Publications by authors named "Anthony G Schache"

81 Publications

A Delphi survey and international e-survey evaluating the Doha agreement meeting classification system in groin pain: Where are we 5 years later?

J Sci Med Sport 2021 Jul 6. Epub 2021 Jul 6.

Aspetar Orthopaedic and Sports Medicine Hospital, Qatar. Electronic address:

Objectives: To evaluate the adoption of and opinions on the Doha agreement meeting classification in groin pain in athletes.

Design: Delphi survey and e-survey.

Methods: A 2-round Delphi survey among the Doha agreement meeting expert group, and a separate international e-survey among clinicians who regularly assess athletes with groin pain. Clinical cases were presented, and participants provided their preferred terms for the diagnoses. All participants reported if they had adopted the Doha agreement meeting classification system in their practice. The Doha agreement meeting experts also shared opinions on amendments to the classification system, and reported their level of agreement with suggested statements.

Results: In the Delphi survey, the Doha agreement meeting experts (n = 21) reported 8-11 different terms for their primary diagnosis of each presented case. The Doha agreement meeting terminology was used by 50-67% of these experts. In the international e-survey (n = 51), 12-15 different diagnostic terms were reported in each clinical case, and 43-55% of clinicians used the Doha agreement meeting terminology. Adoption of the Doha agreement classification system in practice was reported by 73-82% of the Doha agreement meeting experts and 57-69% of the clinicians in the international e-survey. The experts suggested 49 statements regarding amendments to the classification system. Seven of these reached >75% agreement or disagreement.

Conclusions: Five years after publication, the majority of the Doha agreement expert group and independent international clinicians report adopting the Doha agreement meeting classification system. There is still considerable heterogeneity in diagnostic terminology when clinical cases are presented, and disagreement on statements related to amendments of the current classification system.
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http://dx.doi.org/10.1016/j.jsams.2021.06.014DOI Listing
July 2021

How muscles maximize performance in accelerated sprinting.

Scand J Med Sci Sports 2021 Oct 27;31(10):1882-1896. Epub 2021 Jul 27.

Department of Mechanical Engineering, University of Melbourne, Parkville, Victoria, Australia.

We sought to provide a more comprehensive understanding of how the individual leg muscles act synergistically to generate a ground force impulse and maximize the change in forward momentum of the body during accelerated sprinting. We combined musculoskeletal modelling with gait data to simulate the majority of the acceleration phase (19 foot contacts) of a maximal sprint over ground. Individual muscle contributions to the ground force impulse were found by evaluating each muscle's contribution to the vertical and fore-aft components of the ground force (termed "supporter" and "accelerator/brake," respectively). The ankle plantarflexors played a major role in achieving maximal-effort accelerated sprinting. Soleus acted primarily as a supporter by generating a large fraction of the upward impulse at each step whereas gastrocnemius contributed appreciably to the propulsive and upward impulses and functioned as both accelerator and supporter. The primary role of the vasti was to deliver an upward impulse to the body (supporter), but these muscles also acted as a brake by retarding forward momentum. The hamstrings and gluteus medius functioned primarily as accelerators. Gluteus maximus was neither an accelerator nor supporter as it functioned mainly to decelerate the swinging leg in preparation for foot contact at the next step. Fundamental knowledge of lower-limb muscle function during maximum acceleration sprinting is of interest to coaches endeavoring to optimize sprint performance in elite athletes as well as sports medicine clinicians aiming to improve injury prevention and rehabilitation practices.
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http://dx.doi.org/10.1111/sms.14021DOI Listing
October 2021

Patellofemoral and tibiofemoral joint loading during a single-leg forward hop following ACL reconstruction.

J Orthop Res 2021 Apr 19. Epub 2021 Apr 19.

La Trobe Sports & Exercise Medicine Research Centre, La Trobe University, Melbourne, Victoria, Australia.

Altered biomechanics are frequently observed following anterior cruciate ligament reconstruction (ACLR). Yet, little is known about knee-joint loading, particularly in the patellofemoral-joint, despite patellofemoral-joint osteoarthritis commonly occurring post-ACLR. This study compared knee-joint reaction forces and impulses during the landing phase of a single-leg forward hop in the reconstructed knee of people 12-24 months post-ACLR and uninjured controls. Experimental marker data and ground forces for 66 participants with ACLR (28 ± 6 years, 78 ± 15 kg) and 33 uninjured controls (26 ± 5 years, 70 ± 12 kg) were input into scaled-generic musculoskeletal models to calculate joint angles, joint moments, muscle forces, and the knee-joint reaction forces and impulses. The ACLR group exhibited a lower peak knee flexion angle (mean difference: -6°; 95% confidence interval: [-10°, -2°]), internal knee extension moment (-3.63 [-5.29, -1.97] percentage of body weight × participant height (body weight [BW] × HT), external knee adduction moment (-1.36 [-2.16, -0.56]% BW × HT) and quadriceps force (-2.02 [-2.95, -1.09] BW). The ACLR group also exhibited a lower peak patellofemoral-joint compressive force (-2.24 [-3.31, -1.18] BW), net tibiofemoral-joint compressive force (-0.74 [-1.20, 0.28] BW), and medial compartment force (-0.76 [-1.08, -0.44] BW). Finally, only the impulse of the patellofemoral-joint compressive force was lower in the ACLR group (-0.13 [-0.23, -0.03] body weight-seconds). Lower compressive forces are evident in the patellofemoral- and tibiofemoral-joints of ACLR knees compared to uninjured controls during a single-leg forward hop-landing task. Our findings may have implications for understanding the contributing factors for incidence and progression of knee osteoarthritis after ACLR surgery.
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http://dx.doi.org/10.1002/jor.25053DOI Listing
April 2021

Physiotherapist-led treatment for femoroacetabular impingement syndrome (the PhysioFIRST study): a protocol for a participant and assessor-blinded randomised controlled trial.

BMJ Open 2021 04 7;11(4):e041742. Epub 2021 Apr 7.

La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Bundoora, Victoria, Australia.

Introduction: This double-blind, randomised controlled trial (RCT) aims to estimate the effect of a physiotherapist-led intervention with targeted strengthening compared with a physiotherapist-led intervention with standardised stretching, on hip-related quality of life (QOL) or perceived improvement at 6 months in people with femoroacetabular impingement (FAI) syndrome. We hypothesise that at 6 months, targeted strengthening physiotherapist-led treatment will be associated with greater improvements in hip-related QOL or greater patient-perceived global improvement when compared with standardised stretching physiotherapist-led treatment.

Methods And Analysis: We will recruit 164 participants with FAI syndrome who will be randomised into one of the two intervention groups, both receiving one-on-one treatment with the physiotherapist over 6 months. The targeted strengthening physiotherapist-led treatment group will receive a personalised exercise therapy and education programme. The standardised stretching physiotherapist-led treatment group will receive standardised stretching and personalised education programme. Primary outcomes are change in hip-related QOL using International Hip Outcome Tool-33 and patient-perceived global improvement. Secondary outcomes include cost-effectiveness, muscle strength, range of motion, functional task performance, biomechanics, hip cartilage structure and physical activity levels. Statistical analyses will make comparisons between both treatment groups by intention to treat, with all randomised participants included in analyses, regardless of protocol adherence. Linear mixed models (with baseline value as a covariate and treatment condition as a fixed factor) will be used to evaluate the treatment effect and 95% CI at primary end-point (6 months).

Ethics And Dissemination: The study protocol was approved (La Trobe University Human Ethics Committee (HEC17-080)) and prospectively registered with the Australian New Zealand Clinical Trials Registry. The findings of this RCT will be disseminated through peer reviewed scientific journals and conferences. Patients were involved in study development and will receive a short summary following the completion of the RCT.

Trial Registration Number: ACTRN12617001350314.
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http://dx.doi.org/10.1136/bmjopen-2020-041742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8031040PMC
April 2021

Lower-limb work during high- and low-impact activities in hip-related pain: Associations with sex and symptom severity.

Gait Posture 2021 01 29;83:1-8. Epub 2020 Sep 29.

La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Bundoora, Victoria, Australia. Electronic address:

Background: Hip-related pain (HRP) is described as a movement-related disorder. However, little attention is given to the way people with HRP move, especially in populations still participating in sport. Thus, limiting our understanding of movementbased impairments in HRP and their potential relationships with pain/symptoms.

Research Question: (1) What are the differences in absolute and relative amounts of positive and negative lower-limb joint work during walking and the single-leg drop jump (SLDJ) in football players with and without HRP? (2) What are the relationships between lower-limb joint work and HRP burden?

Methods: 88 football players with HRP and 30 control football players were recruited. Positive and negative work done by the hip, knee, and ankle (and each joint's relative contribution to total work done) were calculated. The effect of sex on the relationship between HRP and work done, as well as the association between work done and International Hip Outcome Tool (iHOT33) scores, were assessed using linear and beta regressions models.

Results: Walking: No joint work variables were significantly different between groups, nor were any relationships with iHOT33 scores evident. SLDJ: The knee's relative contribution to total lower-limb negative work done was 37.7 % and 42.4 % for women with and without HRP, respectively (P = 0.04). The iHOT33 was significantly associated with positive (P = 0.03 to <0.01) and negative (P = 0.02 to <0.01) work done by the hip as well as negative work done by the ankle (P = 0.03 to 0.01), independent of sex.

Significance: Only one significant between-group comparison was revealed, involving the knee in female football players. In addition, football players with a greater selfreported burden of HRP tended to display lower hip joint work during the SLDJ. Rehabilitation programs could be targeted to address these impairments and normalize work done during high impact tasks in the management of HRP.
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http://dx.doi.org/10.1016/j.gaitpost.2020.09.025DOI Listing
January 2021

Return to Play and Recurrence After Calf Muscle Strain Injuries in Elite Australian Football Players.

Am J Sports Med 2020 11 8;48(13):3306-3315. Epub 2020 Oct 8.

La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Melbourne, Australia.

Background: Calf muscle strain injuries (CMSI) are prevalent in sport, but information about factors associated with time to return to play (RTP) and recurrence is limited.

Purpose: To determine whether clinical and magnetic resonance imaging (MRI) data are associated with RTP and recurrence after CMSI.

Study Design: Case-control study; Level of evidence, 3.

Methods: Data of 149 CMSI reported to the Soft Tissue injury Registry of the Australian Football League were explored to evaluate the impact of clinical data and index injury MRI findings on RTP and recurrence. Clinical data included age, previous injury history, ethnicity, and the mechanism of injury.

Results: Irrespective of the anatomical location, players with CMSI with severe aponeurotic disruption (AD) took longer to RTP than players with CMSI with no AD: 31.3 ± 12.6 days vs 19.4 ± 10.8 days (mean ± SD; = .003). A running-related mechanism of injury was associated with a longer RTP period for CMSI overall (adjusted hazard ratio [AHR], 0.59; = .02). The presence of AD was associated with a longer RTP period for soleus injuries (AHR, 0.6; = .025). Early recurrence (ie, ≤2 months of the index injury) was associated with older age (AHR, 1.3; = .001) and a history of ankle injury (AHR, 3.9; = .032). Older age (AHR, 1.1; = .013) and a history of CMSI (AHR, 6.7; = .002) increased the risk of recurrence within 2 seasons. The index injury MRI findings were not associated with risk of recurrence.

Conclusion: A running-related mechanism of injury and the presence of AD on MRI were associated with a longer RTP period. Clinical rather than MRI data best indicate the risk of recurrent CMSI.
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http://dx.doi.org/10.1177/0363546520959327DOI Listing
November 2020

Muscle contributions to tibiofemoral shear forces and valgus and rotational joint moments during single leg drop landing.

Scand J Med Sci Sports 2020 Sep 17;30(9):1664-1674. Epub 2020 Jun 17.

School of Behavioural and Health, Australian Catholic University, Melbourne, Vic, Australia.

Anterior cruciate ligament (ACL) injuries commonly occur during single-leg landing tasks and are a burdensome condition. Previous studies indicate that muscle forces play an important role in controlling ligamentous loading, yet these studies have typically used cadaveric models considering only the knee-spanning quadriceps, hamstrings, and gastrocnemius muscle groups. Any muscles (including non-knee-spanning muscles) capable of opposing the anterior shear joint reaction force and the valgus joint reaction moment are thought to have the greatest potential for protecting the ACL from injury. Thus, the purpose of this study was to investigate how lower-limb muscles modulate knee joint loading during a single-leg drop landing task. An electromyography-informed neuromusculoskeletal modeling approach was used to compute lower-limb muscle force contributions to the anterior shear joint reaction force and the valgus joint reaction moment at the knee during a single-leg drop landing task. The average shear joint reaction force ranged from 153 N of anterior shear force to 744 N of posterior shear force. The muscles that generated the greatest posterior shear force were the soleus, medial hamstrings, and biceps femoris, contributing up to 393 N, 359 N, and 162 N, respectively. The average frontal plane joint reaction moment ranged from a 19 Nm varus moment to a 6 Nm valgus moment. The valgus moment was primarily opposed by the gluteus medius, gluteus minimus, and soleus, with these muscles providing contributions of up to 38, 22, and 20 Nm toward a varus moment, respectively. The findings identify key muscles that mitigate loads on the ACL.
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http://dx.doi.org/10.1111/sms.13711DOI Listing
September 2020

Between-Limb Differences in Patellofemoral Joint Forces During Running at 12 to 24 Months After Unilateral Anterior Cruciate Ligament Reconstruction.

Am J Sports Med 2020 06 6;48(7):1711-1719. Epub 2020 May 6.

School of Allied Health, La Trobe University, Victoria, Australia.

Background: Patellofemoral joint (PFJ) osteoarthritis may occur after anterior cruciate ligament reconstruction (ACLR). The mechanisms underpinning the development of PFJ osteoarthritis are not known but may relate to altered PFJ loading. Few studies have assessed PFJ loads during high-impact tasks, such as running, beyond the acute rehabilitation phase (ie, >12 months) after ACLR.

Purpose/hypothesis: The purpose was to compare between-limb joint angles, joint moments, and PFJ contact force during running in individuals at 12 to 24 months after unilateral ACLR. We hypothesized that peak knee flexion angle, knee extension moment, and PFJ contact force during stance would be lower in the ACLR limb compared with the uninjured limb.

Study Design: Controlled laboratory study.

Methods: A total of 55 participants (mean ± SD age, 28 ± 7 years), 12 to 24 months after ACLR, ran at a self-selected speed (2.9 ± 0.3 m/s). Measured kinematics and ground-reaction forces were input into musculoskeletal models to calculate joint moments and muscle forces. These values were subsequently input into a PFJ model to calculate contact force peak and impulse. Outcome measures were compared between the ACLR and uninjured limbs.

Results: In the ACLR limb, compared with the uninjured limb, the PFJ contact force displayed a lower peak (ACLR, 6.1 ± 1.3 body weight [BW]; uninjured, 6.7 ± 1.4 BW; < .001) and impulse (ACLR, 0.72 ± 0.17 BW*seconds [BWs]; uninjured, 0.81 ± 0.17 BWs; < .001). At the time of the peak PFJ contact force, the knee extension moment was lower in the ACLR limb (ACLR, 14.0 ± 2.4 %BW*height [%BW*HT]; uninjured, 15.5 ± 2.5 %BW*HT; < .001). The opposite was true for the ankle plantarflexion moment (ACLR, 12.1 ± 2.6 %BW*HT; uninjured, 11.5 ± 2.7 %BW*HT; = .019) and the hip extension moment (ACLR, 2.3 ± 2.5 %BW*HT; uninjured, 1.6 ± 2.3 %BW*HT; = .013). The foot-ground center of pressure was located more anteriorly with respect to the ankle joint center (ACLR, 5.8 ± 0.9 %height [%HT]; uninjured, 5.4 ± 1.0 %HT; = .001). No differences were found for the sagittal plane hip, knee, and ankle angles.

Conclusion: The ACLR limb experienced lower peak PFJ loads during running, explained by a small anterior shift in the foot-ground center of pressure during stance that offloaded the torque demand away from the ACLR knee.

Clinical Relevance: Lower net PFJ loading during running in the ACLR limb more than 12 months after ACLR suggests that underloading might play a role in the onset of PFJ osteoarthritis after ACLR.
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http://dx.doi.org/10.1177/0363546520914628DOI Listing
June 2020

Lower-Limb Biomechanics in Football Players with and without Hip-related Pain.

Med Sci Sports Exerc 2020 08;52(8):1776-1784

La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Bundoora, Victoria, AUSTRALIA.

Purpose: This study aimed to evaluate the differences in lower-limb biomechanics between adult subelite competitive football players with and without hip-related pain during two contrasting tasks-walking and single-leg drop jump (SLDJ)-and to determine whether potential differences, if present, are sex dependent.

Methods: Eighty-eight football players with hip-related pain (23 women, 65 men) and 30 asymptomatic control football players (13 women, 17 men) who were currently participating in competitive sport were recruited. Biomechanical data were collected for the stance phase of walking and SLDJ. Pelvis, hip, knee, and ankle angles, as well as the impulse of the external joint moments, were calculated. Differences between groups and sex-specific effects were calculated using linear regression models.

Results: Compared with their asymptomatic counterparts, football players with hip-related pain displayed a lower average pelvic drop angle during walking (P = 0.03) and a greater average pelvic hike angle during SLDJ (P < 0.05). Men with hip-related pain displayed a smaller total range of motion (excursion) for the transverse plane pelvis angle (P = 0.03) and a smaller impulse of the hip external rotation moment (P < 0.01) during walking compared with asymptomatic men. Women with hip-related pain displayed a greater total range of motion (excursion) for the sagittal plane knee angle (P = 0.01) during walking compared with asymptomatic women.

Conclusion: Overall, few differences were observed in lower-limb biomechanics between football players with and without hip-related pain, irrespective of the task. This outcome suggests that, despite the presence of symptoms, impairments in lower-limb biomechanics during function do not appear to be a prominent feature of people with hip-related pain who are still participating in sport.
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http://dx.doi.org/10.1249/MSS.0000000000002297DOI Listing
August 2020

Muscle contributions to medial and lateral tibiofemoral compressive loads during sidestep cutting.

J Biomech 2020 03 16;101:109641. Epub 2020 Jan 16.

School of Behavioural and Health Sciences, Australian Catholic University, Melbourne, Australia.

The tibiofemoral compressive forces experienced during functional activities are believed to be important for maintaining tibiofemoral stability. Previous studies have shown that both knee-spanning and non-knee-spanning muscles contribute to tibiofemoral joint compressive forces during walking. However, healthy individuals typically engage in more vigorous activities (e.g. jumping and cutting) that provide greater challenges to tibiofemoral stability. Despite this, no previous studies have investigated how both knee-spanning and non-knee-spanning muscles contribute to tibiofemoral compressive loading during such tasks. The present study investigated how muscles contributed to the medial and lateral compartment tibiofemoral compressive forces during sidestep cutting. Three-dimensional marker trajectories, ground reaction forces and muscle electromyographic signals were collected from eight healthy males whilst they completed unanticipated sidestep cutting. OpenSim was used to perform musculoskeletal simulations to compute the contribution of each lower-limb muscle to compressive loading of each compartment of the knee. The greatest contributors to medial compartment loading were the vasti, gluteus maximus and medius, and the medial gastrocnemius. The greatest contributors to lateral compartment loading were the vasti, adductors, medial and lateral gastrocnemius, and the soleus. The soleus displayed the greatest potential for unloading the medial compartment, whereas the gluteus maximus and medius displayed the greatest potential for unloading the lateral compartment. These findings may help to inform interventions aiming to modulate compressive loading at the knee.
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http://dx.doi.org/10.1016/j.jbiomech.2020.109641DOI Listing
March 2020

Lower-limb joint mechanics during maximum acceleration sprinting.

J Exp Biol 2019 11 25;222(Pt 22). Epub 2019 Nov 25.

Department of Mechanical Engineering, University of Melbourne, Parkville, VIC 3010, Australia.

We explored how humans adjust the stance phase mechanical function of their major lower-limb joints (hip, knee, ankle) during maximum acceleration sprinting. Experimental data [motion capture and ground reaction force (GRF)] were recorded from eight participants as they performed overground sprinting trials. Six alternative starting locations were used to obtain a dataset that incorporated the majority of the acceleration phase. Experimental data were combined with an inverse-dynamics-based analysis to calculate lower-limb joint mechanical variables. As forward acceleration magnitude decreased, the vertical GRF impulse remained nearly unchanged whereas the net horizontal GRF impulse became smaller as a result of less propulsion and more braking. Mechanical function was adjusted at all three joints, although more dramatic changes were observed at the hip and ankle. The impulse from the ankle plantar-flexor moment was almost always larger than those from the hip and knee extensor moments. Forward acceleration magnitude was linearly related to the impulses from the hip extensor moment ( =0.45) and the ankle plantar-flexor moment ( =0.47). Forward acceleration magnitude was also linearly related to the net work done at all three joints, with the ankle displaying the strongest relationship ( =0.64). The ankle produced the largest amount of positive work (1.55±0.17 J kg) of all the joints, and provided a significantly greater proportion of the summed amount of lower-limb positive work as running speed increased and forward acceleration magnitude decreased. We conclude that the hip and especially the ankle represent key sources of positive work during the stance phase of maximum acceleration sprinting.
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http://dx.doi.org/10.1242/jeb.209460DOI Listing
November 2019

Calf muscle strain injuries in elite Australian Football players: A descriptive epidemiological evaluation.

Scand J Med Sci Sports 2020 Jan 8;30(1):174-184. Epub 2019 Oct 8.

La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Melbourne, Australia.

Background: Calf muscle strain injuries (CMSI) show consistent rates of prevalence and re-injury in elite Australian Football players. An epidemiological evaluation is warranted to better understand the clinical presentation and recovery of CMSI.

Purpose: First, to describe the epidemiology of CMSI in elite Australian Football players. Second, to determine if recovery following injury is different according to: (a) injury type (index vs re-injury); (b) muscle injured (soleus vs gastrocnemius); and (c) mechanism of injury (running-related activity vs non running-related activity).

Study Design: Descriptive epidemiological.

Methods: Data retrieved from the Soft Tissue injury Registry of the Australian Football League were analyzed. Sixteen clubs submitted data on CMSI from 2014 to 2017. Data included: player characteristics, training and match history at the time of injury, MRI, and the time to reach recovery milestones.

Results: One hundred and eighty-four CMSI were included (149 index injuries; 35 re-injuries). Soleus injuries were most prevalent (84.6%). Soleus injuries took 25.4 ± 16.2 days to return to play, whereas gastrocnemius injuries took 19.1 ± 14.1 days (P = .097). CMSI sustained during running-related activities took approximately 12 days longer to recover than injuries sustained during non running-related activities (P = .001). Compared to index injuries, re-injuries involved older players (P = .03) and significantly more time was taken to run at >90% of maximum speed, return to full training, and return to play (P ≤ .001). Almost all of the observed re-injuries involved soleus (91.4%).

Conclusion: Soleus injuries are more prevalent than gastrocnemius injuries in elite Australian Football players. Prognosis appears to be influenced by clinical factors, with CMSI sustained during running-related activities and re-injuries needing more time to recover.
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http://dx.doi.org/10.1111/sms.13552DOI Listing
January 2020

Biomechanical Leg Muscle Function During Stair Ambulation in Men Receiving Androgen Deprivation Therapy.

J Gerontol A Biol Sci Med Sci 2020 09;75(9):1715-1722

Department of Medicine (Austin Health), Victoria.

Background: The role of testosterone in maintaining functional performance in older men remains uncertain.

Methods: We conducted a 12-month prospective, observational case-control study including 34 men newly commencing androgen deprivation therapy for prostate cancer and 29 age-matched prostate cancer controls. Video-based motion capture and ground reaction force data combined with computational musculoskeletal modeling, and data were analyzed with a linear mixed model.

Results: Compared with controls over 12 months, men receiving androgen deprivation therapy had a mean reduction in circulating testosterone from 14.1 nmol/L to 0.4 nmol/L, associated with reductions in peak knee extension torque, mean adjusted difference (MAD) -0.07 Nm/kg (95% confidence interval [CI]: -0.18, 0.04), p = .009, with a corresponding more marked decrease in quadriceps force MAD -0.11 × body weight (BW) [-0.27, 0.06], p = .045 (equating to a 9 kg force reduction for the mean body weight of 85 kg), and decreased maximal contribution of quadriceps to upward propulsion, MAD -0.47 m/s2 [-0.95, 0.02], p = .009. We observed between-group differences in several other parameters, including increased gluteus maximus force in men receiving androgen deprivation therapy, MAD 0.11 × BW [0.02, 0.20], p = .043, which may be compensatory.

Conclusions: Severe testosterone deprivation over 12 months is associated with selective deficits in lower-limb function evident with an important task of daily living.
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http://dx.doi.org/10.1093/gerona/glz169DOI Listing
September 2020

Lower limb biomechanics during low- and high-impact functional tasks differ between men and women with hip-related groin pain.

Clin Biomech (Bristol, Avon) 2019 08 3;68:96-103. Epub 2019 Jun 3.

La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Bundoora, Victoria, Australia. Electronic address:

Background: The effect of pain on lower limb biomechanics during walking has been found to be sex specific for certain joint diseases. However, it is not known if sex is an effect-modifier in people with hip pain. Therefore, the aim of the study was to determine the differences in lower limb biomechanics between men and women with hip-related groin pain during functional tasks.

Methods: 65 male and 23 female football players with hip-related groin pain were recruited. Biomechanical data were recorded during walking and the single-leg drop jump. Hip, knee and ankle joint kinematics and kinetics were calculated. Differences between men and women were assessed using statistical parametric mapping.

Findings: Walking: Men with hip-related groin pain walked with lower hip flexion and internal rotation angles during stance compared to women. During different sections of stance, men also displayed a lower hip adduction angle and 'external' adduction moment, a lower knee flexion angle and 'external' flexion moment, as well as greater 'external' dorsi-flexion moment and impulse. Single-leg drop jump: Men with hip-related groin pain displayed a lower hip flexion angle during early stance, and greater 'external' knee flexion and ankle dorsi-flexion moments. The impulse of the 'external' dorsi-flexion moment was also greater for men compared to women.

Interpretation: Men and women with hip-related groin pain display differing lower limb biomechanics in both low and high impact tasks. Sex may therefore be a potential effect modifier in people with hip-related groin pain. Future research in this area should incorporate sex-specific analyses.

Trial Registration Number: NA.
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http://dx.doi.org/10.1016/j.clinbiomech.2019.06.001DOI Listing
August 2019

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

J Orthop Res 2019 03 27;37(3):615-630. Epub 2019 Feb 27.

Department of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia.

Accurate knowledge of knee kinematics is important for a better understanding of normal joint function and for improving patient outcomes subsequent to joint reconstructive surgery. Limited information is available that accurately describes the relative movements of the bones at the knee in vivo, even for the most common of all activities: walking. We used a mobile X-ray imaging system to measure the three-dimensional motion of the entire knee-joint complex-femur, tibia, and patella-when humans walk over ground at their natural speeds. Data were recorded from 15 healthy individuals (9 males, 6 females; age 30.5 ± 6.2 years). The most pronounced rotational motion of the tibia was flexion-extension followed by internal-external rotation and abduction-adduction (peak-to-peak displacements: 70.7°, 9.2°, and 1.9°, respectively). Maximum anterior translation of the tibia was 6.5 mm and occurred in early swing, coinciding with peak knee flexion and peak internal rotation. The most prominent rotational motion of the patella was flexion-extension (peak-to-peak displacement: 50.5°). The tibia pivoted about the medial compartment of the tibiofemoral joint, conferring greater movements of the contact centers in the lateral compartment than the medial compartment (15.4 and 9.7 mm, respectively). Internal-external rotation, anterior-posterior translation and medial-lateral shift of the tibia as well as flexion-extension and anterior-posterior translation of the patella were each coupled to the knee flexion angle, as were movements of the contact centers at each joint. These fundamental data serve as a valuable resource for evaluating knee joint function in normal and pathological gait. The data are available in Supplementary_Material_Data.xlsx. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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http://dx.doi.org/10.1002/jor.24226DOI Listing
March 2019

Impaired ankle joint mechanics during running can be resolved in people with traumatic brain injury.

Brain Inj 2019 20;33(5):670-678. Epub 2019 Jan 20.

c La Trobe Sport and Exercise Medicine Research Centre , La Trobe University , Bundoora , Victoria , Australia.

Objectives: 1) To compare lower-limb joint mechanics during running for people with traumatic brain injury (TBI) to equivalent data obtained from a group of healthy controls (HCs); and 2) To determine if deficits identified in biomechanical variables during running for people with TBI responded to a six-month period of rehabilitation.

Methods: Running biomechanics data were recorded from 12 people with TBI who were attending a large metropolitan rehabilitation hospital for mobility limitations, and a comparative sample of 10 HCs at baseline and six-month follow-up.

Main Measures: Average power absorbed and generated at the hip, knee and ankle joints during stance.

Results: Compared to HCs, participants with TBI at baseline ran with greater average power absorption at the hip (-0.27 W/kg vs -0.61 W/kg; p< 0.05), reduced average power absorption at the knee (-2.03 W/kg vs -1.02 W/kg; p< 0.05) and reduced average power generation at the ankle (2.86 W/kg vs 2.06 W/kg; p< 0.05). Only average power generation at the ankle improved following six-months of rehabilitation for the participants with TBI (2.06 W/kg vs 2.79 W/kg; p< 0.05).

Conclusion: For the participants with TBI in the present study, recovery of high-level mobility following rehabilitation occurred alongside an improvement in ankle joint mechanics during running.
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http://dx.doi.org/10.1080/02699052.2019.1567940DOI Listing
April 2020

Lower-limb muscle function during sidestep cutting.

J Biomech 2019 01 26;82:186-192. Epub 2018 Oct 26.

School of Behavioural and Health Sciences, Australian Catholic University, Melbourne, Australia.

To investigate lower-limb muscle function during sidestep cutting, prior studies have analysed electromyography (EMG) data together with three dimensional motion analysis. Such an approach does not directly quantify the biomechanical role of individual lower-limb muscles during a sidestep cut. This study recorded three dimensional motion analysis, ground reaction force (GRF) and EMG data for eight healthy males executing an unanticipated sidestep cut. Using a musculoskeletal modelling approach, muscle function was determined by computing the muscle contributions to the GRFs and lower-limb joint moments. We found that bodyweight support (vertical GRF) was primarily provided by the vasti, gluteus maximus, soleus and gastrocnemius. These same muscles, along with the hamstrings, were also primarily responsible for modulating braking and propulsion (anteroposterior GRF). The vasti, gluteus maximus and gluteus medius were the key muscles for accelerating the centre-of-mass towards the desired cutting direction by generating a medially-directed GRF. Our findings have implications for designing retraining programs to improve sidestep cutting technique.
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http://dx.doi.org/10.1016/j.jbiomech.2018.10.021DOI Listing
January 2019

Is Running Better than Walking for Reducing Hip Joint Loads?

Med Sci Sports Exerc 2018 11;50(11):2301-2310

Department of Mechanical Engineering, University of Melbourne, Melbourne, Victoria, AUSTRALIA.

Purpose: Knowledge of hip biomechanics during locomotion is necessary for designing optimal rehabilitation programs for hip-related conditions. The purpose of this study was to: 1) determine how lower-limb muscle contributions to the hip contact force (HCF) differed between walking and running; and 2) compare both absolute and per-unit-distance (PUD) loads at the hip during walking and running.

Methods: Kinematic and ground reaction force data were captured from eight healthy participants during overground walking and running at various steady-state speeds (walking: 1.50 ± 0.11 m·s and 1.98 ± 0.03 m·s; running: 2.15 ± 0.18 m·s and 3.47 ± 0.11 m·s). A three-dimensional musculoskeletal model was used to calculate the HCF as well as lower-limb muscular contributions to the HCF in each direction (posterior-anterior; inferior-superior; lateral-medial). The impulse of the resultant HCF was calculated as well as the PUD impulse (BW·s·m) and PUD force (BW·m).

Results: For both walking and running, HCF magnitude was greater during stance than swing and was largest in the inferior-superior direction and smallest in the posterior-anterior direction. Gluteus medius, iliopsoas, and gluteus maximus generated the largest contributions to the HCF during stance, whereas iliopsoas and hamstrings generated the largest contributions during swing. When comparing all locomotion conditions, the impulse of the resultant HCF was smallest for running at 2.15 m·s with an average magnitude of 2.14 ± 0.31 BW·s, whereas the PUD impulse and force were smallest for running at 3.47 m·s with average magnitudes of 0.95 ± 0.18 BW·s·m and 1.25 ± 0.24 BW·m, respectively.

Conclusions: Hip PUD loads were lower for running at 3.47 m·s compared with all other locomotion conditions because of a greater distance travelled per stride (PUD impulse) or a shorter stride duration combined with a greater distance travelled per stride (PUD force).
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http://dx.doi.org/10.1249/MSS.0000000000001689DOI Listing
November 2018

Sub-elite Football Players With Hip-Related Groin Pain and a Positive Flexion, Adduction, and Internal Rotation Test Exhibit Distinct Biomechanical Differences Compared With the Asymptomatic Side.

J Orthop Sports Phys Ther 2018 07 8;48(7):584-593. Epub 2018 May 8.

Background Hip-related groin pain is common in sub-elite football players and may be associated with altered hip biomechanics. Objectives To compare the hip biomechanics, bony hip morphology associated with femoroacetabular impingement (FAI) syndrome, and hip strength and range of motion (ROM) between the symptomatic and asymptomatic limbs of sub-elite football players with unilateral hip-related groin pain and a positive flexion, adduction, and internal rotation (FADIR) test. Methods Fifteen sub-elite football (soccer) players with unilateral hip-related groin pain and a positive FADIR test were recruited for this observational cross-sectional study. Three-dimensional motion analysis and ground reaction force data were recorded for walking and a single-leg drop-jump (SLDJ) task. Participants also underwent a standard anterior-posterior hip radiograph and hip strength and ROM assessment. Between-limb differences were assessed using paired t tests or Wilcoxon signed-rank tests. Results The symptomatic limb displayed a smaller peak hip extension angle (P = .01) and a lower peak hip adduction moment (P = .03) compared with the asymptomatic limb during the stance phase of walking. Additionally, during the SLDJ, the symptomatic limb demonstrated less total sagittal plane ROM (P = .04). The symptomatic limb also demonstrated less external rotation ROM (P = .03). However, no differences were found between limbs for bony hip morphology associated with FAI syndrome or hip strength. Conclusion This study found between-limb asymmetries in low- and high-impact functional tasks, such as walking and an SLDJ, in football players with unilateral hip-related groin pain. Despite unilateral pain, bony morphology associated with FAI syndrome did not differ between limbs. J Orthop Sports Phys Ther 2018;48(7):584-593. Epub 8 May 2018. doi:10.2519/jospt.2018.7910.
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http://dx.doi.org/10.2519/jospt.2018.7910DOI Listing
July 2018

Non-knee-spanning muscles contribute to tibiofemoral shear as well as valgus and rotational joint reaction moments during unanticipated sidestep cutting.

Sci Rep 2018 02 6;8(1):2501. Epub 2018 Feb 6.

School of Exercise Sciences, Australian Catholic University, Melbourne, Australia.

Anterior cruciate ligament (ACL) injuries are a burdensome condition due to potential surgical requirements and increased risk of long term debilitation. Previous studies indicate that muscle forces play an important role in the development of ligamentous loading, yet these studies have typically used cadaveric models considering only the knee-spanning quadriceps, hamstrings and gastrocnemius muscle groups. Using a musculoskeletal modelling approach, we investigated how lower-limb muscles produce and oppose key tibiofemoral reaction forces and moments during the weight acceptance phase of unanticipated sidestep cutting. Muscles capable of opposing (or controlling the magnitude of) the anterior shear force and the external valgus moment at the knee are thought to be have the greatest potential for protecting the anterior cruciate ligament from injury. We found the best muscles for generating posterior shear to be the soleus, biceps femoris long head and medial hamstrings, providing up to 173N, 111N and 77N of force directly opposing the anterior shear force. The valgus moment was primarily opposed by the gluteus medius, gluteus maximus and piriformis, with these muscles providing contributions of up to 32 Nm, 19 Nm and 21 Nm towards a knee varus moment, respectively. Our findings highlight key muscle targets for ACL preventative and rehabilitative interventions.
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http://dx.doi.org/10.1038/s41598-017-19098-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5802728PMC
February 2018

Femoroacetabular impingement and hip OsteoaRthritis Cohort (FORCe): protocol for a prospective study.

J Physiother 2018 01 27;64(1):55. Epub 2017 Dec 27.

La Trobe Sport and Exercise Medicine Research Centre, College of Science, Health and Engineering, La Trobe University; Department of Mechanical Engineering, University of Melbourne, Melbourne.

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http://dx.doi.org/10.1016/j.jphys.2017.10.004DOI Listing
January 2018

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

J Sport Rehabil 2018 Nov 13;27(6):546-553. Epub 2018 Oct 13.

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.
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http://dx.doi.org/10.1123/jsr.2016-0208DOI Listing
November 2018

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

Arthritis Care Res (Hoboken) 2018 02 29;70(2):309-314. Epub 2017 Dec 29.

University of Melbourne, Parkville, Victoria, Australia.

Objective: 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.

Methods: 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).

Results: 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.

Conclusion: 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.
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http://dx.doi.org/10.1002/acr.23261DOI Listing
February 2018

Anatomical and morphological characteristics may explain why groin pain is more common in male than female athletes.

Br J Sports Med 2017 Apr 1;51(7):554-555. Epub 2016 Dec 1.

La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, La Trobe University, Melbourne, Victoria, Australia.

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http://dx.doi.org/10.1136/bjsports-2016-096945DOI Listing
April 2017

Androgen deprivation causes selective deficits in the biomechanical leg muscle function of men during walking: a prospective case-control study.

J Cachexia Sarcopenia Muscle 2017 Feb 2;8(1):102-112. Epub 2016 Aug 2.

Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia.

Background: Although muscle mass declines with testosterone deficiency in men, previous studies of muscle function have not demonstrated consistent deficits, likely due to relatively insensitive methodology. Our objective was to determine the effects of testosterone deprivation on the biomechanical function of individual lower-limb muscles.

Methods: We conducted a 12-month prospective, observational case-control study of 34 men newly commencing androgen deprivation treatment (ADT) for prostate cancer and 29 age-matched prostate cancer controls. Participants were assessed at 0, 6, and 12 months while walking in a biomechanics laboratory. We combined video-based motion capture and ground reaction force data with computerized musculoskeletal modelling to assess the following primary outcomes: (i) peak joint torques at the hip, knee and ankle, and corresponding individual muscle forces; (ii) individual muscle contributions to acceleration of the body's centre of mass; and (iii) walking speed, stride length, and step width. A linear mixed model was used to compare mean differences between groups.

Results: Compared with controls over 12 months, men receiving ADT had a mean reduction in total testosterone level from 14.1 to 0.4 nmol/L, and demonstrated more marked decreases in peak hip flexor torque by 14% [mean difference -0.11 N/kg (-0.19, -0.03), P = 0.01] and peak knee extensor torque by 16% [-0.11 N/kg (-0.20, -0.02), P = 0.02] of the initial mean value. Correspondingly, iliopsoas force decreased by 14% (P = 0.006), and quadriceps force decreased by 11%, although this narrowly missed statistical significance (P = 0.07). Soleus decreased contribution to forward acceleration of the body's centre of mass by 17% [mean difference -0.17 m/s (-0.29, -0.05), P < 0.01]. No significant changes between groups were observed in other joint torques or individual muscle contributions to acceleration of the body. Step width increased by 18% [mean adjusted difference 1.4 cm (0.6, 27.4), P = 0.042] in the ADT group compared with controls, with no change in stride length or walking speed.

Conclusions: Testosterone deprivation selectively decreases lower-limb muscle function, predominantly affecting muscles that support body weight, accelerate the body forwards during walking, and mediate balance. Future exercise and pro-myogenic interventional studies to mitigate ADT-associated sarcopenia should target these deficits.
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http://dx.doi.org/10.1002/jcsm.12133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5326829PMC
February 2017

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

J Orthop Res 2017 08 4;35(8):1634-1643. Epub 2016 Nov 4.

Department of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia.

No data are available to describe six-degree-of-freedom (6-DOF) knee-joint kinematics for one complete cycle of overground walking following total knee arthroplasty (TKA). The aims of this study were firstly, to measure 6-DOF knee-joint kinematics and condylar motion for overground walking following TKA; and secondly, to determine whether such data differed between overground and treadmill gait when participants walked at the same speed during both tasks. A unique mobile biplane X-ray imaging system enabled accurate measurement of 6-DOF TKA knee kinematics during overground walking by simultaneously tracking and imaging the joint. The largest rotations occurred for flexion-extension and internal-external rotation whereas the largest translations were associated with joint distraction and anterior-posterior drawer. Strong associations were found between flexion-extension and adduction-abduction (R  = 0.92), joint distraction (R  = 1.00), and anterior-posterior translation (R  = 0.77), providing evidence of kinematic coupling in the TKA knee. Although the measured kinematic profiles for overground walking were grossly similar to those for treadmill walking, several statistically significant differences were observed between the two conditions with respect to temporo-spatial parameters, 6-DOF knee-joint kinematics, and condylar contact locations and sliding. Thus, caution is advised when making recommendations regarding knee implant performance based on treadmill-measured knee-joint kinematic data. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1634-1643, 2017.
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http://dx.doi.org/10.1002/jor.23466DOI Listing
August 2017

Patients With Chondrolabral Pathology Have Bilateral Functional Impairments 12 to 24 Months After Unilateral Hip Arthroscopy: A Cross-sectional Study.

J Orthop Sports Phys Ther 2016 Nov;46(11):947-956

Study Design Cross-sectional study. Background Functional task performance in patients with chondrolabral pathology following hip arthroscopy is unknown. Objectives To investigate in people with chondrolabral pathology following hip arthroscopy (1) the bilateral differences in functional task performance compared to controls, (2) the association of hip muscle strength with functional task performance, and (3) the association of functional task performance scores with good outcome, as measured by International Hip Outcome Tool score. Methods Seventy-one patients who had unilateral hip arthroscopy for hip pain and 60 controls were recruited. Patient-reported outcomes included the 4 subscales of the International Hip Outcome Tool. Hip muscle strength measures included abduction, adduction, extension, flexion, external rotation, and internal rotation. Functional tasks assessed included the single hop test, the side bridge test, and the single-leg rise test. For aim 1, analyses of covariance tests were used. For aim 2, stepwise multiple linear regression analyses were used. For aim 3, receiver operating characteristic curve analyses were used. Results Compared to controls, the chondrolabral pathology group had significantly worse performance on both legs for each of the functional tasks (P<.001). Greater hip abduction strength was moderately associated with better performance on functional tasks in the chondrolabral pathology group (adjusted R range, 0.197-0.407; P<.001). Cutoff values associated with good outcome were 0.37 (hop distance/height) for the single hop, 16 repetitions for the single-leg rise, and 34 seconds for the side bridge test. Conclusion Patients with hip chondrolabral pathology had reduced functional task performance bilaterally 12 to 24 months after unilateral hip arthroscopy when compared to controls. Level of Evidence Therapy/symptom prevalence, level 3b. J Orthop Sports Phys Ther 2016;46(11):947-956. doi:10.2519/jospt.2016.6577.
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November 2016

Hip Biomechanics Are Altered in Male Runners with Achilles Tendinopathy.

Med Sci Sports Exerc 2017 03;49(3):549-554

1School of Exercise Science, Australian Catholic University, AUSTRALIA; 2School of Physiotherapy, Australian Catholic University, AUSTRALIA; 3Centre for Musculoskeletal Research, Mary MacKillop Institute for Health Research, Australian Catholic University, AUSTRALIA; 4Department of Mechanical Engineering, The University of Melbourne, AUSTRALIA; and 5La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, La Trobe University, AUSTRALIA.

Purpose: Achilles tendinopathy (AT) is a prevalent injury in running sports. Understanding the biomechanical factors associated with AT will assist in its management and prevention. The purpose of this study was to compare hip and ankle kinematics and kinetics in runners with and without AT.

Methods: Fourteen male runners with AT and 11 healthy male runners (CTRL) ran over ground while lower-limb joint motion and ground reaction force data were synchronously captured. Hip and ankle joint angles, moments, and impulses in all three planes (sagittal, transverse, and frontal) were extracted for analysis. Independent t-tests were used to compare the differences between the AT and the CTRL groups for the biomechanical variables of interest. After Bonferroni adjustment, an alpha level of 0.0026 was set for all analyses.

Results: The AT group exhibited an increased peak hip external rotation moment (P = 0.001), hip external rotation impulse (P < 0.001), and hip adduction impulse (P < 0.001) compared with the CTRL group. No significant differences in ankle biomechanics were observed.

Conclusion: This study presents preliminary evidence indicating that male runners with AT display altered hip biomechanics with respect to their healthy counterparts. Because of the retrospective design of the study, it is unknown whether these alterations are a predisposing factor for the disorder, a result of the condition, or a combination of both. The results of this study suggest that optimizing hip joint function should be considered in the rehabilitation of runners with AT.
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http://dx.doi.org/10.1249/MSS.0000000000001126DOI Listing
March 2017

Human ankle plantar flexor muscle-tendon mechanics and energetics during maximum acceleration sprinting.

J R Soc Interface 2016 08;13(121)

Department of Mechanical Engineering, University of Melbourne, Victoria 3010, Australia.

Tendon elastic strain energy is the dominant contributor to muscle-tendon work during steady-state running. Does this behaviour also occur for sprint accelerations? We used experimental data and computational modelling to quantify muscle fascicle work and tendon elastic strain energy for the human ankle plantar flexors (specifically soleus and medial gastrocnemius) for multiple foot contacts of a maximal sprint as well as for running at a steady-state speed. Positive work done by the soleus and medial gastrocnemius muscle fascicles decreased incrementally throughout the maximal sprint and both muscles performed more work for the first foot contact of the maximal sprint (FC1) compared with steady-state running at 5 m s(-1) (SS5). However, the differences in tendon strain energy for both muscles were negligible throughout the maximal sprint and when comparing FC1 to SS5. Consequently, the contribution of muscle fascicle work to stored tendon elastic strain energy was greater for FC1 compared with subsequent foot contacts of the maximal sprint and compared with SS5. We conclude that tendon elastic strain energy in the ankle plantar flexors is just as vital at the start of a maximal sprint as it is at the end, and as it is for running at a constant speed.
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http://dx.doi.org/10.1098/rsif.2016.0391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5014066PMC
August 2016
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