Journal of biomechanics最新文献_第4页

A limitation of projected frontal area as an indicator of active drag in swimming: Focusing on tibial and femoral segments 投射额区作为游泳主动阻力指标的局限性：关注胫骨和股节段

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-19 DOI: 10.1016/j.jbiomech.2025.112972

Sohei Washino , Akihiko Murai , Tomoya Kadi , Kenzo Narita , Hirotoshi Mankyu , Yasuhide Yoshitake

{"title":"A limitation of projected frontal area as an indicator of active drag in swimming: Focusing on tibial and femoral segments","authors":"Sohei Washino , Akihiko Murai , Tomoya Kadi , Kenzo Narita , Hirotoshi Mankyu , Yasuhide Yoshitake","doi":"10.1016/j.jbiomech.2025.112972","DOIUrl":"10.1016/j.jbiomech.2025.112972","url":null,"abstract":"<div><div>The projected frontal area (PFA) is a useful indicator of swimming drag. However, it is inherently limited because it only considers observable frontal areas from a frontal view. To address this limitation, we determined a new indicator, the projected and occluded frontal area (POFA), which includes occluded frontal areas relative to the swimming direction. This study aimed to examine the difference between the PFA and POFA, focusing on the tibial and femoral segments during front crawl. Twelve competitive male swimmers performed a 15-meter front crawl at 1.20 m·s<sup>−1</sup>. The three-dimensional positions of the reflective markers attached to the swimmers’ bodies were collected using an underwater motion-capture system. The body shape of each swimmer was obtained using a body scanner. Two types of digital human models were created: a whole-body model with vertex colors divided into eight body segments and a segment-specific model extracted from the whole-body model. To reconstruct identical motions in both models, the joint angle data obtained through inverse kinematics computations using motion-capture data and the whole-body model were applied to the segment-specific models. The PFA and POFA were determined through image processing of a series of parallel frontal images from whole-body and segment-specific models, respectively. The PFA of the tibial and femoral segments was substantially smaller than the corresponding POFA (<em>p</em> < 0.001), with underestimation ratios of 86.1 % and 42.3 %, respectively. These results suggest that PFA is not a fully reliable indicator for evaluating swimming drag, at least in the tibial and femoral segments.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112972"},"PeriodicalIF":2.4,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155172","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}

引用次数: 0

Hip joint mechanics during swing limb advancement with bone-anchored limb use 在使用骨锚定肢体时摆动肢体推进的髋关节力学

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-19 DOI: 10.1016/j.jbiomech.2025.112978

James B. Tracy , Brecca M.M. Gaffney , Peter B. Thomsen-Freitas , Mohamed E. Awad , Danielle H. Melton , Cory L. Christiansen , Jason W. Stoneback

{"title":"Hip joint mechanics during swing limb advancement with bone-anchored limb use","authors":"James B. Tracy , Brecca M.M. Gaffney , Peter B. Thomsen-Freitas , Mohamed E. Awad , Danielle H. Melton , Cory L. Christiansen , Jason W. Stoneback","doi":"10.1016/j.jbiomech.2025.112978","DOIUrl":"10.1016/j.jbiomech.2025.112978","url":null,"abstract":"<div><div>Walking swing limb advancement after transfemoral amputation relies on the hip for proper limb positioning. We compared hip mechanics and stride characteristics during swing before and after bone-anchored limb (BAL) implantation. We hypothesized swing limb advancement hip mechanics would be different and between-limb differences reduced after BAL implantation without compromising stride characteristics. Twenty participants were included in this retrospective observational investigation including overground walking motion capture before and one-year after BAL implantation. Swing was measured from contralateral foot strike to ipsilateral foot strike during four phases: (1) pre-swing, (2) initial swing, (3) mid-swing, and (4) terminal swing. Hip mechanics were quantified using hip joint angles, moments, and powers, and thigh angular velocities in the sagittal and frontal planes. Most changes with BAL use occurred in the intact limb during mid-swing and terminal swing (p ≤ 0.04) with reduced between-limb differences (p ≤ 0.05). We also observed changes in frontal plane mechanics during initial swing and mid-swing (p ≤ 0.01) suggesting decreased frontal plane deviations (e.g., less swing limb circumduction and lateral leaning) with BAL use. Gait speed and stride length were unchanged (p ≥ 0.76, <em>g</em> ≤ 0.07) and stride width narrowed (p < 0.01, <em>g</em> = 0.89). These changes in the intact limb and increased similarity between limbs suggest that BAL use might increase the contribution of the amputated limb to walking postural control and reduce long-term pain and overuse problems associated with between-limb differences without compromising stride characteristics. Additional investigations of both limbs and gait deviations associated with transfemoral amputation are needed to further understand the impact of BAL use on walking.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112978"},"PeriodicalIF":2.4,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106318","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}

引用次数: 0

Relative power to velocity variation: A new quantification method for assessing swimming kinematics 速度变化的相对力量：一种评估游泳运动学的新的量化方法

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-19 DOI: 10.1016/j.jbiomech.2025.112970

Aléxia Fernandes , João Paulo Vilas-Boas , Ricardo J. Fernandes , Bruno Mezêncio

{"title":"Relative power to velocity variation: A new quantification method for assessing swimming kinematics","authors":"Aléxia Fernandes , João Paulo Vilas-Boas , Ricardo J. Fernandes , Bruno Mezêncio","doi":"10.1016/j.jbiomech.2025.112970","DOIUrl":"10.1016/j.jbiomech.2025.112970","url":null,"abstract":"<div><div>Velocity variation in swimming is commonly assessed using quantification methods that fail to consider the movement mechanical nature in the aquatic environment. The current study proposes the relative power to velocity variation method to evaluate the velocity variation effect in efficiency, accounting the swimmers hydrodynamic drag into the calculation. Twenty regional level swimmers (12 males) performed three 25 m front crawl trials (one at 88 and other at 100 % of their maximum velocity, and another at maximum pace using the velocity perturbation method). Mean, maximum and minimum velocities, stroke rate, length and index, and indexes of coordination and synchronization were obtained for each cycle. The power to overcome drag, power to velocity variation, total mechanical power, intracycle velocity variation (assessed by the coefficient of variation) and difference between maximum and minimum absolute velocities were also computed. Power regressions were performed between mean velocity, standard deviation and the absolute and relative power to velocity variation. Results showed that the absolute and relative power to velocity variation values increased (a = 2.82, b = 1) and decreased (a = 0.07, b = −2.00, respectively) with the mean velocity increment, while both rose with mean velocity standard deviation (a = 142.31, b = 2.00 and a = 1.14, b = 2.00, respectively). The relative power to velocity variation method offers an advanced understanding of front crawl efficiency and enables predicting its effect on overall swimming performance.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112970"},"PeriodicalIF":2.4,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106337","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}

引用次数: 0

Comparative analysis of trunk sensor placement in people with and without Parkinson’s disease 帕金森病患者和非帕金森病患者躯干传感器放置的比较分析

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-19 DOI: 10.1016/j.jbiomech.2025.112975

Charalampos Sotirakis , Anna Pelliet , Niall Conway , James FitzGerald , Chrystalina Antoniades

{"title":"Comparative analysis of trunk sensor placement in people with and without Parkinson’s disease","authors":"Charalampos Sotirakis , Anna Pelliet , Niall Conway , James FitzGerald , Chrystalina Antoniades","doi":"10.1016/j.jbiomech.2025.112975","DOIUrl":"10.1016/j.jbiomech.2025.112975","url":null,"abstract":"<div><div>Wearable devices are widely adopted for monitoring motor symptoms in Parkinson’s Disease (PD), but optimal sensor placement remains under debate. This study compares kinematic data between a smartphone placement on the abdomen (patient-friendly) and a lumbar sensor (gold-standard) in individuals with and without PD. Five PD patients and five healthy controls wore inertial measurement units (IMUs) and consumer smart devices (smartwatch and smartphone) on their wrist and around their waist. Wrist sensors were utilised only to synchronise between the two sensor systems. The lumbar IMU and smartphone were placed at the level of the L5 vertebra and in the abdomen region, respectively. Data were collected during quiet stance with closed eyes and overground walking tasks. For both accelerometer and gyroscope signals, maximum spectral coherence was used to assess the frequency-domain correlation between the smartphone and the lumbar sensor while spectral gain measured their spatial coupling in the anteroposterior, mediolateral, and vertical planes within the 0.1–10 Hz frequency band. Analysis demonstrated a good to excellent inter-device agreement (coherence > 0.9) in both groups in most coordinates. However, coherence decreased (coherence < 0.9) for mediolateral acceleration and pitch rotation in walking. Sensor agreement was substantially lower in the quiet stance tasks particularly for anteroposterior acceleration and pitch rotation. These results were evident in both groups. Abdomen device placement provides clinically valid movement data for PD motor symptom monitoring. Yet, caution is advised for specific parameters, as abdominal movement may introduce noise, affecting measurement accuracy. This research contributes to identifying the patient-centric device positioning without compromising data, in both people with PD and healthy individuals.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112975"},"PeriodicalIF":2.4,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155182","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}

引用次数: 0

Region-specific textured insoles enhance static stability in young adults with chronic ankle instability 区域特定的纹理鞋垫增强静态稳定性的年轻人慢性踝关节不稳定

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-19 DOI: 10.1016/j.jbiomech.2025.112974

Yunqi Tang , Xinyue Li , Lin Liu , Pui Wah Kong , Rong Wang , Meixi Li , Yuhong Niu

{"title":"Region-specific textured insoles enhance static stability in young adults with chronic ankle instability","authors":"Yunqi Tang , Xinyue Li , Lin Liu , Pui Wah Kong , Rong Wang , Meixi Li , Yuhong Niu","doi":"10.1016/j.jbiomech.2025.112974","DOIUrl":"10.1016/j.jbiomech.2025.112974","url":null,"abstract":"<div><div>Chronic ankle instability (CAI) impairs postural control through sensorimotor deficits, yet region-specific plantar stimulation strategies remain underexplored. This randomised crossover trial examined the differential effects of textured insoles targeting specific foot regions on static and dynamic stability in 24 young adults with CAI (age: 22.3 ± 2.5 years; Cumberland Ankle Instability Tool score: 16.0 ± 3.3). Participants completed three functional assessments (static single-leg stance, Y-balance test, and jump-landing task) under four experimental conditions: forefoot-textured, midfoot-textured, rearfoot-textured, and smooth control insoles. Results showed that forefoot-textured insoles significantly improved static postural control, reducing total centre of pressure (COP) sway velocity by 8.9 % (54.2 ± 11.7 vs. 49.4 ± 9.3 mm/s, p = 0.024) and COP ellipse area by 15.6 % (223.6 ± 60.8 vs. 188.8 ± 48.3 mm<sup>2</sup>, p = 0.012) compared to control. However, no significant improvements were observed in dynamic stability metrics during jump landing (all p > 0.05) or Y-balance test composite scores (p = 0.075). Subjective stability and comfort ratings did not significantly differ across conditions (p > 0.05). These findings indicate an acute, task-dependent effect of plantar stimulation; the apparent forefoot advantage may reflect a general cutaneous facilitation of balance rather than a CAI-specific mechanism. Dynamic tasks may require complementary training or longer exposure, and the clinical significance remains to be established.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112974"},"PeriodicalIF":2.4,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155530","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}

引用次数: 0

Neuromuscular pre-activation attenuates mandibular impact injuries: Dynamic finite element analysis of stress modulation in craniomaxillofacial structures 神经肌肉预激活减弱下颌撞击损伤：颅颌面结构应力调节的动态有限元分析

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-18 DOI: 10.1016/j.jbiomech.2025.112969

Fei Chen , Bingmei Shao , Zhan Liu

{"title":"Neuromuscular pre-activation attenuates mandibular impact injuries: Dynamic finite element analysis of stress modulation in craniomaxillofacial structures","authors":"Fei Chen , Bingmei Shao , Zhan Liu","doi":"10.1016/j.jbiomech.2025.112969","DOIUrl":"10.1016/j.jbiomech.2025.112969","url":null,"abstract":"<div><div>The craniomaxillofacial region is highly susceptible to high-intensity impact injuries during contact sports, however, existing passive protective devices have limited energy absorption capacity. This study aimed to quantitatively assess the protective efficacy of neuromuscular pre-activation against mandibular impact injuries. A high-precision craniomaxillofacial biomechanical model was constructed using CT and MRI data from a healthy male subject (glabello-occipital length: 176 mm; vertex-menton height: 212 mm; bizygomatic breadth: 135 mm). The model included the cranium, maxilla, mandible, masticatory muscles (masseter, temporalis, medial pterygoid, and lateral pterygoid), disc, and capsule. Under varying pre-activation durations (0–50 ms, corresponding to 0–92 % of the maximum activation level), the mandible underwent a 500 N anterior impact (10-ms semi-sinusoidal waveform). Finite element analysis was used to simulate the dynamic biomechanical responses of the craniomaxillofacial system. Prolonged pre-activation significantly reduced stress concentrations in critical structures. Without pre-activation, peak von Mises stresses in the condylar neck and coronoid process reached 141 MPa and 193 MPa, respectively. With 50 ms of pre-activation, these stresses decreased by 73 % (condylar neck) and 90.7 % (coronoid process). Contact stress in the disc decreased by 86.2 %, thereby mitigating the risk of collagen fiber tearing in the intermediate zone. The medial pterygoid muscle exhibited an 83.3 % decrease in maximum principal stress, reducing the likelihood of muscle fiber rupture. Neuromuscular pre-activation modulates mandibular motor stiffness, thereby effectively attenuating impact-induced damage to bone, muscle, and disc. These findings lay a biomechanical foundation for the development of mandibular protective devices (aimed at restricting mandibular opening displacement) to reduce acute and chronic craniofacial injuries in athletes.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112969"},"PeriodicalIF":2.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106316","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}

引用次数: 0

The role of friction forces in arterial mechanical thrombectomy: a review 摩擦力在动脉机械取栓中的作用综述。

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-16 DOI: 10.1016/j.jbiomech.2025.112966

Mahesh S. Nagargoje , Virginia Fregona , Giulia Luraghi , Francesco Migliavacca , Guglielmo Pero , Jose Felix Rodriguez Matas

{"title":"The role of friction forces in arterial mechanical thrombectomy: a review","authors":"Mahesh S. Nagargoje , Virginia Fregona , Giulia Luraghi , Francesco Migliavacca , Guglielmo Pero , Jose Felix Rodriguez Matas","doi":"10.1016/j.jbiomech.2025.112966","DOIUrl":"10.1016/j.jbiomech.2025.112966","url":null,"abstract":"<div><div>Multiple clinical trials have demonstrated the superiority of mechanical thrombectomy (MT) over intravenous thrombolysis (tPA) in treating acute ischemic stroke (AIS). Stent retriever (SR) and aspiration techniques are the standard methods for removing occluded emboli, with evolving technologies improving MT efficiency. However, procedural success remains uncertain. Frictional forces, specifically clot-vessel, clot-SR, and SR-vessel interactions, play a critical role in MT outcomes. This review examines frictional forces during MT and their impact on success, analyzing publications from 2015 to 2025. We focus on studies that calculated friction or retrieval forces using in vitro models. We have also included current trends, limitations, and future perspectives on studying and understanding frictional forces and their implementation into in silico models. Findings indicate that fibrin-rich clots are more difficult to retrieve than red blood cell (RBC)-rich clots due to their higher friction coefficient, three to four times greater, an observation supported by multiple studies. SR-vessel and SR-clot friction also influence MT effectiveness. SR-vessel interaction plays a crucial role in acutely curved vessels, as SR compression reduces its efficiency. In SR-clot interaction, RBC-rich clot fragmentation is linked to relative interaction forces. In summary, obtaining in vivo frictional values remains challenging, and inconsistencies persist in past in vitro studies. Further, a deeper understanding of frictional forces is essential for optimizing MT, improving current SRs, and developing next generation thrombectomy technologies.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112966"},"PeriodicalIF":2.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091549","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}

引用次数: 0

Validation of an automated spinal fusion finite element modeling framework for the prediction of pedicle screw loosening 用于预测椎弓根螺钉松动的自动脊柱融合有限元建模框架的验证。

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-16 DOI: 10.1016/j.jbiomech.2025.112967

Tobias Götschi , Gian Maranta , Marie-Rosa Fasser , Mazda Farshad , Jonas Widmer

{"title":"Validation of an automated spinal fusion finite element modeling framework for the prediction of pedicle screw loosening","authors":"Tobias Götschi , Gian Maranta , Marie-Rosa Fasser , Mazda Farshad , Jonas Widmer","doi":"10.1016/j.jbiomech.2025.112967","DOIUrl":"10.1016/j.jbiomech.2025.112967","url":null,"abstract":"<div><div>This study aimed to validate a patient-specific biomechanical simulation pipeline for predicting pedicle screw loosening risk in posterior spinal fusion. In particular, the research questioned whether this simulation, which integrates CT-derived bone properties, musculoskeletal force data, and finite element analysis, can outperform conventional CT attenuation measurements taken in both the vertebral body and along the planned screw trajectory.</div><div>We conducted a retrospective database analysis, including patients who underwent lumbar spinal fusion with preoperative and postoperative CT scans. Screw loosening was identified through manual testing during revision surgeries. CT attenuation was measured manually in the vertebral body and automatically along the screw trajectory. The biomechanical model integrated patient-specific musculoskeletal force data, CT-derived bone properties, and finite element analysis to estimate local bone loading relative to yield stress. The pipeline’s predictive performance was evaluated using receiver operator characteristic (ROC) curves.</div><div>The study included 161 pedicle screws, with 48 classified as loosened. Patient-specific biomechanical modeling demonstrated superior predictive capabilities (ROC AUC = 0.919) compared to screw trajectory HU measurements (ROC AUC = 0.783) and vertebral body HU measurements (ROC AUC = 0.760). Patient-specific biomechanical modeling offers a more comprehensive assessment of screw loosening risk by integrating multiple influential factors compared to simple CT attenuation measurements.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112967"},"PeriodicalIF":2.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102671","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}

引用次数: 0

A normative dataset of thumb muscle fascicle lengths in healthy, young adults: an extended field-of-view ultrasound study 健康年轻人拇指肌束长度的规范数据集：扩展视场超声研究

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-16 DOI: 10.1016/j.jbiomech.2025.112964

Alexis R. Benoit, Jennifer A. Nichols

{"title":"A normative dataset of thumb muscle fascicle lengths in healthy, young adults: an extended field-of-view ultrasound study","authors":"Alexis R. Benoit, Jennifer A. Nichols","doi":"10.1016/j.jbiomech.2025.112964","DOIUrl":"10.1016/j.jbiomech.2025.112964","url":null,"abstract":"<div><div>Understanding <em>in vivo</em> thumb muscle architecture is essential for advancing musculoskeletal modeling and identifying deviations linked to pathologies. As thumb muscle architecture has primarily been studied in cadavers, the objective of this study was to establish normative data on thumb muscle fascicle lengths in a young, healthy population using extended field-of-view ultrasound (EFOV-US). Six thumb muscles [abductor pollicis brevis (APB) and longus (APL); extensor pollicis brevis (EPB) and longus (EPL); flexor pollicis brevis (FPB) and longus (FPL)] and one wrist extensor [extensor carpi ulnaris (ECU; for comparison purposes only)] were imaged in 18 healthy adults (8 female; age: 22.7 ± 2.0 years; height: 172.1 ± 8.8 cm; weight: 79.0 ± 16.5 kg) [mean ± SD]. Measured fascicles were compared to cadaveric data (all thumb muscles) and ultrasound data (APB, ECU, FPL). Mean fascicle lengths (±SD) were 6.5 ± 0.8 cm (FPL), 3.8 ± 0.4 cm (APL), 4.7 ± 0.5 cm (EPL), 3.7 ± 0.5 cm (EPB), 4.5 ± 0.5 cm (APB), 3.6 ± 0.4 cm (FPB), and 4.2 ± 0.5 cm (ECU). The consistency of our measurements is indicated by the small standard deviations within (±0.1 to ± 0.7 cm) and across (±0.4 to ± 0.8 cm) participants. Measurement repeatability is high, as demonstrated by low coefficients of variation (range: 0.04–0.08) for the measured thumb muscles. We also examined to what extent anthropometric measurements can be used to predict fascicle lengths and found some significant relationships; however, these relationships were not consistent across all muscles. This study importantly expands our understanding of the complex anatomy of the healthy thumb and provides normative data for future work evaluating hand pathologies.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112964"},"PeriodicalIF":2.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106322","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}

引用次数: 0

Comparison of kinematics between markerless and marker-based motion capture systems for change of direction maneuvers 无标记和基于标记的运动捕捉系统的运动学比较。

IF 2.4 3区医学

Journal of biomechanics Pub Date : 2025-09-15 DOI: 10.1016/j.jbiomech.2025.112965

Naoto Nishikawa , Shun Watanabe , Keizo Yamamoto

{"title":"Comparison of kinematics between markerless and marker-based motion capture systems for change of direction maneuvers","authors":"Naoto Nishikawa , Shun Watanabe , Keizo Yamamoto","doi":"10.1016/j.jbiomech.2025.112965","DOIUrl":"10.1016/j.jbiomech.2025.112965","url":null,"abstract":"<div><div>Marker-based motion capture, a widely used method for three-dimensional motion analysis, entails important shortcomings, including soft tissue artifacts and constraints on experiment environments. By contrast, markerless systems require no reflective markers, show minimal inter-session variation, and remain unaffected by clothing, making them promising tools for athletic performance evaluation. This study was conducted to compare kinematic data obtained using the respective systems during change of direction (COD) maneuvers and to evaluate the applicability of markerless systems. Five trials of 90° COD maneuvers were performed by 23 male participants. Kinematic data were captured simultaneously using marker-based (Motion Analysis) and markerless systems (Theia Markerless Inc.). The markerless system used synchronized multi-camera deep learning to detect anatomical landmarks and to reconstruct full-body skeletal motion through triangulation and inverse kinematics. Trunk and lower-limb joint angles were calculated for both systems. Bland–Altman analysis, the intraclass correlation coefficient (ICC), root mean square deviation (RMSD), and normalized root mean square error (NRMSE) were used to compare the two systems. Both systems demonstrated good agreement for most joint angles. However, notable mean differences were found in ankle dorsiflexion (−10.92° [−18.38, −3.46]), knee flexion (−8.32° [−14.48, −2.13]), and hip external rotation (12.1° [−2.12, 26.33]). Most angles also showed good ICC values (>0.75), indicating measurement reliability between the systems. These findings suggest that markerless systems can capture kinematic patterns reliably during COD maneuvers. However, comparing the magnitudes of joint angles with those of marker-based systems demands caution. This method is valid for COD analysis if system-specific differences are considered.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"192 ","pages":"Article 112965"},"PeriodicalIF":2.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102694","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}

引用次数: 0