ORCID Profile
0000-0002-8448-9936
Current Organisation
Murdoch University
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Publisher: Human Kinetics
Date: 03-2009
DOI: 10.1123/IJSPP.4.1.18
Abstract: Uncoupled cycling cranks are designed to remove the ability of one leg to assist the other during the cycling action. It has been suggested that training with this type of crank can increase mechanical efficiency. However, whether these improvements can confer performance enhancement in already well-trained cyclists has not been reported. Fourteen well-trained cyclists (13 males, 1 female 32.4 ± 8.8 y 74.5 ± 10.3 kg Vo 2max 60.6 ± 5.5 mL·kg −1 ·min −1 mean ± SD) participated in this study. Participants were randomized to training on a stationary bicycle using either an uncoupled (n = 7) or traditional crank (n = 7) system. Training involved 1-h sessions, 3 days per week for 6 weeks, and at a heart rate equivalent to 70% of peak power output (PPO) substituted into the training schedule in place of other training. Vo 2max , lactate threshold, gross efficiency, and cycling performance were measured before and following the training intervention. Pre- and post testing was conducted using traditional cranks. No differences were observed between the groups for changes in Vo 2max , lactate threshold, gross efficiency, or average power maintained during a 30-minute time trial. Our results indicate that 6 weeks (18 sessions) of training using an uncoupled crank system does not result in changes in any physiological or performance measures in well-trained cyclists.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2020
DOI: 10.1186/S12998-020-00344-3
Abstract: The hip abductor muscle group stabilises the pelvis during gait to prevent excessive pelvic drop. Hip abductor weakness has been linked to musculoskeletal conditions such as chronic low-back pain. As such, it is important that practitioners can correctly diagnose hip abductor weakness in a clinical setting. Although the Trendelenburg test is commonly used by practitioners, the validity of this test to assess hip abductor weakness in the absence of musculoskeletal injury remains questionable. The aim of this study was to determine the validity of the Trendelenburg test, as observed by a practitioner, to assess frontal plane pelvic motion and hip abductor strength in a population without intra-articular hip disorders. This study was performed between June 14th and October 16th 2019. Eighteen participants were recruited for this study. Peak normalised isometric and isokinetic hip abductor torque were measured bilaterally ( n = 36) using the Biodex System 4 isokinetic dynamometer. Each participant performed the Trendelenburg test bilaterally ( n = 36) while a graduate year chiropractic practitioner assessed for a “positive” or “negative” sign. The test was simultaneously recorded using Vicon 3-Dimensional motion capture to measure frontal plane pelvic motion and elevation. Correlation analyses were performed between the measures of peak hip abductor torque and pelvic motion to determine if any relationship existed. Agreement between the practitioner and 3-Dimensional analysis was calculated using the kappa (κ) statistic. Weak, non-significant correlations were found between hip abductor strength and pelvic motion before outlier removal. Significant ( p 0.05) yet weak correlations were found after outlier removal, except for isometric hip abductor strength. Weak agreement was found between the chiropractic practitioner and 3-Dimesnional analysis for the Trendelenburg test assessment (κ = 0.22–0.25). This study found no significant relationship between normalised peak isometric and isokinetic hip abductor torque and frontal plane pelvic motion during the Trendelenburg test in a healthy young adult population. There was also poor agreement between the practitioner and pelvic motion assessments. Caution should be used when using this test, in the absence of intra-articular hip pathology, to assesses hip abductor weakness. Before any definitive conclusion can be made, studies with a larger s le size should be performed.
Publisher: University of Technology, Sydney (UTS)
Date: 08-05-2019
Abstract: The paper explores the risk of work-related musculoskeletal injury in tying steel reinforcement bars. Three tools are compared to determine the extent to which ergonomic tools can reduce the risk of injury to the back and wrist in steel-tying. A whole body system of wearable sensors was used to measure biomechanical risk in tying. Three tools were assessed to determine their impact on the risk of work-related musculoskeletal injury when used at different heights. These were: a conventional pincer-cutting tool a power-driven tying tool, and a long handled stapler tool. No tool was found to work best in all situations. The long handled stapler tool significantly reduced trunk inclination when used from ground to shoulder height, but produced higher trunk extension (backward bending) when used above shoulder height. The power tying tool did not reduce the need to bend when working at lower work heights. The power-tying tool produced significantly lower peak wrist flexion values compared to the conventional pincer-cutter tool at all work heights except overhead. The power tying tool involved significantly lower levels of wrist rotation than the conventional pincer-cutter tool at all work heights above knee level. Many assessments of ergonomic risk factors in construction rely on observational methods. The use of small, lightweight wearable sensors permits the objective measurement of biomechanical risk factors for work-related musculoskeletal injury, as well as providing objective performance data that can be used in the design and selection of task-specific tools. Our analysis of work by height also provides insight into the way in which risk factors and reduction opportunities afforded by different tools vary depending on the height at which work is to be performed.
Publisher: Wiley
Date: 25-09-2011
Publisher: Oxford University Press (OUP)
Date: 26-04-2021
Abstract: Novae are some of the most commonly detected optical transients and have the potential to provide valuable information about binary evolution. Binary population synthesis codes have emerged as the most effective tool for modelling populations of binary systems, but such codes have traditionally employed greatly simplified nova physics, precluding detailed study. In this work, we implement a model treating H and He novae as in idual events into the binary population synthesis code binary_c. This treatment of novae represents a significant improvement on the ‘averaging’ treatment currently employed in modern population synthesis codes. We discuss the evolutionary pathways leading to these phenomena and present nova event rates and distributions of several important physical parameters. Most novae are produced on massive white dwarfs, with approximately 70 and 55 per cent of nova events occurring on O/Ne white dwarfs for H and He novae, respectively. Only 15 per cent of H-nova systems undergo a common-envelope phase, but these systems are responsible for the majority of H nova events. All He-accreting He-nova systems are considered post-common-envelope systems, and almost all will merge with their donor star in a gravitational-wave-driven inspiral. We estimate the current annual rate of novae in M31 (Andromeda) to be approximately 41 ± 4 for H novae, underpredicting the current observational estimate of $65^{+15}_{-16}$, and 0.14 ± 0.015 for He novae. When varying common-envelope parameters, the H nova rate varies between 20 and 80 events per year.
Publisher: Springer Science and Business Media LLC
Date: 23-07-2019
Publisher: Springer Science and Business Media LLC
Date: 12-2020
DOI: 10.1186/S40359-020-00502-5
Abstract: Alopecia Areata (AA) is an autoimmune disease that is characterised by hair loss. In iduals diagnosed with it often describe feelings of trauma and social rejection due to cosmetic repercussions and are at high risk of experiencing psychological distress. Physical activity (PA) participation has been associated with better mental health outcomes in erse populations. A preliminary study of in iduals with AA indicated that severe hair loss is associated with symptomatic depression, anxiety and stress, which negatively impacted PA participation. While strategies to increase PA participation in the general population have been established, little is known about PA participation in people with AA. This study aimed to understand barriers and enablers to PA participation in people with AA to inform the development of evidence-based interventions. The study used a grounded theory (GT) methodology, relying on an iterative and simultaneous process of data collection, coding, theory development, and data comparisons to explore the perceived barriers and enablers to PA. Data were collected through a focus group (8 participants [33.38 ± 10.81 years]) and in idual telephone interviews (8 participants [33.89 ± 11.87 years]). The study was conducted in Melbourne, Australia. Interview data were recorded digitally, transcribed verbatim and analysed. Recruitment continued until theoretical saturation was achieved. The constructivist grounded theory method used has assisted to develop an explanatory model which is used to explain the themes for barriers and enablers to PA participation. The four phases in the explanatory model are as follows (1) onset of AA (2) reaction towards the condition (3) adjustment and (4) acceptance. The findings highlighted perceived barriers and enablers to PA participation in people with AA. Future interventions could consider addressing these barriers specifically to maximise effectiveness and to improve mental health status based on the phases of the explanatory model.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2011
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.JSAMS.2016.02.002
Abstract: To evaluate the associations between an objective measure of different intensities of physical activity, upper- and lower-limb muscle strength and psychomotor performance and set-shifting domains of cognitive executive function in older adults. A cross-sectional study. From the Tasmanian Older Adult Cohort Study, 188 community-dwelling older adults (53.7% female mean age±SD 63.98±7.3 years) undertook 7-day physical activity behaviour monitoring using an accelerometer. Dynamometers were used to assess leg extension strength. The Trail Maker Tests were used to measure psychomotor processing speed and set-shifting performance. When controlling for age, smoking history, alcohol intake, educational achievement and neuropsychological functioning, higher levels of light physical activity, but not sedentary behaviour or moderate or vigorous physical activity, was found to be associated with better set-shifting performance. Neither physical activity behaviour or muscle strength were found to be associated with psychomotor performance. In addition, older age, greater alcohol intake, and lower levels of educational attainment, verbal learning and memory performance were significantly associated with lower scores on the set-shifting task whereas older age and reduced neuropsychological functioning were associated with lower psychomotor processing speed scores. Light physical activity is associated with higher executive functioning in community-dwelling older adults and this strengthens the evidence supporting exercise as a neuroprotective agent. Further studies are needed to understand why light physical activity behaviour positively influences executive functioning, and how such physical activity can be implemented into the daily routine of older adults.
Publisher: Informa UK Limited
Date: 05-12-2016
DOI: 10.1080/03091902.2016.1253795
Abstract: To determine the validity of energy expenditure estimation made by the Fitbit One, Garmin Vivofit and Jawbone UP activity trackers during treadmill walking and running. Determining validity of such trackers will inform the interpretation of the data they generate. Cross-sectional study. Fourteen adults walked at 0.70, 1.25, 1.80 ms Energy expenditure estimates from the Fitbit One and Garmin Vivofit correlated significantly (p< 0.01 r= 0.702 0.854) with criterion across all gait speeds (0.70-3.33 ms Energy expenditure reported by the devices distinguished between walking and running, with a general increase as exercise intensity increased. However, the reported energy expenditure from these devices should be interpreted with caution, given their potential bias and error. Practical implications Although devices report the same outcome of EE estimation, they are not equivalent to each other and differ from criterion measurements during walking and running. These devices are not suitable as research measurement tools for recording precise and accurate EE estimates but may be suitable for use in interventions of behaviour change as they provide feedback to user on trends in energy expenditure. If intending to use these devices in studies where precise measurements of energy expenditure are required, researchers need to undertake specific validation and reliability studies prior to interventions and the collection of cross-sectional data.
Publisher: Springer Singapore
Date: 24-09-2017
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.CLNESP.2019.10.009
Abstract: We aimed to investigate the test-retest reliability and validity of ultrasound for two commonly used types of transducer, using different methods for the estimation of muscle size and echo intensity (EI). Fourteen healthy adults were included in this study. Ultrasound images of the rectus femoris size (thickness in cm and cross-sectional area [CSA] in cm No significant differences between the repeated evaluations of rectus femoris thickness, CSA and EI were found. Reliability for thickness and CSA evaluations was excellent for both transducers (ICC = 0.87-0.97) and moderate for EI (ICC = 0.42-0.44). Mean difference between MRI and ultrasound for CSA (curved = 0.59 cm Our study demonstrates that the test-retest reliability and validity of muscle size estimation by ultrasound for both curved and linear array transducers seems to be adequate. Future studies should focus on the longitudinal evaluation of muscle size and EI by ultrasound.
Publisher: Mark Allen Group
Date: 02-2017
DOI: 10.12968/JOWC.2017.26.SUP2.S23
Abstract: The effectiveness of negative pressure wound therapy (NPWT) in the prevention of postoperative surgical wound dehiscence (SWD) is the subject of much debate and remains to be determined. This study will identify in iduals at risk of postoperative SWD and trial the use of NPWT as a prophylactic measure against the occurrence of SWD, compared with a non-NPWT standard surgical dressing (SSD). A prospective multicentre randomised controlled trial comparing NPWT dressing against standard surgical dressings (SSD) will be conducted. An intention-to-treat (ITT) approach will be used for the trial. The primary outcome is the prevention of postoperative SWD up to and including day 30 postoperative. Secondary outcomes are: prevention of surgical site infection (SSI) and economic analysis of treatment groups. This study will determine the effectiveness of NPWT in the prevention of postoperative abdominal SWD in a predefined level of risk population. This level 1 study will provide further data for abdominal SWD risk classification, which is anticipated to inform preventive postoperative management. The study design uses a prospective real-world scenario in order to identify clinically significant differences between the intervention and control groups. This trial was prospectively registered on 10 December 2012 with Australian and New Zealand Clinical Trials Network (ANZCTR): 12612001275853.
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.EXGER.2009.10.013
Abstract: Aging in humans is associated with a loss in neuromuscular function and performance. This is related, in part, to the reduction in muscular strength and power caused by a loss of skeletal muscle mass (sarcopenia) and changes in muscle architecture. Due to these changes, the force-velocity (f-v) relationship of human muscles alters with age. This change has functional implications such as slower walking speeds. Different methods to reverse these changes have been investigated, including traditional resistance training, power training and eccentric (or eccentrically-biased) resistance training. This review will summarise the changes of the f-v relationship with age, the functional implications of these changes and the various methods to reverse or at least partly ameliorate these changes.
Publisher: Human Kinetics
Date: 10-2016
Abstract: There is evidence that an acute bout of exercise confers cognitive benefits, but it is largely unknown what the optimal mode and duration of exercise is and how cognitive performance changes over time after exercise. We compared the cognitive performance of 31 older adults using the Stroop test before, immediately after, and at 30 and 60 min after a 10 and 30 min aerobic or resistance exercise session. Heart rate and feelings of arousal were also measured before, during, and after exercise. We found that, independent of mode or duration of exercise, the participants improved in the Stroop Inhibition task immediately postexercise. We did not find that exercise influenced the performance of the Stroop Color or Stroop Word Interference tasks. Our findings suggest that an acute bout of exercise can improve cognitive performance and, in particular, the more complex executive functioning of older adults.
Publisher: Georg Thieme Verlag KG
Date: 21-04-2023
DOI: 10.1055/A-2044-8952
Abstract: Traditional continuous training and high-intensity interval training (HIIT) can increase maximal oxygen uptake (V̇O2max). However, there is conflicting evidence regarding which form of training demonstrates the greatest improvements to V̇O2max, and data in women is sparse. We conducted a systematic review and meta-analyses to assess whether moderate to vigorous-intensity continuous training (MVICT) or HIIT was superior at improving V̇O2max in women. Randomised controlled and parallel studies examined the influence of MVICT and/or HIIT on V̇O2max in women. There was no statistical difference in V̇O2max improvements after training between women in the MVICT and HIIT cohorts (mean difference [MD]: −0.42, 95%CI: −1.43 to 0.60, p .05). Both MVICT and HIIT increased V̇O2max from baseline (MD: 3.20, 95% CI: 2.73 to 3.67 and MD: 3.16, 95% CI 2.09 to 4.24, respectively, p .001). Greater improvements in V̇O2max were observed in women who participated in more training sessions in both training formats. Long-HIIT was superior to short-HIIT protocols at increasing V̇O2max. Although MVICT and long-HIIT sessions elicited greater increases in V̇O2max in younger women compared to short-HIIT protocols, these differences were negligible in older women. Our findings suggest MVICT and HIIT are equally effective strategies for improving V̇O2max and indicate an effect of age on its response to training in women.
Publisher: SAGE Publications
Date: 20-12-2020
Abstract: To examine whether a fitness tracker (FT) intervention changes physical activity (PA) behavior compared to a control condition or compared to an alternative intervention. Searches between January 01, 2010, and January 01, 2019, were conducted in PubMed, CINAHL, Cochrane CENTRAL, EMBASE, and PsycINFO. Randomized clinical trials of adults using an FT to change PA behavior were included. Nonclinical trials, studies that included the delivery of structured exercise, and/or studies that only used the FT to assess PA were excluded. Extracted features included characteristics of the study population, intervention components, PA outcomes, and results. Papers were pooled in a statistical meta-analysis using a fixed effects model. Where statistical pooling was not possible, standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated. Findings were presented in a narrative form and tables. Of 2076 articles found, 21 were included in the review. A small yet significant positive effect (SMD = 0.25, 95% CI = 0.17-0.32 Trackers may enhance PA interventions, as a general positive effect is found in step count compared to a control. However, there is no evidence of a positive effect when interventions are compared to an alternative intervention. It is unknown whether results are due to other intervention components and/or clinical heterogeneity.
Publisher: SERDI
Date: 2014
DOI: 10.14283/JFA.2014.14
Abstract: Background: Whilst resistance training has been proven to convey considerable benefits to olderpeople immediately post-exercise there may be elevated transient risks for cardiac events and falls. Objectivesand Measurements:We assessed the acute effects of eccentrically-biased (EB) and conventional (CONV)resistance exercise on: platelet number, activation and granule exocytsosis and mean velocity of centre ofpressure displacement (Vm). Design, Setting, Participants and Intervention:Ten older adults (7 males, 3females 69 ± 4 years) participated in this randomised controlled cross-over study in which they performed EBand CONV training sessions that were matched for total work and a control condition. Results:Immediately post-exercise there was a statistically significant difference in platelet count between the control condition, in which ithad declined (pre 224 ± 35 109/L post 211 ± 30 109/L: P 0.05) and CONV in which it had increased (pre 236 ±55 109/L post 242 ± 51 109/L: P 0.05). There was no change in platelet activation and granule exocytsosis orVm following EB and CONV. Conclusions:Overall, while minor differences between regimens were observed,no major adverse effect on parameters of platelet function or centre of pressure displacement were observedacutely following either regimen. Eccentrically-biased and conventional resistance exercise training regimens donot appear to present an elevated acute risk in the context of changes to platelet function contributing to a cardiacevent or postural stability increasing falls risk for apparently healthy older adults.
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.ULTRASMEDBIO.2016.11.013
Abstract: The goal of this study was to determine whether ultrasound measures of muscle architecture can be used to infer strength and functional capacity in older adults. Thirty-six healthy older adults (aged 68.2 ± 5.3 y) undertook isokinetic dynamometry for isometric and isokinetic concentric knee extensor strength, the 6-m fast walk, timed up and go, stair climb and descent and vertical jump tests. Longitudinal brightness-mode ultrasound scans (probe frequency, 10 MHz) of the vastus lateralis, vastus intermedius, rectus femoris and gastrocnemius medialis were obtained, and muscle architecture measures (thickness, fascicle pennation angle and fascicle length) were correlated with the aforementioned strength and functional measures. Quadriceps thickness was a significant (p < 0.05) independent predictor of isometric and isokinetic knee extensor strength (R
Publisher: Human Kinetics
Date: 05-0011
Abstract: Reliable measures of muscle strength and functional capacity in older adults are essential. The aim of this study was to determine whether coefficients of variation (CVs) of in iduals obtained at the first session can infer repeatability of performance in a subsequent session. Forty-eight healthy older adults (mean age 68.6 ± 6.1 years age range 60–80 years) completed two assessment sessions, and on each occasion undertook: dynamometry for isometric and isokinetic quadriceps strength, 6 meter fast walk (6MFWT), timed up and go (TUG), stair climb and descent, and vertical jump. Significant linear relationships were observed between CVs in session 1 and the percentage difference between sessions 1 and 2 for torque at 60, 120, 240 and 360°/s, 6MFWT, TUG, stair climb, and stair descent. The results of this study could be used to establish criteria for determining an acceptably reliable performance in strength and functional tests.
No related grants have been discovered for Isaac Selva Raj.