ARDC Research Link Australia

Publisher: Elsevier

Date: 1991

DOI: 10.1016/S0166-4115(08)60744-X

Publication

Publisher: Elsevier BV

Date: 07-2020

DOI: 10.1016/J.GAITPOST.2020.06.022

Publication

A musculoskeletal model of the knee for evaluating ligament forces during isometric contractions

Publisher: Elsevier BV

Date: 02-1997

DOI: 10.1016/S0021-9290(96)00119-4

Abstract: A model of the knee in the sagittal plane was developed to study the forces in the ligaments induced by isometric contractions of the extensor and flexor muscles. The geometry of the distal femur was obtained from cadaver data. The tibial plateau and patellar facet were modeled as flat surfaces. Eleven elastic elements were used to describe the mechanical behavior of the anterior and posterior cruciate ligaments (ACL and PCL), the medial and lateral collateral ligaments (MCL and LCL), and the posterior capsule. The model knee was actuated by 11 musculotendinous units, each muscle represented by a Hill-type contractile element, a series-elastic element, and a parallel-elastic element. Tendon was assumed to be elastic. The response of the model to anterior-posterior drawer suggests that the geometrical and mechanical properties of the model ligaments approximate the behavior of real ligaments in the intact knee. Calculations for a simulated quadriceps leg raise indicate further that the two-dimensional model reproduces the response of the three-dimensional knee under similar conditions of loading and constraint. During maximum isometric contractions of the quadriceps, the model ACL is loaded from full extension to 80 degrees C of flexion the model PCL is loaded at 70 degrees of flexion and greater. For maximum isometric extension, ACL forces in the range 0-20 degrees of flexion depend most heavily upon the force-length properties of the quadriceps. At flexion angles greater than 20 degrees, cruciate ligament forces are determined by the geometry of the articulating surfaces of the bones. During isolated contractions of the hamstrings and gastrocnemius muscles, the model ACL is loaded from full extension to 10 degrees of flexion the model PCL is loaded at all flexion angles greater than 10 degrees. Isolated contractions of the flexor muscles cannot unload the ACL near full extension, as the behavior of the ACL in this region is governed by the shapes of the bones. At 10 degrees of flexion or greater, the overall pattern of PCL force is explained by the force length properties of the hamstrings and by the geometrical arrangement of the flexor muscles about the knee.

Publication

Publisher: Institute of Electrical and Electronics Engineers (IEEE)

Date: 2016

DOI: 10.1109/TMI.2015.2473168

Publication

Pelvic and Hip Kinematics During Walking in People With Patellofemoral Joint Osteoarthritis Compared to Healthy Age‐Matched Controls

Publisher: Wiley

Date: 29-12-2017

DOI: 10.1002/ACR.23261

Abstract: Patellofemoral (PF) joint osteoarthritis (OA) is common, yet little is known about how this condition influences lower-extremity biomechanical function. This study compared pelvis and lower-extremity kinematics in people with and without PF joint OA. Sixty-nine participants (64% women, mean ± SD age 56 ± 10 years) with anterior knee pain aggravated by PF joint-loaded activities (e.g., stair ambulation, rising from sitting, or squatting) and radiographic lateral PF joint OA on skyline radiographs were compared with 18 controls (78% women, mean ± SD age 53 ± 7 years) with no lower-extremity pain or radiographic OA. Knee Injury and Osteoarthritis Outcome Score (KOOS) data were collected from participants with PF joint OA. Quantitative gait analyses were conducted during overground walking at a self-selected speed. Pelvis and lower-extremity kinematics were calculated across the stance phase. Data were statistically analyzed using analyses of covariance, with age and sex as covariates (P < 0.05). Participants with PF joint OA reported a mean ± SD KOOS pain subscale score of 65 ± 15, KOOS symptoms subscale score of 63 ± 16, KOOS activities of daily living subscale score of 73 ± 13, KOOS sports/recreation subscale score of 45 ± 23, and KOOS quality of life subscale score of 43 ± 16. Participants with PF joint OA walked with greater anterior pelvic tilt throughout the stance phase, as well as greater lateral pelvic tilt (i.e., pelvis lower on the contralateral side), greater hip adduction, and lower hip extension during the late stance phase. No differences in knee and ankle joint angles were observed between groups. People with PF joint OA walk with altered pelvic and hip movement patterns compared with aged-matched controls. Restoring normal movement patterns during walking in people with PF joint OA may be warranted to help alleviate symptoms.

Publication

Variation of Neck Muscle Strength Along the Human Cervical Spine

Publisher: SAE International

Date: 11-2004

DOI: 10.4271/2004-22-0017

Abstract: The aim of this study was to describe and explain the variation of neck muscle strength along the cervical spine. A three-dimensional model of the head-neck complex was developed to test the hypothesis that the moment-generating capacity of the neck musculature is lower in the upper cervical spine than in the lower cervical spine. The model calculations suggest that the neck muscles can protect the lower cervical spine from injury during extension and lateral bending. The maximum flexor moment developed in the lower cervical spine was 2 times higher than that developed in the upper spine. The model also predicted that the neck musculature is 30% stronger in the lower cervical spine during lateral bending. Peak compressive forces (up to 3 times body weight) were higher in the lower cervical spine. These results are consistent with the clinical finding that extension loading of the neck often leads to injuries in the upper cervical spine. Analysis of the model results showed that neck flexor strength was greater in the lower cervical spine because of the relatively large size of the sternocleidomastoid muscle. The hyoid muscles developed significant flexor moments about the joints of the upper cervical spine, as these muscles had relatively large flexor moment arms however, this effect was offset by the action of the sternocleidomastoid, which exerted a large extensor moment in the upper spine. Lateral bending strength of the neck muscles was governed by geometry (i.e., moment arms) rather than by muscle size.

Publication

Influence of muscle-tendon wrapping on calculations of joint reaction forces in the equine distal forelimb

Publisher: Hindawi Limited

Date: 2008

DOI: 10.1155/2008/165730

Abstract: The equine distal forelimb is a common location of injuries related to mechanical overload. In this study, a two-dimensional model of the musculoskeletal system of the region was developed and applied to kinematic and kinetic data from walking and trotting horses. The forces in major tendons and joint reaction forces were calculated. The components of the joint reaction forces caused by wrapping of tendons around sesamoid bones were found to be of similar magnitude to the reaction forces between the long bones at each joint. This finding highlighted the importance of taking into account muscle-tendon wrapping when evaluating joint loading in the equine distal forelimb.

Publication

Application of ultrasound imaging to subject-specific modelling of the human musculoskeletal system

Publisher: Springer Science and Business Media LLC

Date: 30-06-2017

DOI: 10.1007/S11012-016-0478-Z

Publication

Integrating modelling, motion capture and x-ray fluoroscopy to investigate patellofemoral function during dynamic activity

Publisher: Informa UK Limited

Date: 02-2008

DOI: 10.1080/10255840701551046

Abstract: Accurate measurement of knee-joint kinematics is critical for understanding the biomechanical function of the knee in vivo. Measurements of the relative movements of the bones at the knee are often used in inverse dynamics analyses to estimate the net muscle torques exerted about the joint, and as inputs to finite-element models to accurately assess joint contact. The fine joint translations that contribute to patterns of joint stress are impossible to measure accurately using traditional video-based motion capture techniques. Sub-millimetre changes in joint translation can mean the difference between contact and no contact of the cartilage tissue, leading to incorrect predictions of joint loading. This paper describes the use of low-dose X-ray fluoroscopy, an in vivo dynamic imaging modality that is finding increasing application in human joint motion measurement. Specifically, we describe a framework that integrates traditional motion capture, X-ray fluoroscopy and anatomically-based finite-element modelling for the purpose of assessing joint function during dynamic activity. We illustrate our methodology by applying it to study patellofemoral joint function, wherein the relative movements of the patella are predicted and the corresponding joint-contact stresses are calculated for a step-up task.

Publication

Grand challenge competition to predict in vivo knee loads

Publisher: Wiley

Date: 12-12-2012

DOI: 10.1002/JOR.22023

Publication

Six-degree-of-freedom tibiofemoral and patellofemoral joint motion during activities of daily living

Publisher: Springer Science and Business Media LLC

Date: 22-10-2021

DOI: 10.1007/S10439-020-02646-2

Publication

Strain energy in the femoral neck during exercise

Publisher: Elsevier BV

Date: 06-2014

DOI: 10.1016/J.JBIOMECH.2014.03.036

Abstract: Physical activity is recommended to mitigate the incidence of hip osteoporotic fractures by improving femoral neck strength. However, results from clinical studies are highly variable and unclear about the effects of physical activity on femoral neck strength. We ranked physical activities recommended for promoting bone health based on calculations of strain energy in the femoral neck. According to adaptive bone-remodeling theory, bone formation occurs when the strain energy (S) exceeds its homeostatic value by 75%. The potential effectiveness of activity type was assessed by normalizing strain energy by the applied external load. Tensile strain provided an indication of bone fracture. External force and joint motion data for 15 low- and high-load weight-bearing and resistance-based activities were used. High-load activities included weight-bearing activities generating a ground force above 1 body-weight and maximal resistance exercises about the hip and the knee. Calculations of femoral loads were based on musculoskeletal and finite-element models. Eight of the fifteen activities were likely to trigger bone formation, with isokinetic hip extension (ΔS=722%), one-legged long jump (ΔS=572%), and isokinetic knee flexion (ΔS=418%) inducing the highest strain energy increase. Knee flexion induced approximately ten times the normalized strain energy induced by hip adduction. Strain and strain energy were strongly correlated with the hip-joint reaction force (R(2)=0.90-0.99 p<0.05) for all activities, though the peak load location was activity-dependent. None of the exercises was likely to cause fracture. Femoral neck mechanics is activity-dependent and maximum isokinetic hip-extension and knee-flexion exercises are possible alternative solutions to impact activities for improving femoral neck strength.

Publication

Publisher: Springer Science and Business Media LLC

Date: 09-1998

DOI: 10.1007/BF02945552

Publication

Simultaneous prediction of muscle and contact forces in the knee during gait

Publisher: Elsevier BV

Date: 03-2010

DOI: 10.1016/J.JBIOMECH.2009.10.048

Abstract: Musculoskeletal models are currently the primary means for estimating in vivo muscle and contact forces in the knee during gait. These models typically couple a dynamic skeletal model with in idual muscle models but rarely include articular contact models due to their high computational cost. This study evaluates a novel method for predicting muscle and contact forces simultaneously in the knee during gait. The method utilizes a 12 degree-of-freedom knee model (femur, tibia, and patella) combining muscle, articular contact, and dynamic skeletal models. Eight static optimization problems were formulated using two cost functions (one based on muscle activations and one based on contact forces) and four constraints sets (each composed of different combinations of inverse dynamic loads). The estimated muscle and contact forces were evaluated using in vivo tibial contact force data collected from a patient with a force-measuring knee implant. When the eight optimization problems were solved with added constraints to match the in vivo contact force measurements, root-mean-square errors in predicted contact forces were less than 10 N. Furthermore, muscle and patellar contact forces predicted by the two cost functions became more similar as more inverse dynamic loads were used as constraints. When the contact force constraints were removed, estimated medial contact forces were similar and lateral contact forces lower in magnitude compared to measured contact forces, with estimated muscle forces being sensitive and estimated patellar contact forces relatively insensitive to the choice of cost function and constraint set. These results suggest that optimization problem formulation coupled with knee model complexity can significantly affect predicted muscle and contact forces in the knee during gait. Further research using a complete lower limb model is needed to assess the importance of this finding to the muscle and contact force estimation process.

Publication

Response to “Letter to the Editor on ‘Muscle function during gait is invariant to age when walking speed is controlled’ by Lim YP, Lin Y-C, Pandy MG (Gait Posture 2013;38(2):253–9)”

Publisher: Elsevier BV

Date: 03-2014

DOI: 10.1016/J.GAITPOST.2013.11.004

Publication

An Analytical Framework for Quantifying Muscular Action During Human Movement

Publisher: Springer New York

Date: 1990

DOI: 10.1007/978-1-4613-9030-5_42

Publication

A Three-Dimensional Musculoskeletal Model of the Human Knee Joint. Part 2: Analysis of Ligament Function

Publisher: Informa UK Limited

Date: 1998

DOI: 10.1080/01495739808936707

Abstract: A three-dimensional model of the knee is used to study ligament function during anterior-posterior (a-p) draw, axial rotation, and isometric contractions of the extensor and flexor muscles. The geometry of the model bones is based on cadaver data. The contacting surfaces of the femur and tibia are modeled as deformable those of the femur and patella are assumed to be rigid. Twelve elastic elements are used to describe the geometry and mechanical properties of the cruciate ligaments, the collateral ligaments, and the posterior capsule. The model is actuated by thirteen musculotendinous units, each unit represented as a three-element muscle in series with tendon. The calculations show that the forces applied during a-p draw are substantially different from those applied by the muscles during activity. Principles of knee-ligament function based on the results of in vitro experiments may therefore be overstated. Knee-ligament forces during straight a-p draw are determined solely by the changing geometry of the ligaments relative to the bones: ACL force decreases with increasing flexion during anterior draw because the angle between the ACL and the tibial plateau decreases as knee flexion increases PCL force increases with increasing flexion during posterior draw because the angle between the PCL and the tibial plateau increases. The pattern of ligament loading during activity is governed by the geometry of the muscles spanning the knee: the resultant force in the ACL during isometric knee extension is determined mainly by the changing orientation of the patellar tendon relative to the tibia in the sagittal plane the resultant force in the PCL during isometric knee flexion is dominated by the angle at which the hamstrings meet the tibia in the sagittal plane.

Publication

Publisher: Wiley

Date: 16-07-2009

DOI: 10.1111/J.1469-7580.2009.01090.X

Publication

Publisher: Elsevier BV

Date: 02-2023

DOI: 10.1016/J.JMBBM.2022.105621

Publication

Athletes Rated as Poor Single-Leg Squat Performers Display Measurable Differences in Single-Leg Squat Biomechanics Compared With Good Performers

Publisher: Human Kinetics

Date: 11-2018

DOI: 10.1123/JSR.2016-0208

Abstract: Context : It is important to validate single-leg squat visual rating criteria used in clinical practice and research. Foot orthoses may improve single-leg squat performance in those who demonstrate biomechanics associated with increased risk of lower limb injury. Objective : Validate visual rating criteria proposed by Crossley et al, by determining whether athletes rated as poor single-leg squat performers display different single-leg squat biomechanics than good performers and evaluate immediate effects of foot orthoses on single-leg squat biomechanics in poor performers. Design : Comparative cross-sectional study. Setting : University laboratory. Participants : 79 asymptomatic athletes underwent video classification of single-leg squat performance based on established visual rating criteria (overall impression, trunk posture, pelvis “in space,” hip movement, and knee movement), and were rated as good (n = 23), fair (n = 41), or poor (n = 15) performers. Intervention : A subset of good (n = 16) and poor (n = 12) performers underwent biomechanical assessment, completing 5 continuous single-leg squats on their dominant limb while 3-dimensional motion analysis and ground reaction force data were recorded. Poor performers repeated the task standing on prefabricated foot orthoses. Main Outcome Measures : Peak external knee adduction moment (KAM) and peak angles for the trunk, hip, knee, and ankle. Results : Compared with good performers, poor performers had a significantly lower peak KAM (mean difference = 0.11 Nm/kg, 95% confidence interval = 0.02 to 0.2 Nm/kg), higher peak hip adduction angle (−4.3°, −7.6° to −0.9°), and higher peak trunk axial rotation toward their stance limb (3.8°, 0.4° to 7.2°). Foot orthoses significantly increased the peak KAM in poor performers (−0.06 Nm/kg, −0.1 to −0.01 Nm/kg), with values approximating those observed in good performers. Conclusions : Findings validate Crossley et al’s visual rating criteria for single-leg squat performance in asymptomatic athletes, and suggest that “off-the-shelf” foot orthoses may be a simple intervention for poor performers to normalize the magnitude of the external KAM during single-leg squat.

Publication

Sensitivity of femoral strain calculations to anatomical scaling errors in musculoskeletal models of movement

Publisher: Elsevier BV

Date: 10-2015

DOI: 10.1016/J.JBIOMECH.2015.08.001

Abstract: The determination of femoral strain in post-menopausal women is important for studying bone fragility. Femoral strain can be calculated using a reference musculoskeletal model scaled to participant anatomies (referred to as scaled-generic) combined with finite-element models. However, anthropometric errors committed while scaling affect the calculation of femoral strains. We assessed the sensitivity of femoral strain calculations to scaled-generic anthropometric errors. We obtained CT images of the pelves and femora of 10 healthy post-menopausal women and collected gait data from each participant during six weight-bearing tasks. Scaled-generic musculoskeletal models were generated using skin-mounted marker distances. Image-based models were created by modifying the scaled-generic models using muscle and joint parameters obtained from the CT data. Scaled-generic and image-based muscle and hip joint forces were determined by optimisation. A finite-element model of each femur was generated from the CT images, and both image-based and scaled-generic principal strains were computed in 32 regions throughout the femur. The intra-participant regional RMS error increased from 380 με (R2=0.92, p<0.001) to 4064 με (R2=0.48, p<0.001), representing 5.2% and 55.6% of the tensile yield strain in bone, respectively. The peak strain difference increased from 2821 με in the proximal region to 34,166 με at the distal end of the femur. The inter-participant RMS error throughout the 32 femoral regions was 430 με (R2=0.95, p<0.001), representing 5.9% of bone tensile yield strain. We conclude that scaled-generic models can be used for determining cohort-based averages of femoral strain whereas image-based models are better suited for calculating participant-specific strains throughout the femur.

Publication

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 05-2010

DOI: 10.2106/JBJS.I.00001

Publication

Effects of foot orthoses and valgus bracing on the knee adduction moment and medial joint load during gait

Publisher: Elsevier BV

Date: 07-2008

DOI: 10.1016/J.CLINBIOMECH.2008.02.005

Abstract: Lateral shoe wedges and valgus knee braces are designed to decrease the force acting in the medial knee compartment by reducing the external adduction moment applied at the knee. The biomechanical changes introduced by these orthoses can be relatively small. Computer modeling and simulation offers an alternative approach for assessing the biomechanical performance of these devices. A three-dimensional model of the lower-limb was used to calculate muscle, ligament, and joint loading at the knee during gait. A lateral shoe wedge was simulated by moving the center of pressure of the ground reaction force up to 5mm laterally. A valgus knee brace was simulated by applying abduction moments of up to 12 Nm at the knee. Knee adduction moment and medial compartment load decreased linearly with lateral displacement of the center of pressure of the ground reaction force. A 1 mm displacement of the center of pressure decreased the peak knee adduction moment by 2%, while the peak medial compartment load was reduced by 1%. Knee adduction moment and medial compartment force also decreased linearly with valgus moments applied about the knee. A 1 Nm increase in brace moment decreased the peak knee adduction moment by 3%, while the peak medial compartment load was reduced by 1%. Changes in knee joint loading due to lateral shoe wedges and valgus bracing are small and may be difficult to measure by conventional gait analysis methods. The relationships between lateral shift in the center of pressure of the ground force, valgus brace moment, knee adduction moment, and medial joint load can be quantified and explained using computer modeling and simulation. These relationships may serve as a useful guide for evaluating the biomechanical efficacy of a generic wedge insole or knee brace.

Publication

Contribution of tibiofemoral joint contact to net loads at the knee in gait

Publisher: Wiley

Date: 02-03-2015

DOI: 10.1002/JOR.22845

Abstract: Inverse dynamics analysis is commonly used to estimate the net loads at a joint during human motion. Most lower-limb models of movement represent the knee as a simple hinge joint when calculating muscle forces. This approach is limited because it neglects the contributions from tibiofemoral joint contact forces and may therefore lead to errors in estimated muscle forces. The aim of this study was to quantify the contributions of tibiofemoral joint contact loads to the net knee loads calculated from inverse dynamics for multiple subjects and multiple gait patterns. Tibiofemoral joint contact loads were measured in four subjects with instrumented implants as each subject walked at their preferred speed (normal gait) and performed prescribed gait modifications designed to treat medial knee osteoarthritis. Tibiofemoral contact loads contributed substantially to the net knee extension and knee adduction moments in normal gait with mean values of 16% and 54%, respectively. These findings suggest that knee-contact kinematics and loads should be included in lower-limb models of movement for more accurate determination of muscle forces. The results of this study may be used to guide the development of more realistic lower-limb models that account for the effects of tibiofemoral joint contact at the knee.

Publication

Pattern of anterior cruciate ligament force in normal walking

Publisher: Elsevier BV

Date: 06-2004

DOI: 10.1016/J.JBIOMECH.2003.10.010

Publication

Publisher: Springer Science and Business Media LLC

Date: 03-01-2012

DOI: 10.1007/S11044-011-9289-0

Publication

Measuring Femoral Torsion In Vivo Using Freehand 3-D Ultrasound Imaging

Publisher: Elsevier BV

Date: 02-2016

DOI: 10.1016/J.ULTRASMEDBIO.2015.10.014

Abstract: Despite variation in bone geometry, muscle and joint function is often investigated using generic musculoskeletal models. Patient-specific bone geometry can be obtained from computerised tomography, which involves ionising radiation, or magnetic resonance imaging (MRI), which is costly and time consuming. Freehand 3-D ultrasound provides an alternative to obtain bony geometry. The purpose of this study was to determine the accuracy and repeatability of 3-D ultrasound in measuring femoral torsion. Measurements of femoral torsion were performed on 10 healthy adults using MRI and 3-D ultrasound. Measurements of femoral torsion from 3-D ultrasound were, on average, smaller than those from MRI (mean difference = 1.8° 95% confidence interval: -3.9°, 7.5°). MRI and 3-D ultrasound had Bland and Altman repeatability coefficients of 3.1° and 3.7°, respectively. Accurate measurements of femoral torsion were obtained with 3-D ultrasound offering the potential to acquire patient-specific bone geometry for musculoskeletal modelling. Three-dimensional ultrasound is non-invasive and relatively inexpensive and can be integrated into gait analysis.

Publication

Publisher: Wiley

Date: 24-09-2008

DOI: 10.1111/J.1469-7580.2008.00965.X

Publication

Dynamic simulation of knee-joint loading during gait using force-feedback control and surrogate contact modelling

Publisher: Elsevier BV

Date: 10-2017

DOI: 10.1016/J.MEDENGPHY.2017.06.043

Abstract: The aim of this study was to perform multi-body, muscle-driven, forward-dynamics simulations of human gait using a 6-degree-of-freedom (6-DOF) model of the knee in tandem with a surrogate model of articular contact and force control. A forward-dynamics simulation incorporating position, velocity and contact force-feedback control (FFC) was used to track full-body motion capture data recorded for multiple trials of level walking and stair descent performed by two in iduals with instrumented knee implants. Tibiofemoral contact force errors for FFC were compared against those obtained from a standard computed muscle control algorithm (CMC) with a 6-DOF knee contact model (CMC6) CMC with a 1-DOF translating hinge-knee model (CMC1) and static optimization with a 1-DOF translating hinge-knee model (SO). Tibiofemoral joint loads predicted by FFC and CMC6 were comparable for level walking, however FFC produced more accurate results for stair descent. SO yielded reasonable predictions of joint contact loading for level walking but significant differences between model and experiment were observed for stair descent. CMC1 produced the least accurate predictions of tibiofemoral contact loads for both tasks. Our findings suggest that reliable estimates of knee-joint loading may be obtained by incorporating position, velocity and force-feedback control with a multi-DOF model of joint contact in a forward-dynamics simulation of gait.

Publication

Comparison of posterior‐stabilized, cruciate‐retaining, and medial‐stabilized knee implant motion during gait

Publisher: Wiley

Date: 13-02-2020

DOI: 10.1002/JOR.24613

Abstract: Accurate knowledge of knee joint motion is needed to evaluate the effects of implant design on functional performance and component wear. We conducted a randomized controlled trial to measure and compare 6-degree-of-freedom (6-DOF) kinematics and femoral condylar motion of posterior-stabilized (PS), cruciate-retaining (CR), and medial-stabilized (MS) knee implant designs for one cycle of walking. A mobile biplane X-ray imaging system was used to accurately measure 6-DOF tibiofemoral motion as patients implanted with PS (n = 23), CR (n = 25), or MS (n = 26) knees walked over ground at their self-selected speeds. Knee flexion angle did not differ significantly between the three designs. Relative movements of the femoral and tibial components were generally similar for PS and CR with significant differences observed only for anterior tibial drawer. Knee kinematic profiles measured for MS were appreciably different: external rotation and abduction of the tibia were increased while peak-to-peak anterior drawer was significantly reduced for MS compared with PS and CR. Anterior-posterior drawer and medial-lateral shift of the tibia were strongly coupled to internal-external rotation for MS, as was anterior-posterior translation of the contact center in the lateral compartment. MS exhibited the least amount of paradoxical anterior translation of the femur relative to the tibia during knee flexion. The joint center of rotation in the transverse plane was located in the lateral compartment for PS and CR and in the medial compartment for MS. Substantial differences were evident in 6-DOF knee kinematics between the healthy knee and all three prosthetic designs. Overall, knee kinematic profiles observed for MS resemble those of the healthy joint more closely than PS and CR.

Publication

Dependence of cruciate-ligament loading on muscle forces and external load

Publisher: Elsevier BV

Date: 10-1997

DOI: 10.1016/S0021-9290(97)00070-5

Abstract: A sagittal-plane model of the knee is used to predict and explain the relationships between the forces developed by the muscles, the external loads applied to the leg, and the forces induced in the cruciate ligaments during isometric exercises. The geometry of the model bones is adapted from cadaver data. Eleven elastic elements describe the geometric and mechanical properties of the cruciate ligaments, the collateral ligaments, and the posterior capsule. The model is actuated by 11 musculotendinous units, each unit represented as a three-element muscle in series with tendon. For isolated contractions of the quadriceps, ACL force increases as quadriceps force increases for all flexion angles between 0 and 80 degrees the ACL is unloaded at flexion angles greater than 80 degrees. When quadriceps force is held constant, ACL force decreases monotonically as knee-flexion angle increases. The relationship between ACL force, quadriceps force, and knee-flexion angle is explained by the geometry of the knee-extensor mechanism and by the changing orientation of the ACL in the sagittal plane. For isolated contractions of the hamstrings, PCL force increases as hamstrings force increases for all flexion angles greater than 10 degrees the PCL is unloaded at flexion angles less than 10 degrees. When hamstrings force is held constant, PCL force increases monotonically with increasing knee flexion. The relationship between PCL force, hamstrings force, and knee-flexion angle is explained by the geometry of the hamstrings and by the changing orientation of the PCL in the sagittal plane. At nearly all knee-flexion angles, hamstrings co-contraction is an effective means of reducing ACL force. Hamstrings co-contraction cannot protect the ACL near full extension of the knee because these muscles meet the tibia at small angles near full extension, and so cannot apply a sufficiently large posterior shear force to the leg. Moving the restraining force closer to the knee-flexion axis decreases ACL force varying the orientation of the restraining force has only a small effect on cruciate-ligament loading.

Publication

Rupture of the conjoint tendon at the proximal musculotendinous junction of the biceps femoris long head: a case report

Publisher: Springer Science and Business Media LLC

Date: 12-05-2028

DOI: 10.1007/S00167-008-0517-Y

Abstract: This case report describes a 20-year-old elite-level Australian Rules football player who suffered three unilateral hamstring injuries within a 2 month period. The first two episodes were managed conservatively. Magnetic resonance imaging following the third episode revealed full thickness disruption of the proximal musculotendinous junction of the biceps femoris long head and semitendinosus muscles and the common proximal (conjoint) tendon. The injury was subsequently surgically repaired. At 16 months following surgery, the player had successfully completed a full competitive season of elite-level Australian Rules football symptom free. Follow-up magnetic resonance imaging demonstrated the repaired tendon to be uniformly hypointense in keeping with reparative granulation tissue formation and restoration of normal muscle morphology. These findings are consistent with an intact repair. The case demonstrates that complete functional and radiological resolution is possible following surgical repair of significant hamstring musculotendinous junction tears.

Publication

Publisher: Informa UK Limited

Date: 2003

DOI: 10.1533/ABIB.2003.1.1.45

Publication

Publisher: Frontiers Media SA

Date: 19-07-2022

DOI: 10.3389/FBIOE.2022.943553

Publication

Publisher: Wiley

Date: 02-08-2017

DOI: 10.1002/JCSM.12133

Publication

Non-invasive assessment of soft-tissue artifact and its effect on knee joint kinematics during functional activity

Publisher: Elsevier BV

Date: 05-2010

DOI: 10.1016/J.JBIOMECH.2010.01.002

Abstract: The soft-tissue interface between skin-mounted markers and the underlying bones poses a major limitation to accurate, non-invasive measurement of joint kinematics. The aim of this study was twofold: first, to quantify lower limb soft-tissue artifact in young healthy subjects during functional activity and second, to determine the effect of soft-tissue artifact on the calculation of knee joint kinematics. Subject-specific bone models generated from magnetic resonance imaging (MRI) were used in conjunction with X-ray images obtained from single-plane fluoroscopy to determine three-dimensional knee joint kinematics for four separate tasks: open-chain knee flexion, hip axial rotation, level walking, and a step-up. Knee joint kinematics was derived using the anatomical frames from the MRI-based, 3D bone models together with the data from video motion capture and X-ray fluoroscopy. Soft-tissue artifact was defined as the degree of movement of each marker in the anteroposterior, proximodistal and mediolateral directions of the corresponding anatomical frame. A number of different skin-marker clusters (total of 180) were used to calculate knee joint rotations, and the results were compared against those obtained from fluoroscopy. Although a consistent pattern of soft-tissue artifact was found for each task across all subjects, the magnitudes of soft-tissue artifact were subject-, task- and location-dependent. Soft-tissue artifact for the thigh markers was substantially greater than that for the shank markers. Markers positioned in the vicinity of the knee joint showed considerable movement, with root mean square errors as high as 29.3mm. The maximum root mean square errors for calculating knee joint rotations occurred for the open-chain knee flexion task and were 24.3 degrees , 17.8 degrees and 14.5 degrees for flexion, internal-external rotation and abduction-adduction, respectively. The present results on soft-tissue artifact, based on fluoroscopic measurements in healthy adult subjects, may be helpful in developing location- and direction-specific weighting factors for use in global optimization algorithms aimed at minimizing the effects of soft-tissue artifact on calculations of knee joint rotations.

Publication

Musculoskeletal loading in the symptomatic and asymptomatic knees of middle‐aged osteoarthritis patients

Publisher: Wiley

Date: 04-05-2016

DOI: 10.1002/JOR.23264

Abstract: This study quantified the contributions by muscles, gravity, and inertia to the tibiofemoral compartment forces in the symptomatic (SYM) and asymptomatic (ASYM) limbs of varus mal-aligned medial knee osteoarthritis (OA) patients, and compared the results with healthy controls (CON). Muscle forces and tibiofemoral compartment loads were calculated using gait data from 39 OA patients and 15 controls aged 49 ± 7 years. Patients exhibited lower knee flexion angle, higher hip abduction, and knee adduction angles, lower internal knee flexion torque but higher external knee adduction moment. Muscle forces were highest in CON except hamstrings, which was highest in SYM. ASYM muscle forces were lowest for biceps femoris short head and gastrocnemius but otherwise intermediate between SYM and CON. In all subjects, vasti, hamstrings, gastrocnemius, soleus, gluteus medius, gluteus maximus, and gravity were the largest contributors to medial compartment force (MCF). Inertial contributions were negligible. Highest MCF was found in SYM throughout stance. Small increases in contributions from hamstrings, gluteus maximus, gastrocnemius, and gravity at the first peak soleus and rectus femoris at the second peak and soleus, gluteus maximus, gluteus medius, and gravity during mid-stance summed to produce significantly higher total MCF. Compared to CON, the ASYM limb exhibited similar peak MCF but higher mid-stance MCF. In patients, diminished non-knee-spanning muscle forces did not produce correspondingly diminished MCF contributions due to the influence of mal-alignment. Our findings emphasize consideration of muscle function, lower-limb alignment, and mid-stance loads in developing interventions for OA, and inclusion of the asymptomatic limb in clinical assessments. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:321-330, 2017.

Publication

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 29-03-2023

DOI: 10.1249/MSS.0000000000003175

Publication

Muscle and joint‐contact loading at the glenohumeral joint after reverse total shoulder arthroplasty

Publisher: Wiley

Date: 12-05-2011

DOI: 10.1002/JOR.21437

Abstract: The purposes of this study were to determine the contributions of each shoulder muscle to glenohumeral joint force during abduction and flexion in both the anatomical and post-operative shoulder and to identify factors that may contribute to the incidence of glenoid component loosening/failure and joint instability in the shoulder after reverse shoulder arthroplasty (RSA). Eight cadaveric upper extremities were mounted onto a testing apparatus. Muscle lines of action were measured, and muscle forces and muscle contributions to glenohumeral joint forces were determined during abduction and flexion of the pre-operative anatomical shoulder and of the shoulder after arthroplasty. Muscle forces in the middle deltoid during abduction and those in the middle and anterior deltoid during flexion were significantly lower in the reverse shoulder than the pre-operative shoulder (p < 0.017). The resultant glenohumeral joint force in the reverse shoulder was significantly lower than that in the pre-operative shoulder however, the superior shear force acting at the glenohumeral joint was significantly higher (p < 0.001). Reverse total shoulder arthroplasty reduces muscle effort in performing lifting and pushing tasks however, reduced joint compressive force has the potential to compromise joint stability, while an increased superior joint shear force may contribute to component loosening/failure. Because greater superior shear force is generated in flexion than in abduction, care should be taken to avoid excessive shoulder loading in this plane of elevation.

Publication

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 07-2011

DOI: 10.1249/MSS.0B013E3182084929

Publication

Muscle and Joint Function in Human Locomotion

Publisher: Annual Reviews

Date: 07-2010

DOI: 10.1146/ANNUREV-BIOENG-070909-105259

Abstract: This review describes how computational modeling can be combined with noninvasive gait measurements to describe and explain muscle and joint function in human locomotion. Five muscles—the gluteus maximus, gluteus medius, vasti, soleus, and gastrocnemius—contribute most significantly to the accelerations of the center of mass in the vertical, fore-aft, and medio-lateral directions when humans walk and run at their preferred speeds. Humans choose to switch from a walk to a run at speeds near 2 m s −1 to enhance the biomechanical performance of the ankle plantarflexors and to improve coordination of the knee and ankle muscles during stance. Muscles that do not span a joint can contribute to the contact force transmitted by that joint and therefore affect its stability. In walking, for ex le, uniarticular muscles that cross the hip and ankle act to create the adduction moment at the knee, thereby contributing to the contact force present in the medial compartment.

Publication

Articular contact motion at the knee during daily activities

Publisher: Wiley

Date: 08-12-2021

DOI: 10.1002/JOR.25222

Abstract: We combined mobile biplane X‐ray imaging and magnetic resonance imaging to measure the regions of articular cartilage contact and cartilage thickness at the tibiofemoral and patellofemoral joints during six functional activities: standing, level walking, downhill walking, stair ascent, stair descent, and open‐chain (non‐weight‐bearing) knee flexion. The contact centers traced similar paths on the medial and lateral femoral condyles, femoral trochlea, and patellar facet in all activities while their locations on the tibial plateau were more varied. The translations of the contact centers on the femur and patella were tightly coupled to the tibiofemoral flexion angle in all activities ( r 2 0.95) whereas those on the tibia were only moderately related to the flexion angle ( r 2 0.62). The regions of contacting cartilage were significantly thicker than the regions of non‐contacting cartilage on the patella, femoral trochlea, and the medial and lateral tibial plateaus in all activities ( p 0.001). There were no significant differences in thickness between contacting and non‐contacting cartilage on the medial and lateral femoral condyles in all activities, except open‐chain knee flexion. Our results provide partial support for the proposition that cartilage thickness is adapted to joint load and do not exclude the possibility that other factors, such as joint congruence, also play a role in regulating the structure and organization of healthy cartilage. The data obtained in this study may serve as a guide when evaluating articular contact motion in osteoarthritic and reconstructed knees.

Publication

Lower-Limb Muscular Strategies for Increasing Running Speed

Publisher: Journal of Orthopaedic & Sports Physical Therapy (JOSPT)

Date: 10-2014

DOI: 10.2519/JOSPT.2014.5433

Abstract: This clinical commentary discusses the mechanisms used by the lower-limb musculature to achieve faster running speeds. A variety of methodological approaches have been taken to evaluate lower-limb muscle function during running, including direct recordings of muscle electromyographic signal, inverse dynamics-based analyses, and computational musculoskeletal modeling. Progressing running speed from jogging to sprinting is mostly dependent on ankle and hip muscle performance. For speeds up to approximately 7.0 m/s, the dominant strategy is to push on the ground forcefully to increase stride length, and the major ankle plantar flexors (soleus and gastrocnemius) have a particularly important role in this regard. At speeds beyond approximately 7.0 m/s, the force-generating capacity of these muscles becomes less effective. Therefore, as running speed is progressed toward sprinting, the dominant strategy shifts toward the goal of increasing stride frequency and pushing on the ground more frequently. This strategy is achieved by generating substantially more power at the hip joint, thereby increasing the biomechanical demand on proximal lower-limb muscles such as the iliopsoas, gluteus maximus, rectus femoris, and hamstrings. Basic science knowledge regarding lower-limb muscle function during running has implications for understanding why sprinting performance declines with age. It is also of great value to the clinician for designing rehabilitation programs to restore running ability in young, previously active adults who have sustained a traumatic brain injury and have severe impairments of muscle function (eg, weakness, spasticity, poor motor control) that limit their capacity to run at any speed.

Publication

Admittance-matched structures for the reduction of noise in tank making operations

Publisher: Elsevier BV

Date: 07-1984

DOI: 10.1016/0022-460X(84)90547-9

Publication

A Dynamic Model of the Knee and Lower Limb for Simulating Rising Movements

Publisher: Informa UK Limited

Date: 2015

DOI: 10.1080/10255840290010265

Publication

Publisher: Public Library of Science (PLoS)

Date: 09-12-2020

DOI: 10.1371/JOURNAL.PBIO.3001049

Publication

Sensitivity of model predictions of muscle function to changes in moment arms and muscle–tendon properties: A Monte-Carlo analysis

Publisher: Elsevier BV

Date: 05-2012

DOI: 10.1016/J.JBIOMECH.2012.02.023

Abstract: Hill-type muscle models are commonly used in musculoskeletal models to estimate muscle forces during human movement. However, the sensitivity of model predictions of muscle function to changes in muscle moment arms and muscle-tendon properties is not well understood. In the present study, a three-dimensional muscle-actuated model of the body was used to evaluate the sensitivity of the function of the major lower limb muscles in accelerating the whole-body center of mass during gait. Monte-Carlo analyses were used to quantify the effects of entire distributions of perturbations in the moment arms and architectural properties of muscles. In most cases, varying the moment arm and architectural properties of a muscle affected the torque generated by that muscle about the joint(s) it spanned as well as the torques generated by adjacent muscles. Muscle function was most sensitive to changes in tendon slack length and least sensitive to changes in muscle moment arm. However, the sensitivity of muscle function to changes in moment arms and architectural properties was highly muscle-specific muscle function was most sensitive in the cases of gastrocnemius and rectus femoris and insensitive in the cases of hamstrings and the medial sub-region of gluteus maximus. The sensitivity of a muscle's function was influenced by the magnitude of the muscle's force as well as the operating region of the muscle on its force-length curve. These findings have implications for the development of subject-specific models of the human musculoskeletal system.

Publication

Musculoskeletal Model of the Upper Limb Based on the Visible Human Male Dataset

Publisher: Informa UK Limited

Date: 2001

DOI: 10.1080/10255840008908000

Abstract: A mathematical model of the human upper limb was developed based on high-resolution medical images of the muscles and bones obtained from the Visible Human Male (VHM) project. Three-dimensional surfaces of the muscles and bones were reconstructed from Computed Tomography (CT) images and Color Cryosection images obtained from the VHM cadaver. Thirteen degrees of freedom were used to describe the orientations of seven bones in the model: clavicle, scapula, humerus, radius, ulna, carpal bones, and hand. All of the major articulations from the shoulder girdle down to the wrist were included in the model. The model was actuated by 42 muscle bundles, which represented the actions of 26 muscle groups in the upper limb. The paths of the muscles were modeled using a new approach called the Obstacle-set Method [33]. The calculated paths of the muscles were verified by comparing the muscle moment arms computed in the model with the results of anatomical studies reported in the literature. In-vivo measurements of maximum isometric muscle torques developed at the shoulder, elbow, and wrist were also used to estimate the architectural properties of each musculotendon actuator in the model. The entire musculoskeletal model can be reconstructed using the data given in this paper, along with information presented in a companion paper which defines the kinematic structure of the model [26].

Publication

Three-dimensional data-tracking dynamic optimization simulations of human locomotion generated by direct collocation

Publisher: Elsevier BV

Date: 07-2017

DOI: 10.1016/J.JBIOMECH.2017.04.038

Abstract: The aim of this study was to perform full-body three-dimensional (3D) dynamic optimization simulations of human locomotion by driving a neuromusculoskeletal model toward in vivo measurements of body-segmental kinematics and ground reaction forces. Gait data were recorded from 5 healthy participants who walked at their preferred speeds and ran at 2m/s. Participant-specific data-tracking dynamic optimization solutions were generated for one stride cycle using direct collocation in tandem with an OpenSim-MATLAB interface. The body was represented as a 12-segment, 21-degree-of-freedom skeleton actuated by 66 muscle-tendon units. Foot-ground interaction was simulated using six contact spheres under each foot. The dynamic optimization problem was to find the set of muscle excitations needed to reproduce 3D measurements of body-segmental motions and ground reaction forces while minimizing the time integral of muscle activations squared. Direct collocation took on average 2.7±1.0h and 2.2±1.6h of CPU time, respectively, to solve the optimization problems for walking and running. Model-computed kinematics and foot-ground forces were in good agreement with corresponding experimental data while the calculated muscle excitation patterns were consistent with measured EMG activity. The results demonstrate the feasibility of implementing direct collocation on a detailed neuromusculoskeletal model with foot-ground contact to accurately and efficiently generate 3D data-tracking dynamic optimization simulations of human locomotion. The proposed method offers a viable tool for creating feasible initial guesses needed to perform predictive simulations of movement using dynamic optimization theory. The source code for implementing the model and computational algorithm may be downloaded at ome/datatracking.

Publication

High-coverage plasma lipidomics reveals novel sex-specific lipidomic fingerprints of age and BMI: Evidence from two large population cohort studies

Publisher: Public Library of Science (PLoS)

Date: 28-09-2020

DOI: 10.1371/JOURNAL.PBIO.3000870

Publication

A numerical method for simulating the dynamics of human walking

Publisher: Elsevier BV

Date: 1988

DOI: 10.1016/0021-9290(88)90250-3

Abstract: This paper presents a general method for simulating the movement of the lower extremity during human walking. It is based upon two separate algorithms: one for single support (an open kinematic chain), and the other for the double support phase (a closed-loop linkage). Central to each of these is the recursive Newton-Euler inverse dynamics algorithm, applicable, as given, to any serial, spatial linkage. For the unconstrained single support model, the Newton-Euler scheme is applied directly to numerically generate the equations of motion. In the case of double support, however, the kinematic constraint equations are used to first eliminate the redundant degrees of freedom, and then solve for the unknown ground reactions under the constrained limb. The attractiveness of the method is that it offers a compact alternative to manually deriving the equations defining a mathematical model for human gait.

Marcus Pandy

Researcher

Research Topics

Top 5 Research Topics

ANZSRC Field of Research (FoR)

ANZSRC Socio-Economic Objective (SEO)

Related Links

Publications

Anterior-cruciate-ligament reconstruction does not alter the knee-extensor moment arm during gait

Simple and complex models for studying muscle function in walking

Direct Methods for Predicting Movement Biomechanics Based Upon Optimal Control Theory with Implementation in OpenSim

Direct Validation of Human Knee-Joint Contact Mechanics Derived From Subject-Specific Finite-Element Models of the Tibiofemoral and Patellofemoral Joints

Effect of muscle wrapping on model estimates of neck muscle strength

In vivo biomechanical assessment of a novel handle-based wheelchair drive

Forelimb muscle activity during equine locomotion

Evaluation of predicted knee‐joint muscle forces during gait using an instrumented knee implant

Muscle function during gait is invariant to age when walking speed is controlled

A Two-Degree-of-Freedom Knee Model Predicts Full Three-Dimensional Tibiofemoral and Patellofemoral Joint Motion During Functional Activity

Estimates of muscle function in human gait depend on how foot-ground contact is modelled

Evaluation of a subject-specific finite-element model of the equine metacarpophalangeal joint under physiological load

Dynamic Musculoskeletal Models of Human Locomotion: Perspectives on Model Formulation and Control

Targeted physiotherapy for patellofemoral joint osteoarthritis: A protocol for a randomised, single-blind controlled trial

Determinants of cruciate-ligament loading during rehabilitation exercise

Quantitative assessment of gait determinants during single stance via a three-dimensional model—Part 2. Pathological gait

The relationship between tibiofemoral geometry and musculoskeletal function during normal activity

A musculoskeletal model of the knee for evaluating ligament forces during isometric contractions

Load Distribution at the Patellofemoral Joint During Walking

Accuracy of mobile biplane X-ray imaging in measuring 6-degree-of-freedom patellofemoral kinematics during overground gait

Biomechanical response to hamstring muscle strain injury

Mobile biplane X-Ray imaging system for measuring 3D dynamic joint motion during overground gait

Pelvic and Hip Kinematics During Walking in People With Patellofemoral Joint Osteoarthritis Compared to Healthy Age‐Matched Controls

Variation of Neck Muscle Strength Along the Human Cervical Spine

Influence of muscle-tendon wrapping on calculations of joint reaction forces in the equine distal forelimb

Application of ultrasound imaging to subject-specific modelling of the human musculoskeletal system

Integrating modelling, motion capture and x-ray fluoroscopy to investigate patellofemoral function during dynamic activity

Grand challenge competition to predict in vivo knee loads

Six-degree-of-freedom tibiofemoral and patellofemoral joint motion during activities of daily living

Strain energy in the femoral neck during exercise

Mechanics of the human hamstring muscles during sprinting

Shoulder muscle function depends on elbow joint position: An illustration of dynamic coupling in the upper limb

Predictive Simulations of Human Sprinting: Effects of Muscle–Tendon Properties on Sprint Performance

Metabolic Cost and Mechanical Efficiency of a Novel Handle-Based Device for Wheelchair Propulsion

Passive knee joint range of motion is unrelated to the mechanical properties of the patellar tendon

Metabolic Phenotyping of BMI to Characterize Cardiometabolic Risk: Evidence from Large Population-Based Cohorts

In vivo six-degree-of-freedom knee-joint kinematics in overground and treadmill walking following total knee arthroplasty

Mechanical properties of normal and osteoarthritic human articular cartilage

Moment arm of the knee-extensor mechanism measured in vivo across a range of daily activities

Muscles that support the body also modulate forward progression during walking

Tendon elastic strain energy in the human ankle plantar-flexors and its role with increased running speed

Optimal muscular coordination strategies for jumping

Muscular contributions to hip and knee extension during the single limb stance phase of normal gait: a framework for investigating the causes of crouch gait

On the potential of lower limb muscles to accelerate the body's centre of mass during walking

Patellofemoral Joint Loading During Stair Ambulation in People With Patellofemoral Osteoarthritis

In vivo behavior of the human soleus muscle with increasing walking and running speeds

Modulation of work and power by the human lower-limb joints with increasing steady-state locomotion speed

Subject-specific evaluation of patellofemoral joint biomechanics during functional activity

Quantitative evaluation of the major determinants of human gait

Lipidomics Profiling and Risk of Coronary Artery Disease in the BioHEART-CT Discovery Cohort

An optimal control model for determining articular contact forces at the human knee during rising from a static squat position

Simultaneous prediction of muscle and contact forces in the knee during gait

Response to “Letter to the Editor on ‘Muscle function during gait is invariant to age when walking speed is controlled’ by Lim YP, Lin Y-C, Pandy MG (Gait Posture 2013;38(2):253–9)”

An Analytical Framework for Quantifying Muscular Action During Human Movement

A Three-Dimensional Musculoskeletal Model of the Human Knee Joint. Part 2: Analysis of Ligament Function

Measurement of 3D Dynamic Joint Motion Using Biplane Videoradiography

Contributions of muscles, ligaments, and the ground-reaction force to tibiofemoral joint loading during normal gait

Model predictions of increased knee joint loading in regions of thinner articular cartilage after patellar tendon adhesion

Lines of action and stabilizing potential of the shoulder musculature

Muscles that influence knee flexion velocity in double support: implications for stiff-knee gait

Static and dynamic optimization solutions for gait are practically equivalent

Quadriceps volumes are reduced in people with patellofemoral joint osteoarthritis

Influence of muscle loading on early-stage bone fracture healing

Athletes Rated as Poor Single-Leg Squat Performers Display Measurable Differences in Single-Leg Squat Biomechanics Compared With Good Performers

Sensitivity of femoral strain calculations to anatomical scaling errors in musculoskeletal models of movement

Axial Rotation Moment Arms of the Shoulder Musculature After Reverse Total Shoulder Arthroplasty

Three‐dimensional motion of the knee‐joint complex during normal walking revealed by mobile biplane x‐ray imaging

Dynamic Optimization of Human Walking

Force- and moment-generating capacities of muscles in the distal forelimb of the horse

Lower-limb joint mechanics during maximum acceleration sprinting

Moment Arms of the Shoulder Musculature After Reverse Total Shoulder Arthroplasty

Effects of foot orthoses and valgus bracing on the knee adduction moment and medial joint load during gait