Journal of biomechanics最新文献

{"title":"Semi-automated algorithm for rotational axis determination of the ulno-humeral joint","authors":"Sylvano Mania,&nbsp;Farah Selman,&nbsp;Franziska C.S. Altorfer,&nbsp;Stijn de Joode,&nbsp;Florian Grubhofer,&nbsp;Karl Wieser","doi":"10.1016/j.jbiomech.2025.112842","DOIUrl":"10.1016/j.jbiomech.2025.112842","url":null,"abstract":"<div><div>Preoperative simulation of the elbow joint motion has been proposed for prosthesis alignment, ligament reconstruction or treatment of impingement-inducing osteophytes. However, its daily application remains seldom. This study proposes an algorithm to simulate the ulno-humeral joint motion in flexion/extension.</div><div>Four observers placed reference points on 3D surface models of elbows. The algorithm generated five spheres representing specific joint surface: medial and lateral trochlea humeri (MT and LT), capitellum (CAP), medial and lateral trochlear notch (MED- and LAT NOTCH). Three rotational axes were defined: MT-LT, CAP-MT and MED-LAT NOTCH. A fourth axis, COMB, was computed using the average 3D distance between MT-MED NOTCH and LT-LAT NOTCH. Interobserver average distance between the reference points and the computed sphere as well as the average interobserver 3D angle between the axis were analysed. The dynamic articular congruence of the axes in relation to the MED-LAT NOTCH axis was assessed by calculating their respective 3D angle variation from 0° extension to 150° flexion. The number of patients needed to reach stable dynamic articular congruence was assessed.</div><div>The computed spheres exhibit lower interobserver average translation compared to the reference points. The CAP-MT axis shows the lowest interobserver variation of 3D angle (4.8°). However, COMB axis has the lowest dynamic articular incongruency (3D angle variation of 7.4°, p &lt; 0.001). Once a learning curve of six patients is reached, an average congruence of 4.8° can be achieved.</div><div>An algorithm based on multiple articular references can reduce observer-induced inaccuracies in simulation of elbow joint motion.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112842"},"PeriodicalIF":2.4,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534118","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}

{"title":"Validation of a screw implantation safety index for bone conduction implants","authors":"Emile Talon ,&nbsp;Stefan Bracher ,&nbsp;Philipp Aebischer ,&nbsp;Caversaccio Marco ,&nbsp;Philippe Zysset ,&nbsp;Wilhelm Wimmer","doi":"10.1016/j.jbiomech.2025.112827","DOIUrl":"10.1016/j.jbiomech.2025.112827","url":null,"abstract":"<div><div>Bone conduction implants are used to treat hearing loss by transmitting mechanical vibrations to the inner ear via bone screws anchored in the temporal bone. Secure screw fixing is essential for an efficient signal transmission and implant stability. We hypothesized that regions of higher bone density should be prioritized for screw placement to optimize fixing. This ex-vivo study aimed to validate the Screw Implantation Safety Index (SISI), computed as the percentage of the insertion path characterized by dense bone, as a preoperative marker for safe and effective screw placement. We analyzed 24 bone samples (1<!--> <!-->cm³) extracted from the temporal bones of two Thiel-preserved cadaver heads. Each specimen underwent quantitative computed-tomography (CT) and micro-CT (<span><math><mi>μ</mi></math></span>CT) imaging to determine SISI values. Self-tapping titanium screws (5<!--> <!-->mm) were inserted, and pull-out testing was conducted to assess maximum pull-out force, stiffness, and strain energy at the bone-screw interface. Linear regression models were used to evaluate associations between SISI and mechanical stability. SISI values ranged from 29% to 81% (<span><math><mi>μ</mi></math></span>CT) and 39% to 93% (clinical CT). The average pull-out force was 535<!--> <!-->N (standard deviation of 151<!--> <!-->N), with weak but statistically significant correlations between CT-based SISI scores and pull-out force (<span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>24</mn></mrow></math></span>, <span><math><mrow><mi>p</mi><mo>=</mo><mo>.</mo><mn>01</mn></mrow></math></span>), as well as strain energy (<span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>23</mn></mrow></math></span>, <span><math><mrow><mi>p</mi><mo>=</mo><mo>.</mo><mn>01</mn></mrow></math></span>). Comparison with <span><math><mi>μ</mi></math></span>CT data validated the clinical CT results. Our findings suggest that the SISI score could enhance preoperative planning for bone conduction implants by guiding optimal screw placement. Further research is needed to assess its clinical feasibility and impact on long-term implantation outcomes.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112827"},"PeriodicalIF":2.4,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518524","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}

{"title":"Frequency-dependent regulation of osteogenesis by nuclear displacement in osteoblasts under mechanical vibrations","authors":"Nagi Eto,&nbsp;Yuto Mizuta,&nbsp;Toshihiko Shiraishi","doi":"10.1016/j.jbiomech.2025.112838","DOIUrl":"10.1016/j.jbiomech.2025.112838","url":null,"abstract":"<div><div>Mechanical vibrations are potent regulators of bone formation in vivo and in vitro, promoting osteoblast differentiation. Despite extensive research on the cellular responses to vibration, the underlying mechanisms remain unclear. In this study, the effects of mechanical vibrations on osteoblast differentiation and nuclear displacement were examined, focusing on the dynamics of the cell nucleus, actin stress fibers, and focal adhesions, which connect the nucleus to the extracellular matrix. Alkaline phosphatase gene expression, an osteoblast differentiation marker, was significantly upregulated in MC3T3-E1 cells at 50 Hz compared to 12.5 and 100 Hz (p &lt; 0.05) under 0.5 G. The frequency-dependent response was independent of vibration direction, as confirmed using an exciter in horizontal or vertical vibration, and also independent of fluid shear stress in medium, as validated by observing medium sloshing using slow-motion imaging. Nuclear displacement under horizontal vibration (0.5 G) was analyzed across 20–70 Hz at 10-Hz intervals, and peaked at 40–50 Hz with significant increases at 40 Hz vs. 20/30 Hz and 50 Hz vs. 20 Hz (p &lt; 0.05). These findings indicate a distinct correlation between osteoblast differentiation and nuclear displacement, implying that mechanical vibrations modulate cellular differentiation by altering actin stress fiber and focal adhesion dynamics in a frequency-dependent manner. This is supported by an elastic model estimating actin stress fiber tension based on observed nuclear displacement. This study offers new insights into the frequency dependence of osteoblast differentiation and its mechanotransduction mechanism, and supports the development of optimized mechanical stimulation therapies for bone regeneration.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112838"},"PeriodicalIF":2.4,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534117","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}

{"title":"Body segment inertial parameters of children derived from a large database of 3D body scans","authors":"Bhrigu K. Lahkar ,&nbsp;Thomas Robert ,&nbsp;Fermín Basso ,&nbsp;Raphaël Dumas ,&nbsp;Helios De Rosario","doi":"10.1016/j.jbiomech.2025.112840","DOIUrl":"10.1016/j.jbiomech.2025.112840","url":null,"abstract":"<div><div>Body segment inertial parameters (BSIPs) are critical for human movement analysis. However, child-specific BSIPs remains limited. This study aimed to develop regression models for BSIPs (mass, CoM-position, and moments of inertia) using 3D body scans from 688 children aged 2.9–12.7 years. A 3D scanning system was used to capture body surfaces as point clouds, which were automatically processed to generate segmented, personalized volumetric body meshes with embedded segment coordinate systems. These meshes were then used to compute 3D BSIPs, which were normalized (relative to body mass and corresponding segment length) and fitted by regression models separately for males and females. The regression models demonstrated high predictive accuracy for normalized mass and moderate-to-good accuracy for normalized CoM-positions and radii of gyration. Age-related changes were observed as reductions in normalized mass for the head-neck and abdomen, alongside increases for the thigh. Normalized CoM-positions shifted posteriorly for the abdomen, anteriorly for the thigh, and proximally for the forearm. Normalized radii of gyration declined across all directions, particularly for the hand and thigh. This work provides the first comprehensive BSIP regressions for a large, gender-balanced cohort of children up to 12 years old, addressing limitations in prior research with a fully automated approach. These regressions are expected to advance biomechanical modeling and enhance movement analysis in pediatric populations.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112840"},"PeriodicalIF":2.4,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522258","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}

{"title":"The Impact of ankle range of motion on lower-limb gait biomechanics","authors":"Michael J. Rose ,&nbsp;Will Flanagan ,&nbsp;Brandon T. Peterson ,&nbsp;Paige K. Steffler ,&nbsp;Brandon T. Tran ,&nbsp;Lisa Su ,&nbsp;Rachel Gehlhar Humann ,&nbsp;Tyler R. Clites","doi":"10.1016/j.jbiomech.2025.112811","DOIUrl":"10.1016/j.jbiomech.2025.112811","url":null,"abstract":"<div><div>Movement at the ankle joint serves several purposes during unimpaired locomotion, including stabilization and propulsion. While the healthy ankle can achieve 71°range of plantar/dorsiflexion, only about 30°is used in level-ground walking. Little is known about how gait is affected by isolated limitation of ankle range of motion (RoM) using end-range hard stops. To study this, we developed a simple exoskeleton that restricts ankle range of motion and evaluated the impact of this exoskeleton during level-ground treadmill walking at two speeds, in ten young adults with no ankle pathology. We found that even with 30°range of motion (±15°), significant hard-stop contact occurred compared to when there was no restricted motion, and that individuals did not adjust their gait to avoid contact in this condition. Hard-stop contact time was greater for conditions with less permitted motion, but we did not find significant differences in global kinematic asymmetry at any joint except the ankle, and only in comparisons of other conditions against simulated fusion (<span><math><mrow><mi>p</mi><mo>&lt;</mo><mn>0</mn><mo>.</mo><mn>02</mn></mrow></math></span> for all comparisons); providing even ±10°at the ankle did not lead us to observe significant differences in kinematic asymmetry. We also observed significant changes to ankle positive work at RoMs lower than ±15°(<span><math><mrow><mi>p</mi><mo>&lt;</mo><mn>0</mn><mo>.</mo><mn>03</mn></mrow></math></span> for all comparisons), but we did not observe significant changes in net work over the gait cycle at any other joint of the lower limb in any conditions except simulated fusion. These results suggest that hard-stop contact does not disturb gait enough for users to adapt to gait strategies that avoided contact, and that ankle range of motion can be restricted in level-ground walking without causing significant differences in gait kinematics and joint work.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112811"},"PeriodicalIF":2.4,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501230","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}

{"title":"Estimating tibial bone load during running using only inertial measurement units on the tibias and sternum: a Centre of Pressure approach","authors":"Robbert P. van Middelaar,&nbsp;Jasper Reenalda","doi":"10.1016/j.jbiomech.2025.112839","DOIUrl":"10.1016/j.jbiomech.2025.112839","url":null,"abstract":"<div><div>Inverse dynamics is a method to estimate joint forces and external moments needed for movement by analysing kinematics and ground reaction forces (GRF). In a bottom-up inverse dynamics analysis using a full-body inertial measurement unit (IMU) setup, the Centre of Pressure (CoP) is the only missing variable to complete the calculation. This study aimed to estimate the anteroposterior CoP from the tibia IMU orientation to calculate the sagittal ankle moment and tibial bone load (TBL) in rearfoot strikers running at 2.5, 3.1, and 3.6 m/s, using both tibia and the sternum IMU. This achieved strong correlations (≥0.90) for the CoP, sagittal ankle moment, and TBL compared with a marker/force plate reference. While the CoP estimate had fair accuracy, the sagittal ankle moment (rRMSE ≤ 12.9 %) and TBL (rRMSE ≤ 10.2 %) showed high accuracy. No significant differences were found between the IMU-only method and the reference for maximum ankle plantar flexion moment and TBL across all speeds. Future work should explore the multidimensional CoP, the inclusion of 3D GRF, and validation for non-rearfoot strike runners. These findings highlight the potential of using both tibia and the sternum IMU to monitor lower extremity forces and moments during running, independent of measurement location.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112839"},"PeriodicalIF":2.4,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534116","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}

{"title":"Contact mechanics following medial meniscus posterior root tears and suture anchor repair in simulated gait: A cadaveric study","authors":"Yizhao Li ,&nbsp;Adam Garry Redgrift ,&nbsp;Takaaki Hiranaka ,&nbsp;Alan Getgood ,&nbsp;Ryan Willing","doi":"10.1016/j.jbiomech.2025.112837","DOIUrl":"10.1016/j.jbiomech.2025.112837","url":null,"abstract":"<div><div>Medial Meniscus Posterior Root Tears (MMPRTs) are increasingly recognized, whereas research on contact mechanics associated with MMPRT during activities of daily living is limited. This study evaluated the effect of MMPRT on tibiofemoral pressure and the effectiveness of surgical repair during simulated gait. Eight fresh-frozen human cadaveric knees were tested using a joint motion simulator. Subject-specific loading profiles comprising seven key stages of the gait cycle were applied to (1) intact meniscus, (2) MMPRT, and (3) repair models. Contact pressure was measured at each stage using thin film pressure sensors beneath the menisci. The peak contact pressure (PCP), mean contact pressure (MCP), contact area (CA), and Dice similarity coefficient (DSC) that compares pressure distributions between conditions were evaluated. Compared to the intact condition, MMPRT caused significant differences in medial PCP, MCP, and CA, but only during the stance phase under the applied biomechanical model and loading conditions. Averaged across the stages within the stance phase, medial PCP and MPC were 32 % and 78 % higher, and CA was 35 % lower after MMPRT. After repair, these pressures generally remained significantly greater than their corresponding intact values. Specifically, medial PCP and MPC were on average 19 % and 40 % higher, and CA was 25 % lower than for the intact condition during the stance phase. DSCs relative to the intact state indicated that repair significantly improved pressure distributions (0.67–0.87) compared to MMPRT (0.47–0.78). The anatomic repair of MMPRT did not appear to fully restore intact contact pressure distributions in this study, suggesting that further improvement of surgical techniques may be beneficial.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112837"},"PeriodicalIF":2.4,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144548815","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}

{"title":"Upper limb movement analysis during the mug transportation task in post-stroke individuals and why efficiency matters","authors":"Bruno Freire,&nbsp;Letícia Yolanda Silva,&nbsp;Isadora Mello Gaidzinski,&nbsp;Letícia Pereira Padilha,&nbsp;Stella Maris Michaelsen","doi":"10.1016/j.jbiomech.2025.112841","DOIUrl":"10.1016/j.jbiomech.2025.112841","url":null,"abstract":"<div><div>Individuals with stroke often have impaired paretic arm function. While alterations in the paretic limb’s movement during tasks like reaching and grasping have been noted, these do not fully capture the motor behavior in transport tasks. This study aimed to examine the movement of paretic and non-paretic limbs during a mug transportation task using kinematic metrics and assess their correlation with a transport clinical test. Twenty-two individuals with chronic hemiparesis from a stroke were asked to transport a mug across a table using their non-paretic limb and then with their paretic limb. The kinematic analysis compared accuracy, precision, movement time, peak velocity, motor control strategy, efficiency, and interjoint coordination between limbs. The box and block test was used for correlation analysis. Results indicated the non-paretic limb had higher precision (∼52 %; forward end-range: 10.7 ± 5.7 mm) and efficiency (∼34 %; object path ratio: 1.38 ± 0.14 index) than the paretic limb (16.3 ± 13.5 mm and 1.51 ± 0.26 index, respectively), with no significant differences in other kinematic metrics. A strong correlation was found in the paretic limb between the box and block test and efficiency (r = −0.75), and good correlations with movement time (r = −0.66) and smoothness (r = −0.69). Despite the relevance of other kinematic metrics, efficiency was key for the transport task and a major factor in motor impairment. Rehabilitation for post-stroke individuals should thus emphasize transport tasks, aiming to increase efficiency.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"190 ","pages":"Article 112841"},"PeriodicalIF":2.4,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604242","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}

{"title":"Examination of dynamic gait stability during overground walking in people with mild cognitive impairment","authors":"Caroline Simpkins,&nbsp;Diané Brown,&nbsp;Jiyun Ahn,&nbsp;Sara Mahmoudzadeh Khalili,&nbsp;Feng Yang","doi":"10.1016/j.jbiomech.2025.112836","DOIUrl":"10.1016/j.jbiomech.2025.112836","url":null,"abstract":"<div><div>Although mild cognitive impairment (MCI) is known to compromise balance in older adults, its influence on dynamic gait stability is less understood. This study is the first to examine dynamic gait stability within the Feasible Stability Region framework during level overground walking at a self-selected speed in individuals with MCI. Eighteen people with MCI (66.4 ± 5.9 years) and 20 age- and sex-matched healthy controls (66.9 ± 6.2 years) completed overground walking trials at their comfortable speed while their full-body kinematics were collected. Dynamic gait stability at touchdown and liftoff served as the primary outcome. Secondary outcomes included the center of mass velocity and position, along with standard spatiotemporal gait parameters. Dynamic gait stability was similar between groups at touchdown (<em>p</em> = 0.299) and liftoff (<em>p</em> = 0.185). However, people with MCI positioned their center of mass more anteriorly relative to the base of support than the healthy controls at touchdown (<em>p</em> &lt; 0.001) and liftoff (<em>p</em> = 0.012). The center of mass velocity was slower in the MCI group than in cognitively healthy individuals at touchdown (<em>p</em> = 0.013) and comparable between groups at liftoff (<em>p</em> = 0.109). People with MCI exhibited a reduced gait speed (<em>p</em> = 0.018), decreased cadence (<em>p</em> = 0.018), shortened step length (<em>p</em> = 0.047), and prolonged stance phase (<em>p</em> = 0.067) compared to their healthy counterparts. Our study suggests that older adults with MCI adopt a cautious gait pattern, allowing them to maintain dynamic gait stability. These findings provide insight into the dynamic stability control in people with MCI during gait, broadening our understanding of dynamic balance control in human locomotion across populations.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112836"},"PeriodicalIF":2.4,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517559","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}

{"title":"Ground reaction force asymmetry underestimates asymmetries in knee joint reaction forces during countermovement jumps","authors":"Jonas Enqvist ,&nbsp;L. Joakim Holmberg ,&nbsp;Michael Skipper Andersen ,&nbsp;Anton Arndt","doi":"10.1016/j.jbiomech.2025.112834","DOIUrl":"10.1016/j.jbiomech.2025.112834","url":null,"abstract":"<div><div>Inter-limb asymmetry in function or performance is an external measure used in sports science and medicine assessing readiness. How asymmetries propagate and affect internal joint loading is, however, poorly understood. This study presents the first investigation of asymmetries in ground reaction forces and knee joint reaction forces during a countermovement jump. Eleven uninjured male participants performed three countermovement jumps. Forces and motion were analysed in the Anybody Modelling System. Total resultant knee joint reaction force (KJRF[R]) was six times higher than the total resultant ground reaction force (GRF[R]) and the magnitude of the interlimb asymmetry was 6.6 times higher for KJRF[R] than GRF[R] indicating a significantly (p &lt; 0.05) higher load in the joint structures of the dominant knee than the non-dominant knee. KJRF[AP] reached 1743 ± 556(877–2910) N in the posterior direction at a knee angle of 105°, representing a load carried solely by the passive structures of the knee together with the articular contact surfaces. Even a small asymmetry determined through external measures such as GRF, therefore had a high impact on joint loading. Previously used thresholds (10 % deficit) for return to sport may therefore be questioned, and lower thresholds may be relevant to prevent injuries in the dominant limb.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"189 ","pages":"Article 112834"},"PeriodicalIF":2.4,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517560","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}