Pub Date : 2025-11-13DOI: 10.1016/j.clinbiomech.2025.106695
Dawson S. Sheehan , Jason P. Oliemans , Donald W. Golden , Kalinda D. Walls , Eric C. Bennett , Spencer J. Skaper , Michael J. Asmussen , Ranita H.K. Manocha , Jared R. Fletcher
Background
Individuals with hypermobile Ehlers-Danlos Syndrome (hEDS) and Hypermobility Spectrum Disorders (HSD) often experience chronic pain, muscle fatigue, and exercise intolerance, potentially due to altered muscle-tendon mechanics. This study investigated the influence of Achilles tendon (AT) compliance and plantar flexor muscle function on the metabolic cost of walking in individuals with and without HSD/hEDS.
Methods
Eleven individuals with HSD/hEDS and 11 age- and sex-matched controls completed walking trials at, below, and above their preferred walking speed. Achilles tendon stiffness, medial gastrocnemius muscle shortening, AT energy storage, pain, and lower limb electromyographic activity were evaluated during stance phase. The energy cost of walking was also computed.
Findings
The hypermobile conditions were associated with significantly lower AT stiffness, higher energy cost of walking and increased pain. Muscle fascicle shortening, shortening velocity, muscle energy cost and mechanical efficiency were similar between groups. Greater muscle activation and antagonist coactivation were observed in HSD/hEDS, particularly during early stance, likely reflecting compensatory mechanisms for joint instability.
Interpretation
Elevated cost of walking in HSD/hEDS appears driven not by increased plantar flexor work, but by a redistribution of joint work to more proximal joints. These findings suggest that altered muscle-tendon properties and neuromuscular control strategies contribute to exercise intolerance and fatigue in the Hypermobility Spectrum Disorders and hypermobile Ehlers-Danlos Syndrome.
{"title":"To what extent do the muscles and tendons influence metabolic cost and exercise tolerance in the hypermobile Ehlers-Danlos Syndrome and Hypermobility Spectrum Disorders?","authors":"Dawson S. Sheehan , Jason P. Oliemans , Donald W. Golden , Kalinda D. Walls , Eric C. Bennett , Spencer J. Skaper , Michael J. Asmussen , Ranita H.K. Manocha , Jared R. Fletcher","doi":"10.1016/j.clinbiomech.2025.106695","DOIUrl":"10.1016/j.clinbiomech.2025.106695","url":null,"abstract":"<div><h3>Background</h3><div>Individuals with hypermobile Ehlers-Danlos Syndrome (hEDS) and Hypermobility Spectrum Disorders (HSD) often experience chronic pain, muscle fatigue, and exercise intolerance, potentially due to altered muscle-tendon mechanics. This study investigated the influence of Achilles tendon (AT) compliance and plantar flexor muscle function on the metabolic cost of walking in individuals with and without HSD/hEDS.</div></div><div><h3>Methods</h3><div>Eleven individuals with HSD/hEDS and 11 age- and sex-matched controls completed walking trials at, below, and above their preferred walking speed. Achilles tendon stiffness, medial gastrocnemius muscle shortening, AT energy storage, pain, and lower limb electromyographic activity were evaluated during stance phase. The energy cost of walking was also computed.</div></div><div><h3>Findings</h3><div>The hypermobile conditions were associated with significantly lower AT stiffness, higher energy cost of walking and increased pain. Muscle fascicle shortening, shortening velocity, muscle energy cost and mechanical efficiency were similar between groups. Greater muscle activation and antagonist coactivation were observed in HSD/hEDS, particularly during early stance, likely reflecting compensatory mechanisms for joint instability.</div></div><div><h3>Interpretation</h3><div>Elevated cost of walking in HSD/hEDS appears driven not by increased plantar flexor work, but by a redistribution of joint work to more proximal joints. These findings suggest that altered muscle-tendon properties and neuromuscular control strategies contribute to exercise intolerance and fatigue in the Hypermobility Spectrum Disorders and hypermobile Ehlers-Danlos Syndrome.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106695"},"PeriodicalIF":1.4,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145551497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.clinbiomech.2025.106684
Sara M. Magdziarz, Molly S. Pacha, David M. Williams, Ruth L. Chimenti, Jason M. Wilken
Background
Exercise-based rehabilitation is the standard conservative treatment for Achilles tendinopathy, however, symptoms often persist post-treatment. Forefoot biasing footwear may augment rehabilitation by influencing tendon loading and ankle kinematics. This study aims to determine its effect on Achilles tendon loading and ankle kinematics in individuals with Achilles tendinopathy.
Methods
Fifteen participants with chronic symptomatic midportion Achilles tendinopathy (7 female; mean(SD) age: 39.5(6.4) years) performed seven commonly prescribed activities wearing only athletic shoes and with forefoot biasing footwear, in randomized order. Activities included walking and unilateral and bilateral heel raises and hops. Kinematics and kinetics were collected using computerized motion analysis. Achilles tendon force was estimated by dividing the ankle moment by an approximated tendon moment arm. Non-parametric statistical analyses assessed differences between footwear conditions (α = 0.05).
Findings
Forefoot biasing footwear significantly increased peak ankle dorsiflexion angle (range: 1.8–5.4 degrees) in all activities except unilateral hop, while reducing peak ankle plantarflexion angle (6.2–15.5 degrees) and ankle range of motion (1.8–10.6 degrees) with moderate to large effect sizes. Achilles tendon force impulse increased significantly (12 %–87 %) with forefoot biasing footwear in the five lowest peak loading activities, with large effect sizes. Walking showed consistent significant differences in tendon loading between footwear conditions (P ≤ 0.020). No significant differences in loading were observed between conditions for bilateral hopping (P ≥ 0.078).
Interpretation
Forefoot biasing footwear can modulate ankle angles and Achilles tendon loading in individuals with midportion Achilles tendinopathy and may be useful for progressing loading prior to introducing more advanced movements.
{"title":"Impact of forefoot biasing footwear on Achilles tendon and ankle biomechanics in individuals with Achilles tendinopathy","authors":"Sara M. Magdziarz, Molly S. Pacha, David M. Williams, Ruth L. Chimenti, Jason M. Wilken","doi":"10.1016/j.clinbiomech.2025.106684","DOIUrl":"10.1016/j.clinbiomech.2025.106684","url":null,"abstract":"<div><h3>Background</h3><div>Exercise-based rehabilitation is the standard conservative treatment for Achilles tendinopathy, however, symptoms often persist post-treatment. Forefoot biasing footwear may augment rehabilitation by influencing tendon loading and ankle kinematics. This study aims to determine its effect on Achilles tendon loading and ankle kinematics in individuals with Achilles tendinopathy.</div></div><div><h3>Methods</h3><div>Fifteen participants with chronic symptomatic midportion Achilles tendinopathy (7 female; mean(SD) age: 39.5(6.4) years) performed seven commonly prescribed activities wearing only athletic shoes and with forefoot biasing footwear, in randomized order. Activities included walking and unilateral and bilateral heel raises and hops. Kinematics and kinetics were collected using computerized motion analysis. Achilles tendon force was estimated by dividing the ankle moment by an approximated tendon moment arm. Non-parametric statistical analyses assessed differences between footwear conditions (α = 0.05).</div></div><div><h3>Findings</h3><div>Forefoot biasing footwear significantly increased peak ankle dorsiflexion angle (range: 1.8–5.4 degrees) in all activities except unilateral hop, while reducing peak ankle plantarflexion angle (6.2–15.5 degrees) and ankle range of motion (1.8–10.6 degrees) with moderate to large effect sizes. Achilles tendon force impulse increased significantly (12 %–87 %) with forefoot biasing footwear in the five lowest peak loading activities, with large effect sizes. Walking showed consistent significant differences in tendon loading between footwear conditions (<em>P</em> ≤ 0.020). No significant differences in loading were observed between conditions for bilateral hopping (<em>P</em> ≥ 0.078).</div></div><div><h3>Interpretation</h3><div>Forefoot biasing footwear can modulate ankle angles and Achilles tendon loading in individuals with midportion Achilles tendinopathy and may be useful for progressing loading prior to introducing more advanced movements.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106684"},"PeriodicalIF":1.4,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145551475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1016/j.clinbiomech.2025.106707
Thomas B. Birchmeier , Todd A. Schwartz , Alex E. Edison , Justin D. Dennis , J. Troy Blackburn , Sandra J. Shultz
Background
Altered gait biomechanics following anterior cruciate ligament reconstruction (ACLR) contribute to the 3–6 times greater risk of osteoarthritis development in this population compared to those without a knee injury. To mitigate the onset of osteoarthritis, it is necessary to understand gait recovery during the first year post-ACLR when patients have access to rehabilitative care. The purpose of this review was to compare ACLR limb gait biomechanics to the uninjured limb and healthy controls during the first year of recovery.
Methods
Online database searches of PubMed, CINAHL, Scopus, and SportDiscus were conducted from inception to January 2025. Eligibility criteria included longitudinal studies of individuals with ACL injury who underwent ACLR (≤35 years of age) with a baseline gait assessment between pre-ACLR and 6 months post-ACLR and a follow up assessment <12 months post-surgical; and cross-sectional studies that met the same criteria except for study design. Methodological quality was assessed with the Black and Downs scale. Demographic and surgical characteristics and biomechanical outcomes were extracted from each study.
Findings
Nine studies were included in the review. The ACLR limb gait biomechanics incrementally improved in the first year of recovery. However, the ACLR limb displayed smaller sagittal plane knee angles and internal moments and was underloaded in the first 50 % stance compared to the uninjured limb and healthy controls throughout the first year post-ACLR. Differences in frontal plane loading were inconsistent.
Interpretation
Aberrant gait biomechanics associated with osteoarthritis development are not resolved during the time when patients have access to care.
{"title":"Differences in gait biomechanics in the first year after anterior cruciate ligament reconstruction: A systematic review","authors":"Thomas B. Birchmeier , Todd A. Schwartz , Alex E. Edison , Justin D. Dennis , J. Troy Blackburn , Sandra J. Shultz","doi":"10.1016/j.clinbiomech.2025.106707","DOIUrl":"10.1016/j.clinbiomech.2025.106707","url":null,"abstract":"<div><h3>Background</h3><div>Altered gait biomechanics following anterior cruciate ligament reconstruction (ACLR) contribute to the 3–6 times greater risk of osteoarthritis development in this population compared to those without a knee injury. To mitigate the onset of osteoarthritis, it is necessary to understand gait recovery during the first year post-ACLR when patients have access to rehabilitative care. The purpose of this review was to compare ACLR limb gait biomechanics to the uninjured limb and healthy controls during the first year of recovery.</div></div><div><h3>Methods</h3><div>Online database searches of PubMed, CINAHL, Scopus, and SportDiscus were conducted from inception to January 2025. Eligibility criteria included longitudinal studies of individuals with ACL injury who underwent ACLR (≤35 years of age) with a baseline gait assessment between pre-ACLR and 6 months post-ACLR and a follow up assessment <12 months post-surgical; and cross-sectional studies that met the same criteria except for study design. Methodological quality was assessed with the Black and Downs scale. Demographic and surgical characteristics and biomechanical outcomes were extracted from each study.</div></div><div><h3>Findings</h3><div>Nine studies were included in the review. The ACLR limb gait biomechanics incrementally improved in the first year of recovery. However, the ACLR limb displayed smaller sagittal plane knee angles and internal moments and was underloaded in the first 50 % stance compared to the uninjured limb and healthy controls throughout the first year post-ACLR. Differences in frontal plane loading were inconsistent.</div></div><div><h3>Interpretation</h3><div>Aberrant gait biomechanics associated with osteoarthritis development are not resolved during the time when patients have access to care.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106707"},"PeriodicalIF":1.4,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145529130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.clinbiomech.2025.106706
Adam J. Janowski , Andrew A. Post , Alberto Marcos Heredia-Rizo , Laura A. Frey-Law , Emine O. Bayman , Kathleen A. Sluka , Ruth L. Chimenti
Background
Movement-evoked pain contributes to disability, yet factors that predict improvement in pain with rehabilitation remain largely unknown. We aimed to identify predictors and response biomarkers of the reduction in movement-evoked pain intensity with rehabilitation in individuals with Achilles tendinopathy (AT).
Methods
Individuals with AT (n = 65) were evaluated at baseline and after 8-weeks of rehabilitation. Pain (Numeric Rating Scale, 0 to 10) was collected during increasingly difficult tendon-loading (resting, walking, heel raises) and stretching (resting, standing, calf stretch) tasks. Psychological, ankle biomechanics, and clinical variables were collected. Linear mixed effects models were built around two paradigms of pain (tendon loading and stretching tasks) to determine variables predictive of change in pain (predictive biomarkers) and variables that changed along with change in pain (response biomarkers) with rehabilitation.
Findings
Lower ankle dorsiflexion during walking (β = 0.178, 95 %CI:0.06, 0.29), higher ankle dorsiflexion during stretching (β = −0.111, 95 %CI:-0.174, −0.05), a lower Victorian Institute of Sports Assessment- Achilles (VISA-A) score (β = 0.031, 95 % CI:0.010, 0.054), and younger age (β = 0.047, 95 %CI:0.022, 0.072) at baseline predicted a greater reduction in pain. For response biomarkers, reductions in duration of tendon stiffness (β = 0.018, 95 %CI: 0.001, 0.036), increases in ankle dorsiflexion during walking (β = −0.15, 95 %CI:-0.285, −0.016), reductions in depression (β = 0.109, 95 % CI:0.041, 0.178), and reductions in kinesiophobia (β = 0.151, 95 %CI:0.083, 0.219) were associated with greater reductions in pain. AT type was not associated with pain.
Interpretation
Regardless of AT type, kinesiophobia, ankle dorsiflexion, and clinical factors may be important factors to consider as predictors and/or response indicators for reductions in movement-evoked pain with rehabilitation.
{"title":"Exploring biomarkers of change in movement-evoked pain in Achilles tendinopathy: A secondary analysis of a randomized controlled trial","authors":"Adam J. Janowski , Andrew A. Post , Alberto Marcos Heredia-Rizo , Laura A. Frey-Law , Emine O. Bayman , Kathleen A. Sluka , Ruth L. Chimenti","doi":"10.1016/j.clinbiomech.2025.106706","DOIUrl":"10.1016/j.clinbiomech.2025.106706","url":null,"abstract":"<div><h3>Background</h3><div>Movement-evoked pain contributes to disability, yet factors that predict improvement in pain with rehabilitation remain largely unknown. We aimed to identify predictors and response biomarkers of the reduction in movement-evoked pain intensity with rehabilitation in individuals with Achilles tendinopathy (AT).</div></div><div><h3>Methods</h3><div>Individuals with AT (<em>n</em> = 65) were evaluated at baseline and after 8-weeks of rehabilitation. Pain (Numeric Rating Scale, 0 to 10) was collected during increasingly difficult tendon-loading (resting, walking, heel raises) and stretching (resting, standing, calf stretch) tasks. Psychological, ankle biomechanics, and clinical variables were collected. Linear mixed effects models were built around two paradigms of pain (tendon loading and stretching tasks) to determine variables predictive of change in pain (predictive biomarkers) and variables that changed along with change in pain (response biomarkers) with rehabilitation.</div></div><div><h3>Findings</h3><div>Lower ankle dorsiflexion during walking (β = 0.178, 95 %CI:0.06, 0.29), higher ankle dorsiflexion during stretching (β = −0.111, 95 %CI:-0.174, −0.05), a lower Victorian Institute of Sports Assessment- Achilles (VISA-A) score (β = 0.031, 95 % CI:0.010, 0.054), and younger age (β = 0.047, 95 %CI:0.022, 0.072) at baseline predicted a greater reduction in pain. For response biomarkers, reductions in duration of tendon stiffness (β = 0.018, 95 %CI: 0.001, 0.036), increases in ankle dorsiflexion during walking (β = −0.15, 95 %CI:-0.285, −0.016), reductions in depression (β = 0.109, 95 % CI:0.041, 0.178), and reductions in kinesiophobia (β = 0.151, 95 %CI:0.083, 0.219) were associated with greater reductions in pain. AT type was not associated with pain.</div></div><div><h3>Interpretation</h3><div>Regardless of AT type, kinesiophobia, ankle dorsiflexion, and clinical factors may be important factors to consider as predictors and/or response indicators for reductions in movement-evoked pain with rehabilitation.</div><div><strong>Study Registration:</strong></div><div><span><span>https://clinicaltrials.gov/study/NCT04059146</span><svg><path></path></svg></span></div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106706"},"PeriodicalIF":1.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145483901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.clinbiomech.2025.106696
Olivia F. Simpson , Dimitar Stanev , Joe Pitt-Francis , Mattia Zanon , Mike D. Rinderknecht , Amy B. Zavatsky
Background
Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system, which can impact postural control. The Margin of Stability (MoS) is a biomechanical measure of how close someone is to falling without corrective action. Walking MoS has been extensively studied in people with MS (PwMS), while standing MoS is less studied. This work explores the relationship between the standing MoS and clinical measures, identifying a standing MoS summary feature that quantifies the level of balance impairment due to MS, across a range of stances.
Methods
In an observational study, participants stood in five stances, with different bases of support, each for 30 s. Standing MoS was calculated using motion capture data and compared with established clinical scales.
Findings
Ninety-six PwMS (EDSS: 1.5–6.5) completed at least one stance. The range and standard deviation of the Global (two-dimensional) standing MoS were significantly correlated (p < 0.05) with MS-related impairment (EDSS) in all but one stance. Correlations were also found between the Standing MoS and patient-reported outcomes: ABC and MSWS-12. The range of Global MoS demonstrated strong known-group validity (p < 0.001), distinguishing mild from moderate and severe MS across all stances.
Interpretation
There are strong correlations between the standing MoS and established clinical scales. MSWS-12 has the weakest correlations as it is designed to capture information relevant to walking, not standing. The range of the Global MoS should be used for standing MoS studies involving PwMS. The standing MoS could be explored for use as a trial outcome measure or clinical scale.
{"title":"Standing margin of stability as a measure of balance for people with multiple sclerosis","authors":"Olivia F. Simpson , Dimitar Stanev , Joe Pitt-Francis , Mattia Zanon , Mike D. Rinderknecht , Amy B. Zavatsky","doi":"10.1016/j.clinbiomech.2025.106696","DOIUrl":"10.1016/j.clinbiomech.2025.106696","url":null,"abstract":"<div><h3>Background</h3><div>Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system, which can impact postural control. The Margin of Stability (MoS) is a biomechanical measure of how close someone is to falling without corrective action. Walking MoS has been extensively studied in people with MS (PwMS), while standing MoS is less studied. This work explores the relationship between the standing MoS and clinical measures, identifying a standing MoS summary feature that quantifies the level of balance impairment due to MS, across a range of stances.</div></div><div><h3>Methods</h3><div>In an observational study, participants stood in five stances, with different bases of support, each for 30 s. Standing MoS was calculated using motion capture data and compared with established clinical scales.</div></div><div><h3>Findings</h3><div>Ninety-six PwMS (EDSS: 1.5–6.5) completed at least one stance. The range and standard deviation of the Global (two-dimensional) standing MoS were significantly correlated (<em>p</em> < 0.05) with MS-related impairment (EDSS) in all but one stance. Correlations were also found between the Standing MoS and patient-reported outcomes: ABC and MSWS-12. The range of Global MoS demonstrated strong known-group validity (<em>p</em> < 0.001), distinguishing mild from moderate and severe MS across all stances.</div></div><div><h3>Interpretation</h3><div>There are strong correlations between the standing MoS and established clinical scales. MSWS-12 has the weakest correlations as it is designed to capture information relevant to walking, not standing. The range of the Global MoS should be used for standing MoS studies involving PwMS. The standing MoS could be explored for use as a trial outcome measure or clinical scale.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106696"},"PeriodicalIF":1.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145508023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gait speed is a major determinant of daily function and quality of life in hip osteoarthritis, yet evidence on how trunk muscles are associated with gait is scarce. We investigated factors associated with gait speed in hip osteoarthritis, focusing on the transversus abdominis (TrA).
Methods
Forty-nine women with hip osteoarthritis (64.2 ± 7.1 years) awaiting first unilateral total hip arthroplasty were enrolled. On the day before surgery, physical condition and function, including gait speed, gait pain, lower-limb strength, and TrA contraction ratio, were evaluated. To clarify which physical and functional variables are associated with gait speed, we entered gait pain, hip and knee-strength, TrA contraction ratio, age, Japan Orthopaedic Association stage for the hip on the unaffected side, leg length discrepancy and cane use during gait into a stepwise multiple-regression model with gait speed as the outcome.
Findings
Stepwise regression showed that hip abductor strength on the unaffected side, cane use during gait, age, and the TrA contraction ratio were independently associated with gait speed (overall p < 0.001). The model explained 46 % of the variance in gait speed (R2 = 0.463) and showed acceptable predictive accuracy (PRESS = 3.555; predicted R2 = 0.347; large effect size f2 = 0.862).
Interpretation
Beyond lower-limb strength, cane use during gait and age, our findings show that TrA function is also associated with gait speed in hip osteoarthritis. This study demonstrates that TrA function is an independent correlate of gait speed in hip osteoarthritis and should be routinely assessed in clinical practice.
{"title":"Association of Transversus Abdominis with gait speed in patients with hip osteoarthritis","authors":"Hideki Suzuki , Eiki Tsushima , Tatsuya Nakanowatari , Yoko Ono , Yumetaka Shinden , Shigeo Aota , Kazuo Ouchi , Tetsuo Hayashi","doi":"10.1016/j.clinbiomech.2025.106690","DOIUrl":"10.1016/j.clinbiomech.2025.106690","url":null,"abstract":"<div><h3>Background</h3><div>Gait speed is a major determinant of daily function and quality of life in hip osteoarthritis, yet evidence on how trunk muscles are associated with gait is scarce. We investigated factors associated with gait speed in hip osteoarthritis, focusing on the transversus abdominis (TrA).</div></div><div><h3>Methods</h3><div>Forty-nine women with hip osteoarthritis (64.2 ± 7.1 years) awaiting first unilateral total hip arthroplasty were enrolled. On the day before surgery, physical condition and function, including gait speed, gait pain, lower-limb strength, and TrA contraction ratio, were evaluated. To clarify which physical and functional variables are associated with gait speed, we entered gait pain, hip and knee-strength, TrA contraction ratio, age, Japan Orthopaedic Association stage for the hip on the unaffected side, leg length discrepancy and cane use during gait into a stepwise multiple-regression model with gait speed as the outcome.</div></div><div><h3>Findings</h3><div>Stepwise regression showed that hip abductor strength on the unaffected side, cane use during gait, age, and the TrA contraction ratio were independently associated with gait speed (overall <em>p</em> < 0.001). The model explained 46 % of the variance in gait speed (<em>R</em><sup>2</sup> = 0.463) and showed acceptable predictive accuracy (PRESS = 3.555; predicted <em>R</em><sup>2</sup> = 0.347; large effect size <em>f</em><sup>2</sup> = 0.862).</div></div><div><h3>Interpretation</h3><div>Beyond lower-limb strength, cane use during gait and age, our findings show that TrA function is also associated with gait speed in hip osteoarthritis. This study demonstrates that TrA function is an independent correlate of gait speed in hip osteoarthritis and should be routinely assessed in clinical practice.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106690"},"PeriodicalIF":1.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145524930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-04DOI: 10.1016/j.clinbiomech.2025.106694
Alexandria Mallinos , Camille Pillot , Xiaoyu Wang , Todd F. Ritzman , Lorena V. Floccari , Carl-Eric Aubin , Richard M. Schwend
Background
Pedicle screw density and rod contouring are crucial in the posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS) patients. This study evaluates the three-dimensional (3D) biomechanical interaction between rod contouring and the number/pattern of implants anchoring these rods to determine a range of advisable combinations that improve clinical outcomes.
Methods
Patient-specific, deterministic computational models were developed based on ten Lenke 1 AIS surgical cases. First order assessment with various pedicle screw patterns and rod contouring angles was performed. Rod material properties consisted of cobalt chrome (CoCr) and titanium (Ti). The primary correction maneuvers were concave rod translation followed by convex rod translation. Four screw configurations were tested: a reference pattern with two screws per level, and three alternatives (alternate, convex alternate, and convex peri-apical dropout) averaging 1.11 to 1.56 screws per level.
Findings
Across the four screw density patterns tested, no statistically significant differences were observed in all three anatomical planes (p > 0.05). Significant differences in thoracic kyphosis (TK) were observed with increasing rod angulations (p < 0.05). Coronal plane correction diminished with greater rod contouring (p < 0.05). Axial bone-screw forces were negatively influenced by screw density and varied significantly amongst rod contouring combinations (p < 0.05). Apical vertebral rotation (AVR) was not influenced by rod properties or screw density (p > 0.05).
Interpretation
Screw density had the greatest impact on axial bone-screw forces. Regardless of the screw density pattern, more aggressive rod contouring angles reduced coronal plane correction but improved sagittal plane alignment.
{"title":"Biomechanical analysis of pedicle screw density and rod contouring in adolescent idiopathic scoliosis instrumentation","authors":"Alexandria Mallinos , Camille Pillot , Xiaoyu Wang , Todd F. Ritzman , Lorena V. Floccari , Carl-Eric Aubin , Richard M. Schwend","doi":"10.1016/j.clinbiomech.2025.106694","DOIUrl":"10.1016/j.clinbiomech.2025.106694","url":null,"abstract":"<div><h3>Background</h3><div>Pedicle screw density and rod contouring are crucial in the posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS) patients. This study evaluates the three-dimensional (3D) biomechanical interaction between rod contouring and the number/pattern of implants anchoring these rods to determine a range of advisable combinations that improve clinical outcomes.</div></div><div><h3>Methods</h3><div>Patient-specific, deterministic computational models were developed based on ten Lenke 1 AIS surgical cases. First order assessment with various pedicle screw patterns and rod contouring angles was performed. Rod material properties consisted of cobalt chrome (CoCr) and titanium (Ti). The primary correction maneuvers were concave rod translation followed by convex rod translation. Four screw configurations were tested: a reference pattern with two screws per level, and three alternatives (alternate, convex alternate, and convex peri-apical dropout) averaging 1.11 to 1.56 screws per level.</div></div><div><h3>Findings</h3><div>Across the four screw density patterns tested, no statistically significant differences were observed in all three anatomical planes (<em>p</em> > 0.05). Significant differences in thoracic kyphosis (TK) were observed with increasing rod angulations (<em>p</em> < 0.05). Coronal plane correction diminished with greater rod contouring (<em>p</em> < 0.05). Axial bone-screw forces were negatively influenced by screw density and varied significantly amongst rod contouring combinations (<em>p</em> < 0.05). Apical vertebral rotation (AVR) was not influenced by rod properties or screw density (<em>p</em> > 0.05).</div></div><div><h3>Interpretation</h3><div>Screw density had the greatest impact on axial bone-screw forces. Regardless of the screw density pattern, more aggressive rod contouring angles reduced coronal plane correction but improved sagittal plane alignment.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106694"},"PeriodicalIF":1.4,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Controlling flatfoot biomechanics is crucial in preventing lower limb musculoskeletal injuries. Short foot exercise (SFE) and toe curl exercise (TCE) are interventions for flatfoot; however, their effects on foot biomechanics remain inconsistent. We aimed to compare the impact of SFE and TCE on plantar pressure during single-leg standing (SLS) in individuals with flatfoot.
Methods
This randomized controlled trial recruited 34 participants with flatfoot (Foot Posture Index-6 > 7). Participants were randomly assigned to SFE or TCE groups and completed 8 weeks of exercise. Plantar pressure during SLS was assessed pre- and post-intervention using a plantar pressure sensor. The foot was divided into eight regions: heel, midfoot, medial, central, lateral metatarsophalangeal joint (MTPJ), hallux, second toe, and 3rd–5th toes. Peak plantar pressure and contact area were analyzed using intention-to-treat (ITT) and per-protocol (PP) analysis.
Findings
In the ITT analysis, SFE significantly increased peak plantar pressure in the medial MTPJ (p = 0.016), hallux (p < 0.001), and second toe (p = 0.004), while reducing midfoot pressure (p = 0.0012). TCE significantly increased the heel pressure (p < 0.001). The PP analysis showed similar trends, with additional increases in the lateral MTPJ pressure (p = 0.032) and contact areas of the 3rd–5th toes (p = 0.008) in the SFE group.
Interpretation
SFE increased the medial and lateral MTPJ, hallux, and toe pressure while reducing midfoot pressure. TCE increased the heel pressure. These findings suggest that SFE improves the midfoot, medial and lateral MTPJ, and toe pressure in individuals with flatfoot.
{"title":"Comparing the effect of short foot exercise and toe curl exercise on plantar pressure during single-leg standing in individuals with flatfoot: A randomized controlled trial","authors":"Misaki Suzuki , Hironobu Kuruma , Kunihiro Kato , Hiromu Kase , Hayato Fujimoto , Rento Nagashima","doi":"10.1016/j.clinbiomech.2025.106693","DOIUrl":"10.1016/j.clinbiomech.2025.106693","url":null,"abstract":"<div><h3>Background</h3><div>Controlling flatfoot biomechanics is crucial in preventing lower limb musculoskeletal injuries. Short foot exercise (SFE) and toe curl exercise (TCE) are interventions for flatfoot; however, their effects on foot biomechanics remain inconsistent. We aimed to compare the impact of SFE and TCE on plantar pressure during single-leg standing (SLS) in individuals with flatfoot.</div></div><div><h3>Methods</h3><div>This randomized controlled trial recruited 34 participants with flatfoot (Foot Posture Index-6 > 7). Participants were randomly assigned to SFE or TCE groups and completed 8 weeks of exercise. Plantar pressure during SLS was assessed pre- and post-intervention using a plantar pressure sensor. The foot was divided into eight regions: heel, midfoot, medial, central, lateral metatarsophalangeal joint (MTPJ), hallux, second toe, and 3rd–5th toes. Peak plantar pressure and contact area were analyzed using intention-to-treat (ITT) and per-protocol (PP) analysis.</div></div><div><h3>Findings</h3><div>In the ITT analysis, SFE significantly increased peak plantar pressure in the medial MTPJ (<em>p</em> = 0.016), hallux (<em>p</em> < 0.001), and second toe (<em>p</em> = 0.004), while reducing midfoot pressure (<em>p</em> = 0.0012). TCE significantly increased the heel pressure (<em>p</em> < 0.001). The PP analysis showed similar trends, with additional increases in the lateral MTPJ pressure (<em>p</em> = 0.032) and contact areas of the 3rd–5th toes (<em>p</em> = 0.008) in the SFE group.</div></div><div><h3>Interpretation</h3><div>SFE increased the medial and lateral MTPJ, hallux, and toe pressure while reducing midfoot pressure. TCE increased the heel pressure. These findings suggest that SFE improves the midfoot, medial and lateral MTPJ, and toe pressure in individuals with flatfoot.</div><div>Clinical trial registration number: UMIN000049963.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106693"},"PeriodicalIF":1.4,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145453958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-30DOI: 10.1016/j.clinbiomech.2025.106687
Mehar Dhillon , Mark Lenz , Klaus Edgar Roth , Felix Christian Kohler , Ivan Zderic , Boyko Gueorguiev , Kajetan Klos
Background
Severe arthrosis involving ankle and subtalar joints or hindfoot deformities refractory to other forms of treatment is currently managed by tibiotalocalcaneal arthrodesis (TTCA). Relief of pain and acceptable gait pattern along with appropriate alignment are primary goals of treatment. The spectrum of techniques includes using screws, plates, external fixators and various types of intramedullary nails. The aim of this study was to compare the biomechanical stability of a plate specifically developed for hindfoot arthrodesis to an well-established nailing system.
Methods
Sixteen paired human cadaveric specimens were assigned to two groups for TTCA treatment via nailing or plating and tested under quasi-static and progressively increasing cyclic loading.
Findings
Range of motion during quasi-static testing in dorsiflexion and varus bending was significantly higher for plated specimens (P ≤ 0.048), with no further significant differences between the groups detected among all other loading directions (P ≥ 0.106). Cycles to failure and failure load were not significantly different between the groups (P = 0.600).
Interpretations
Although the intramedullary nail performed superiorly to the plate under quasi-static testing in terms of range of motion in dorsiflexion and varus bending, from a biomechanical point of view the hindfoot arthordesis plate demonstrated comparable promising outcomes under dynamic loading and could be considered as an alternative option to the nailing system for TTCA.
{"title":"Nailing versus plating in tibiotalocalcaneal arthrodesis – A biomechanical human cadaveric study","authors":"Mehar Dhillon , Mark Lenz , Klaus Edgar Roth , Felix Christian Kohler , Ivan Zderic , Boyko Gueorguiev , Kajetan Klos","doi":"10.1016/j.clinbiomech.2025.106687","DOIUrl":"10.1016/j.clinbiomech.2025.106687","url":null,"abstract":"<div><h3>Background</h3><div>Severe arthrosis involving ankle and subtalar joints or hindfoot deformities refractory to other forms of treatment is currently managed by tibiotalocalcaneal arthrodesis (TTCA). Relief of pain and acceptable gait pattern along with appropriate alignment are primary goals of treatment. The spectrum of techniques includes using screws, plates, external fixators and various types of intramedullary nails. The aim of this study was to compare the biomechanical stability of a plate specifically developed for hindfoot arthrodesis to an well-established nailing system.</div></div><div><h3>Methods</h3><div>Sixteen paired human cadaveric specimens were assigned to two groups for TTCA treatment via nailing or plating and tested under quasi-static and progressively increasing cyclic loading.</div></div><div><h3>Findings</h3><div>Range of motion during quasi-static testing in dorsiflexion and varus bending was significantly higher for plated specimens (<em>P</em> ≤ 0.048), with no further significant differences between the groups detected among all other loading directions (<em>P</em> ≥ 0.106). Cycles to failure and failure load were not significantly different between the groups (<em>P</em> = 0.600).</div></div><div><h3>Interpretations</h3><div>Although the intramedullary nail performed superiorly to the plate under quasi-static testing in terms of range of motion in dorsiflexion and varus bending, from a biomechanical point of view the hindfoot arthordesis plate demonstrated comparable promising outcomes under dynamic loading and could be considered as an alternative option to the nailing system for TTCA.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106687"},"PeriodicalIF":1.4,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145551440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pedicle screw loosening is a clinically-relevant failure mode following spinal fusion procedures, resulting from damage and compaction to the surrounding bone with loading of the bone-implant interface. Current in vitro tests for investigating pedicle screw loosening commonly apply uniaxial loading (e.g. screw pullout or toggle testing). However, these methods do not replicate multiaxial spinal loading associated with activities of daily living. The goals of this study were to (1) develop and assess a novel test method for inducing pedicle screw loosening under multiaxial loading conditions, and (2) compare this approach to uniaxial toggle testing.
Methods
Eight osteoporotic human lumbar vertebrae (L2-L4, 70.1 ± 5.5 years old) underwent testing to compare volumetric bone damage and screw displacement under uniaxial and multiaxial loading. Load magnitudes were incrementally increased in a step-wise fashion after 1000 and 2000 cycles, with the final load step continuing until the screw head displaced more than 6 mm. Post-test computed tomography (CT) imaging was used to quantify volumetric bone damage.
Findings
Multiaxial loading accelerated bone damage leading to earlier implant loosening (p < 0.001). Failure predominantly occurred in the inferior direction (p = 0.06). Medial (p = 0.07) and lateral (p < 0.001) screw displacement were greater under multiaxial loading. CT imaging showed greater volumetric bone deformation with multiaxial loading (p = 0.01).
Interpretation
This study demonstrated that physiologically-derived multiaxial loading accelerates volumetric bone damage and pedicle screw loosening. Further, the increased bone deformation in the medial and lateral directions suggests that spinal movements involving these loads may accelerate risk of screw loosening.
{"title":"Comparison of pedicle screw loosening under uniaxial and multiaxial loading","authors":"Martine McGregor , Chloe Cadieux , Claire Thompson , Renan Fernandes , Jonah Leinwand , Parham Rasoulinejad , Stewart McLachlin","doi":"10.1016/j.clinbiomech.2025.106692","DOIUrl":"10.1016/j.clinbiomech.2025.106692","url":null,"abstract":"<div><h3>Background</h3><div>Pedicle screw loosening is a clinically-relevant failure mode following spinal fusion procedures, resulting from damage and compaction to the surrounding bone with loading of the bone-implant interface. Current <em>in vitro</em> tests for investigating pedicle screw loosening commonly apply uniaxial loading (<em>e.g.</em> screw pullout or toggle testing). However, these methods do not replicate multiaxial spinal loading associated with activities of daily living. The goals of this study were to (1) develop and assess a novel test method for inducing pedicle screw loosening under multiaxial loading conditions, and (2) compare this approach to uniaxial toggle testing.</div></div><div><h3>Methods</h3><div>Eight osteoporotic human lumbar vertebrae (L2-L4, 70.1 ± 5.5 years old) underwent testing to compare volumetric bone damage and screw displacement under uniaxial and multiaxial loading. Load magnitudes were incrementally increased in a step-wise fashion after 1000 and 2000 cycles, with the final load step continuing until the screw head displaced more than 6 mm. Post-test computed tomography (CT) imaging was used to quantify volumetric bone damage.</div></div><div><h3>Findings</h3><div>Multiaxial loading accelerated bone damage leading to earlier implant loosening (<em>p</em> < 0.001). Failure predominantly occurred in the inferior direction (<em>p</em> = 0.06). Medial (<em>p</em> = 0.07) and lateral (p < 0.001) screw displacement were greater under multiaxial loading. CT imaging showed greater volumetric bone deformation with multiaxial loading (<em>p</em> = 0.01).</div></div><div><h3>Interpretation</h3><div>This study demonstrated that physiologically-derived multiaxial loading accelerates volumetric bone damage and pedicle screw loosening. Further, the increased bone deformation in the medial and lateral directions suggests that spinal movements involving these loads may accelerate risk of screw loosening.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"131 ","pages":"Article 106692"},"PeriodicalIF":1.4,"publicationDate":"2025-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145460286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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