimated the tibiofemoral contact forces during walking (1.44±0.22ms(-1)), running (4.38±0.42ms(-1)) and sidestepping (3.58±0.50ms(-1)) in healthy adults (n=60, 27.3±5.4years, 1.75±0.11m, and 69.8±14.0kg). Contact forces increased from walking (∼1-2.8 BW) to running (∼3-8 BW), sidestepping had largest maximum total (8.47±1.57 BW) and lateral contact forces (4.3±1.05 BW), while running had largest maximum medial contact forces (5.1±0.95 BW). Relative muscle contributions increased across gait tasks (up to 80-90% of medial contact forces), and peaked during running for lateral contact forces (∼90%). Knee adduction moment (KAM) had weak relationships with tibiofemoral contact forces (all R(2)<0.36) and the relationships were gait task-specific. Step-wise regression of multiple external gait measures strengthened relationships (0.20<Radj(2)<0.78), but were variable across gait tasks. Step-wise regression equations from a particular gait task (e.g. walking) produced large errors when applied to a different gait task (e.g. running or sidestepping). Muscles well stabilized the knee, increasing their role in stabilization from walking to running to sidestepping. KAM was a poor predictor of medial contact force and load distributions. Step-wise regression models results suggest the relationships between external gait measures and contact forces cannot be generalized across tasks. Neuromusculoskeletal modelling may be required to examine tibiofemoral contact forces and role of muscle in knee stabilization across gait tasks.
Radiological Assessment of Accelerated versus Traditional Approaches to Postoperative Rehabilitation following Matrix-Induced Autologous Chondrocyte Implantation
Publisher: SAGE Publications
Date: 18-10-2010
Abstract: To assess the safety and efficacy of accelerated compared with traditional postoperative weightbearing (WB) rehabilitation following matrix-induced autologous chondrocyte implantation (MACI) of the knee, using MRI. A randomized controlled study design was used to assess MRI-based outcomes of MACI grafts in 70 patients (45 men, 25 women) who underwent MACI to the medial or lateral femoral condyle, in combination with either traditional or accelerated approaches to postoperative WB rehabilitation. High-resolution MRI was undertaken and assessed 8 previously defined pertinent parameters of graft repair, as well as a combined MRI composite score at 3, 12, and 24 months postsurgery. The association between clinical and MRI-based outcomes, patient demographics, chondral defect parameters, and injury/surgery history was investigated. Both groups significantly improved ( P 0.05) in the MRI composite score and pertinent descriptors of graft repair throughout the postoperative period until 24 months postsurgery. There were no differences ( P 0.05) observed between the 2 groups. Patient age, body mass index, chondral defect size, and duration of preoperative symptoms were significantly correlated ( P 0.05) with several MRI-based outcomes at 24 months, whereas there were no significant pertinent correlations ( P 0.05) observed between clinical and MRI-based outcomes. The accelerated WB approach was not detrimental to graft development at any stage throughout the postoperative assessment timeline from baseline to 24 months postsurgery and may potentially accelerate patient return to normal function, while reducing postoperative muscle loss, intra-articular adhesions, and associated gait abnormalities.
Bioinspired Technologies to Connect Musculoskeletal Mechanobiology to the Person for Training and Rehabilitation
Publisher: Frontiers Media SA
Date: 18-10-2017
Visual search differs but not reaction time when intercepting a 3D versus a 2D videoed opponent
Publisher: Informa UK Limited
Date: 03-2013
DOI: 10.1080/00222895.2012.760512
Abstract: The authors aimed to identify differences in (a) visual search and (b) reaction time when athletes sidestepped to intercept 2D versus 3D videoed opponents. They hypothesized that participants would (a) fixate on different parts of the opponent's body and (b) react quicker when responding to the 3D versus 2D opponent due to the added depth cues. A customized integrated stereoscopic system projected the video stimuli and synchronously recorded the gaze and motor behaviors of 10 men when they responded to two- (2D) and three-dimensional (3D) opponents. The number and duration of gaze fixations were coded according to locations on the opponent's body (head, shoulders, arms, trunk, pelvis, legs) or otherwise (other). Mediolateral pelvic movement was used to infer reaction time. Participants spent 16% less time fixating on the trunk and 23% more time outside the 3D opponent's body compared with the 2D stimulus. No reaction time differences were found. Although participants fixated less on the 3D opponent's body and, by inference, invested less perceptual processing toward interpreting the opponent's movements compared with the 2D condition, they performed the interception task equally fast in both conditions. Three-dimensional depth cues may provide more meaningful information per fixation for successful task performance.
Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces
Publisher: Elsevier BV
Date: 11-2013
Neural Data-Driven Musculoskeletal Modeling for Personalized Neurorehabilitation Technologies
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2016
Cyclic mechanical stimulation rescues achilles tendon from degeneration in a bioreactor system
Publisher: Wiley
Date: 17-07-2015
DOI: 10.1002/JOR.22960
Abstract: Physiotherapy is one of the effective treatments for tendinopathy, whereby symptoms are relieved by changing the biomechanical environment of the pathological tendon. However, the underlying mechanism remains unclear. In this study, we first established a model of progressive tendinopathy-like degeneration in the rabbit Achilles. Following ex vivo loading deprivation culture in a bioreactor system for 6 and 12 days, tendons exhibited progressive degenerative changes, abnormal collagen type III production, increased cell apoptosis, and weakened mechanical properties. When intervention was applied at day 7 for another 6 days by using cyclic tensile mechanical stimulation (6% strain, 0.25 Hz, 8 h/day) in a bioreactor, the pathological changes and mechanical properties were almost restored to levels seen in healthy tendon. Our results indicated that a proper biomechanical environment was able to rescue early-stage pathological changes by increased collagen type I production, decreased collagen degradation and cell apoptosis. The ex vivo model developed in this study allows systematic study on the effect of mechanical stimulation on tendon biology.
Priorities for Investment in Injury Prevention in Community Australian Football
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2013
Fast operation of anatomical and stiff tendon neuromuscular models in EMG-driven modeling
Publisher: IEEE
Date: 05-2010
Three dimensional microstructural network of elastin, collagen, and cells in Achilles tendons
Publisher: Wiley
Date: 02-05-2017
DOI: 10.1002/JOR.23240
Abstract: Similar to most biological tissues, the biomechanical, and functional characteristics of the Achilles tendon are closely related to its composition and microstructure. It is commonly reported that type I collagen is the predominant component of tendons and is mainly responsible for the tissue's function. Although elastin has been found in varying proportions in other connective tissues, previous studies report that tendons contain very small quantities of elastin. However, the morphology and the microstructural relationship among the elastic fibres, collagen, and cells in tendon tissue have not been well examined. We hypothesize the elastic fibres, as another fibrillar component in the extracellular matrix, have a unique role in mechanical function and microstructural arrangement in Achilles tendons. It has been shown that elastic fibres present a close connection with the tenocytes. The close relationship of the three components has been revealed as a distinct, integrated and complex microstructural network. Notably, a "spiral" structure within fibril bundles in Achilles tendons was observed in some s les in specialized regions. This study substantiates the hierarchical system of the spatial microstructure of tendon, including the mapping of collagen, elastin and tenocytes, with 3-dimensional confocal images. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1203-1214, 2017.
Morphologic Characteristics and Strength of the Hamstring Muscles Remain Altered at 2 Years after Use of a Hamstring Tendon Graft in Anterior Cruciate Ligament Reconstruction
Publisher: SAGE Publications
Date: 21-07-2016
Abstract: The hamstring tendon graft used in anterior cruciate ligament (ACL) reconstruction has been shown to lead to changes to the semitendinosus and gracilis musculature. We hypothesized that (1) loss of donor muscle size would significantly correlate with knee muscle strength deficits, (2) loss of donor muscle size would be greater for muscles that do not experience tendon regeneration, and (3) morphological adaptations would also be evident in nondonor knee muscles. Cross-sectional study Level of evidence, 3. Twenty participants (14 men and 6 women, mean age 29 ± 7 years, mean body mass 82 ± 15 kg) who had undergone an ACL reconstruction with a hamstring tendon graft at least 2 years previously underwent bilateral magnetic resonance imaging and subsequent strength testing. Muscle and tendon volumes, peak cross-sectional areas (CSAs), and lengths were determined for 12 muscles and 6 functional muscle groups of the surgical and contralateral limbs. Peak isokinetic concentric strength was measured in knee flexion/extension and internal/external tibial rotation. Only 35% of the patients showed regeneration of both the semitendinosus and gracilis tendons. The regenerated tendons were longer with larger volume and CSA compared with the contralateral side. Deficits in semitendinosus and gracilis muscle size were greater for muscles in which tendons did not regenerate. In addition, combined hamstring muscles (semitendinosus, semimembranosus, and biceps femoris) and combined medial knee muscles (semitendinosus, semimembranosus, gracilis, vastus medialis, medial gastrocnemius, and sartorius) on the surgical side were reduced in volume by 12% and 10%, respectively. A 7% larger volume was observed in the surgical limb for the biceps femoris muscle and corresponded with a lower internal/external tibial rotation strength ratio. The difference in volume, peak CSA, and length of the semitendinosus and gracilis correlated significantly with the deficit in knee flexion strength, with Pearson correlations of 0.51, 0.57, and 0.61, respectively. The muscle-tendon properties of the semitendinosus and gracilis are substantially altered after harvesting, and these alterations may contribute to knee flexor weakness in the surgical limb. These deficits are more pronounced in knees with tendons that do not regenerate and are only partially offset by compensatory hypertrophy of other hamstring muscles.
A novel role for non-muscle γ-actin in skeletal muscle sarcomere assembly
Publisher: Elsevier BV
Date: 07-2004
An EMG-Assisted Muscle-Force Driven Finite Element Analysis Pipeline to Investigate Joint- and Tissue-Level Mechanical Responses in Functional Activities: Towards a Rapid Assessment Toolbox
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2022
Traditional vs accelerated approaches to post-operative rehabilitation following matrix-induced autologous chondrocyte implantation (MACI): comparison of clinical, biomechanical and radiographic outco
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.JOCA.2008.03.010
Abstract: To determine the effectiveness of 'accelerated' compared to 'traditional' post-operative load bearing rehabilitation protocols following matrix-induced autologous chondrocyte implantation (MACI). A randomized controlled study design was used to investigate clinical, biomechanical and radiographic assessment at 3 months post-surgery in 62 patients following MACI to the medial or lateral femoral condyle. Both rehabilitation interventions sought to protect the implant for an initial period, then incrementally increase load bearing. Under the 'accelerated' protocol, patients reached full weight bearing at 8 weeks post-surgery, compared to 11 weeks for the 'traditional' group. Patients in the 'accelerated' group achieved greater 6 min walk distances and daily activity levels as measured by accelerometry (P<0.05) compared to the 'traditional' group. Furthermore, the 'accelerated' group reported significantly better improvement in knee pain at 12 weeks as indicated by the Knee Injury and Osteoarthritis Outcome Score (P<0.05), and regardless of the rehabilitation protocol employed, no patient suffered any adverse effect to the implant as assessed by magnetic resonance imaging at 3 months. Comparison of each rehabilitation group with an unaffected control group revealed a significant difference in peak knee adduction and flexion moments for the traditional group (P 0.05), which may demonstrate a faster return to knee loading patterns typically observed in unaffected subjects. The 'accelerated' load bearing approach that reduced the length of time spent ambulating on crutches resulted in reduced knee pain, improved function, no graft complications and may speed up the recovery of normal gait function. Patient follow-up to at least 24 months would be required to observe longer-term graft outcomes.
The effect of technique change on knee loads during sidestep cutting
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2007
A conceptual framework for computational models of Achilles tendon homeostasis
Publisher: Wiley
Date: 11-06-2013
DOI: 10.1002/WSBM.1229
Abstract: Computational modeling of tendon lags the development of computational models for other tissues. A major bottleneck in the development of realistic computational models for Achilles tendon is the absence of detailed conceptual and theoretical models as to how the tissue actually functions. Without the conceptual models to provide a theoretical framework to guide the development and integration of multiscale computational models, modeling of the Achilles tendon to date has tended to be piecemeal and focused on specific mechanical or biochemical issues. In this paper, we present a new conceptual model of Achilles tendon tissue homeostasis, and discuss this model in terms of existing computational models of tendon. This approach has the benefits of structuring the research on relevant computational modeling to date, while allowing us to identify new computational models requiring development. The critically important functional issue for tendon is that it is continually damaged during use and so has to be repaired. From this follows the centrally important issue of homeostasis of the load carrying collagen fibrils within the collagen fibers of the Achilles tendon. Collagen fibrils may be damaged mechanically-by loading, or damaged biochemically-by proteases. Upon reviewing existing computational models within this conceptual framework of the Achilles tendon structure and function, we demonstrate that a great deal of theoretical and experimental research remains to be done before there are reliably predictive multiscale computational model of Achilles tendon in health and disease.
Evolution of limb bone loading and body size in varanid lizards
Publisher: The Company of Biologists
Date: 15-09-2011
DOI: 10.1242/JEB.059345
Abstract: Geometric scaling predicts that stresses on limb bones and muscles should increase with body size. Mammals counter this size-related increase in stress partially through changes in bone geometry, but largely through changes in posture, with larger species having a more erect stance. However, the ability to counter size-related stresses in this fashion may be limited to those taxa that have a parasagittal gait (such as mammals), where legs are swung underneath the body. We examined locomotor kinematics for 11 species of varanid lizards (from 0.04 to 8 kg body mass) that have a sprawling gait, to determine how they moderate size-related stresses. Posture, as indicated by femur adduction and hip heights, did not change significantly with body size, beyond that expected from geometrical scaling. Instead, lizards mitigated size-related increases in stress by increasing duty factor and possibly reducing femur rotation. Incorporating these factors in biomechanical models predicted that both bending (∝M0.016, where M is mass) and torsional (∝M–0.049) stresses should be nearly independent of body size over the size range examined. However, increasing duty factor and reducing femur rotation probably have deleterious effects on speed, and this difference in kinematics with size may explain why speed scales lower for sprawling lizards than for parasagittal mammals (∝M0.17 and ∝M0.24, respectively). Further, paralleling conclusions for the synapsid lineage, these findings suggest that evolution from sprawling to upright posture did not occur in archosaurs as a response to larger size rather, these archosaurs likely became upright first and larger later.
An EMG-driven musculoskeletal model to estimate muscle forces and knee joint moments in vivo
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S0021-9290(03)00010-1
Abstract: This paper examined if an electromyography (EMG) driven musculoskeletal model of the human knee could be used to predict knee moments, calculated using inverse dynamics, across a varied range of dynamic contractile conditions. Muscle-tendon lengths and moment arms of 13 muscles crossing the knee joint were determined from joint kinematics using a three-dimensional anatomical model of the lower limb. Muscle activation was determined using a second-order discrete non-linear model using rectified and low-pass filtered EMG as input. A modified Hill-type muscle model was used to calculate in idual muscle forces using activation and muscle tendon lengths as inputs. The model was calibrated to six in iduals by altering a set of physiologically based parameters using mathematical optimisation to match the net flexion/extension (FE) muscle moment with those measured by inverse dynamics. The model was calibrated for each subject using 5 different tasks, including passive and active FE in an isokinetic dynamometer, running, and cutting manoeuvres recorded using three-dimensional motion analysis. Once calibrated, the model was used to predict the FE moments, estimated via inverse dynamics, from over 200 isokinetic dynamometer, running and sidestepping tasks. The inverse dynamics joint moments were predicted with an average R(2) of 0.91 and mean residual error of approximately 12 Nm. A re-calibration of only the EMG-to-activation parameters revealed FE moments prediction across weeks of similar accuracy. Changing the muscle model to one that is more physiologically correct produced better predictions. The modelling method presented represents a good way to estimate in vivo muscle forces during movement tasks.
Reliability of functional and predictive methods to estimate the hip joint centre in human motion analysis in healthy adults
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.GAITPOST.2017.01.023
Abstract: In human motion analysis predictive or functional methods are used to estimate the location of the hip joint centre (HJC). It has been shown that the Harrington regression equations (HRE) and geometric sphere fit (GSF) method are the most accurate predictive and functional methods, respectively. To date, the comparative reliability of both approaches has not been assessed. The aims of this study were to (1) compare the reliability of the HRE and the GSF methods, (2) analyse the impact of the number of thigh markers used in the GSF method on the reliability, (3) evaluate how alterations to the movements that comprise the functional trials impact HJC estimations using the GSF method, and (4) assess the influence of the initial guess in the GSF method on the HJC estimation. Fourteen healthy adults were tested on two occasions using a three-dimensional motion capturing system. Skin surface marker positions were acquired while participants performed quite stance, perturbed and non-perturbed functional trials, and walking trials. Results showed that the HRE were more reliable in locating the HJC than the GSF method. However, comparison of inter-session hip kinematics during gait did not show any significant difference between the approaches. Different initial guesses in the GSF method did not result in significant differences in the final HJC location. The GSF method was sensitive to the functional trial performance and therefore it is important to standardize the functional trial performance to ensure a repeatable estimate of the HJC when using the GSF method.
Gait selection in the ostrich: Mechanical and metabolic characteristics of walking and running with and without an aerial phase
Publisher: The Royal Society
Date: 22-05-2004
Tibio-femoral cartilage defects 3-5 years following arthroscopic partial medial meniscectomy
Publisher: Elsevier BV
Date: 12-2008
DOI: 10.1016/J.JOCA.2008.04.014
Abstract: Arthroscopic partial medial meniscectomy (APMM) is a common procedure to treat a medial meniscal tear. In iduals who undergo APMM have a heightened risk of developing tibio-femoral osteoarthritis (OA). Cartilage defects scored from magnetic resonance imaging (MRI) scans predict cartilage loss over time. It is not known whether cartilage defects in the early years following APMM are more common or of greater severity than in age-matched controls. This study compared the prevalence and severity of tibio-femoral cartilage defects in patients 3-5 years post-APMM with that of age-matched controls. Twenty-five in iduals who had undergone APMM in the previous 46.9+/-5.0 months and 24 age-matched controls participated in this study. Sagittal plane knee MRI scans were acquired from the operated knees of patients and from randomly assigned knees of the controls and graded (0-4) for tibio-femoral cartilage defects. Defect prevalence (score of >or=2 for any compartment) and severity of the cartilage from both tibio-femoral compartments were compared between the groups. The APMM group had greater prevalence (77 vs 42%, P=0.012) and severity (4.1+/-1.9 vs 2.8+/-1.1, P=0.005) of tibio-femoral cartilage defects than controls. Age was positively associated with tibio-femoral cartilage defect severity for APMM, r=0.523, P=0.007, but not for controls, r=0.045, P=0.834. Tibio-femoral joint cartilage defects are more prevalent and of greater severity in in iduals who had undergone APMM approximately 44 months earlier than in age-matched controls.
Predicting athlete ground reaction forces and moments from motion capture.
Publisher: Springer Science and Business Media LLC
Date: 17-03-2018
DOI: 10.1007/S11517-018-1802-7
Abstract: An understanding of athlete ground reaction forces and moments (GRF/Ms) facilitates the biomechanist's downstream calculation of net joint forces and moments, and associated injury risk. Historically, force platforms used to collect kinetic data are housed within laboratory settings and are not suitable for field-based installation. Given that Newton's Second Law clearly describes the relationship between a body's mass, acceleration, and resultant force, is it possible that marker-based motion capture can represent these parameters sufficiently enough to estimate GRF/Ms, and thereby minimize our reliance on surface embedded force platforms? Specifically, can we successfully use partial least squares (PLS) regression to learn the relationship between motion capture and GRF/Ms data? In total, we analyzed 11 PLS methods and achieved average correlation coefficients of 0.9804 for GRFs and 0.9143 for GRMs. Our results demonstrate the feasibility of predicting accurate GRF/Ms from raw motion capture trajectories in real-time, overcoming what has been a significant barrier to non-invasive collection of such data. In applied biomechanics research, this outcome has the potential to revolutionize athlete performance enhancement and injury prevention. Graphical Abstract Using data science to model high-fidelity motion and force plate data frees biomechanists from the laboratory.
Knee biomechanics during jogging after arthroscopic partial meniscectomy: A longitudinal study
Publisher: SAGE Publications
Date: 18-04-2017
Abstract: Altered knee joint biomechanics is thought to play a role in the pathogenesis of knee osteoarthritis and has been reported in patients after arthroscopic partial meniscectomy (APM) while performing various activities. Longitudinally, understanding knee joint biomechanics during jogging may assist future studies to assess the implications of jogging on knee joint health in this population. To investigate knee joint biomechanics during jogging in patients 3 months after APM and a healthy control group at baseline and 2 years later at follow-up. Controlled laboratory study. Seventy-eight patients who underwent medial APM and 38 healthy controls underwent a 3-dimensional motion analysis during barefoot overground jogging at baseline. Sixty-four patients who underwent APM and 23 controls returned at follow-up. External peak moments (flexion and adduction) and the peak knee flexion angle during stance were evaluated for the APM leg, non-APM leg (nonoperated leg), and control leg. At baseline, the peak knee flexion angle was 1.4° lower in the APM leg compared with the non-APM leg ( P = .03). No differences were found between the moments in the APM leg compared with the control leg (all P .05). However, the normalized peak knee adduction moment was 35% higher in the non-APM leg compared with the control leg ( P = .008). In the non-APM leg, the normalized peak knee adduction and flexion moments were higher compared with the APM leg by 16% and 10%, respectively, at baseline ( P ≤ .004). Despite the increase in the peak knee flexion moment in the APM leg compared with the non-APM leg ( P .001), there were no differences in the peak knee flexion moment or any other parameter assessed at 2-year follow-up between the legs ( P .05). Comparing the APM leg and control leg, no differences in knee joint biomechanics during jogging for the variables assessed were observed. Higher knee moments in the non-APM leg may have clinical implications for the noninvolved leg. Kinematic differences were small (~1.4°) and therefore of questionable clinical relevance. These results may facilitate future clinical research regarding the implications of jogging on knee joint health in middle-aged, overweight patients after APM.
Stereoscopic filming for investigating evasive side-stepping and anterior cruciate ligament injury risk
Publisher: SPIE
Date: 04-02-2010
DOI: 10.1117/12.840153
Best methods and data to reconstruct paediatric lower limb bones for musculoskeletal modelling
Publisher: Springer Science and Business Media LLC
Date: 05-11-2019
DOI: 10.1007/S10237-019-01245-Y
Abstract: In biomechanical simulations, generic linearly scaled musculoskeletal anatomies are commonly used to represent children, often neglecting or oversimplifying subject-specific features that may affect model estimates. Inappropriate bone sizing may influence joint angles due to erroneous joint centre identification. Alternatively, subject-specific image-based musculoskeletal models allow for more realistic representations of the skeletal system. To this end, statistical shape modelling (SSM) and morphing techniques may help to reconstruct bones rapidly and accurately. Specifically, the musculoskeletal atlas project (MAP) Client, which employs magnetic resonance imaging (MRI) and/or motion capture data to inform SSM and nonrigid morphing techniques, proved able to accurately reconstruct adult pelvis and femur bones. Nonetheless, to date, the above methods have never been applied to paediatric data. In this study, pelvis, femurs and tibiofibular bones of 18 typically developing children were reconstructed using the MAP Client. Ten different combinations of SSM and morphing techniques, i.e. pipelines, were developed. Generic bone geometries from the gait2392 OpenSim model were linearly scaled for comparisons. Jaccard index, root mean square distance error and Hausdorff distance were computed to quantify reconstruction accuracy. For the pelvis bone, colour maps were produced to identify areas prone to inaccuracies and hip joint centres (HJC) location was compared. Finally, per cent difference between MRI- and MAP-measured left-to-right HJC distances was computed. Pipelines informed by MRI data, alone or in combination with motion capture data, accurately reconstructed paediatric lower limb bones (i.e. Jaccard index > 0.8). Scaled OpenSim geometries provided the least accurate reconstructions. Principal component-based scaling methods produced size-dependent results, which were worse for smaller children.
Integrating a hip belt with body armour reduces the magnitude and changes the location of shoulder pressure and perceived discomfort in soldiers
Publisher: Informa UK Limited
Date: 24-10-2018
DOI: 10.1080/00140139.2017.1381278
Abstract: Soldiers carry heavy loads that may cause general discomfort, shoulder pain and injury. This study assessed if new body armour designs that incorporated a hip belt reduced shoulder pressures and improved comfort. Twenty-one Australian soldiers completed treadmill walking trials wearing six different body armours with two different loads (15 and 30 kg). Contact pressures applied to the shoulders were measured using pressure pads, and qualitative assessment of comfort and usability were acquired from questionnaires administered after walking trials. Walking with hip belt compared to no hip belt armour resulted in decreased mean and maximum shoulder pressures (p < 0.005), and 30% fewer participants experiencing shoulder discomfort (p < 0.005) in best designs, although hip discomfort did increase. Laterally concentrated shoulder pressures were associated with 1.34-times greater likelihood of discomfort (p = 0.026). Results indicate body armour and backpack designs should integrate a hip belt and distribute load closer to shoulder midline to reduce load carriage discomfort and, potentially, injury risk. Practitioner Summary: Soldiers carry heavy loads that increase their risk of discomfort and injury. New body armour designs are thought to ease this burden by transferring the load to the hips. This study demonstrated that designs incorporating a hip belt reduced shoulder pressure and shoulder discomfort compared to the current armour design.
A 3D-printed phantom twin and multi-transducer holder for dynamic anatomical ultrasonography of the lower limb
Publisher: Future Medicine Ltd
Date: 06-2023
Abstract: We aim to improve the residuum health of in iduals suffering from lower-limb loss through ‘digital twin’ computational simulations for the creation of optimized 3D-printed prosthetic attachments. Our objective is to utilize 4D tracking data of various tissue interfaces as a primary input into the digital twin. Dynamic anatomical ultrasonography (DAU) is a novel technique in which synchronized in idual transducers are positioned at known locations utilizing a 3D-printed holder. Pulse-echo ultrasound data are recorded and subsequently analyzed, providing plots of tissue interface depths versus recording time. For the scientific validation of the DAU technique, a bespoke 3D-printed phantom twin has been created incorporating replica compartments of soft-tissue interfaces and bone tissue of a healthy thigh. To demonstrate its utility, a preliminary experiment was performed in which the phantom twin was positioned within the DAU device and the replica bone manually traversed randomly subsequent DAU analysis provided a plot of interface depth versus recording time.
Could Targeted Exercise Programmes Prevent Lower Limb Injury in Community Australian Football?
Publisher: Springer Science and Business Media LLC
Date: 17-05-2013
DOI: 10.1007/S40279-013-0056-7
Abstract: Australian football is a popular sport in Australia, at both the community and elite levels. It is a high-speed contact sport with a higher incidence of medically treated injuries when compared with most other organized sports. Hamstring injuries, ligament injuries to the knee or ankle, hip/groin injuries and tendinopathies are particularly common and often result in considerable time lost from sport. Consequently, the prevention of lower limb injuries is a priority for both community and elite Australian football organizations. There is considerable literature available on exercise programmes aimed at reducing lower limb injuries in Australian football and other running-related sports. The quality and outcomes of these studies have varied considerably, but indicate that exercise protocols may be an effective means of preventing lower limb injuries. Despite this, there has been limited high-quality and systematic evaluation of these data. The aim of this literature review is to systematically evaluate the evidence about the benefits of lower limb injury prevention exercise protocols aimed at reducing the most common severe lower limb injuries in Australian football. The Cochrane Central Register of Controlled Trials, the Cochrane Bone Joint and Muscle Trauma Group Specialized Register, MEDLINE and other electronic databases were searched, from January 1990 to December 2010. Papers reporting the results of randomized controlled trials (RCTs), quasi-RCTs, cohort and case-control studies were extracted. Primary outcomes were injury reduction or risk factor identification and/or modification. Secondary outcomes were adherence to any trialled interventions, injury severity and adverse effects such as secondary injuries and muscle soreness. The methodological quality of extracted manuscripts was assessed and results were collated. Forty-seven papers were identified and reviewed of which 18 related to hamstring injury, eight related to knee or ankle ligament injury, five related to tendon injury and four were hip or groin injury related. Another 12 papers targeted general lower limb injuries. Most (n = 27 [57%]) were observational studies, investigating injury risk factors. Twenty reported the results of intervention trials. Of these, 15 were efficacy trials reporting the effects of an intervention in reducing injury rates, four were biomechanical interventions in which the impact of the intervention on a known injury risk factor was assessed and one reported changes in injury risk factors as well as injury rates. The strength of the evidence base for exercise programmes for lower limb injury prevention was found to be limited, primarily due to the research methods employed, low adherence to interventions by the study participants and a lack of statistical power. Limited evidence obtained from a small number of RCTs suggests that balance and control exercises might be efficacious in preventing ankle ligament injuries and a programme involving a combination of balance and control exercises, eccentric hamstring, plyometrics and strength exercises could be efficacious in preventing all lower limb injuries. Overall, the evidence for exercise programmes as an efficacious lower limb injury prevention strategy is predominantly restricted to studies addressing injury aetiology and mechanisms. The findings of this review highlight the need to develop and test interventions in well designed population-based trials with an emphasis on promoting intervention uptake and adherence and, hence, intervention effectiveness. The results of this review can inform the development of the components of a future lower limb injury prevention exercise protocol for community-level Australian football.
Neuromuscular Biomechanical Modeling to Understand Knee Ligament Loading
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2005
DOI: 10.1249/01.MSS.0000176676.49584.BA
Abstract: This article examines our use of EMG-driven neuromuscular biomechanical models to study how muscles stabilize the knee. EMG can be used to establish which activation patterns are used by people for knee stabilization. However, it does not reveal the effectiveness of these patterns. The EMG-driven models provide quantitative comparisons of the effectiveness of the different knee-stabilizing activation patterns. Subjects performed static tasks and common sporting maneuvers that challenged knee joint stability. EMG, joint posture and motion, and external forces and moments were measured during these tasks. These data were used to calibrate the EMG-driven neuromuscular biomechanical model. We then used the model to predict the role of muscles in supporting varus and valgus moments at the knee. We found specific muscle activation patterns to support varus and valgus moments. The most potent activation pattern to stabilize the knee is when the hamstrings or quadriceps are required to generate flexion or extension moments, respectively. The next most effective knee-stabilizing pattern is cocontraction of the hamstring and quadriceps. The small biarticular muscles at the knee provided the least support of varus and valgus moments. In the sporting tasks, sidestepping was found to place the anterior cruciate ligament at high risk of injury. We found that the muscles are the main defense against knee ligament injuries in these tasks. Traditional biomechanical and neurophysiological methods have shown that there are specific activation patterns used to stabilize the knee. By also using the EMG-driven neuromuscular biomechanical model, we have shown how effective muscles are in stabilizing the knee. This modeling method provides a new tool to understand knee joint stabilization.
Physical activity patterns and function 3 months after arthroscopic partial meniscectomy
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.JSAMS.2012.08.007
Abstract: To compare physical activity levels, subject-reported function, and knee strength in 21 arthroscopic partial meniscectomy (APM) patients (age 45.7 (6.06) years, BMI 27.3 (5.96) female 60%) 3 months post-surgery with 21 healthy controls (age 43.6 (5.71) years, BMI 24.5(4.2) female 60%) matched at the cohort level for age, gender and BMI. Case control study. Physical activity intensity, number of steps, and minutes spent in activity were objectively quantified using an accelerometer-based activity monitor worn for 7 days. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and concentric quadriceps strength were used to evaluate function post-surgery. Differences in activity levels and functional outcomes between the APM and control participants were assessed using t-tests, while multiple linear regression was used to quantify the best predictors of physical activity. APM patients engaged in a similar duration of activity to controls (469.0 (128.39)min vs. 497.1 (109.9)min), and take a similar number of steps per day (9227 (2977) vs. 10,383 (3501), but performed their activity at lower levels of intensity than controls. Time spent in moderate (r(2)=0.19) and hard (r(2)=0.145) intensity physical activity was best predicted by the Symptoms sub-scale of the KOOS for both controls and APM patients. APM patients participate in similar levels of activity at lower intensities, but with reduced activity at higher intensities which is related to the presence of symptoms of knee osteoarthritis.
Shape differences in the semitendinosus following tendon harvesting for anterior cruciate ligament reconstruction
Publisher: Wiley
Date: 17-04-2023
DOI: 10.1002/JOR.25337
Abstract: Following hamstring autograft anterior cruciate ligament reconstruction (ACLR), muscle length, cross‐sectional area, and volume are reduced. However, these discrete measures of morphology do not account for complex three‐dimensional muscle shape. The primary aim of this study was to determine between‐limb semitendinosus (ST) shape and regional morphology differences in young adults following tendon harvest for ACLR and to compare these differences with those in healthy controls. In this cross‐sectional study, magnetic resonance imaging was performed on 18 in iduals with unilateral ACLR and 18 healthy controls. Bilaterally, ST muscles were segmented, and shape differences assessed between limbs and compared between groups using Jaccard index (0–1) and Hausdorff distance (mm). Length (cm), peak cross‐sectional area (cm 2 ), and volume (cm 3 ) were measured for the entire muscle and proximal, middle, and distal regions, and compared between limbs and groups. Compared to healthy controls, the ACLR group had significantly ( p 0.001, Cohen's d = −2.33) lower bilateral ST shape similarity and shape deviation was significantly ( p 0.001, d = 2.12) greater. Shape deviation was greatest within the distal region of the ACLR (Hausdorff: 23.1 ± 8.68 mm). Compared to both the uninjured contralateral limb and healthy controls, deficits in peak cross‐sectional area and volume in ACLR group were largest in proximal ( p 0.001, d = −2.52 to −1.28) and middle ( p 0.001, d = −1.81 to −1.04) regions of the ST. Overall, shape analysis provides unique insight into regional adaptations in ST morphology post‐ACLR. Findings highlight morphological features in distal ST not identified by traditional discrete morphology measures. Clinical significance: Following ACLR, risk of a secondary knee or primary hamstring injury has been reported to be between 2‐to‐5 times greater compared to those without ACLR. Change in semitendinosus (ST) shape following ACLR may affect force transmission and distribution within the hamstrings and might contribute to persistent deficits in knee flexor and internal rotator strength.
Muscle size explains low passive skeletal muscle force in heart failure patients
Publisher: PeerJ
Date: 15-09-2016
DOI: 10.7717/PEERJ.2447
Abstract: Alterations in skeletal muscle function and architecture have been linked to the compromised exercise capacity characterizing chronic heart failure (CHF). However, how passive skeletal muscle force is affected in CHF is not clear. Understanding passive force characteristics in CHF can help further elucidate the extent to which altered contractile properties and/or architecture might affect muscle and locomotor function. Therefore, the aim of this study was to investigate passive force in a single muscle for which non-invasive measures of muscle size and estimates of fiber force are possible, the soleus (SOL), both in CHF patients and age- and physical activity-matched control participants. Passive SOL muscle force and size were obtained by means of a novel approach combining experimental data (dynamometry, electromyography, ultrasound imaging) with a musculoskeletal model. We found reduced passive SOL forces (∼30%) (at the same relative levels of muscle stretch) in CHF vs. healthy in iduals. This difference was eliminated when force was normalized by physiological cross sectional area, indicating that reduced force output may be most strongly associated with muscle size. Nevertheless, passive force was significantly higher in CHF at a given absolute muscle length (non length-normalized) and likely explained by the shorter muscle slack lengths and optimal muscle lengths measured in CHF compared to the control participants. This later factor may lead to altered performance of the SOL in functional tasks such gait. These findings suggest introducing exercise rehabilitation targeting muscle hypertrophy and, specifically for the calf muscles, exercise that promotes muscle lengthening.
Finite element analysis of the performance of additively manufactured scaffolds for scapholunate ligament reconstruction
Publisher: Public Library of Science (PLoS)
Date: 19-11-2021
DOI: 10.1371/JOURNAL.PONE.0256528
Abstract: Rupture of the scapholunate interosseous ligament can cause the dissociation of scaphoid and lunate bones, resulting in impaired wrist function. Current treatments (e.g., tendon-based surgical reconstruction, screw-based fixation, fusion, or carpectomy) may restore wrist stability, but do not address regeneration of the ruptured ligament, and may result in wrist functional limitations and osteoarthritis. Recently a novel multiphasic bone-ligament-bone scaffold was proposed, which aims to reconstruct the ruptured ligament, and which can be 3D-printed using medical-grade polycaprolactone. This scaffold is composed of a central ligament-scaffold section and features a bone attachment terminal at either end. Since the ligament-scaffold is the primary load bearing structure during physiological wrist motion, its geometry, mechanical properties, and the surgical placement of the scaffold are critical for performance optimisation. This study presents a patient-specific computational biomechanical evaluation of the effect of scaffold length, and positioning of the bone attachment sites. Through segmentation and image processing of medical image data for natural wrist motion, detailed 3D geometries as well as patient-specific physiological wrist motion could be derived. This data formed the input for detailed finite element analysis, enabling computational of scaffold stress and strain distributions, which are key predictors of scaffold structural integrity. The computational analysis demonstrated that longer scaffolds present reduced peak scaffold stresses and a more homogeneous stress state compared to shorter scaffolds. Furthermore, it was found that scaffolds attached at proximal sites experience lower stresses than those attached at distal sites. However, scaffold length, rather than bone terminal location, most strongly influences peak stress. For each scaffold terminal placement configuration, a basic metric was computed indicative of bone fracture risk. This metric was the minimum distance from the bone surface to the internal scaffold bone terminal. Analysis of this minimum bone thickness data confirmed further optimisation of terminal locations is warranted.
Predicting Athlete Ground Reaction Forces and Moments From Spatio-Temporal Driven CNN Models
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2019
Osteoarthritis year in review 2016: mechanics
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.JOCA.2016.09.023
Abstract: Inappropriate biomechanics, namely wear-and-tear, has been long believed to be a main cause of osteoarthritis (OA). However, this view is now being re-evaluated, especially when examined alongside mechanobiology and new biomechanical studies. These are multiscale experimental and computational studies focussing on cell- and tissue-level mechanobiology through to organ- and whole-body-level biomechanics, which focuses on the biomechanical and biochemical environment of the joint tissues. This review examined papers from April 2015 to April 2016, with a focus on multiscale experimental and computational biomechanical studies of OA. Assessing the onset or progression of OA at organ- and whole-body-levels, gait analysis, medical imaging and neuromusculoskeletal modelling revealed the extent to which tissue damage changes the view of inappropriate biomechanics. Traditional gait analyses studies reported that conservative treatments can alter joint biomechanics, thereby improving pain and function experienced by those with OA. Results of animal models of OA were consistent with these human studies, showing interactions among bone, cartilage and meniscus biomechanics and the onset and/or progression OA. Going down size scales, experimental and computational studies probed the nanosize biomechanics of molecules, cells and extracellular matrix, and demonstrated how the interactions between biomechanics and morphology affect cartilage dynamic poroelastic behaviour and pathways to OA. Finally, integration of multiscale experimental data and computational models were proposed to predict cartilage extracellular matrix remodelling and the development of OA. Summarising, experimental and computational methods provided a nuanced biomechanical understanding of the sub-cellular, cellular, tissue, organ and whole-body mechanisms involved in OA.
Structured white light scanning of rabbit Achilles tendon.
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.JBIOMECH.2016.09.042
Abstract: The cross-sectional area (CSA) of a material is used to calculate stress under load. The mechanical behaviour of soft tissue is of clinical interest in the management of injury however, measuring CSA of soft tissue is challenging as s les are geometrically irregular and may deform during measurement. This study presents a simple method, using structured light scanning (SLS), to acquire a 3D model of rabbit Achilles tendon in vitro for measuring CSA of a tendon. The Artec Spider™ 3D scanner uses structured light and stereophotogrammetry technologies to acquire shape data and reconstruct a 3D model of an object. In this study, the 3D scanner was integrated with a custom mechanical rig, permitting 360-degree acquisition of the morphology of six New Zealand White rabbit Achilles tendons. The reconstructed 3D model was then used to measure CSA of the tendon. SLS, together with callipers and micro-CT, was used to measure CSA of objects with a regular or complex shape, such as a drill flute and human cervical vertebra, for validating the accuracy and repeatability of the technique. CSA of six tendons was measured with a coefficient of variation of less than 2%. The mean CSA was 9.9±1.0mm The technique developed in this study offers a simple and accurate method for effectively measuring CSA of soft tissue such as tendons. This allows for localised calculation of stress along the length, assisting in the understanding of the function, injury mechanisms and rehabilitation of tissue.
Running in ostriches (Struthio camelus): Three-dimensional joint axes alignment and joint kinematics
Publisher: The Company of Biologists
Date: 15-07-2007
DOI: 10.1242/JEB.02792
Abstract: Although locomotor kinematics in walking and running birds have been examined in studies exploring many biological aspects of bipedalism, these studies have been largely limited to two-dimensional analyses. Incorporating a five-segment, 17 degree-of-freedom (d.f.) kinematic model of the ostrich hind limb developed from anatomical specimens, we quantified the three-dimensional(3-D) joint axis alignment and joint kinematics during running (at ∼3.3 m s–1) in the largest avian biped, the ostrich. Our analysis revealed that the majority of the segment motion during running in the ostrich occurs in flexion/extension. Importantly, however, the alignment of the average flexion/extension helical axes of the knee and ankle are rotated externally to the direction of travel (37° and 21°, respectively) so that pure flexion and extension at the knee will act to adduct and adbuct the tibiotarsus relative to the plane of movement, and pure flexion and extension at the ankle will act to abduct and adduct the tarsometatarsus relative to the plane of movement. This feature of the limb anatomy appears to provide the major lateral (non-sagittal) displacement of the lower limb necessary for steering the swinging limb clear of the stance limb and replaces what would otherwise require greater adduction/abduction and/or internal/external rotation, allowing for less complex joints, musculoskeletal geometry and neuromuscular control. Significant rotation about the joints'non-flexion/extension axes nevertheless occurs over the running stride. In particular, hip abduction and knee internal/external and varus/valgus motion may further facilitate limb clearance during the swing phase, and substantial non-flexion/extension movement at the knee is also observed during stance. Measurement of 3-D segment and joint motion in birds will be aided by the use of functionally determined axes of rotation rather than assumed axes, proving important when interpreting the biomechanics and motor control of avian bipedalism.
Patellofemoral joint alignment is a major risk factor for recurrent patellar dislocation in children and adolescents: a systematic review
Publisher: Elsevier BV
Date: 09-2018
Instantaneous progression reference frame for calculating pelvis rotations: Reliable and anatomically-meaningful results independent of the direction of movement.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.GAITPOST.2016.02.011
Abstract: In motion analysis, pelvis angles are conventionally calculated as the rotations between the pelvis and laboratory reference frame. This approach assumes that the participant's motion is along the anterior-posterior laboratory reference frame axis. When this assumption is violated interpretation of pelvis angels become problematic. In this paper a new approach for calculating pelvis angles based on the rotations between the pelvis and an instantaneous progression reference frame was introduced. At every time-point, the tangent to the trajectory of the midpoint of the pelvis projected into the horizontal plane of the laboratory reference frame was used to define the anterior-posterior axis of the instantaneous progression reference frame. This new approach combined with the rotation-obliquity-tilt rotation sequence was compared to the conventional approach using the rotation-obliquity-tilt and tilt-obliquity-rotation sequences. Four different movement tasks performed by eight healthy adults were analysed. The instantaneous progression reference frame approach was the only approach that showed reliable and anatomically meaningful results for all analysed movement tasks (mean root-mean-square-differences below 5°, differences in pelvis angles at pre-defined gait events below 10°). Both rotation sequences combined with the conventional approach led to unreliable results as soon as the participant's motion was not along the anterior-posterior laboratory axis (mean root-mean-square-differences up to 30°, differences in pelvis angles at pre-defined gait events up to 45°). The instantaneous progression reference frame approach enables the gait analysis community to analysis pelvis angles for movements that do not follow the anterior-posterior axis of the laboratory reference frame.
Lizard tricks: Overcoming conflicting requirements of speed versus climbing ability by altering biomechanics of the lizard stride
Publisher: The Company of Biologists
Date: 2013
DOI: 10.1242/JEB.089060
Abstract: Adaptations promoting greater performance in one habitat are thought to reduce performance in others. However, there are many ex les of where, despite habitat differences, such predicted differences in performance do not occur. One such ex le is the relationship between locomotory performance to habitat for varanid lizards. To explain the lack of difference in locomotor performance we examined detailed observation of the kinematics of each lizard's stride. Differences in kinematics were greatest between climbing and non-climbing species. For terrestrial lizards, the kinematics indicated that increased femur adduction, femur rotation and ankle angle all contributed positively to changes in stride length, but they were constrained for climbing species, probably due to biomechanical restrictions on the centre of mass height (to increase stability on vertical surfaces). Despite climbing species having restricted stride length, no differences have been previously reported in sprint speed between climbing and non-climbing varanids. This is best explained by climbing varanids using an alternative speed modulation strategy of varying stride frequency to avoid the potential trade-off of speed vs stability on vertical surfaces. Thus, by measuring the relevant biomechanics for lizard strides, we have shown how kinematic differences among species can mask performance differences typically associated with habitat variation.
The History and Future of Neuromusculoskeletal Biomechanics
Publisher: Human Kinetics
Date: 10-2023
An upper limb kinematic model for the examination of cricket bowling: A case study of Mutiah Muralitharan
Publisher: Informa UK Limited
Date: 2000
Abstract: We show how biomechanics can be used to accurately assess spin-bowling techniques (offspin, legspin and topspin) in cricket, under controlled conditions, when the player is suspected of throwing. A 50 Hz six-camera Vicon Motion Analysis system was used to record the movements of markers strategically placed on the upper limb during each of the above bowling actions. A kinematic model of the upper limb, created using Vicon BodyBuilder software, enabled the movements of the upper arm and forearm to be described during each delivery. Selected physical characteristics of the upper limb were also measured. The present 'no ball' law in cricket with reference to throwing states that 'the arm should not be straightened in the part of the delivery that immediately precedes ball release'. The bowler, Mutiah Muralitharan, was shown to maintain a relatively constant elbow angle in the 0.06 s before ball release. Furthermore, this angle changed little from the time that the upper arm was angled vertically downward until ball release during the three spin-bowling actions.
Selective muscle activation following rapid varus/valgus perturbations at the knee
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-1996
DOI: 10.1097/00005768-199607000-00014
Abstract: Knee muscles are generally ided into groups based on their function as flexors or extensors. In this study we sought to determine if muscles were selectively activated according to their potential roles as varus or valgus stabilizers following rapid loads to the knee. While subjects were supine, varus or valgus moments were applied to the knees of 10 human subjects using a servomotor-driven perturbation device. During the experiments, electromyograms (EMG) were recorded from seven muscles, four of which had medial moment arms relative to the knee center, and three of which had lateral moment arms. It was observed that, for all medial muscles, a statistically significant increase in muscle activation followed valgus loads as compared with varus loads. All lateral muscles except the vastus lateralis showed the opposite response (as expected). These results suggest that muscles can be reflexively activated independent of their roles as flexors or extensors to provide stability to the human knee during varus or valgus loads. The timing of the reflex is consistent with that arising from joint mechanoreceptors, although polysynaptic stretch reflex may also be involved.
Hip joint contact loads in older adults during recovery from forward loss of balance by stepping
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.JBIOMECH.2016.05.033
Abstract: Hip joint contact loads during activities of daily living are not generally considered high enough to cause acute bone or joint injury. However there is some evidence that hip joint loads may be higher in stumble recovery from loss of balance. A common laboratory method used to evaluate balance recovery performance involves suddenly releasing participants from various static forward lean magnitudes (perturbation intensities). Prior studies have shown that when released from the same perturbation intensity, some older adults are able to recover with a single step, whereas others require multiple steps. The main purpose of this study was to use a musculoskeletal model to determine the effect of three balance perturbation intensities and the use of single versus multiple recovery steps on hip joint contact loads during recovery from forward loss of balance in community dwelling older adults (n=76). We also evaluated the association of peak hip contact loads with perturbation intensity, step length and trunk flexion angle at foot contact at each participant׳s maximum recoverable lean angle (MRLA). Peak hip joint contact loads were computed using muscle force estimates obtained using Static Optimisation and increased as lean magnitude was increased and were on average 32% higher for Single Steppers compared to Multiple Steppers. At the MRLA, peak hip contact loads ranged from 4.3 to 12.7 body weights and multiple linear stepwise regression further revealed that initial lean angle, step length and trunk angle at foot contact together explained 27% of the total variance in hip joint contact load. Overall findings indicated that older adults experience peak hip joint contact loads during maximal balance recovery by stepping that in some cases exceeded loads reported to cause mechanical failure of cadaver femurs. While step length and trunk flexion angle are strong predictors of step recovery performance they are at best moderate predictors of peak hip joint loading.
Washable Garment-Embedded Textile Electrodes Can Measure High-Quality Surface EMG Data Across a Range of Motor Tasks
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2023
Multiscale musculoskeletal modelling, data–model fusion and electromyography-informed modelling
Publisher: The Royal Society
Date: 06-04-2016
Abstract: This paper proposes methods and technologies that advance the state of the art for modelling the musculoskeletal system across the spatial and temporal scales and storing these using efficient ontologies and tools. We present population-based modelling as an efficient method to rapidly generate in idual morphology from only a few measurements and to learn from the ever-increasing supply of imaging data available. We present multiscale methods for continuum muscle and bone models and efficient mechanostatistical methods, both continuum and particle-based, to bridge the scales. Finally, we examine both the importance that muscles play in bone remodelling stimuli and the latest muscle force prediction methods that use electromyography-assisted modelling techniques to compute musculoskeletal forces that best reflect the underlying neuromuscular activity. Our proposal is that, in order to have a clinically relevant virtual physiological human, (i) bone and muscle mechanics must be considered together (ii) models should be trained on population data to permit rapid generation and use underlying principal modes that describe both muscle patterns and morphology and (iii) these tools need to be available in an open-source repository so that the scientific community may use, personalize and contribute to the database of models.
Repeatability of upper limb kinematics for children with and without cerebral palsy
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.GAITPOST.2010.02.015
Abstract: There is increasing demand for a standardised and reliable protocol for the objective assessment of upper limb motion in clinical populations. This paper describes the repeatability of a three-dimensional (3D) kinematic model and protocol to assess upper limb movement for children with and without cerebral palsy (CP). Ten typically developing (TD) children (m=10.5years+/-1.18) and seven children with CP (spastic hemiplegia) (m=11.14years+/-1.86) completed upper limb motion analysis on two occasions separated by at least one week. Participants performed three trials of four functional tasks, where 3D joint angles were calculated at the thorax, shoulder, elbow and wrist. Within and between-day repeatability was assessed using coefficients of multiple determination (CMD). There were distinct kinematic patterns for both groups for each functional task. In relation to their peers, children with CP consistently displayed reduced elbow extension, and compensatory patterns at the shoulder and thorax. High within and between-day CMD scores were revealed for specific rotations, with the highest being obtained at joints with large ranges of motion. The chosen tasks delineate the upper limb kinematic patterns of those with and without CP. The model has high within and between-day repeatability particularly where joint rotations demonstrate a large range of movement. 3D motion analysis is a feasible assessment tool for use with clinical populations.
Minimal medical imaging can accurately reconstruct geometric bone models for musculoskeletal models
Publisher: Public Library of Science (PLoS)
Date: 11-02-2019
The association between external-ground-reaction force and knee-joint kinetics during partial- and full-weight-bearing gait
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.CLINBIOMECH.2009.12.013
Abstract: Progressive weight-bearing is recommended following autologous chondrocyte implantation. This weight-bearing program assumes that increasing external loads experienced at the foot during gait are closely related to external-knee-joint moments. We investigated this relationship, and examined other variables that may contribute to knee-joint kinetics of which the clinician can modify using practical instruction within a clinical setting. Gait analysis was performed in 51 patients following autologous chondrocyte implantation, during various partial- and full-weight-bearing conditions. The contribution of ground-reaction force, kinematic and spatio-temporal gait parameters to external-knee moments was investigated within weight-bearing levels less than 60%, between 60% and 90% and more than 90% of in idual body weight. There was no association between peak-ground-reaction force and the knee-adduction moment within the 60-90% and more than 90% weight-bearing conditions, nor the peak-knee-flexion moment at less than 60% weight-bearing. Peak-ground-reaction force accounted for no more than 21.4% and 18.6% of the variance in the knee-adduction and flexion moments, respectively, within any weight-bearing condition, while the combination of peak-ground-reaction force, kinematic and spatio-temporal parameters investigated accounted for no more than 39.7% and 52.2%, respectively. Foot-progression angle and knee-flexion during weight acceptance accounted for a significant (P<0.05) portion of the variance in external-knee moments, particularly at higher levels of weight-bearing. A large amount of variance in knee moments may be attributed to variables other than external loads, some of which can be modified by the clinician. Clinically, this is important for any therapist implementing progressive weight-bearing protocols.
A neuromusculoskeletal model of the human lower limb: Towards EMG-driven actuation of multiple joints in powered orthoses
Publisher: IEEE
Date: 06-2011
Protocol for a multi-centre randomised controlled trial comparing arthroscopic hip surgery to physiotherapy-led care for femoroacetabular impingement (FAI): the Australian FASHIoN trial
Publisher: Springer Science and Business Media LLC
Date: 26-09-2017
Accuracy of Partial Weight Bearing After Autologous Chondrocyte Implantation
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.APMR.2008.02.019
Abstract: To determine whether patients can accurately replicate and retain weight-bearing restrictions in both stationary (static) and dynamic conditions after autologous chondrocyte implantation (ACI). Case series. Rehabilitation clinic. A consecutive s le of patients (N=48) who had undergone ACI to a medial or lateral femoral condylar defect in the knee. Patients were trained to partially weight bear using bathroom scales and forearm crutches prior to assessment. A force platform was used to measure peak vertical ground reaction forces in patients during static and dynamic conditions immediately after weight-bearing instruction and training, and again during gait 7 days after training. Immediately after instruction and weight-bearing practice on a set of scales, patients exerted a mean of 15.8% body weight more than expected during walking for 20% weight-bearing trials, 8.3% more for the 40% trials, 11.9% more for the 60% trials, and 1.2% less for the prescribed 80% trials. Accuracy of weight-bearing replication improved across all weight-bearing levels when assessed 7 days later, when patients exerted a mean of 6.6% body weight more than expected during walking for 20% weight-bearing trials (9.2% body weight improvement), 4.2% more for the 40% trials (4.1% body weight improvement), 9.9% more for the 60% trials (2% body weight improvement), and 0.2% more for the 60% trials (1% body weight improvement). Patients were unable to follow weight-bearing restrictions after instruction and practice on a set of scales, and patients were unable to replicate weight-bearing levels in both static and dynamic conditions.
Changing sidestep cutting technique reduces knee valgus loading
Publisher: SAGE Publications
Date: 09-06-2009
Abstract: Common lower limb postures have been found when noncontact anterior cruciate ligament (ACL) injuries occur during sidestep cutting tasks. These same postures have been linked to knee loadings known to stress the ACL. Whole body technique modification would reduce knee loading. Controlled laboratory study. Experienced team sport athletes were recruited for whole body sidestep cutting technique modification. Before and after a 6-week technique modification training, participants performed sidestep cutting tasks while ground-reaction force and motion data were collected. A kinematic and inverse dynamics model was used to calculate 3-dimensional knee loading during sidestep cutting. At initial foot contact, the participants placed their stance foot closer to the body’s midline and held their torso more upright, in line with the aims of the technique modification training. This was accompanied by significantly lower peak valgus moments in the weight acceptance phase of stance. Both postural changes were correlated with the change in peak valgus moment. Whole body sidestep cutting technique modification resulted in reduced knee loading. Implementation of whole body technique modification may produce effective ACL injury prevention programs in sports involving sidestep cutting.
Soleus Muscle as a Surrogate for Health Status in Human Heart Failure
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2016
Repeatability of 3D gait kinematics obtained from an electromagnetic tracking system during treadmill locomotion
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.JBIOMECH.2006.06.017
Abstract: The purpose of this paper was to describe a technique that enables three-dimensional (3D) gait kinematics to be obtained using an electromagnetic tracking system, and to report the intra-trial, intra-day/inter-tester and inter-day/intra-tester repeatability of kinematic gait data obtained using this technique. Ten able-bodied adults underwent four gait assessments the same two testers tested each subject independently on two different days. Gait assessments were conducted on a custom-built long-bed treadmill with no metal components between the rollers. Each gait assessment involved familiarisation to treadmill walking, subject anatomical and functional calibration, and a period of steady-state treadmill walking at a self-selected speed. Following data collection, 3D joint kinematics were calculated using the joint coordinate system approach. 3D joint angle waveforms for 10 left and right strides were extracted and temporally normalised for each trial. Intra-trial, intra-day/inter-tester and inter-day/intra-tester repeatability of the temporally normalised kinematic waveforms were quantified using the coefficient of multiple determination (CMD). CMDs for joint kinematics averaged 0.942 intra-trial, 0.849 intra-day/inter-tester and 0.773 inter-day/intra-tester. In general, sagittal plane kinematics were more repeatable than frontal or transverse plane kinematics, and kinematics at the hip were more repeatable than at the knee or ankle. The level of repeatability of kinematic gait data obtained during treadmill walking using this protocol was equal or superior to that reported previously for overground walking using image-based protocols.
Static optimization underestimates antagonist muscle activity at the glenohumeral joint: a musculoskeletal modeling study
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.JBIOMECH.2019.109348
Abstract: Static optimization is commonly employed in musculoskeletal modeling to estimate muscle and joint loading however, the ability of this approach to predict antagonist muscle activity at the shoulder is poorly understood. Antagonist muscles, which contribute negatively to a net joint moment, are known to be important for maintaining glenohumeral joint stability. This study aimed to compare muscle and joint force predictions from a subject-specific neuromusculoskeletal model of the shoulder driven entirely by measured muscle electromyography (EMG) data with those from a musculoskeletal model employing static optimization. Four healthy adults performed six sub-maximal upper-limb contractions including shoulder abduction, adduction, flexion, extension, internal rotation and external rotation. EMG data were simultaneously measured from 16 shoulder muscles using surface and intramuscular electrodes, and joint motion evaluated using video motion analysis. Muscle and joint forces were calculated using both a calibrated EMG-driven neuromusculoskeletal modeling framework, and musculoskeletal model simulations that employed static optimization. The EMG-driven model predicted antagonistic muscle function for pectoralis major, latissimus dorsi and teres major during abduction and flexion supraspinatus during adduction middle deltoid during extension and subscapularis, pectoralis major and latissimus dorsi during external rotation. In contrast, static optimization neural solutions showed little or no recruitment of these muscles, and preferentially activated agonistic prime movers with large moment arms. As a consequence, glenohumeral joint force calculations varied substantially between models. The findings suggest that static optimization may under-estimate the activity of muscle antagonists, and therefore, their contribution to glenohumeral joint stability.
Calculation of quantitative shunt values using photoluminescence imaging
Publisher: Wiley
Date: 27-03-2012
DOI: 10.1002/PIP.2180
12 Degrees of Freedom Muscle Force Driven Fibril-Reinforced Poroviscoelastic Finite Element Model of the Knee Joint
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Modeling the human knee for assistive technologies
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2012
The measurement of shoulder alignment in cricket fast bowling
Publisher: Informa UK Limited
Date: 2002
DOI: 10.1080/02640410252925170
Abstract: The aim of this study was to compare thoracic spine alignment with two- and three-dimensional calculations of shoulder alignment (defined as a line joining the acromion processes of the right and left scapula) when all measures were projected onto the transverse plane. A six-camera Vicon system was used to reconstruct three markers positioned on the plane of the thorax such that the orthogonal vector to the thoracic spine, projected onto the transverse plane, was used as a virtual shoulder alignment during cricket fast bowling. This same measurement system was used to calculate the three-dimensional line between the acromion processes projected onto the transverse plane. These acromion markers were also used to calculate the two-dimensional transverse plane alignment of the shoulders from images recorded by a video camera positioned above ball release. All cameras operated at 50 Hz. A significant association was recorded between thorax alignment and the three- (0.97) and two-dimensional (0.87) shoulder alignment estimations at back-foot impact. The strength of association remained at front-foot impact, when correlations of 0.89 (three-dimensional) and 0.84 (two-dimensional) were recorded. However, at ball release, non-significant associations of 0.58 (three-dimensional) and 0.41 (two-dimensional), representing shoulder alignment differences of approximately 10 degrees, were recorded. The 95% limits of agreement comparisons for shoulder alignment at back-foot impact, front-foot impact and ball release produced mean random errors for the two comparisons of 9.5 degrees, 11.7 degrees and 22.5 degrees respectively. Three- and two-dimensional transverse plane projections of shoulder alignment are reasonable estimates of thorax alignment at back-foot impact and front-foot impact but not at ball release.
Achilles tendon stress is more sensitive to subject-specific geometry than subject-specific material properties: A finite element analysis
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.JBIOMECH.2017.02.031
Abstract: This study used subject-specific measures of three-dimensional (3D) free Achilles tendon geometry in conjunction with a finite element method to investigate the effect of variation in subject-specific geometry and subject-specific material properties on tendon stress during submaximal isometric loading. Achilles tendons of eight participants (Aged 25-35years) were scanned with freehand 3D ultrasound at rest and during a 70% maximum voluntary isometric contraction. Ultrasound images were segmented, volume rendered and transformed into subject-specific 3D finite element meshes. The mean (±SD) lengths, volumes and cross-sectional areas of the tendons at rest were 62±13mm, 3617±984mm
Muscle and external load contribution to knee joint contact loads during normal gait
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.JBIOMECH.2009.06.019
Abstract: Large knee adduction moments during gait have been implicated as a mechanical factor related to the progression and severity of tibiofemoral osteoarthritis and it has been proposed that these moments increase the load on the medial compartment of the knee joint. However, this mechanism cannot be validated without taking into account the internal forces and moments generated by the muscles and ligaments, which cannot be easily measured. Previous musculoskeletal models suggest that the medial compartment of the tibiofemoral joint bears the majority of the tibiofemoral load, with the lateral compartment unloaded at times during stance. Yet these models did not utilise explicitly measured muscle activation patterns and measurements from an instrumented prosthesis which do not portray lateral compartment unloading. This paper utilised an EMG-driven model to estimate muscle forces and knee joint contact forces during healthy gait. Results indicate that while the medial compartment does bear the majority of the load during stance, muscles provide sufficient stability to counter the tendency of the external adduction moment to unload the lateral compartment. This stability was predominantly provided by the quadriceps, hamstrings, and gastrocnemii muscles, although the contribution from the tensor fascia latae was also significant. Lateral compartment unloading was not predicted by the EMG-driven model, suggesting that muscle activity patterns provide useful input to estimate muscle and joint contact forces.
An alternative whole-body marker set to accurately and reliably quantify joint kinematics during load carriage
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.GAITPOST.2017.04.002
Abstract: Body armor covers anatomical landmarks that would otherwise be used to track trunk and pelvis movement in motion analysis. This study developed and evaluated a new marker set, and compared it to placing markers on the skin and over-top of body armor. In our method, pelvis and trunk motions were measured using a custom-built sacral and upper-back marker cluster, respectively. Joint angles and ranges of motion were determined while participants walked without and with body armor. Angles were obtained from the new marker set and compared against conventional marker sets placed on the skin or over-top the body armor. Bland-Altman analyses compared the agreement of kinematic parameters between marker sets, while joint angle waveforms were compared using inter-protocol coefficient of multiple correlations (CMCs). The intra- and inter-session similarities of joint angle waveforms from each marker set were also assessed using CMCs. There was a strong agreement between joint angles from the new marker set and markers placed directly on the skin at key anatomical landmarks. The agreement worsened with markers placed on top of body armor. Inter-protocol CMCs comparing markers on body armor to the new marker set were poor compared to CMCs between skin-mounted markers and the new marker set. Intra- and inter-session repeatability were higher for the new marker set compared to placing markers over-top of body armor. The new marker set provides a viable alternative for researchers to reliably measure trunk and pelvis motion when equipment, such as body armor, obscures marker placement.
A muscle synergy-based method to estimate muscle activation patterns of children with cerebral palsy using data collected from typically developing children
Publisher: Springer Science and Business Media LLC
Date: 04-03-2022
DOI: 10.1038/S41598-022-07541-5
Abstract: Preparing children with cerebral palsy prior to gait analysis may be a challenging and time-intensive task, especially when large number of sensors are involved. Collecting minimum number of electromyograms (EMG) and yet providing adequate information for clinical assessment might improve clinical workflow. The main goal of this study was to develop a method to estimate activation patterns of lower limb muscles from EMG measured from a small set of muscles in children with cerebral palsy. We developed and implemented a muscle synergy extrapolation method able to estimate the full set of lower limbs muscle activation patterns from only three experimentally measured EMG. Specifically, we extracted a set of hybrid muscle synergies from muscle activation patterns of children with cerebral palsy and their healthy counterparts. Next, those muscle synergies were used to estimate activation patterns of muscles, which were not initially measured in children with cerebral palsy. Two best combinations with three (medial gastrocnemius, semi membranous, and vastus lateralis) and four (lateral gastrocnemius, semi membranous, sartorius, and vastus medialis) experimental EMG were able to estimate the full set of 10 muscle activation patterns with mean (± standard deviation) variance accounted for of 79.93 (± 9.64)% and 79.15 (± 6.40)%, respectively, using only three muscle synergies. In conclusion, muscle activation patterns of unmeasured muscles in children with cerebral palsy can be estimated from EMG measured from three to four muscles using our muscle synergy extrapolation method. In the future, the proposed muscle synergy-based method could be employed in gait clinics to minimise the required preparation time.
Reliability of four models for clinical gait analysis.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.GAITPOST.2017.04.001
Abstract: Three-dimensional gait analysis (3DGA) has become a common clinical tool for treatment planning in children with cerebral palsy (CP). Many clinical gait laboratories use the conventional gait analysis model (e.g. Plug-in-Gait model), which uses Direct Kinematics (DK) for joint kinematic calculations, whereas, musculoskeletal models, mainly used for research, use Inverse Kinematics (IK). Musculoskeletal IK models have the advantage of enabling additional analyses which might improve the clinical decision-making in children with CP. Before any new model can be used in a clinical setting, its reliability has to be evaluated and compared to a commonly used clinical gait model (e.g. Plug-in-Gait model) which was the purpose of this study. Two testers performed 3DGA in eleven CP and seven typically developing participants on two occasions. Intra- and inter-tester standard deviations (SD) and standard error of measurement (SEM) were used to compare the reliability of two DK models (Plug-in-Gait and a six degrees-of-freedom model solved using Vicon software) and two IK models (two modifications of 'gait2392' solved using OpenSim). All models showed good reliability (mean SEM of 3.0° over all analysed models and joint angles). Variations in joint kinetics were less in typically developed than in CP participants. The modified 'gait2392' model which included all the joint rotations commonly reported in clinical 3DGA, showed reasonable reliable joint kinematic and kinetic estimates, and allows additional musculoskeletal analysis on surgically adjustable parameters, e.g. muscle-tendon lengths, and, therefore, is a suitable model for clinical gait analysis.
Non-negative matrix factorisation is the most appropriate method for extraction of muscle synergies in walking and running
Publisher: Springer Science and Business Media LLC
Date: 19-05-2020
DOI: 10.1038/S41598-020-65257-W
Abstract: Muscle synergies provide a simple description of a complex motor control mechanism. Synergies are extracted from muscle activation patterns using factorisation methods. Despite the availability of several factorisation methods in the literature, the most appropriate method for muscle synergy extraction is currently unknown. In this study, we compared four muscle synergy extraction methods: non-negative matrix factorisation, principal component analysis, independent component analysis, and factor analysis. Probability distribution of muscle activation patterns were compared with the probability distribution of synergy excitation primitives obtained from the four factorisation methods. Muscle synergies extracted using non-negative matrix factorisation best matched the probability distribution of muscle activation patterns across different walking and running speeds. Non-negative matrix factorisation also best tracked changes in muscle activation patterns compared to the other factorisation methods. Our results suggest that non-negative matrix factorisation is the best factorisation method for identifying muscle synergies in dynamic tasks with different levels of muscle contraction.
Using step width to compare locomotor biomechanics between extinct, non-avian theropod dinosaurs and modern obligate bipeds
Publisher: The Royal Society
Date: 07-2017
Abstract: How extinct, non-avian theropod dinosaurs locomoted is a subject of considerable interest, as is the manner in which it evolved on the line leading to birds. Fossil footprints provide the most direct evidence for answering these questions. In this study, step width—the mediolateral (transverse) distance between successive footfalls—was investigated with respect to speed (stride length) in non-avian theropod trackways of Late Triassic age. Comparable kinematic data were also collected for humans and 11 species of ground-dwelling birds. Permutation tests of the slope on a plot of step width against stride length showed that step width decreased continuously with increasing speed in the extinct theropods ( p 0.001), as well as the five tallest bird species studied ( p 0.01). Humans, by contrast, showed an abrupt decrease in step width at the walk–run transition. In the modern bipeds, these patterns reflect the use of either a discontinuous locomotor repertoire, characterized by distinct gaits (humans), or a continuous locomotor repertoire, where walking smoothly transitions into running (birds). The non-avian theropods are consequently inferred to have had a continuous locomotor repertoire, possibly including grounded running. Thus, features that characterize avian terrestrial locomotion had begun to evolve early in theropod history.
The Preventing Australian Football Injuries with Exercise (PAFIX) Study: A group randomised controlled trial
Publisher: BMJ
Date: 06-2009
Predicting Gait Patterns of Children With Spasticity by Simulating Hyperreflexia
Publisher: Human Kinetics
Date: 10-2023
Abstract: Spasticity is a common impairment within pediatric neuromusculoskeletal disorders. How spasticity contributes to gait deviations is important for treatment selection. Our aim was to evaluate the pathophysiological mechanisms underlying gait deviations seen in children with spasticity, using predictive simulations. A cluster analysis was performed to extract distinct gait patterns from experimental gait data of 17 children with spasticity to be used as comparative validation data. A forward dynamic simulation framework was employed to predict gait with either velocity- or force-based hyperreflexia. This framework entailed a generic musculoskeletal model controlled by reflexes and supraspinal drive, governed by a multiobjective cost function. Hyperreflexia values were optimized to enable the simulated gait to best match experimental gait patterns. Three experimental gait patterns were extracted: (1) increased knee flexion, (2) increased ankle plantar flexion, and (3) increased knee flexion and ankle plantar flexion when compared with typical gait. Overall, velocity-based hyperreflexia outperformed force-based hyperreflexia. The first gait pattern could mostly be explained by rectus femoris and hamstrings velocity-based hyperreflexia, the second by gastrocnemius velocity-based hyperreflexia, and the third by gastrocnemius, soleus, and hamstrings velocity-based hyperreflexia. This study shows how velocity-based hyperreflexia from specific muscles contributes to different spastic gait patterns, which may help in providing targeted treatment.
Scientific evidence is just the starting point: A generalizable process for developing sports injury prevention interventions
Publisher: Elsevier BV
Date: 09-2016
Knee Muscle Strength After Recent Partial Meniscectomy Does Not Relate to 2-year Change in Knee Adduction Moment
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2014
The effects of electromyography-assisted modelling in estimating musculotendon forces during gait in children with cerebral palsy
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.JBIOMECH.2019.05.026
Abstract: Neuro-musculoskeletal modelling can provide insight into the aberrant muscle function during walking in those suffering cerebral palsy (CP). However, such modelling employs optimization to estimate muscle activation that may not account for disturbed motor control and muscle weakness in CP. This study evaluated different forms of neuro-musculoskeletal model personalization and optimization to estimate musculotendon forces during gait of nine children with CP (GMFCS I-II) and nine typically developing (TD) children. Data collection included 3D-kinematics, ground reaction forces, and electromyography (EMG) of eight lower limb muscles. Four different optimization methods estimated muscle activation and musculotendon forces of a scaled-generic musculoskeletal model for each child walking, i.e. (i) static optimization that minimized summed-excitation squared (ii) static optimization with maximum isometric muscle forces scaled to body mass (iii) an EMG-assisted approach using optimization to minimize summed-excitation squared while reducing tracking errors of experimental EMG-linear envelopes and joint moments and (iv) EMG-assisted with musculotendon model parameters first personalized by calibration. Both static optimization approaches showed a relatively low model performance compared to EMG envelopes. EMG-assisted approaches performed much better, especially in CP, with only a minor mismatch in joint moments. Calibration did not affect model performance significantly, however it did affect musculotendon forces, especially in CP. A model more consistent with experimental measures is more likely to yield more physiologically representative results. Therefore, this study highlights the importance of calibrated EMG-assisted modelling when estimating musculotendon forces in TD children and even more so in children with CP.
The future of in-field sports biomechanics: wearables plus modelling compute real-time in vivo tissue loading to prevent and repair musculoskeletal injuries
Publisher: Informa UK Limited
Date: 08-09-2021
We have the programme, what next? Planning the implementation of an injury prevention programme
Publisher: BMJ
Date: 19-01-2016
Increase in vastus medialis cross-sectional area is associated with reduced pain, cartilage loss, and joint replacement risk in knee osteoarthritis
Publisher: Wiley
Date: 28-11-2012
DOI: 10.1002/ART.34681
Abstract: Although there is evidence for a beneficial effect of increased quadriceps strength on knee symptoms, the effect on knee structure is unclear. We undertook this study to examine the relationship between change in vastus medialis cross-sectional area (CSA) and knee pain, tibial cartilage volume, and risk of knee replacement in subjects with symptomatic knee osteoarthritis (OA). One hundred seventeen subjects with symptomatic knee OA underwent magnetic resonance imaging of the knee at baseline and at 2 and 4.5 years. Vastus medialis CSA was measured at baseline and at 2 years. Tibial cartilage volume was measured at baseline and at 2 and 4.5 years. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index at baseline and at 2 years. The frequency of knee joint replacement over 4 years was determined. Regression coefficients (B) and odds ratios were determined along with 95% confidence intervals (95% CIs). After adjusting for confounders, baseline vastus medialis CSA was inversely associated with current knee pain (r = -0.16, P = 0.04) and with medial tibial cartilage volume loss from baseline to 2 years (B coefficient -10.9 [95% CI -19.5, -2.3]), but not with baseline tibial cartilage volume. In addition, an increase in vastus medialis CSA from baseline to 2 years was associated with reduced knee pain over the same time period (r = 0.24, P = 0.007), reduced medial tibial cartilage loss from 2 to 4.5 years (B coefficient -16.8 [95% CI -28.9, -4.6]), and reduced risk of knee replacement over 4 years (odds ratio 0.61 [95% CI 0.40, 0.94]). In a population of patients with symptomatic knee OA, increased vastus medialis size was associated with reduced knee pain and beneficial structural changes at the knee, suggesting that management of knee pain and optimizing vastus medialis size are important in reducing OA progression and subsequent knee replacement.
Muscle contributions to medial tibiofemoral compartment contact loading following ACL reconstruction using semitendinosus and gracilis tendon grafts
Publisher: Public Library of Science (PLoS)
Date: 19-04-2017
Tibiofemoral joint contact forces increase with load magnitude and walking speed but remain almost unchanged with different types of carried load
Publisher: Public Library of Science (PLoS)
Date: 05-11-2018
Cartilage quantitative T2 relaxation time 2-4 years following isolated anterior cruciate ligament reconstruction.
Publisher: Wiley
Date: 24-01-2018
DOI: 10.1002/JOR.23846
Abstract: Cartilage T2 relaxation time in isolated anterior cruciate ligament reconstruction (ACLR) without concomitant meniscal pathology and their changes over time remain unclear. The purpose of this exploratory study was to: (i) compare cartilage T2 relaxation time (T2 values) in people with isolated ACLR at 2-3 years post-surgery (baseline) and matched healthy controls and (ii) evaluate the subsequent 2-year change in T2 values in people with ACLR. Twenty-eight participants with isolated ACLR and nine healthy volunteers underwent knee magnetic resonance imaging (MRI) at baseline 16 ACLR participants were re-imaged 2 years later. Cartilage T2 values in full thickness, superficial layers, and deep layers were quantified in the tibia, femur, trochlear, and patella. Between-group comparisons at baseline were performed using analysis of covariance adjusting for age, sex, and body mass index. Changes over time in the ACLR group were evaluated using paired s le t-tests. ACLR participants showed significantly higher (p = 0.03) T2 values in the deep layer of medial femoral condyle at baseline compared to controls (mean difference 4.4 ms [13%], 95%CI 0.4, 8.3 ms). Over 2 years, ACLR participants showed a significant reduction (p = 0.04) in T2 value in the deep layer of lateral tibia (mean change 1.4 ms [-7%], 95%CI 0.04, 2.8 ms). The decrease in T2 values suggests improvement in cartilage composition in the lateral tibia (deep layer) of ACLR participants. Further research with larger ACLR cohorts ided according to meniscal status and matched healthy cohorts are needed to further understand cartilage changes post-ACLR. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2022-2029, 2018.
Level of agreement between field-based data collectors in a large scale injury prevention randomised controlled trial
Publisher: Elsevier BV
Date: 03-2011
DOI: 10.1016/J.JSAMS.2010.09.003
Abstract: In sports injury prevention field trials, data collectors are often club volunteers with considerable knowledge of the game but with limited detailed medical backgrounds or knowledge of formal scientific processes. The aim of this paper is to determine the agreement among trained primary data collectors (PDCs) with a sport science background and no prior involvement in data collection in a large randomised controlled trial. During the 'Preventing Australian Football Injury through eXercise' (PAFIX) project, player participation and injury data were collected by trained PDCs at training and games over the 2007 and 2008 playing seasons in 40 community level Australian football teams. PDC-collected data relating to player exposure and whether or not a player sustained an injury and subsequently left the field of play was compared to the same information from independent observers (IOs) who attended one randomly selected game for each of the 40 teams. There was 98% agreement between the PDC and the IO on game details (i.e., date, time, grade and score), 79% (ICC 0.9, 95% CI 0.85-0.95) agreement on the number of players per game and 76% (ICC 0.8, 95% CI 0.69-0.91) agreement on the number of injuries sustained in the games. There was 100% agreement on whether the player left the field for all injuries. This study found that exercise and sport science students are reliable data collectors in sports injury fieldwork studies.
Multi-level personalization of neuromusculoskeletal models to estimate physiologically plausible knee joint contact forces in children
Publisher: Springer Science and Business Media LLC
Date: 13-10-2022
DOI: 10.1007/S10237-022-01626-W
Abstract: Neuromusculoskeletal models are a powerful tool to investigate the internal biomechanics of an in idual. However, commonly used neuromusculoskeletal models are generated via linear scaling of generic templates derived from elderly adult anatomies and poorly represent a child, let alone children with a neuromuscular disorder whose musculoskeletal structures and muscle activation patterns are profoundly altered. Model personalization can capture abnormalities and appropriately describe the underlying (altered) biomechanics of an in idual. In this work, we explored the effect of six different levels of neuromusculoskeletal model personalization on estimates of muscle forces and knee joint contact forces to tease out the importance of model personalization for normal and abnormal musculoskeletal structures and muscle activation patterns. For six children, with and without cerebral palsy, generic scaled models were developed and progressively personalized by (1) tuning and calibrating musculotendon units’ parameters, (2) implementing an electromyogram-assisted approach to synthesize muscle activations, and (3) replacing generic anatomies with image-based bony geometries, and physiologically and physically plausible muscle kinematics. Biomechanical simulations of gait were performed in the OpenSim and CEINMS software on ten overground walking trials per participant. A mixed-ANOVA test, with Bonferroni corrections, was conducted to compare all models’ estimates. The model with the highest level of personalization produced the most physiologically plausible estimates. Model personalization is crucial to produce physiologically plausible estimates of internal biomechanical quantities. In particular, personalization of musculoskeletal anatomy and muscle activation patterns had the largest effect overall. Increased research efforts are needed to ease the creation of personalized neuromusculoskeletal models.
Subject-specific finite element analysis to characterize the influence of geometry and material properties in Achilles tendon rupture
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.JBIOMECH.2014.10.001
Abstract: Achilles tendon injuries including rupture are one of the most frequent musculoskeletal injuries, but the mechanisms for these injuries are still not fully understood. Previous in vivo and experimental studies suggest that tendon rupture mainly occurs in the tendon mid-section and predominantly more in men than women due to reasons yet to be identified. Therefore we aimed to investigate possible mechanisms for tendon rupture using finite element (FE) analysis. Specifically, we have developed a framework for generating subject-specific FE models of human Achilles tendon. A total of ten 3D FE models of human Achilles tendon were generated. Subject-specific geometries were obtained using ultrasound images and a mesh morphing technique called Free Form Deformation. Tendon material properties were obtained by performing material optimization that compared and minimized difference in uniaxial tension experimental results with model predictions. Our results showed that both tendon geometry and material properties are highly subject-specific. This subject-specificity was also evident in our rupture predictions as the locations and loads of tendon ruptures were different in all specimens tested. A parametric study was performed to characterize the influence of geometries and material properties on tendon rupture. Our results showed that tendon rupture locations were dependent largely on geometry while rupture loads were more influenced by tendon material properties. Future work will investigate the role of microstructural properties of the tissue on tendon rupture and degeneration by using advanced material descriptions.
Hybrid neuromusculoskeletal modeling
Publisher: Springer Berlin Heidelberg
Date: 2013
Tibiofemoral contact forces in the anterior cruciate ligament-reconstructed knee
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2016
Muscle activation strategies at the knee during running and cutting maneuvers
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2003
DOI: 10.1097/00005768-200301000-00019
Abstract: The purpose of this article was to investigate the activation patterns of muscles surrounding the knee during preplanned (PP) and unanticipated (UN) running and cutting tasks, with respect to the external moments applied to the joint. It was hypothesized that activation strategies during PP tasks would correspond to the magnitude and direction of the external loads applied to the knee joint, and the muscle activation patterns would differ between PP and UN tasks. Eleven healthy male subjects performed a series of running and cutting tasks under PP and UN conditions. Activation from 10 knee muscles were determined using full-wave rectified, filtered, and normalized EMG calculated during a precontact phase and two epochs across the stance phase. Knee joint flexor and extensor muscle group ratios indicated the level of co-contraction. In idual muscles were also grouped into medial/lateral and internal/external rotation muscle groups, based upon their ability to counter externally applied varus/valgus and internal/external rotation joint loads, respectively. Selective activation of medial/lateral and internal/external rotation muscles and co-contraction of flexors and extensors were used to stabilize the joint under PP conditions, whereas generalized co-contraction strategies were employed during the UN condition. Net muscle activation during the UN sidestepping tasks increased by 10-20%, compared with an approximately 100% increase in applied varus/valgus and internal/external rotation joint moments. In PP conditions, activation patterns appear to be selected to support the external loads experienced at the knee, e.g., medial muscles activated to resist applied valgus moments. Under UN conditions, there was no selective activation of muscles to counter the external knee load, with generalized co-contraction being the activation pattern adopted. These findings have implications for the etiology of noncontact knee ligament injuries.
Repeatability of gait data using a functional hip joint centre and a mean helical knee axis
Publisher: Elsevier BV
Date: 08-2003
DOI: 10.1016/S0021-9290(03)00087-3
Abstract: Repeatability of traditional kinematic and kinetic models is affected by the ability to accurately locate anatomical landmarks (ALs) to define joint centres and anatomical coordinate systems. Numerical methods that define joint centres and axes of rotation independent of ALs may also improve the repeatability of kinematic and kinetic data. The purpose of this paper was to compare the repeatability of gait data obtained from two models, one based on ALs (AL model), and the other incorporating a functional method to define hip joint centres and a mean helical axis to define knee joint flexion/extension axes (FUN model). A foot calibration rig was also developed to define the foot segment independent of ALs. The FUN model produced slightly more repeatable hip and knee joint kinematic and kinetic data than the AL model, with the advantage of not having to accurately locate ALs. Repeatability of the models was similar comparing within-tester sessions to between-tester sessions. The FUN model may also produce more repeatable data than the AL model in subject populations where location of ALs is difficult. The foot calibration rig employed in both the AL and FUN model provided an easy alternative to define the foot segment and obtain repeatable data, without accurately locating ALs on the foot.
Effects of different technical coordinate system definitions on the three dimensional representation of the glenohumeral joint centre
Publisher: Springer Science and Business Media LLC
Date: 13-03-2009
DOI: 10.1007/S11517-009-0467-7
Abstract: This study aimed to find the most appropriate marker location, or combination thereof, for the centre of the humeral head (Wang et al. in J Biomech 31: 899-908, 1998) location representation during humeral motion. Ten male participants underwent three MRI scans in three different humeral postures. Seven technical coordinate systems (TCS) were defined from various combinations of an acromion, distal upper arm and proximal upper arm clusters of markers in a custom Matlab program. The CHH location was transformed between postures and then compared with the original MRI CHH location. The results demonstrated that following the performance of two near 180 degrees humeral elevations, a combined acromion TCS and proximal upper arm TCS produced an average error of 23 +/- 9 mm, and 18 +/- 4 mm, which was significantly smaller (p < 0.01) than any other TCS. A combination of acromion and proximal upper arm TCSs should therefore be used to reference the CHH location when analysing movements incorporating large ranges of shoulder motion.
Individuals with mild-to-moderate hip osteoarthritis walk with lower hip joint contact forces despite higher levels of muscle co-contraction compared to healthy individuals
Publisher: Elsevier BV
Date: 07-2020
Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.JBIOMECH.2016.03.052
Abstract: Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates.
Preventing lower limb injuries: Is the latest evidence being translated into the football field?
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.JSAMS.2008.04.002
Abstract: There is accumulating international evidence that lower limb injuries in sport can be prevented through targeted training but the extent to which this knowledge has been translated to real-world sporting practice is not known. A semi-structured questionnaire of all coaches from the nine Sydney Australian Football League Premier Division teams was conducted. Information was sought about their knowledge and behaviours in relation to delivering training programs, including their uptake of the latest scientific evidence for injury prevention. Direct observation of a s le of the coach-delivered training sessions was also undertaken to validate the questionnaire. Coaches ranked training session elements directly related to the game as being of most importance. They strongly favoured warming-up and cooling-down as injury prevention measures but changing direction and side-stepping training was considered to be of little/no importance for safety. Only one-third believed that balance training had some importance for injury prevention, despite accumulating scientific evidence to the contrary. Drills, set play, ball handling and kicking skills were all considered to be of least importance to injury prevention. These views were consistent with the content of the observed coach-led training sessions. In conclusion, current football training sessions do not give adequate attention to the development of skills most likely to reduce the risk of lower limb injury in players. There is a need to improve the translation of the latest scientific evidence about effective injury prevention into coaching practices.
Effects of hip joint centre mislocation on gait kinematics of children with cerebral palsy calculated using patient-specific direct and inverse kinematic models
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.GAITPOST.2017.06.002
Abstract: Joint kinematics can be calculated by Direct Kinematics (DK), which is used in most clinical gait laboratories, or Inverse Kinematics (IK), which is mainly used for musculoskeletal research. In both approaches, joint centre locations are required to compute joint angles. The hip joint centre (HJC) in DK models can be estimated using predictive or functional methods, while in IK models can be obtained by scaling generic models. The aim of the current study was to systematically investigate the impact of HJC location errors on lower limb joint kinematics of a clinical population using DK and IK approaches. Subject-specific kinematic models of eight children with cerebral palsy were built from magnetic resonance images and used as reference models. HJC was then perturbed in 6mm steps within a 60mm cubic grid, and kinematic waveforms were calculated for the reference and perturbed models. HJC perturbations affected only hip and knee joint kinematics in a DK framework, but all joint angles were affected when using IK. In the DK model, joint constraints increased the sensitivity of joint range-of-motion to HJC location errors. Mean joint angle offsets larger than 5° were observed for both approaches (DK and IK), which were larger than previously reported for healthy adults. In the absence of medical images to identify the HJC, predictive or functional methods with small errors in anterior-posterior and medial-lateral directions and scaling procedures minimizing HJC location errors in the anterior-posterior direction should be chosen to minimize the impact on joint kinematics.
Trunk, pelvis and lower limb walking biomechanics are similarly altered in those with femoroacetabular impingement syndrome regardless of cam morphology size
Publisher: Elsevier BV
Date: 2021
MRI development and validation of two new predictive methods of glenohumeral joint centre location identification and comparison with established techniques
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.JBIOMECH.2009.03.039
Abstract: Identification of the centre of the glenohumeral joint (GHJ) is essential for three-dimensional (3D) upper limb motion analysis. A number of convenient, yet un-validated methods are routinely used to estimate the GHJ location in preference to the International Society of Biomechanics (ISB) recommended methods. The current study developed a new regression model, and simple 3D offset method for GHJ location estimation, employing easy to administer measures, and compared the estimates with the known GHJ location measured with magnetic resonance imaging (MRI). The accuracy and reliability of the new regression and simple 3D offset techniques were compared with six established predictive methods. Twenty subjects wore a 3D motion analysis marker set that was also visible in MRI. Immediately following imaging, they underwent 3D motion analysis acquisition. The GHJ and anatomical landmark positions of 15 participants were used to determine the new regression and simple 3D generic offset methods. These were compared for accuracy with six established methods using 10 subject's data. A cross validation on 5 participants not used for regression model development was also performed. Finally, 10 participants underwent a further two MRI's and subsequent 3D motion analysis analyses for inter-tester and intra-tester reliability quantification. When compared with any of the other established methods, our newly developed regression model found an average GHJ location closer to the actual MRI location, having an GHJ location error of 13+/-2 mm, and had significantly lower inter-tester reliability error, 6+/-4 mm (p<0.01).
In vitro loading models for tendon mechanobiology.
Publisher: Wiley
Date: 02-11-2017
DOI: 10.1002/JOR.23752
Abstract: Tendons are the connective tissue responsible for transferring force from muscles to bones. A key factor in tendon development, maturation, repair, and degradation is its biomechanical environment. Understanding tendon mechanobiology is essential for the development of injury prevention strategies, rehabilitation protocols and potentially novel treatments in tendon injury and degeneration. Despite the simple overall loading on tendon tissue, cells within the tissue in vivo experience a much more complex mechanical environment including tension, compression and shear forces. This creates a substantial challenge in the establishment of in vitro loading models of the tendon. This article reviews multiple loading models used for the study of tendon mechanobiology and summarizes the main findings. Although impressive progress has been achieved in the functionality and mimicry of in vitro loading models, an ideal platform is yet to be developed. Multidisciplinary approaches and collaborations will be the key to unveiling the tendon mechanobiology. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:566-575, 2018.
Electromyography-driven modeling for simulating subject-specific movement at the neuromusculoskeletal level
Publisher: Wiley
Date: 15-04-2016
The Free Achilles Tendon Is Shorter, Stiffer, Has Larger Cross-Sectional Area and Longer T2* Relaxation Time in Trained Middle-Distance Runners Compared to Healthy Controls
Publisher: Frontiers Media SA
Date: 27-08-2020
Soleus fascicle length changes are conserved between young and old adults at their preferred walking speed
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.GAITPOST.2013.03.021
Abstract: Older adults have been shown to naturally select a walking speed approximately 20% slower than younger adults. We explored the possibility that a reduction in preferred speed in older adults represents a strategy to preserve the mechanical function of the leg muscles. We examined this question in the soleus muscle in eight healthy young (25.8±3.5 years) and eight healthy older adults (66.1±2.3 years) who were paired so that their preferred speed differed by ∼20%. Soleus muscle fascicle lengths were recorded dynamically using ultrasound, together with simultaneous measurements of soleus EMG activity and ankle joint kinematics while (a) older adults walked on a treadmill at a speed 20% above their preferred speed (speeds matched to the preferred speed of young adults), and (b) young and older adults walked at their preferred treadmill speeds. Analyses of mean muscle fascicle length changes revealed that, at matched speeds, older adults had a statistically different soleus fascicle length pattern compared to young adults, where the muscle's stretch-shorten cycle during stance was diminished. However, older adults walking at their preferred speed exhibited a more pronounced stretch-shorten cycle that was not statistically different from young adults. Conserving muscle length patterns through a reduction in speed in older adults may represent a physiologically relevant modulation of muscle function that permits greater force and power production. Our findings offer a novel mechanical explanation for the slower walking speed in older adults, whereby a reduction in speed may permit muscles to function in a mechanically similar manner to that of younger adults.
Knee extension and flexion weakness in people with knee osteoarthritis: Is antagonist cocontraction a factor?
Publisher: Journal of Orthopaedic & Sports Physical Therapy (JOSPT)
Date: 11-2009
Abstract: Controlled laboratory study, cross-sectional data. To investigate isometric knee flexion and extension strength, failure of voluntary muscle activation, and antagonist cocontraction of subjects with knee osteoarthritis (OA) compared with age-matched asymptomatic control subjects. Quadriceps weakness is a common impairment in in iduals with knee OA. Disuse atrophy, failure of voluntary muscle activation, and antagonist muscle cocontraction are thought to be possible mechanisms underlying this weakness but antagonist cocontraction has not been examined during testing requiring maximum voluntary isometric contraction. Fifty-four subjects with knee OA (mean +/- SD age, 65.6 +/- 7.6 years) and 27 similarly aged control subjects (age, 64.2 +/- 5.1 years) were recruited for this study. Isometric knee flexion and extension strength were measured, and electromyographic data were recorded, from 7 muscles crossing the knee and used to calculate cocontraction ratios during maximal effort knee flexion and extension trials. The burst superimposition technique was used to measure failure of voluntary activation. Knee extension strength of subjects with knee OA (mean +/- SD, 115.9 +/- 6.7 Nm) was significantly lower than for those in the control group (152.3 +/- 9.6 Nm). No significant between-group difference was found for failure of voluntary muscle activation, or the cocontraction ratios during maximum effort knee flexion or extension. These results demonstrate that the reduction in isometric extension strength, measured with a 90 degrees knee flexion angle, in subjects with knee OA is not associated with increased antagonist cocontraction.
EMG-Assisted Algorithm to Account for Shoulder Muscles Co-Contraction in Overhead Manual Handling
Publisher: MDPI AG
Date: 20-05-2020
DOI: 10.3390/APP10103522
Abstract: Glenohumeral stability is essential for a healthy function of the shoulder. It is ensured partly by the scapulohumeral muscular balance. Accordingly, modelling muscle interactions is a key factor in the understanding of occupational pathologies, and the development of ergonomic interventions. While static optimization is commonly used to estimate muscle activations, it tends to underestimate the role of shoulder’s antagonist muscles. The purpose of this study was to implement experimental electromyographic (EMG) data to predict muscle activations that could account for the stabilizing role of the shoulder muscles. Kinematics and EMG were recorded from 36 participants while lifting a box from hip to eye level. Muscle activations and glenohumeral joint reactions were estimated using an EMG-assisted algorithm and compared to those obtained using static optimization with a generic and calibrated model. Muscle activations predicted with the EMG-assisted method were generally larger. Additionally, more interactions between the different rotator cuff muscles, as well as between primer actuators and stabilizers, were predicted with the EMG-assisted method. Finally, glenohumeral forces calculated from a calibrated model remained within the boundaries of the glenoid stability cone. These findings suggest that EMG-assisted methods could account for scapulohumeral muscle co-contraction, and thus their contribution to the glenohumeral stability.
Statistical shape modelling versus linear scaling: Effects on predictions of hip joint centre location and muscle moment arms in people with hip osteoarthritis
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JBIOMECH.2019.01.031
Abstract: Marker-based dynamic functional or regression methods are used to compute joint centre locations that can be used to improve linear scaling of the pelvis in musculoskeletal models, although large errors have been reported using these methods. This study aimed to investigate if statistical shape models could improve prediction of the hip joint centre (HJC) location. The inclusion of complete pelvis imaging data from computed tomography (CT) was also explored to determine if free-form deformation techniques could further improve HJC estimates. Mean Euclidean distance errors were calculated between HJC from CT and estimates from shape modelling methods, and functional- and regression-based linear scaling approaches. The HJC of a generic musculoskeletal model was also perturbed to compute the root-mean squared error (RMSE) of the hip muscle moment arms between the reference HJC obtained from CT and the different scaling methods. Shape modelling without medical imaging data significantly reduced HJC location error estimates (11.4 ± 3.3 mm) compared to functional (36.9 ± 17.5 mm, p = <0.001) and regression (31.2 ± 15 mm, p = <0.001) methods. The addition of complete pelvis imaging data to the shape modelling workflow further reduced HJC error estimates compared to no imaging (6.6 ± 3.1 mm, p = 0.002). Average RMSE were greatest for the hip flexor and extensor muscle groups using the functional (16.71 mm and 8.87 mm respectively) and regression methods (16.15 mm and 9.97 mm respectively). The effects on moment-arms were less substantial for the shape modelling methods, ranging from 0.05 to 3.2 mm. Shape modelling methods improved HJC location and muscle moment-arm estimates compared to linear scaling of musculoskeletal models in patients with hip osteoarthritis.
Muscle Synergy Constraints Improve Prediction of Knee Contact Force During Gait
Publisher: American Society of Mechanical Engineers
Date: 26-06-2013
Abstract: Knowledge of patient-specific muscle and joint contact forces during activities of daily living could improve the treatment of movement-related disorders (e.g., osteoarthritis, stroke, cerebral palsy, Parkinson’s disease). Unfortunately, it is currently impossible to measure these quantities directly under common clinical conditions, and calculation of these quantities using computer models is limited by the redundant nature of human neural control (i.e., more muscles than theoretically necessary to actuate the available degrees of freedom in the skeleton). Walking is a particularly important task to understand, since loss of mobility is associated with increased morbidity and decreased quality of life [1]. Though numerous musculoskeletal computer modeling studies have used optimization methods to resolve the neural control redundancy problem, these estimates remain unvalidated due to the lack of internal force measurements that can be used for validation purposes.
Optimizing whole-body kinematics to minimize valgus knee loading during sidestepping: Implications for ACL injury risk
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.JBIOMECH.2012.02.010
Abstract: The kinematic mechanisms associated with elevated externally applied valgus knee moments during non-contact sidestepping and subsequent anterior cruciate ligament (ACL) injury risk are not well understood. To address this issue, the residual reduction algorithm (RRA) in OpenSim was used to create nine subject-specific, full-body (37 degrees of freedom) torque-driven simulations of athletic males performing unplanned sidestep (UnSS) sport tasks. The RRA was used again to produce an optimized kinematic solution with reduced peak valgus knee torques during the weight acceptance phase of stance. Pre-to-post kinematic optimization, mean peak valgus knee moments were significantly reduced by 44.2 Nm (p=0.045). Nine of a possible 37 upper and lower body kinematic changes in all three planes of motion were consistently used during the RRA to decrease peak valgus knee moments. The generalized kinematic strategy used by all nine simulations to reduce peak valgus knee moments and subsequent ACL injury risk during UnSS was to redirect the whole-body center of mass medially, towards the desired direction of travel.
Why go bipedal? Locomotion and morphology in Australian agamid lizards
Publisher: The Company of Biologists
Date: 07-2008
DOI: 10.1242/JEB.018044
Abstract: Bipedal locomotion by lizards has previously been considered to provide a locomotory advantage. We examined this premise for a group of quadrupedal Australian agamid lizards, which vary in the extent to which they will become bipedal. The percentage of strides that each species ran bipedally, recorded using high speed video cameras, was positively related to body size and the proximity of the body centre of mass to the hip, and negatively related to running endurance. Speed was not higher for bipedal strides, compared with quadrupedal strides, in any of the four species, but acceleration during bipedal strides was significantly higher in three of four species. Furthermore, a distinct threshold between quadrupedal and bipedal strides, was more evident for acceleration than speed, with a threshold in acceleration above which strides became bipedal. We calculated these thresholds using probit analysis, and compared these to the predicted threshold based on the model of Aerts et al. Although there was a general agreement in order, the acceleration thresholds for lizards were often lower than that predicted by the model. We suggest that bipedalism, in Australian agamid lizards, may have evolved as a simple consequence of acceleration, and does not confer any locomotory advantage for increasing speed or endurance. However, both behavioural and threshold data suggest that some lizards actively attempt to run bipedally, implying some unknown advantage to bipedal locomotion.
Electromyography-Assisted Neuromusculoskeletal Models Can Estimate Physiological Muscle Activations and Joint Moments Across the Neck Before Impacts
Publisher: ASME International
Date: 02-11-2021
DOI: 10.1115/1.4052555
Abstract: Knowledge of neck muscle activation strategies before sporting impacts is crucial for investigating mechanisms of severe spinal injuries. However, measurement of muscle activations during impacts is experimentally challenging and computational estimations are not often guided by experimental measurements. We investigated neck muscle activations before impacts with the use of electromyography (EMG)-assisted neuromusculoskeletal models. Kinematics and EMG recordings from four major neck muscles of a rugby player were experimentally measured during rugby activities. A subject-specific musculoskeletal model was created with muscle parameters informed from MRI measurements. The model was used in the calibrated EMG-informed neuromusculoskeletal modeling toolbox and three neural solutions were compared: (i) static optimization (SO), (ii) EMG-assisted (EMGa), and (iii) MRI-informed EMG-assisted (EMGaMRI). EMGaMRI and EMGa significantly (p & 0.01) outperformed SO when tracking cervical spine net joint moments from inverse dynamics in flexion/extension (RMSE = 0.95, 1.14, and 2.32 N·m) but not in lateral bending (RMSE = 1.07, 2.07, and 0.84 N·m). EMG-assisted solutions generated physiological muscle activation patterns and maintained experimental cocontractions significantly (p & 0.01) outperforming SO, which was characterized by saturation and nonphysiological “on-off” patterns. This study showed for the first time that physiological neck muscle activations and cervical spine net joint moments can be estimated without assumed a priori objective criteria before impacts. Future studies could use this technique to provide detailed initial loading conditions for theoretical simulations of neck injury during impacts.
Effects of Pubertal Maturation on ACL Forces During a Landing Task in Females
Publisher: SAGE Publications
Date: 08-09-2021
DOI: 10.1177/03635465211038332
Abstract: Rates of anterior cruciate ligament (ACL) rupture in young people have increased by % over the past two decades. Adolescent and young adult females are at higher risk of ACL injury as compared with their prepubertal counterparts. To determine ACL loading during a standardized drop-land-lateral jump in females at different stages of pubertal maturation. Controlled laboratory study. On the basis of the Tanner classification system, 19 pre-, 19 early-/mid-, and 24 late- ostpubertal females performed a standardized drop-land-lateral jump while 3-dimensional body motion, ground-reaction forces, and surface electromyography data were acquired. These data were used to model external biomechanics, lower limb muscle forces, and knee contact forces, which were subsequently used in a validated computational model to estimate ACL loading. Statistical parametric mapping analysis of variance was used to compare ACL force and its causal contributors among the 3 pubertal maturation groups during stance phase of the task. When compared with pre- and early-/midpubertal females, late- ostpubertal females had significantly higher ACL force with mean differences of 471 and 356 N during the first 30% and 48% to 85% of stance, and 343 and 274 N during the first 24% and 59% to 81% of stance, respectively, which overlapped peaks in ACL force. At the point of peak ACL force, contributions from sagittal and transverse plane loading mechanisms to ACL force were higher in late- ostpubertal compared with pre- and early-/midpubertal groups (medium effect sizes from 0.44 to 0.77). No differences were found between pre- and early-/midpubertal groups in ACL force or its contributors. The highest ACL forces were observed in late- ostpubertal females, consistent with recently reported rises of ACL injury rates in females aged 15 to 19 years. It is important to quantify ACL force and its contributors during dynamic tasks to advance our understanding of the loading mechanism and thereby provide guidance to injury prevention. Growth of ACL volume plateaus around 10 years of age, before pubertal maturation, meaning that a late- ostpubertal female could have an ACL of similar size to their less mature counterparts. However, late- ostpubertal females have higher body mass requiring higher muscle forces to accelerate the body during dynamic tasks, which may increase ACL loading. Thus, if greater forces develop in these females, in part because of their increased body mass, these higher forces will be applied to an ACL that is not proportionally larger. This may partially explain the higher rates of ACL injury in late- ostpubertal females.
Rotational Malalignment of the Knee Extensor Mechanism
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2019
Abstract: Osseous rotational malalignment of the lower limb is widely accepted as a factor contributing to patellofemoral instability, particularly in pediatric patients. Patellar instability occurs when the lateral force vector generated by the quadriceps exceeds the restraints provided by osseous and soft-tissue anatomy. The anatomy and activation of the quadriceps are responsible for the force applied across the patellofemoral joint, which has previously been measured using the quadriceps (Q)-angle. To our knowledge, the contribution of the quadriceps anatomy in generating a force vector in the axial plane has not previously been assessed. The primary aim of this study was to introduce the quadriceps torsion angle, a measure of quadriceps rotational alignment in the juvenile population. The secondary aims of this study were to determine the inter-assessor and intra-assessor reliability of the quadriceps torsion angle in the juvenile population and to investigate whether a large quadriceps torsion angle is a classifier of patellar dislocator group membership in a mixed cohort of patellar dislocators and typically developing controls. Participants between the ages of 8 and 19 years were recruited as either controls or recurrent patellar dislocators. A total of 58 knees in both groups were assessed from magnetic resonance imaging scans of the entire lower limbs. Axial cuts midway between the superior aspect of the femoral head and the articular surface of the medial femoral condyle were used to calculate the proximal reference for the quadriceps torsion angle. The quadriceps torsion angle was defined as the angle between the line connecting the anterior aspect of the sartorius and the junction of the anterior and posterior compartments at the lateral intermuscular septum and the posterior condylar axis line. Inter-assessor reliability was calculated using the intraclass correlation coefficient. The relationship between the quadriceps torsion angle and the femoral torsion was assessed in the entire cohort. These values were compared between the control group and the dislocator group to determine if the raw values or an interplay between the 2 factors played a role in the pathoanatomy of recurrent patellofemoral dislocation. The quadriceps torsion angle was a reproducible assessment in both inter-assessor and intra-assessor reliability analyses. A moderate positive correlation (r = 0.624 p 0.01) was found between the femoral torsion and the quadriceps torsion angle. Although the quadriceps torsion angle was a fair classifier of patellar dislocation group membership, femoral torsion was not. This study has quantified the rotational alignment of the extensor mechanism using the quadriceps torsion angle. The measurement is shown to be reliable and reproducible and a fair classifier of patellofemoral instability. This article introduces an objective measure of soft-tissue rotational malalignment in the pathogenesis of recurrent patellar dislocation.
Cartilage morphology at 2–3 years following anterior cruciate ligament reconstruction with or without concomitant meniscal pathology
Publisher: Springer Science and Business Media LLC
Date: 27-10-2017
DOI: 10.1007/S00167-015-3831-1
Abstract: To examine differences in cartilage morphology between young adults 2-3 years post-anterior cruciate ligament reconstruction (ACLR), with or without meniscal pathology, and control participants. Knee MRI was performed on 130 participants aged 18-40 years (62 with isolated ACLR, 38 with combined ACLR and meniscal pathology, and 30 healthy controls). Cartilage defects, cartilage volume and bone marrow lesions (BMLs) were assessed from MRI using validated methods. Cartilage defects were more prevalent in the isolated ACLR (69 %) and combined group (84 %) than in controls (10 %, P < 0.001). Furthermore, the combined group showed higher prevalence of cartilage defects on medial femoral condyle (OR 4.7, 95 % CI 1.3-16.6) and patella (OR 7.8, 95 % CI 1.5-40.7) than the isolated ACLR group. Cartilage volume was lower in both ACLR groups compared with controls (medial tibia, lateral tibia and patella, P < 0.05), whilst prevalence of BMLs was higher on lateral tibia (P < 0.001), with no significant differences between the two ACLR groups for either measure. Cartilage morphology was worse in ACLR patients compared with healthy controls. ACLR patients with associated meniscal pathology have a higher prevalence of cartilage defects than ACLR patients without meniscal pathology. The findings suggest that concomitant meniscal pathology may lead to a greater risk of future OA than isolated ACLR. III.
Can technique modification training reduce knee moments in a landing task?
Publisher: Human Kinetics
Date: 04-2014
Abstract: Anterior cruciate ligament (ACL) injuries are costly. Sidestep technique training reduces knee moments that load the ACL. This study examined whether landing technique training alters knee moments. Nineteen team sport athletes completed the study. Motion analysis and ground reaction forces were recorded before and after 6 weeks of technique modification. An inverse dynamic model was used to calculate three-dimensional knee loading. Pre- and postintervention scores were compared using paired t tests. Maximal knee flexion angle during landing was increased following training. There was no change in valgus or flexion moments, but an increase in peak internal rotation moment. This increase in internal rotation moment may increase the risk of ACL injury. However, the increased angle at which the peak internal rotation moment occurred at follow up may mitigate any increase in injury risk by reducing load transmission.
Erratum: Corrigendum to “Moderate to vigorous physical activity is associated with greater patellar cartilage volume over 2 years following anterior cruciate ligament reconstruction” (Osteoarthritis and Cartilage (2016) 24(S1) (S195–S196) (S1063458416004040) (10.1016/j.joca.2016.01.385))
Publisher: Elsevier BV
Date: 09-2016
Development and validation of subject-specific pediatric multibody knee kinematic models with ligamentous constraints
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.JBIOMECH.2019.07.001
Abstract: Computational knee models that replicate the joint motion are important tools to discern difficult-to-measure functional joint biomechanics. Numerous knee kinematic models of different complexity, with either generic or subject-specific anatomy, have been presented and used to predict three-dimensional tibiofemoral (TFJ) and patellofemoral (PFJ) joint kinematics of cadavers or healthy adults, but not pediatric populations. The aims of this study were: (i) to develop subject-specific TFJ and PFJ kinematic models, with TFJ models having either rigid or extensible ligament constraints, for eight healthy pediatric participants and (ii) to validate the estimated joint and ligament kinematics against in vivo kinematics measured from magnetic resonance imaging (MRI) at four TFJ flexion angles. Three different TFJ models were created from MRIs and used to solve the TFJ kinematics: (i) 5-rigid-link parallel mechanism with rigid surface contact and isometric anterior cruciate (ACL), posterior cruciate (PCL) and medial collateral (MCL) ligaments (ΔL
Prolonged running increases knee moments in sidestepping and cutting manoeuvres in sport
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.JSAMS.2017.07.007
Abstract: To investigate how knee kinematics, kinetics and loading changes during sidestepping tasks following a prolonged running protocol performed in a laboratory setting. All participants performed sidestepping, and crossover cutting tasks in a randomised order before and after a 60min running protocol on a non-motorised treadmill that simulated an AF game. Eight healthy male participants who partook in semi-professional and amateur Australian Football undertook a series of straight line runs, sidestepping (SS), and crossover cutting (XO) tasks before and after a simulated game of Australian football. Kinematic data were analysed at initial foot contact of the SS and XO manoeuvres and kinetic data were analysed during the weight acceptance phase of the stance. The knee was significantly more flexed at foot contact following fatigue compared to pre-fatigue states. Fatigue was also a factor contributing to significant increases in internal knee extension moments. Significant differences were also observed between SS and XO trials with flexion/extension moments, with notable differences in varus/valgus and internal/external rotation moments. Acute angles of knee flexion at foot strike in a fatigued state may place the joint at an increased risk of injury. Increases in knee extension moments in the fatigued state suggests the knee joint must withstand significantly high stresses once fatigued.
Different visual stimuli affect muscle activation at the knee during sidestepping
Publisher: Informa UK Limited
Date: 19-11-2019
DOI: 10.1080/02640414.2018.1545276
Abstract: Increasing knee stability via appropriate muscle activation could reduce anterior cruciate ligament (ACL) injury risk during unplanned sidestepping. High-level athletes may activate their knee muscles differently from low-level athletes when responding to quasi-game realistic versus non game-realistic stimuli. Eleven high-level and 10 low-level soccer players responded to a non game-realistic arrow-planned condition (AP), a quasi game-realistic one-defender scenario (1DS) and two-defender scenario (2DS), and an arrow-unplanned condition (AUNP), that imposed increasing time constraints to sidestep. Activation from eight knee muscles during sidestepping was measured during pre-contact and weight-acceptance. Knee flexor-extensor co-activation ratios were established. Muscle activation levels increased by approximately 27% solely in the 1DS in both sidestepping phases. In the 2DS, the shift from a flexor dominant co-activation strategy in pre-contact toward extensor dominance in weight-acceptance commenced earlier for the high-level players. Quasi game-realistic information allowed for anticipatory increases in knee muscle activation regardless of expertise levels but only when the time demands to respond were low (1DS). High-level players were better at interpreting complex game-realistic information (2DS) to activate their knee extensors earlier in preparation for single-leg landing during weight-acceptance.
Set cover algorithms for very large datasets
Publisher: ACM
Date: 26-10-2010
Individual muscle contributions to the swing phase of gait: An EMG-based forward dynamics modelling approach
Publisher: Elsevier BV
Date: 10-2007
Influence of altered geometry and material properties on tissue stress distribution under load in tendinopathic Achilles tendons – A subject-specific finite element analysis
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JBIOMECH.2018.10.027
Abstract: Achilles tendon material properties and geometry are altered in Achilles tendinopathy. The purpose of this study was to determine the relative contributions of altered material properties and geometry to free Achilles tendon stress distribution during a sub-maximal contraction in tendinopathic relative to healthy tendons. Tendinopathic (n = 8) and healthy tendons (n = 8) were imaged at rest and during a sub-maximal voluntary isometric contraction using three-dimensional freehand ultrasound. Images were manually segmented and used to create subject-specific finite element models. The resting cross-sectional area of the free tendon was on average 31% greater for the tendinopathic compared to healthy tendons. Material properties for each tendon were determined using a numerical parameter optimisation approach that minimised the difference in experimentally measured longitudinal strain and the strain predicted by the finite element model under submaximal loading conditions for each tendon. The mean Young's modulus for tendinopathic tendons was 53% lower than the corresponding control value. Finite element analyses revealed that tendinopathic tendons experience 24% less stress under the same submaximal external loading conditions compared to healthy tendons. The lower tendon stress in tendinopathy was due to a greater influence of tendon cross-sectional area, which alone reduced tendon stress by 30%, compared to a lower Young's modulus, which alone increased tendon stress by 8%. These findings suggest that the greater tendon cross-sectional area observed in tendinopathy compensates for the substantially lower Young's modulus, thereby protecting pathological tendon against excessive stress.
Ground hardness and injury in community level Australian football
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.JSAMS.2011.12.003
Abstract: To describe the risk and details of injuries associated with ground hardness in community level Australian football (AF). Prospective injury surveillance with periodic objective ground hardness measurement. 112 ground hardness assessments were undertaken using a Clegg hammer at nine locations across 20 grounds, over the 2007 and 2008 AF seasons. Details of 352 injuries sustained by community level players on those grounds were prospectively collected as part of a large randomised controlled trial. The ground location of the injury was matched to the nearest corresponding ground hardness Clegg hammer readings, in gravities (g), which were classified from unacceptably low ( 120 g). Clegg hammer readings ranged from 25 to 301 g. Clegg hammer hardness categories from low/normal to high/normal were associated with the majority of injuries, with only 3.7% (13 injuries) on unacceptably high hardness and 0.3% (1 injury) on the unacceptably low hardness locations. Relative to the preferred range of hardness, the risk of sustaining an injury on low/normal hardness locations was 1.31 (95%CI: 1.06-1.62) times higher and 1.82 (95%CI: 1.17-2.85) times higher on locations with unacceptably high hardness. The more severe injuries occurred with low/normal ground hardness. Despite the low number of injuries, the risk of sustaining an injury on low/normal and unacceptably hard grounds was significantly greater than on the preferred range of hardness. Notably, the severity of the injuries sustained on unacceptably hard grounds was lower than for other categories of hardness.
Gait analysis in chronic heart failure: The calf as a locus of impaired walking capacity
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.JBIOMECH.2014.09.015
Abstract: Reduced walking capacity, a hallmark of chronic heart failure (CHF), is strongly correlated with hospitalization and morbidity. The aim of this work was to perform a detailed biomechanical gait analysis to better identify mechanisms underlying reduced walking capacity in CHF. Inverse dynamic analyses were conducted in CHF patients and age- and exercise level-matched control subjects on an instrumented treadmill at self-selected treadmill walking speeds and at speeds representing +20% and -20% of the subjects' preferred speed. Surprisingly, no difference in preferred speed was observed between groups, possibly explained by an optimization of the mechanical cost of transport in both groups (the mechanical cost to travel a given distance J/kg/m). The majority of limb kinematics and kinetics were also similar between groups, with the exception of greater ankle dorsiflexion angles during stance in CHF. Nevertheless, over two times greater ankle plantarflexion work during stance and per distance traveled is required for a given triceps surae muscle volume in CHF patients. This, together with a greater reliance on the ankle compared to the hip to power walking in CHF patients, especially at faster speeds, may contribute to the earlier onset of fatigue in CHF patients. This observation also helps explain the high correlation between triceps surae muscle volume and exercise capacity that has previously been reported in CHF. Considering the key role played by the plantarflexors in powering walking and their association with exercise capacity, our findings strongly suggest that exercise-based rehabilitation in CHF should not omit the ankle muscle group.
Development of predictive statistical shape models for paediatric lower limb bones
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.CMPB.2022.107002
Abstract: Accurate representation of bone shape is important for subject-specific musculoskeletal models as it may influence modelling of joint kinematics, kinetics, and muscle dynamics. Statistical shape modelling is a method to estimate bone shape from minimal information, such as anatomical landmarks, and to avoid the time and cost associated with reconstructing bone shapes from comprehensive medical imaging. Statistical shape models (SSM) of lower limb bones have been developed and validated for adult populations but are not applicable to paediatric populations. This study aimed to develop SSM for paediatric lower limb bones and evaluate their reconstruction accuracy using sparse anatomical landmarks. We created three-dimensional models of 56 femurs, 29 pelves, 56 tibias, 56 fibulas, and 56 patellae through segmentation of magnetic resonance images taken from 29 typically developing children (15 females 13 ± 3.5 years). The SSM for femur, pelvis, tibia, fibula, patella, haunch (i.e., combined femur and pelvis), and shank (i.e., combined tibia and fibula) were generated from manual segmentation of comprehensive magnetic resonance images to describe the shape variance of the cohort. We implemented a leave-one-out cross-validation method wherein SSM were used to reconstruct novel bones (i.e., those not included in SSM generation) using full- (i.e., full segmentation) and sparse- (i.e., anatomical landmarks) input, and then compared these reconstructions against bones segmented from magnetic resonance imaging. Reconstruction performance was evaluated using root mean squared errors (RMSE, mm), Jaccard index (0-1), Dice similarity coefficient (DSC) (0-1), and Hausdorff distance (mm). All results reported in this abstract are mean ± standard deviation. Femurs, pelves, tibias, fibulas, and patellae reconstructed via SSM using full-input had RMSE between 0.89 ± 0.10 mm (patella) and 1.98 ± 0.38 mm (pelvis), Jaccard indices between 0.77 ± 0.03 (pelvis) and 0.90 ± 0.02 (tibia), DSC between 0.87 ± 0.02 (pelvis) and 0.95 ± 0.01 (tibia), and Hausdorff distances between 2.45 ± 0.57 mm (patella) and 9.01 ± 2.36 mm (pelvis). Reconstruction using sparse-input had RMSE ranging from 1.33 ± 0.61 mm (patella) to 3.60 ± 1.05 mm (pelvis), Jaccard indices ranging from 0.59 ± 0.10 (pelvis) to 0.83 ± 0.03 (tibia), DSC ranging from 0.74 ± 0.08 (pelvis) to 0.90 ± 0.02 (tibia), and Hausdorff distances ranging from 3.21 ± 1.19 mm (patella) to 12.85 ± 3.24 mm (pelvis). The SSM of paediatric lower limb bones showed reconstruction accuracy consistent with previously developed SSM and outperformed adult-based SSM when used to reconstruct paediatric bones.
Primarily hip-borne load carriage does not alter biomechanical risk factors for overuse injuries in soldiers
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.JSAMS.2018.06.013
Abstract: To determine the effects of different body armour types, carried loads, and walking speeds on trunk and lower-limb joint biomechanics. Within-subjects repeated measures to determine the effects of different body armour types, carried loads, and walking speeds on trunk and lower-limb joint biomechanics. Twenty soldiers (29.5±7.1yrs) completed a treadmill walking protocol in an unloaded (baseline) condition and wearing a control, Tiered Body Armour System (TBAS) and five different armour types (cARM1-2, pARM1) with two load configurations (15 and 30kg) for a total of eight armour×load ensembles. In each ensemble, participants walked for 10min at 1.53ms Peak plantarflexion and hip abduction moments were reduced when wearing cARM1 (p=0.040, p=0.045) and cARM2 (p=0.045, p=0.003) compared to TBAS, while carrying 30kg and/or walking fast. This suggests positive benefits of load distribution at higher task demands. Joint moments increased when participants carried greater load and/or walked faster, and the combined effects of carried load and walking speed were mostly additive. Primarily hip-borne load carriage does not negatively alter joint kinetics, and some positive adaptations occurred during tasks with higher demands. These results can inform equipment design and physical training programs for load carriage.
Lower-limb joint work and power are modulated during load carriage based on load configuration and walking speed
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JBIOMECH.2018.11.036
Abstract: Soldiers regularly transport loads weighing >20 kg at slow speeds for long durations. These tasks elicit high energetic costs through increased positive work generated by knee and ankle muscles, which may increase risk of muscular fatigue and decrease combat readiness. This study aimed to determine how modifying where load is borne changes lower-limb joint mechanical work production, and if load magnitude and/or walking speed also affect work production. Twenty Australian soldiers participated, donning a total of 12 body armor variations: six different body armor systems (one standard-issue, two commercially available [cARM1-2], and three prototypes [pARM1-3]), each worn with two different load magnitudes (15 and 30 kg). For each armor variation, participants completed treadmill walking at two speeds (1.51 and 1.83 m/s). Three-dimensional motion capture and force plate data were acquired and used to estimate joint angles and moments from inverse kinematics and dynamics, respectively. Subsequently, hip, knee, and ankle joint work and power were computed and compared between armor types and walking speeds. Positive joint work over the stance phase significantly increased with walking speed and carried load, accompanied by 2.3-2.6% shifts in total positive work production from the ankle to the hip (p < 0.05). Compared to using cARM1 with 15 kg carried load, carrying 30 kg resulted in significantly greater hip contribution to total lower-limb positive work, while knee and ankle work decreased. Substantial increases in hip joint contributions to total lower-limb positive work that occur with increases in walking speed and load magnitude highlight the importance of hip musculature to load carriage walking.
Knee biomechanics during walking gait following matrix-induced autologous chondrocyte implantation
Publisher: Elsevier BV
Date: 12-2010
DOI: 10.1016/J.CLINBIOMECH.2010.07.004
Abstract: Matrix-induced autologous chondrocyte implantation is a technique for repairing articular cartilage defects in the knee. Despite reported improvements in pain, little is known about the recovery of knee biomechanics during walking gait. A randomized controlled study design was used to investigate knee biomechanics during gait in 61 patients following matrix-induced autologous chondrocyte implantation, in conjunction with either 'accelerated' or 'traditional' approaches to post-operative weight-bearing rehabilitation. Gait analysis was performed at 3, 6 and 12 months post-surgery in both patient groups, and two matched, unaffected control groups for comparison. The spatiotemporal and ground reaction force parameters were similar between patient groups and their respective control groups at all time points. When compared with controls, both patient groups demonstrated significantly reduced knee extension moments up until, and including, 12 months. The traditional group demonstrated a significantly reduced knee adduction moment at 3, 6 and 12 months, and a significantly reduced knee flexion moment at 3 months. There were no differences in these knee moments between the accelerated patient group and controls. Overall, a higher level of gait dysfunction was observed in patients who underwent traditional rehabilitation. Future research is needed to investigate the recovery of normal gait following matrix-induced autologous chondrocyte implantation, and its effect on repair tissue development.
Moving away from traditional foci may help us understand sporting performance and injuries
Publisher: Elsevier BV
Date: 08-2006
Mechanisms underpinning longitudinal increases in the knee adduction moment following arthroscopic partial meniscectomy
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.CLINBIOMECH.2014.07.002
Abstract: Knee osteoarthritis is common following arthroscopic partial meniscectomy and a higher external peak knee adduction moment is believed to be a contributor. The peak knee adduction moment has been shown to increase over 2 years (from 3-months post-arthroscopic partial meniscectomy). The aim of this study was to evaluate mechanisms underpinning the increase in peak knee adduction moment over 2 years observed in people 3-months following arthroscopic partial meniscectomy. Sixty-six participants with medial arthroscopic partial meniscectomy were assessed at baseline and again 2 years later. Parameters were evaluated at time of peak knee adduction moment as participants walked barefoot at their self-selected normal and fast pace for both time points. For normal pace walking, an increase in frontal plane ground reaction force-to-knee lever arm accounted for 30% of the increase in peak knee adduction moment (B=0.806 [95% CI 0.501-1.110], P<0.001). For fast pace walking, an increase in the frontal plane ground reaction force magnitude accounted for 21% of the increase in peak knee adduction moment (B=2.343 [95% CI 1.219-3.468], P<0.001) with an increase in tibia varus angle accounting for a further 15% (B=0.310 [95% CI 0.145-0.474], P<0.001). Our data suggest that an increase in lever arm and increase in frontal plane ground reaction force magnitude are contributors to the increased knee adduction moment observed over time in people following arthroscopic partial meniscectomy.
Estimation of Muscle Forces and Joint Moments Using a Forward-Inverse Dynamics Model
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2005
DOI: 10.1249/01.MSS.0000176684.24008.6F
Abstract: This paper presents a forward dynamic neuromusculoskeletal model that can be used to estimate and predict joint moments and muscle forces. It uses EMG signals as inputs to the model, and joint moments predicted are verified through inverse dynamics. The aim of the model is to estimate or predict muscle forces about a joint, which can be used to estimate the corresponding joint compressive forces, and/or ligament forces in healthy and impaired subjects, based on the way they activate their muscles. The estimation of joint moments requires three steps. In the first step, muscle activation dynamics govern the transformation from the EMG signal to a measure of muscle activation--a time-varying parameter between 0 and 1. In the second step, muscle contraction dynamics characterize how muscle activations are transformed into muscle forces. The final step requires a model of the musculoskeletal geometry to transform muscle forces to joint moments. Each of these steps involves complex, nonlinear relationships. An application is provided to demonstrate how this model can be used to study the forces in the healthy ankle during dynamometer trials and during gait. The model-predicted estimates of joint moment were found to match experimentally determined values closely. Neuromusculoskeletal models that use EMG as inputs can be employed to accurately estimate joint moments. The muscle forces predicted from these models can be used to better understand tissue loading in joints, and to provide in vivo estimates of tensile ligament forces and compressive cartilage loads during dynamic tasks. This tool has great potential for aiding in the study of injury mechanisms in sports.
Muscle activations to stabilize the knee following arthroscopic partial meniscectomy
Publisher: Elsevier BV
Date: 03-2011
DOI: 10.1016/J.CLINBIOMECH.2010.11.003
Abstract: Arthroscopic partial meniscectomy patients are at increased risk of developing knee osteoarthritis. This population, particularly those with weaker quadriceps, have larger-than-normal knee adduction moments, which tend to load the medial tibiofemoral joint. Larger knee adduction moments predict progression of knee osteoarthritis and may contribute to the increased risk in meniscectomy patients. Increased muscle activity to support these large moments may further elevate articular loads. We examined a) the muscle activity while walking in a meniscectomy and control population, and b) the relationship between knee strength and muscle activity. Gait patterns and knee extension strength were assessed in 89 male arthroscopic partial meniscectomy patients and 30 age-matched healthy controls. Surface electromyography was recorded during walking from ten muscles that cross the knee. Compared to controls, the meniscectomy group displayed greater muscle activity while walking, with increased hamstrings activation, yet no difference in directed co-contraction. While controlling for age, no differences were found between meniscectomy subjects with weak and normal knee extension strength, in hamstrings activity, quadriceps activity or directed co-contraction. The generalised increase in non-directed muscle activity in the meniscectomy group may provide enhanced muscular support of larger-than-normal knee adduction moments. Higher levels of antagonist co-contraction may increase muscle forces and, subsequently, joint articular loads, contributing to the increased risk of developing knee osteoarthritis following arthroscopic partial meniscectomy.
Muscle contributions to the acceleration of the whole body centre of mass during recovery from forward loss of balance by stepping in young and older adults
Publisher: Public Library of Science (PLoS)
Date: 25-10-2017
The influence and biomechanical role of cartilage split line pattern on tibiofemoral cartilage stress distribution during the stance phase of gait
Publisher: Springer Science and Business Media LLC
Date: 10-04-2015
DOI: 10.1007/S10237-015-0668-Y
Abstract: This study presents an evaluation of the role that cartilage fibre 'split line' orientation plays in informing femoral cartilage stress patterns. A two-stage model is presented consisting of a whole knee joint coupled to a tissue-level cartilage model for computational efficiency. The whole joint model may be easily customised to any MRI or CT geometry using free-form deformation. Three 'split line' patterns (medial-lateral, anterior-posterior and random) were implemented in a finite element model with constitutive properties referring to this 'split line' orientation as a finite element fibre field. The medial-lateral orientation was similar to anatomy and was derived from imaging studies. Model predictions showed that 'split lines' are formed along the line of maximum principal strains and may have a biomechanical role of protecting the cartilage by limiting the cartilage deformation to the area of higher cartilage thickness.
Sensori-motor function, gait patterns and falls in community-dwelling women
Publisher: Oxford University Press (OUP)
Date: 1996
Abstract: Tests of vision, vestibular function, peripheral sensation, strength, reaction time, balance and gait were administered to 183 community-dwelling women aged 22-99 years. Walking speed, stride length and cadence declined with age with corresponding increases in stance duration and percentage of the stride in the stance phase. Visual acuity and contrast sensitivity, tactile and vibration sense in the lower limb, vestibular function (as assessed by the vestibular X Writing Test), quadriceps and ankle dorsiflexion strength and reaction time were significantly associated with all five gait parameters. Postural sway measures were associated with walking speed, stride length and percentage of the stride in the stance phase. Multiple regression analyses revealed seven sensori-motor measures as significant predictors for one or more of the gait parameters: low contrast visual acuity, tactile sensitivity, vibration sense, vestibular X-test writing performance, quadriceps strength, reaction time and sway. Quadriceps strength was included as a predictor variable for every gait parameter and in each case had the strongest beta weight. Women who fell on two or more occasions in a one-year prospective period had significantly reduced and more variable cadence and significantly increased stance duration (measured in absolute terms and as a percentage of stride) than those who did not fall or fell on one occasion only. The study findings elucidate the relative importance of specific physiological systems in the maintenance of normal gait and identify temporal gait measures that are associated with falling in older people.
The deep hip muscles are unlikely to contribute to hip stability in the sagittal plane during walking: a stiffness approach
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2022
Effects of different visual stimuli on postures and knee moments during sidestepping
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2013
Finding the sweet spot via personalised Achilles tendon training: the future is within reach
Publisher: BMJ
Date: 20-07-2019
Mechanisms underpinning the peak knee flexion moment increase over 2-years following arthroscopic partial meniscectomy
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.CLINBIOMECH.2015.09.006
Abstract: Knee osteoarthritis is common in people who have undergone partial meniscectomy, and a higher external knee flexion moment during gait may be a potential contributor. Although the peak external knee flexion moment has been shown to increase from 3 months to 2 years following partial meniscectomy, mechanisms underpinning the increase in the peak knee flexion moment are unknown. Sixty-six participants with partial meniscectomy completed three-dimensional gait (normal and fast pace) and quadriceps strength assessment at baseline (3 months following partial meniscectomy) and again 2 years later. Variables included external knee flexion moment, vertical ground reaction force, knee flexion kinematics, and quadriceps peak torque. For normal pace walking, the main significant predictors of change in peak knee flexion moment were an increase in peak vertical ground reaction force (R(2)=0.55), mostly due to an increase in walking speed, and increase in peak knee flexion angle (R(2)=0.19). For fast pace walking, the main significant predictors of change in peak knee flexion moment were an in increase in peak vertical ground reaction force (R(2)=0.51) and increase in knee flexion angle at initial contact (R(2)=0.17). Change in peak vertical force was mostly due to an increase in walking speed. Findings suggest that increases in vertical ground reaction force and peak knee flexion angle during stance are predominant contributors to the 2-year change in peak knee flexion moment. Future studies are necessary to refine our understanding of joint loading and its determinants following meniscectomy.
Hybrid neuromusculoskeletal modeling to best track joint moments using a balance between muscle excitations derived from electromyograms and optimization
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.JBIOMECH.2014.10.009
Abstract: Current electromyography (EMG)-driven musculoskeletal models are used to estimate joint moments measured from an in idual׳s extremities during dynamic movement with varying levels of accuracy. The main benefit is the underlying musculoskeletal dynamics is simulated as a function of realistic, subject-specific, neural-excitation patterns provided by the EMG data. The main disadvantage is surface EMG cannot provide information on deeply located muscles. Furthermore, EMG data may be affected by cross-talk, recording and post-processing artifacts that could adversely influence the EMG׳s information content. This limits the EMG-driven model׳s ability to calculate the multi-muscle dynamics and the resulting joint moments about multiple degrees of freedom. We present a hybrid neuromusculoskeletal model that combines calibration, subject-specificity, EMG-driven and static optimization methods together. In this, the joint moment tracking errors are minimized by balancing the information content extracted from the experimental EMG data and from that generated by a static optimization method. Using movement data from five healthy male subjects during walking and running we explored the hybrid model׳s best configuration to minimally adjust recorded EMGs and predict missing EMGs while attaining the best tracking of joint moments. Minimally adjusted and predicted excitations substantially improved the experimental joint moment tracking accuracy than current EMG-driven models. The ability of the hybrid model to predict missing muscle EMGs was also examined. The proposed hybrid model enables muscle-driven simulations of human movement while enforcing physiological constraints on muscle excitation patterns. This might have important implications for studying pathological movement for which EMG recordings are limited.
Running biomechanics and lower limb strength associated with prior hamstring injury
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2009
A calibrated EMG-informed neuromusculoskeletal model can appropriately account for muscle co-contraction in the estimation of hip joint contact forces in people with hip osteoarthritis
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JBIOMECH.2018.11.042
Abstract: Abnormal hip joint contact forces (HJCF) are considered a primary mechanical contributor to the progression of hip osteoarthritis (OA). Compared to healthy controls, people with hip OA often present with altered muscle activation patterns and greater muscle co-contraction, both of which can influence HJCF. Neuromusculoskeletal (NMS) modelling is non-invasive approach to estimating HJCF, whereby different neural control solutions can be used to estimate muscle forces. Static optimisation, available within the popular NMS modelling software OpenSim, is a commonly used neural control solution, but may not account for an in idual's unique muscle activation patterns and/or co-contraction that are often evident in pathological population. Alternatively, electromyography (EMG)-assisted neural control solutions, available within CEINMS software, have been shown to account for in idual activation patterns in healthy people. Nonetheless, their application in people with hip OA, with conceivably greater levels of co-contraction, is yet to be explored. The aim of this study was to compare HJCF estimations using static optimisation (in OpenSim) and EMG-assisted (in CEINMS) neural control solutions during walking in people with hip OA. EMG-assisted neural control solution was more consistent with both EMG and joint moment data than static optimisation, and also predicted significantly higher HJCF peaks (p < 0.001). The EMG-assisted neural control solution also accounted for more muscle co-contraction than static optimisation (p = 0.03), which probably contributed to these higher HJCF peaks. Findings suggest that the EMG-assisted neural control solution may estimate more physiologically plausible HJCF than static optimisation in a population with high levels of co-contraction, such as hip OA.
Programmable mechanical stimulation influences tendon homeostasis in a bioreactor system
Publisher: Wiley
Date: 04-02-2013
DOI: 10.1002/BIT.24809
Abstract: Identification of functional programmable mechanical stimulation (PMS) on tendon not only provides the insight of the tendon homeostasis under physical athological condition, but also guides a better engineering strategy for tendon regeneration. The aims of the study are to design a bioreactor system with PMS to mimic the in vivo loading conditions, and to define the impact of different cyclic tensile strain on tendon. Rabbit Achilles tendons were loaded in the bioreactor with/without cyclic tensile loading (0.25 Hz for 8 h/day, 0-9% for 6 days). Tendons without loading lost its structure integrity as evidenced by disorientated collagen fiber, increased type III collagen expression, and increased cell apoptosis. Tendons with 3% of cyclic tensile loading had moderate matrix deterioration and elevated expression levels of MMP-1, 3, and 12, whilst exceeded loading regime of 9% caused massive rupture of collagen bundle. However, 6% of cyclic tensile strain was able to maintain the structural integrity and cellular function. Our data indicated that an optimal PMS is required to maintain the tendon homeostasis and there is only a narrow range of tensile strain that can induce the anabolic action. The clinical impact of this study is that optimized eccentric training program is needed to achieve maximum beneficial effects on chronic tendinopathy management.
Reappraisal of the comparative cost of human locomotion using gait-specific allometric analyses
Publisher: The Company of Biologists
Date: 15-10-2007
DOI: 10.1242/JEB.000992
Abstract: The alleged high net energy cost of running and low net energy cost of walking in humans have played an important role in the interpretation of the evolution of human bipedalism and the biomechanical determinants of the metabolic cost of locomotion. This study re-explores how the net metabolic energy cost of running and walking (J kg–1m–1) in humans compares to that of animals of similar mass using new allometric analyses of previously published data. Firstly, this study shows that the use of the slope of the regression between the rate of energy expenditure and speed to calculate the net energy cost of locomotion overestimates the net cost of human running. Also, the net energy cost of human running is only 17% higher than that predicted based on their mass. This value is not exceptional given that over a quarter of the previously examined mammals and birds have a net energy cost of running that is 17% or more above their allometrically predicted value. Using a new allometric equation for the net energy cost of walking, this study also shows that human walking is 20%less expensive than predicted for their mass. Of the animals used to generate this equation, 25% have a relatively lower net cost of walking compared with their allometrically predicted value. This new walking allometric analysis also indicates that the scaling of the net energy cost of locomotion with body mass is gait dependent. In conclusion, the net costs of running and walking in humans are moderately different from those predicted from allometry and are not remarkable for an animal of its size.
Tibiofemoral joint structural change from 2.5 to 4.5years following ACL reconstruction with and without combined meniscal pathology
Publisher: Springer Science and Business Media LLC
Date: 04-07-2019
Triangular Fuzzy Partitioned Bonferroni Mean Operators and Their Application to Multiple Attribute Decision Making
Publisher: IEEE
Date: 11-2018
Kinematic and electromyography analysis of submaximal differences running on a firm surface compared with soft, dry sand
Publisher: Springer Science and Business Media LLC
Date: 07-04-2005
DOI: 10.1007/S00421-005-1323-6
Abstract: Kinematic and electromyography (EMG) aspects of running on a firm surface and on soft, dry sand were studied to elucidate mechanisms contributing to the higher energy cost (EC) of sand running. Eight well-trained males (mean VO(2max) 64.3+/-8.6 ml.kg(-1).min(-1)) performed barefoot running trials on a firm surface (wooden floor) and on a soft, dry sand surface (track dimensions 8.8 mx60 cm depth 13 cm) at 8 and 11 km.h(-1). Kinematic and EMG data were collected simultaneously using an integrated six-camera 50 Hz VICON motion analysis system, an AMTI force-plate and a 10-channel EMG system. Running at 8 km.h(-1) on sand resulted in a greater (P<0.05) stance time (t(s)) compared with the firm surface. At 11 km.h(-1), sand running resulted in a greater stance-to-stride ratio (P<0.005), a shorter stride length (SL) (P<0.05), and a greater cadence (P<0.001) compared with the firm surface values. Hip and knee flexion at initial foot contact (IFC), mid-support (MS) and flexion maximum were greater (P<0.001) running on sand compared with firm surface values at 8 and 11 km.h(-1). Over duration of stride, Hamstring (semimembranosus and biceps femoris) EMG was greater running on sand compared with the firm surface at 8 (P<0.001) and 11 (P<0.05) km.h(-1). During the stance phase in the 8-km.h(-1) trials, EMG in the Hamstrings (P<0.001), Vastii (Vastus lateralis and Vastus Medialis) (P<0.02), Rectus femoris (Rec Fem) (P<0.01) and Tensor Fascia Latae (Tfl) (P<0.0001) were greater than the firm surface measures. During stance in the 11-km.h(-1) trials, Tfl EMG was greater (P<0.02) running on sand compared with the firm surface. At IFC and MS, Hamstrings' EMG was greater on sand at both running speeds (P<0.001). For the Vastii (P<0.02), Rec Fem (P<0.0001) and Tfl (P<0.0001) muscles, the EMG at MS running on sand at both speeds was greater than the firm surface values. The increased EC of running on sand can be attributed in part to the increased EMG activation associated with greater hip and knee range of motion compared with firm surface running.
Estimation of musculotendon parameters for scaled and subject specific musculoskeletal models using an optimization technique
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.JBIOMECH.2015.11.006
Abstract: A challenging aspect of subject specific musculoskeletal modeling is the estimation of muscle parameters, especially optimal fiber length and tendon slack length. In this study, the method for scaling musculotendon parameters published by Winby et al. (2008), J. Biomech. 41, 1682-1688, has been reformulated, generalized and applied to two cases of practical interest: 1) the adjustment of muscle parameters in the entire lower limb following linear scaling of a generic model and 2) their estimation "from scratch" in a subject specific model of the hip joint created from medical images. In the first case, the procedure maintained the muscles׳ operating range between models with mean errors below 2.3% of the reference model normalized fiber length value. In the second case, a subject specific model of the hip joint was created using segmented bone geometries and muscle volumes publicly available for a cadaveric specimen from the Living Human Digital Library (LHDL). Estimated optimal fiber lengths were found to be consistent with those of a previously published dataset for all 27 considered muscle bundles except gracilis. However, computed tendon slack lengths differed from tendon lengths measured in the LHDL cadaver, suggesting that tendon slack length should be determined via optimization in subject-specific applications. Overall, the presented methodology could adjust the parameters of a scaled model and enabled the estimation of muscle parameters in newly created subject specific models. All data used in the analyses are of public domain and a tool implementing the algorithm is available at ome/opt_muscle_par.
A longitudinal study of strength and gait after arthroscopic partial meniscectomy
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2013
Safety and Effectiveness of a Nurse-Led Outreach Program for Assessment and Treatment of Chronic Hepatitis C in the Custodial Setting
Publisher: Oxford University Press (OUP)
Date: 29-01-2013
DOI: 10.1093/CID/CIS1202
Abstract: The global burden of disease attributable to chronic hepatitis C virus (HCV) is very large, yet the uptake of curative antiviral therapies remains very low, reflecting the marginalized patient population and the arduous nature of current treatments. The safety and effectiveness of a nurse-led model of care of inmates with chronic HCV was evaluated in 3 Australian correctional centers. The model featured protocol-driven assessment, triage, and management of antiviral therapy by specifically trained nurses, with specialist physician support utilizing telemedicine. Outcomes were evaluated qualitatively with key informant interviews, and quantitatively with patient numbers completing key clinical milestones and adverse events. A total of 391 patients with chronic HCV infection were enrolled, of whom 141 (36%) completed the clinical and laboratory evaluations for eligibility for antiviral therapy over 24 months. Treatment was initiated in 108 patients (28%), including 85 (79%) triaged for specialist review conducted by telemedicine only. The demographic and clinical characteristics of the patients who entered the model and completed workup and those who initiated treatment featured a high prevalence of in iduals of indigenous background, injection drug users, and those with psychiatric disorder. Serious adverse events occurred in 13 of 108 treated patients (12%) with discontinuation in 8 (7%). The sustained virologic response rate among those with complete follow-up data (n=68) was 69%, and by intention-to treat analysis was 44%. This nurse-led and specialist-supported assessment and treatment model for inmates with chronic HCV offers potential to substantively increase treatment uptake and reduce the burden of disease.
A longitudinal study of impact and early stance loads during gait following arthroscopic partial meniscectomy
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.JBIOMECH.2014.07.029
Abstract: People following arthroscopic partial medial meniscectomy (APM) are at increased risk of developing knee osteoarthritis. High impact loading and peak loading early in the stance phase of gait may play a role in the pathogenesis of knee osteoarthritis. This was a secondary analysis of longitudinal data to investigate loading-related indices at baseline in an APM group (3 months post-surgery) and a healthy control group, and again 2 years later (follow-up). At baseline, 82 participants with medial APM and 38 healthy controls were assessed, with 66 and 23 re-assessed at follow-up, respectively. Outcome measures included: (i) heel strike transient (HST) presence and magnitude, (ii) maximum loading rate, (iii) peak vertical force (Fz) during early stance. At baseline, maximum loading rate was lower in the operated leg (APM) and non-operated leg (non-APM leg) compared to controls (p ≤ 0.03) and peak Fz was lower in the APM leg compared to non-APM leg (p ≤ 0.01). Over 2 years, peak Fz increased in the APM leg compared to the non-APM leg and controls (p ≤ 0.01). Following recent APM, people may adapt their gait to protect the operated knee from excessive loads, as evidenced by a lower maximum loading rate in the APM leg compared to controls, and a reduced peak Fz in the APM leg compared to the non-APM leg. No differences at follow-up may suggest an eventual return to more typical gait. However, the increase in peak Fz in the APM leg may be of concern for long-term joint health given the compromised function of the meniscus.
Activation of the deep hip muscles can change the direction of loading at the hip
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.JBIOMECH.2022.111019
Abstract: A better understanding of deep hip muscle function is needed to establish whether retraining and strengthening these muscles is a worthwhile target for rehabilitation. This study aimed to determine the contribution of the deep hip muscles to the direction of hip loading in the acetabulum. Hip contact forces were calculated during walking and squatting for 12 participants (age: 24 ± 4 yrs, 4 females) using electromyography-informed neuromusculoskeletal modelling. Models were configured with different deep hip muscle activation levels: deep hip muscles (piriformis, obturator internus and externus, gemellus superior and inferior, and quadratus femoris) informed by intramuscular electromyography measurements (i.e., normal activation assisted activation) and simulated with zero (no activation) or maximal (maximal activation) activation. The angle between the hip contact force and the vector from the femoral head to the acetabular center (hip contact force angle) was calculated for all configurations, where lower angles equated to hip loading directed towards the acetabular center. The position and spread of acetabular loading during both tasks were calculated for all configurations and compared using a within-participant analysis of variance via statistical parametric mapping (P < 0.05). Maximal activation resulted in lower hip contact force angles and more anterior-inferior oriented, albeit a slightly reduced, spread of acetabular loading compared to assisted activation and no activation. Results suggest that, if activated maximally, the deep hip muscles can change the direction of hip loading away from commonly damaged areas of acetabular cartilage. Targeted training of these muscles may be relevant for in iduals with hip pathology who present with unfavorable regional loading and/or cartilage lesions.
Preventing Australian football injuries with a targeted neuromuscular control exercise programme: Comparative injury rates from a training intervention delivered in a clustered randomised controlled trial
Publisher: BMJ
Date: 23-09-2015
Estimation of musculotendon kinematics in large musculoskeletal models using multidimensional B-splines
Publisher: Elsevier BV
Date: 02-2012
Different Visual Stimuli Affect Body Reorientation Strategies During Sidestepping
Publisher: Wiley
Date: 03-2016
DOI: 10.1111/SMS.12668
Abstract: Sidestepping in response to unplanned stimuli is a high-risk maneuver for anterior cruciate ligament (ACL) injuries. Yet, differences in body reorientation strategies between high- and low-level soccer players prior to sidestepping in response to quasi-game-realistic vs non-game-realistic stimuli, remain unknown. Fifteen high-level (semi-professional) and 15 low-level (amateur) soccer players responded to a quasi-game-realistic one-defender scenario (1DS) and two-defender scenario (2DS), and non-game-realistic arrow-planned condition (AP) and arrow-unplanned condition (AUNP). The AP, 1DS, 2DS to AUNP represented increasing time constraints to sidestep. Selected biomechanics from the penultimate step to foot-off were assessed using a mixed-model (stimuli × skill) ANOVA (P < 0.05). Step length decreased in the defender scenarios compared with the arrow conditions. Support foot placement increased laterally, away from mid-pelvis, with increasing temporal constraints. Greater trunk lateral flexion in the 1DS, 2DS, and AUNP has been associated with ACL injury onsets. Higher level players pushed off closer to their pelvic midline at initial foot contact in the 2DS especially. Higher level perception of game-realistic visual information could have contributed to this safer neuromuscular strategy that, when understood better, could potentially be trained in lower level players to reduce ACL injury risk associated with dangerous sidestepping postures.
The off-break and doosra: Kinematic variations of elite and sub-elite bowlers in creating ball spin in cricket bowling
Publisher: Informa UK Limited
Date: 09-2009
DOI: 10.1080/14763140903229476
Abstract: This study sought to identify kinematic differences in finger-spin bowling actions required to generate variations in ball speed and spin between different playing groups. A 12-camera Vicon system recorded the off-spin bowling actions of six elite and 13 high-performance spin bowlers, and the "doosra" actions of four elite and two high-performance players. Forearm abduction and fixed elbow flexion in the bowling arm were higher for the elite players compared with the high-performance players. The elite bowlers when compared with the high-performance players delivered the off-break at a statistically significant higher velocity (75.1 and 67.1 km/hr respectively) and with a higher level of spin (26.7 and 22.2 rev/s respectively). Large effect sizes were seen between ball rotation, pelvic and shoulder alignment rotations in the transverse plane. Elbow extension was larger for elite bowlers over the period upper arm horizontal to ball release. Compared to the off-break, larger ranges of shoulder horizontal rotation, elbow and wrist extension were evident for the "doosra". Furthermore, the "doosra" was bowled with a significantly longer stride length and lower ball release height. Although not significantly different, moderate to high effect size differences were recorded for pelvis rotation, elbow extension and elbow rotation ranges of motion.
Surgical applications of intracorporal tissue adhesive agents: current evidence and future development
Publisher: Informa UK Limited
Date: 07-04-2020
Multidimensional ground reaction forces and moments from wearable sensor accelerations via deep learning
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Subject-Specificity via 3D Ultrasound and Personalized Musculoskeletal Modeling
Publisher: Springer International Publishing
Date: 13-10-2017
CEINMS: A toolbox to investigate the influence of different neural control solutions on the prediction of muscle excitation and joint moments during dynamic motor tasks
Publisher: Elsevier BV
Date: 11-2015
Biofeedback for Gait Retraining Based on Real-Time Estimation of Tibiofemoral Joint Contact Forces
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2017
Adaptations for economical bipedal running: The effect of limb structure on three-dimensional joint mechanics
Publisher: The Royal Society
Date: 28-10-2011
Abstract: The purpose of this study was to examine the mechanical adaptations linked to economical locomotion in cursorial bipeds. We addressed this question by comparing mass-matched humans and avian bipeds (ostriches), which exhibit marked differences in limb structure and running economy. We hypothesized that the nearly 50 per cent lower energy cost of running in ostriches is a result of: (i) lower limb-swing mechanical power, (ii) greater stance-phase storage and release of elastic energy, and (iii) lower total muscle power output. To test these hypotheses, we used three-dimensional joint mechanical measurements and a simple model to estimate the elastic and muscle contributions to joint work and power. Contradictory to our first hypothesis, we found that ostriches and humans generate the same amounts of mechanical power to swing the limbs at a similar self-selected running speed, indicating that limb swing probably does not contribute to the difference in energy cost of running between these species. In contrast, we estimated that ostriches generate 120 per cent more stance-phase mechanical joint power via release of elastic energy compared with humans. This elastic mechanical power occurs nearly exclusively at the tarsometatarso-phalangeal joint, demonstrating a shift of mechanical power generation to distal joints compared with humans. We also estimated that positive muscle fibre power is 35 per cent lower in ostriches compared with humans, and is accounted for primarily by higher capacity for storage and release of elastic energy. Furthermore, our analysis revealed much larger frontal and internal/external rotation joint loads during ostrich running than in humans. Together, these findings support the hypothesis that a primary limb structure specialization linked to economical running in cursorial species is an elevated storage and release of elastic energy in tendon. In the ostrich, energy-saving specializations may also include passive frontal and internal/external rotation load-bearing mechanisms.
Muscle activation at the human knee during isometric flexion-extension and varus-valgus loads
Publisher: Wiley
Date: 1997
Abstract: We examined the role of muscles in counteracting static loads in the transverse plane at the knee to determine if (a) knee muscles are activated to counteract isometric varus or valgus loads, (b) muscle activity during varus and valgus loads changes with the angle of knee flexion, and (c) the direction of a muscle's activation can be predicted by its moment arm orientations. For seven subjects, muscle activity was recorded during isometric tasks using surface and intramuscular electrodes from 10 muscles that span the knee. A six-degree-of-freedom load cell was rigidly attached to each subject's lower leg just above the ankle, and the subjects were instructed to push against the load cell so as to produce moments in the flexion-extension-varus-valgus plane at the knee. Moments in this plane were all of equal magnitude and varied in direction the full 360 degrees in 20 degrees increments. Most muscles were not activated to stabilize the knee against varus-valgus loads, but the sartorius, gracilis, and tensor fasciae latae showed substantial electromyographic activation in these directions. The load directions where muscles were principally active were observed to be dependent on joint angle for some muscles. In particular, the principal directions of activation for these three muscles changed as the angle of knee flexion changed. Similarly, a muscle's moment arm orientation was a good predictor of direction of activation for some muscles and a poor one for others. These results suggest that different muscles may play different roles in providing joint stability and that these roles are complex functions of muscle moment arm orientations, joint angles, external load directions, and possibly other undetermined parameters.
Injuries in community-level Australian football: Results from a club-based injury surveillance system
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.JSAMS.2014.11.390
Abstract: Far fewer injury surveillance systems exist within community sport than elite sport. As a result, most epidemiological data on sports injuries have limited relevance to community-level sporting populations. There is potential for data from community club-based injury surveillance systems to provide a better understanding of community sports injuries. This study aimed to describe the incidence and profile of community-level Australian football injuries reported using a club-based injury surveillance system. Prospective, epidemiological study. Sports trainers from five community-level Australian football leagues recorded injury data during two football seasons using the club-based system. An online surveillance tool developed by Sports Medicine Australia ('Sports Injury Tracker') was used for data collection. The injury incidence, profile and match injury rate were reported. Injury data for 1205 players were recorded in season one and for 823 players in season two. There was significant variability in injury incidence across clubs. However, aggregated data were consistent across football seasons, with an average of 0.7 injuries per player per season and 38-39 match injuries per 1000 h match exposure. A large proportion of injuries occurred during matches, involved the lower limb and resulted from contact. Data from the club-based system provided a profile of injuries consistent with previous studies in community-level Australian football. Moreover, injury incidence was consistent with other studies using similar personnel to record data. However, injury incidence was lower than that reported in studies using player self-report or healthcare professionals and may be an underestimate of true values.
Towards Tailored Rehabilitation by Implementation of a Novel Musculoskeletal Finite Element Analysis Pipeline
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Biomechanical and neuromuscular considerations in the maintenance of an active lifestyle
Publisher: Elsevier
Date: 2003
Magnetic Resonance Imaging and Freehand 3-D Ultrasound Provide Similar Estimates of Free Achilles Tendon Shape and 3-D Geometry
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.ULTRASMEDBIO.2019.07.679
Abstract: The purpose of this study was to assess the similarity of free Achilles tendon shape and 3-D geometry between magnetic resonance imaging (MRI) and freehand 3-D ultrasound (3-DUS) imaging methods. Fourteen elite/sub-elite middle-distance runners participated in the study. MRI and 3-DUS scans of the Achilles tendon were acquired on two separate imaging sessions, and all 3-D reconstructions were performed using identical methods. Shape similarity of free Achilles tendon reconstructed from MRI and 3-DUS data was assessed using Jaccard index, Hausdorff distance and root mean square error (RMSE). The Jaccard index, Hausdorff distance and RMSE values were 0.76 ± 0.05, 2.70 ± 0.70 and 0.61 ± 0.10 mm, respectively. The level of agreement between MRI and 3-DUS for free Achilles tendon volume, length and average cross-sectional area (CSA) was assessed using Bland-Altman analysis. Compared to MRI, freehand 3-DUS overestimated volume, length and average CSA by 30.6 ± 15.8 mm
Corrections to “Neural Data-Driven Musculoskeletal Modeling for Personalized Neurorehabilitation Technologies” [May 16 879-893]
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2016
Strategies of muscular support of varus and valgus isometric loads at the human knee
Publisher: Elsevier BV
Date: 10-2001
DOI: 10.1016/S0021-9290(01)00095-1
Abstract: In this paper we studied how subjects activate their muscles in response to static varus and valgus loads at the knee. The muscles' contributions to the external moments were estimated using an EMG driven biomechanical model of the knee. The in idual muscle activation and loading patterns were examined to identify the strategies that the nervous system uses to support varus and valgus knee moments. It was found that the (1) co-contraction of the hamstrings and quadriceps, and (2) activation of the gracilis and tensor fascia lata increased with the increasing magnitude of the varus and valgus moments. These 2 activation patterns provided positive support of valgus and varus loads at the knee The sartorius appears to be activated to provide positive support of valgus loads at the knee, whereas during varus moments this muscle increases the varus load on the knee, i.e. provides negative support. Generally, the hamstrings and quadriceps co-contraction contributed to most of the muscular support of the varus and valgus moments. In addition, co-contraction supported 11-14% of the external moment in pure varus and pure valgus respectively. It appears that there are activation strategies with the specific purpose to support varus and valgus moments, albeit small, which suggest dual goals of the neuromotor system during the support of varus and valgus moments.
Characteristics of anterior cruciate ligament injuries in Australian football
Publisher: Elsevier BV
Date: 04-2007
DOI: 10.1016/J.JSAMS.2006.05.015
Abstract: Anterior cruciate ligament (ACL) injuries are the most costly injuries in football at both professional and amateur levels (Orchard J, Seward H, McGivern J, Hood S. Intrinsic and extrinsic risk factors for anterior cruciate ligament injury in Australian footballers. Am J Sports Med 2001 :196-200.). In this study video analysis of 34 ACL injuries in Australian football was performed to investigate the causes of these injuries. Factors that may have contributed to the cause of the injury were analysed, rated and reported. The factors analysed were: type of manoeuvre, direction the knee 'gave way', running speed, knee angle, cutting angle and if the player was accelerating or decelerating. The majority of the injuries analysed occurred in non-contact situations (56%). Of these 37% occurred during sidestepping manoeuvres, 32% in landing, 16% land and step, 10% stopping/slowing and 5% crossover cut manoeuvres. Ninety-two percent of the non-contact injuries occurred at extended knee angles of 30 degrees or less, which is also commonly known to place stress on the ACL and reduce the protective role of hamstrings. Over half (54%) of non-contact injuries occurred whilst decelerating. It would be expected that greater speed and angle cut too would increase the frequency of ACL injury. The results could not confirm this with most injuries occurring at running speeds of slow jogging to running and equal number of injuries occurred at cutting to angles of the ranges 15-45 degrees and 45-75 degrees. These results give greater understanding into potential causes or contributors of ACL injury and information to assist in the development of knee injury prevention programs.
Relationships Between Tibiofemoral Contact Forces and Cartilage Morphology at 2 to 3 Years After Single-Bundle Hamstring Anterior Cruciate Ligament Reconstruction and in Healthy Knees
Publisher: SAGE Publications
Date: 08-2017
Abstract: Prevention of knee osteoarthritis (OA) following anterior cruciate ligament (ACL) rupture and reconstruction is vital. Risk of postreconstruction knee OA is markedly increased by concurrent meniscal injury. It is unclear whether reconstruction results in normal relationships between tibiofemoral contact forces and cartilage morphology and whether meniscal injury modulates these relationships. Since patients with isolated reconstructions (ie, without meniscal injury) are at lower risk for knee OA, we predicted that relationships between tibiofemoral contact forces and cartilage morphology would be similar to those of normal, healthy knees 2 to 3 years postreconstruction. In knees with meniscal injuries, these relationships would be similar to those reported in patients with knee OA, reflecting early degenerative changes. Cross-sectional study Level of evidence, 3. Three groups were examined: (1) 62 patients who received single-bundle hamstring reconstruction with an intact, uninjured meniscus (mean age, 29.8 ± 6.4 years mean weight, 74.9 ± 13.3 kg) (2) 38 patients with similar reconstruction with additional meniscal injury (ie, tear, repair) or partial resection (mean age, 30.6 ± 6.6 years mean weight, 83.3 ± 14.3 kg) and (3) 30 ligament-normal, healthy in iduals (mean age, 28.3 ± 5.2 years mean weight, 74.9 ± 14.9 kg) serving as controls. All patients underwent magnetic resonance imaging to measure the medial and lateral tibial articular cartilage morphology (volumes and thicknesses). An electromyography-driven neuromusculoskeletal model determined medial and lateral tibiofemoral contact forces during walking. General linear models were used to assess relationships between tibiofemoral contact forces and cartilage morphology. In control knees, cartilage was thicker compared with that of isolated and meniscal-injured ACL-reconstructed knees, while greater contact forces were related to both greater tibial cartilage volumes (medial: R 2 = 0.43, β = 0.62, P = .000 lateral: R 2 = 0.19, β = 0.46, P = .03) and medial thicknesses ( R 2 = 0.24, β = 0.48, P = .01). In the overall group of ACL-reconstructed knees, greater contact forces were related to greater lateral cartilage volumes ( R 2 = 0.08, β = 0.28, P = .01). In ACL-reconstructed knees with lateral meniscal injury, greater lateral contact forces were related to greater lateral cartilage volumes ( R 2 = 0.41, β = 0.64, P = .001) and thicknesses ( R 2 = 0.20, β = 0.46, P = .04). At 2 to 3 years postsurgery, ACL-reconstructed knees had thinner cartilage compared with healthy knees, and there were no positive relationships between medial contact forces and cartilage morphology. In lateral meniscal-injured reconstructed knees, greater contact forces were related to greater lateral cartilage volumes and thicknesses, although it was unclear whether this was an adaptive response or associated with degeneration. Future clinical studies may seek to establish whether cartilage morphology can be modified through rehabilitation programs targeting contact forces directly in addition to the current rehabilitation foci of restoring passive and dynamic knee range of motion, knee strength, and functional performance.
Kinematics, maximal metabolic rate, sprint and endurance for a slow-moving lizard, the thorny devil (Moloch horridus)
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/ZO04026
Abstract: Metabolic physiology, morphology, activity patterns, performance traits and movement kinematics are thought to have coevolved in lizards. We examined links between these parameters for the thorny devil (Moloch horridus), a morphologically and ecologically specialised agamid lizard (body mass ~30 g). It has a maximum sustainable metabolic rate (VO2max) of 0.99 mL O2 g–1 h–1 while running at a velocity of 0.11�m�sec–1 at 35°C. This VO2 is typical of that for other lizards (except varanids), but its burst speed (1.21�m�sec–1) is slower than for a typical agamid (e.g. Ctenophorus ornatus at 3.59 m sec–1) and its endurance is appreciably higher. The kinematic pattern of hind-limb movement for M. horridus is different to that of a 'typical' similar-sized agamid, Ctenophorus ornatus, which is a fast-moving lizard that shelters in rock crevices. It is also different to the ecologically equivalent Phrynosoma platyrhinos. The slow and erratic ventilation of M. horridus (2.3 breaths min–1) at its maximum sustainable aerobic running speed occurs when it stops running. This might be a consequence of the hypaxial muscles being used for both lung ventilation and locomotion, which might be impairing pulmonary ventilation when running, but might also contribute to its high endurance. M. horridus is metabolically typical of agamids, but its body shape, movement patterns and locomotory performance traits are different, and might have coevolved with its specialisation for eating ants.
Changes in knee joint biomechanics following balance and technique training and a season of Australian football
Publisher: BMJ
Date: 30-04-2012
DOI: 10.1136/BJSPORTS-2011-090829
Abstract: Determine if balance and technique training (BTT) implemented adjunct to normal Australian football (AF) training reduces external knee loading during sidestepping. Additionally, the authors determined if an athlete's knee joint kinematics and kinetics change over a season of AF. Eight amateur-level AF clubs (n=1,001 males) volunteered to participate in either 28 weeks of BTT or a 'sham' training (ST) adjunct to their normal preseason and regular training. A subset of 34 athletes (BTT, n=20 ST, n=14) were recruited for biomechanical testing in weeks 1-7 and 18-25 of the 28-week training intervention. During biomechanical testing, participants completed a series running, preplanned (PpSS) and unplanned sidestepping (UnSS) tasks. A linear mixed model (α=0.05) was used to determine if knee kinematics and peak moments during PpSS and UnSS were influenced by BTT and/or a season of AF. Both training groups significantly (p=0.025) decreased their peak internal-rotation knee moments during PpSS, and significantly (p=0.022) increased their peak valgus knee moments during UnSS following their respective training interventions. BTT was not effective in changing an athlete's knee joint biomechanics during sidestepping when conducted in 'real-world' training environments. Following normal AF training, the players had different changes to their knee joint biomechanics during both preplanned and unplanned sidestepping. When performing an unplanned sidestepping task in the latter half of a playing season, athletes are at an increased risk of ACL injury. The authors therefore recommend both sidestepping tasks are performed during biomechanical testing when assessing the effectiveness of prophylactic training protocols.
Knee joint biomechanics following arthroscopic partial meniscectomy
Publisher: Wiley
Date: 08-2008
DOI: 10.1002/JOR.20610
Abstract: We investigated spatiotemporal data, joint kinematics, and joint kinetics during gait in a group of subjects who had recently undergone arthroscopic partial meniscectomy and compared the results to those of healthy controls. Gait analysis was performed on 105 pain-free meniscectomy patients and 47 controls, walking at a self-selected speed. The meniscectomy population was comparable to controls in spatiotemporal parameters and knee kinematics. However, they had reduced range of motion (ROM) and lower peak moments in the sagittal plane on the operated limb compared to the nonoperated limb. Compared to controls, the meniscectomy patients had significantly larger knee adduction moments over stance, even after accounting for their greater body weight. These differences likely increase articular loads on the medial compartment of the tibiofemoral joint and may contribute to the high risk of knee osteoarthritis following arthroscopic meniscal surgery.
The reach and adoption of a coach-led exercise training programme in community football
Publisher: BMJ
Date: 12-03-2014
Controlled ecological evaluation of an implemented exercise training programme to prevent lower limb injuries in sport: differences in implementation activity.
Publisher: BMJ
Date: 24-04-2018
DOI: 10.1136/INJURYPREV-2017-042579
Abstract: The public health benefits of injury prevention programmes are maximised when programmes are widely adopted and adhered to. Therefore, these programmes require appropriate implementation support. This study evaluated implementation activity outcomes associated with the implementation of FootyFirst, an exercise training injury prevention programme for community Australian football, both with (FootyFirst+S) and without (FootyFirst+NS) implementation support. An evaluation plan based on the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) Sports Setting Matrix was applied in a controlled ecological evaluation of the implementation of FootyFirst. RE-AIM dimension-specific (range: 0–2) and total RE-AIM scores (range: 0–10) were derived by triangulating data from a number of sources (including surveys, interviews, direct observations and notes) describing FootyFirst implementation activities. The mean dimension-specific and total scores were compared for clubs in regions receiving FootyFirst+S and FootyFirst+NS, through analysis of variance. The mean total RE-AIM score forclubs in the FootyFirst+S regions was 2.4 times higher than for clubs in the FootyFirst+NS region (4.73 vs 1.94 95% CI for the difference: 1.64 to 3.74). Similarly, all dimension-specific scores were significantly higher for clubs in the FootyFirst+S regions compared with clubs in the FootyFirst+NS region. In all regions, the dimension-specific scores were highest for reach and adoption, and lowest for implementation. Implementing exercise training injury prevention programmes in community sport is challenging. Delivering programme content supported by a context-specific and evidence-informed implementation plan leads to greater implementation activity, which is an important precursor to injury reductions.
Training affects knee kinematics and kinetics in cutting maneuvers in sport
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2010
Combining in silico and in vitro experiments to characterize the role of fascicle twist in the Achilles tendon
Publisher: Springer Science and Business Media LLC
Date: 14-09-2018
DOI: 10.1038/S41598-018-31587-Z
Abstract: The Achilles tendon (AT), the largest tendon in the human body has a unique structural feature, that is the fascicles in the AT display spiral twist. However, their functional and structural roles are still unclear. We used subject-specific computational models and tissue mechanical experiment to quantitatively characterize the role of fascicle twist in the Achilles tendon. Ten subject-specific finite element (FE) models of the Achilles tendon were developed from ultrasound images. Fascicle twist was implemented in these models using the material coordinate system available in our FE framework. Five different angles (0~60°) were implemented and material property optimization was performed for each of them (total 50 sets) using results from uniaxial stretch experiment. We showed that fascicle twist allows for even distribution of stress across the whole tendon, thus improving tissue strength. The predicted rupture load increased up to 40%. A number of connective tissues display similar fascicle twists in their structure. The resulting non-uniform strain distribution has been hypothesized as a primary factor in tissue degeneration and injuries. Therefore, our technique will be used to design biomechanically informed training and rehabilitation protocols for management of connective tissue injuries and degeneration.
The effects of cracks on the quantification of the cancellous bone fabric tensor in fossil and archaeological specimens: a simulation study
Publisher: Wiley
Date: 29-11-2017
DOI: 10.1111/JOA.12569
Neuromusculoskeletal Modeling-Based Prostheses for Recovery After Spinal Cord Injury
Publisher: Frontiers Media SA
Date: 02-12-2019
Modelling Human Locomotion to Inform Exercise Prescription for Osteoporosis
Publisher: Springer Science and Business Media LLC
Date: 25-04-2020
DOI: 10.1007/S11914-020-00592-5
Abstract: We review the literature on hip fracture mechanics and models of hip strain during exercise to postulate the exercise regimen for best promoting hip strength. The superior neck is a common location for hip fracture and a relevant exercise target for osteoporosis. Current modelling studies showed that fast walking and stair ambulation, but not necessarily running, optimally load the femoral neck and therefore theoretically would mitigate the natural age-related bone decline, being easily integrated into routine daily activity. High intensity jumps and hopping have been shown to promote anabolic response by inducing high strain in the superior anterior neck. Multidirectional exercises may cause beneficial non-habitual strain patterns across the entire femoral neck. Resistance knee flexion and hip extension exercises can induce high strain in the superior neck when performed using maximal resistance loadings in the average population. Exercise can stimulate an anabolic response of the femoral neck either by causing higher than normal bone strain over the entire hip region or by causing bending of the neck and localized strain in the superior cortex. Digital technologies have enabled studying interdependences between anatomy, bone distribution, exercise, strain and metabolism and may soon enable personalized prescription of exercise for optimal hip strength.
Whole body kinematics and knee moments that occur during an overhead catch and landing task in sport
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.CLINBIOMECH.2011.12.001
Abstract: Athletes suffering an anterior cruciate ligament injury tend to exhibit similar body postures that in sidestep cutting are associated with increased knee moments. This relationship, however, has not been investigated in landing. Catching a ball in different overhead positions may affect landing postures and knee joint moments. This study investigated these possible relationships. It was anticipated that some joint postures would be associated increased knee loads during the landing task. Twenty-five healthy male team sports athletes performed four variations of a landing task. Full body kinematics were identified at initial contact. Peak flexion, valgus and internal rotation moments at the knee, measured during early landing, were normalized to mass and height and statistically compared. Intra-participant correlations were performed between all kinematics and each moment. Mean slopes for each correlation were used to identify the existence of relationships between full body kinematics and knee joint moments. Findings Landing after an overhead catch when the ball moved towards a player's support leg resulted in increased peak valgus moments. These increased valgus moments were correlated with increased knee flexion, hip flexion, and torso lean, as well as torso rotation towards the support leg, and foot and knee external rotation. Increased internal rotation moments were correlated with reduced hip abduction and external rotation, increased ankle inversion, knee external rotation and torso lean away from the support leg. Interpretation Learning to land with techniques that do not reflect postures associated with high knee moments may reduce an athlete's risk of non-contact anterior cruciate ligament injury.
Targeted Achilles Tendon Training and Rehabilitation Using Personalized and Real-Time Multiscale Models of the Neuromusculoskeletal System
Publisher: Frontiers Media SA
Date: 12-08-2020
When ‘just doing it’ is not enough: Assessing the fidelity of player performance of an injury prevention exercise program
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.JSAMS.2014.05.001
Abstract: To obtain benefits from sports injury prevention programs, players are instructed to perform the exercises as prescribed. We developed an observational checklist to measure the quality of exercise performance by players participating in FootyFirst, a coach-led, exercise-based, lower-limb injury prevention program in community Australian Football (AF). Observational. The essential performance criteria for each FootyFirst exercise were described in terms of the technique, volume and intensity required to perform each exercise. An observational checklist was developed to evaluate each criterion through direct visual observation of players at training. The checklist was trialled by two independent raters who observed the same 70 players completing the exercises at eight clubs. Agreement between observers was assessed by Kappa-statistics. Exercise fidelity was defined as the proportion of observed players who performed all aspects of their exercises correctly. The raters agreed on 61/70 observations (87%) (Kappa=0.72, 95% CI: 0.55 0.89). Of the observations with agreed ratings, 41 (67%) players were judged as performing the exercises as prescribed. The observational checklist demonstrated high inter-rater reliability. Many players observed did not perform the exercises as prescribed, raising concern as to whether they would be receiving anticipated program benefits. Where quality of exercise performance is important, evaluation and reporting of program fidelity should include direct observations of participants.
Increasing level of neuromusculoskeletal model personalisation to investigate joint contact forces in cerebral palsy: A twin case study
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.CLINBIOMECH.2019.12.011
Abstract: Cerebral palsy is a complex neuromuscular disorder that affects the sufferers in multiple different ways. Neuromusculoskeletal models are promising tools that can be used to plan patient-specific treatments for cerebral palsy. However, current neuromusculoskeletal models are typically scaled from generic adult templates that poorly represent paediatric populations. Furthermore, muscle activations are commonly computed via optimisation methods, which may not reproduce co-contraction observed in cerebral palsy. Alternatively, calibrated EMG-informed approaches within OpenSim can capture pathology-related muscle activation abnormalities, possibly enabling more feasible estimations of muscle and joint contact forces. Two identical twin brothers, aged 13, one with unilateral cerebral palsy and the other typically developing, were enrolled in the study. Four neuromusculoskeletal models with increasing subject-specificity were built in OpenSim and CEINMS combining literature findings, experimental motion capture, EMG and MR data for both participants. The physiological and biomechanical validity of each model was assessed by quantifying its ability to track experimental joint moments and muscle excitations. All developed models accurately tracked external joint moments however EMG-informed models better tracked muscle excitations compared to neural solutions generated by static optimisation. Calibrating muscle-tendon unit parameters with EMG data allowed for more physiologically plausible joint contact forces estimates. Further scaling the maximal isometric force of muscles with MR-derived muscle volumes did not affect model predictions. Given their ability to identify atypical joint contact forces profiles and accurately reproduce experimental data, calibrated EMG-informed models should be preferred over generic models using optimisation methods in informing the management of cerebral palsy.
A kinematic and kinetic analysis of walking after total knee arthroplasty with and without patellar resurfacing
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.CLINBIOMECH.2005.11.007
Abstract: Clarification of the indications for patellar resurfacing in total knee arthroplasty (TKA) is still necessary. Few studies of adequate power have evaluated functional differences between total knee arthroplasty with and without patellar resurfacing, in particular walking gait. This study aimed to identify clinically relevant differences in knee kinematic or kinetic parameters during level walking between total knee arthroplasty with and without patellar resurfacing, after controlling for pre-surgery gait parameters. Kinematic and kinetic gait analysis of level walking was performed on 34 subjects (41 knees) before and 12-18 months after total knee arthroplasty with patellar resurfacing performed randomly. Linear regression analysis was used to examine the influence of patellar resurfacing upon gait variables whilst controlling for the corresponding pre-surgery measure. The pre-surgery value was a moderate to strong significant predictor of all post-surgery temporal-spatial and kinetic gait parameters (p < 0.001-0.008), and most kinematic parameters (p < 0.001-0.066). The addition of patellar resurfacing to the regression models did not improve the predictive power in any case. Only one parameter, knee flexion at heel-strike, displayed a difference near statistical significance between total knee arthroplasty with and without patellar resurfacing (10 degrees versus 7 degrees respectively, p = 0.023). Pre-surgery gait patterns are an important determinant of post-surgery gait. There are no clinically relevant differences in walking gait between total knee arthroplasty performed with or without patellar resurfacing, using the Profix design.
What do community football players think about different exercise-training programmes? Implications for the delivery of lower limb injury prevention programmes
Publisher: BMJ
Date: 18-09-2014
Minimal medical imaging can accurately reconstruct geometric bone models for musculoskeletal models
Publisher: Cold Spring Harbor Laboratory
Date: 10-2018
DOI: 10.1101/432310
Abstract: Accurate representation of subject-specific bone anatomy in lower-limb musculoskeletal models is important for human movement analyses and simulations. Mathematical methods can reconstruct geometric bone models using incomplete imaging of bone by morphing bone model templates, but the validity of these methods has not been fully explored. The purpose of this study was to determine the minimal imaging requirements for accurate reconstruction of geometric bone models. Complete geometric pelvis and femur models of 14 healthy adults were reconstructed from magnetic resonance imaging through segmentation. From each complete bone segmentation, three sets of incomplete segmentations (set 1 being the most incomplete) were created to test the effect of imaging incompleteness on reconstruction accuracy. Geometric bone models were reconstructed from complete sets, three incomplete sets, and two motion capture-based methods. Reconstructions from (in)complete sets were generated using statistical shape modelling, followed by host-mesh and local-mesh fitting through the Musculoskeletal Atlas Project Client. Reconstructions from motion capture-based methods used positional data from skin surface markers placed atop anatomic landmarks and estimated joint centre locations as target points for statistical shape modelling and linear scaling. Accuracy was evaluated with distance error (mm) and overlapping volume similarity (%) between complete bone segmentation and reconstructed bone models, and statistically compared using a repeated measure analysis of variance (p .05). Motion capture-based methods produced significantly higher distance error than reconstructions from (in)complete sets. Pelvis volume similarity reduced significantly with the level of incompleteness: complete set (92.70±1.92%), set 3 (85.41±1.99%), set 2 (81.22±3.03%), set 1 (62.30±6.17%), motion capture-based statistical shape modelling (41.18±9.54%), and motion capture-based linear scaling (26.80±7.19%). A similar trend was observed for femur volume similarity. Results indicate that imaging two relevant bone regions produces overlapping volume similarity 80% compared to complete segmented bone models. These findings have implications for improving movement analysis and simulation with subject-specific musculoskeletal models.
Evaluating cost function criteria in predicting healthy gait
Publisher: Elsevier BV
Date: 06-2021
Trabecular bone texture detected by plain radiography and variance orientation transform method is different between knees with and without cartilage defects
Publisher: Wiley
Date: 04-03-2011
DOI: 10.1002/JOR.21396
Abstract: The objective of this work is to evaluate differences in trabecular bone (TB) texture between subjects with and without tibiofemoral cartilage defects using a variance orientation transform (VOT) method. A case-control study was performed in subjects without radiographic knee osteoarthritis (OA) (K&L grade <2) matched on sex, BMI, age, knee compartment, and meniscectomy where cases (n = 28) had cartilage defects (grade ≥2) and controls (n = 28) had no cartilage defects (grade <2). Cartilage defects were assessed from MRI using validated methods. The VOT was applied to TB regions selected on medial and lateral compartments in knee X-rays and fractal signatures (FS) in the horizontal (FS(H) ) and vertical (FS(V) ) directions, and along the roughest part of TB (FS(Sta) ) and texture aspect ratio signatures (StrS), at different trabecular image sizes (0.30-0.70 mm) were calculated. Compared with controls, FS(V) for cases were higher (p < 0.011) at image sizes 0.30-0.40 mm and 0.45-0.55 mm in the medial compartment. In the lateral compartment, FS(H) and FS(Sta) for cases were higher (p < 0.028) than those for controls at 0.30-0.40 mm and 0.45-0.55 mm, while FS(V) was higher (p 0.05) were found.
Moving beyond the optimal transmission switching: stochastic linearised SCUC for the integration of wind power generation and equipment failures uncertainties
Publisher: Institution of Engineering and Technology (IET)
Date: 25-04-2018
Correlation between EMG-based co-activation measures and medial and lateral compartment loads of the knee during gait
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.CLINBIOMECH.2013.09.006
Abstract: Inappropriate tibiofemoral joint contact loading during gait is thought to contribute to the development of osteoarthritis. Increased co-activation of agonist/antagonist pair of muscles during gait has commonly been observed in pathological populations and it is thought that this results in increased articular loading and subsequent risk of disease development. However, these hypotheses assume that there is a close relationship between muscle electromyography and force production, which is not necessarily the case. This study investigated the relationship between different electromyography-based co-activation measures and articular loading during gait using an electromyography-driven model to estimate joint contact loads. The results indicated that significant correlations do exist between selected electromyography-based activity measures and articular loading, but these are inconsistent and relatively low. However despite this, it was found that it may still be possible to use carefully selected measures of muscle activation in conjunction with external adduction moment measures to account for up to 50% of the variance in medial and lateral compartment loads. The inconsistency in correlations between many electromyography-based co-activation measures and articular loading still highlights the danger of inferring joint contact loads during gait using these measures. These results suggest that some form of electromyography-driven modelling is required to estimate joint contact loads in the tibiofemoral joint.
Pre-surgery knee joint loading patterns during walking predict the presence and severity of anterior knee pain after total knee arthroplasty
Publisher: Wiley
Date: 03-2004
Accuracy and Reliability of Marker Based Approaches to Scale the Pelvis, Thigh and Shank Segments in Musculoskeletal Models.
Publisher: Human Kinetics
Date: 10-2017
Abstract: Gait analysis together with musculoskeletal modeling is widely used for research. In the absence of medical images, surface marker locations are used to scale a generic model to the in idual’s anthropometry. Studies evaluating the accuracy and reliability of different scaling approaches in a pediatric and/or clinical population have not yet been conducted and, therefore, formed the aim of this study. Magnetic resonance images (MRI) and motion capture data were collected from 12 participants with cerebral palsy and 6 typically developed participants. Accuracy was assessed by comparing the scaled model’s segment measures to the corresponding MRI measures, whereas reliability was assessed by comparing the model’s segments scaled with the experimental marker locations from the first and second motion capture session. The inclusion of joint centers into the scaling process significantly increased the accuracy of thigh and shank segment length estimates compared to scaling with markers alone. Pelvis scaling approaches which included the pelvis depth measure led to the highest errors compared to the MRI measures. Reliability was similar between scaling approaches with mean ICC of 0.97. The pelvis should be scaled using pelvic width and height and the thigh and shank segment should be scaled using the proximal and distal joint centers.
A review of methods to measure tendon dimensions.
Publisher: Springer Science and Business Media LLC
Date: 14-01-2019
Related Organisations
Related Funding Activities
Can Exercise Programs Prevent Knee Injuries?
Start Date: 2006
End Date: 2009
Funder: National Health and Medical Research Council
View Funded ActivityNovel Movement Retraining For Musculoskeletal And Neurological Disorders Using Artificial Muscle
Start Date: 2013
End Date: 2016
Funder: Marsden Fund
View Funded ActivityOsteoarthritis Compass: Predicting Personalized Disease Onset And Progression With Future Capacity For Clinical Use
Start Date: 2021
End Date: 2024
Funder: National Health and Medical Research Council
View Funded ActivityInnovative In Vivo Kinetic System With Digital Twin Technology To Facilitate Rehabilitation And Maintenance Residuum Health After Limb Loss
Start Date: 2021
End Date: 2023
Funder: U.S. Department of Defense
View Funded ActivityUnderstanding The Importance Of Liana Dominance For Tropical And Subtropical Forest Health, Value And Management
Start Date: 2017
End Date: 2022
Funder: Australian Research Council
View Funded ActivityCan Exercise Programs Prevent Knee Injuries?
Start Date: 2006
End Date: 2009
Funder: National Health and Medical Research Council
View Funded ActivityExercise As Medicine For Heart Failure: A Novel Intervention To Improve Outcomes
Start Date: 2018
End Date: 2021
Funder: National Health and Medical Research Council
View Funded ActivityBioengineered Bioscaffolds For Achilles Tendinopathy Treatment
Start Date: 2011
End Date: 2014
Funder: Australian Research Council
View Funded ActivityBridging The Gap Between Cartilage Biology And Osteoarthritis Risk Prediction
Start Date: 2013
End Date: 2016
Funder: National Health and Medical Research Council
View Funded ActivityProject LP150100905
Start Date: 2015
End Date: 2018
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP110100581
Start Date: 11-2011
End Date: 12-2016
Amount: $840,000.00
Funder: Australian Research Council
View Funded ActivityIndustrial Transformation Training Centres - Grant ID: IC180100024
Start Date: 09-2019
End Date: 07-2025
Amount: $4,000,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE170100057
Start Date: 09-2017
End Date: 09-2018
Amount: $250,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP150100905
Start Date: 06-2016
End Date: 12-2021
Amount: $430,000.00
Funder: Australian Research Council
View Funded Activity