Journal of biomechanics最新文献

Simultaneous stabilizing feedback control of linear and angular momentum in human walking 人类行走中线动量和角动量的同步稳定反馈控制。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-02 DOI: 10.1016/j.jbiomech.2026.113240

Jaap H. van Dieën, Sjoerd M. Bruijn, Koen K. Lemaire, Dinant A. Kistemaker

Stabilizing bipedal gait is mechanically challenging. To analyze how gait is stabilized, previous studies have focused on the control of the body center of mass (CoM). These studies often linked deviations in linear momentum of the CoM to subsequent shifts in position of the center of pressure (CoP), or of the foot, relative to the COM, and interpreted these as stabilizing responses to correct linear CoM momentum. Mechanically, however, CoP shifts do not cause changes of linear CoM momentum, whereas they do cause changes in whole-body angular momentum. We hypothesized that experimentally observed correlations between CoP to CoM distance and horizontal ground reaction forces are related to the need to control both linear and whole-body angular momentum. We show that, in human walking, linear and angular momentum follow quasi-periodic functions with similar periodicity and phase. Combining the equations of linear and rotational motion for a system of linked rigid segments shows that, in this case, the horizontal distance between CoP and CoM should be correlated to horizontal force in the corresponding direction. This suggests that linear and angular momentum are simultaneously controlled and may explain the success of preceding studies that correlated CoM states to CoP or foot locations. Regression models fitted to experimental data of participants walking at normal and slow speeds showed that deviations in horizontal ground reaction forces and in moments of the ground reaction force about the sagittal and transverse axes could be predicted from deviations in the preceding linear and angular momentum respectively. Our analyses support that linear and angular momentum are indeed controlled simultaneously in human walking.

稳定双足步态在机械上具有挑战性。为了分析步态是如何稳定的，以往的研究主要集中在身体质量中心的控制上。这些研究通常将CoM的线性动量偏差与随后压力中心（CoP）或足部相对于CoM的位置变化联系起来，并将其解释为对纠正线性CoM动量的稳定反应。然而，从机械上讲，CoP位移不会引起线性CoM动量的变化，而会引起全身角动量的变化。我们假设，实验观察到的CoP到CoM距离和水平地面反作用力之间的相关性与控制线性和全身角动量的需要有关。我们发现，在人类行走中，线动量和角动量遵循具有相似周期和相位的准周期函数。结合连接刚性段系统的直线运动方程和旋转运动方程可以看出，在这种情况下，CoP和CoM之间的水平距离应该与相应方向的水平力相关。这表明线动量和角动量同时受到控制，这可能解释了之前将CoM状态与CoP或足部位置相关的研究的成功。对正常和慢速行走实验数据拟合的回归模型表明，水平地面反作用力和地面反作用力力矩在矢状轴和横轴上的偏差可以分别由之前的线动量和角动量的偏差来预测。我们的分析支持，线动量和角动量确实在人类行走中同时受到控制。

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引用次数: 0

Joint angle and muscle length manipulation reveal regional uniformity of sarcomere lengths in the passive rat medial gastrocnemius 关节角度和肌肉长度操作揭示了被动大鼠腓肠肌内侧肌节长度的区域均匀性。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-02-26 DOI: 10.1016/j.jbiomech.2026.113232

Guido Geusebroek , Chris Tijs , Wendy Noort , Han Houdijk , Jaap van Dieën , Huub Maas

The elongation of musculotendinous substructures attained during muscle stretching determines acute and long-term effects of stretching. We assessed how elongation is distributed across substructures of the rat medial gastrocnemius (MG) and how MG sarcomere elongation relates to plantarflexion resistance when the MG is stretched through joint rotation. We fixated 48 rat hindlimbs in 16 combinations of knee and ankle joint angles (55°, 90°, 125° and 160°), with three limbs per combination. We measured the MG muscle-belly length and the pennation angle in the proximal and distal region. We dissected four to five muscle-fibers from proximal, intermediate and distal muscle-belly regions and measured fiber and sarcomere length. We compared fiber and sarcomere lengths across regions and assessed how muscle-belly lengthening induced by knee or ankle rotation affected fiber length, sarcomere length and pennation angle. Lastly we measured plantarflexion torque of 12 rats in a range of ankle angles from 120° to 70° with the knee fixed in 90°. We found that pennation angles decreased and that fibers and sarcomeres lengthened uniformly across MG regions in response to muscle-belly lengthening. The onset of sarcomere lengthening (beyond 2.1 µm) preceded the onset of passive plantarflexion torque by aproximately 20°. Muscle-belly lengthening induced by ankle rotation had a greater impact on mean sarcomere length, fiber length, and pennation angle compared to knee rotation. In conclusion, sarcomeres lengthen uniformly across MG regions.

在肌肉拉伸过程中获得的肌腱亚结构的伸长决定了拉伸的急性和长期效果。我们评估了伸长如何分布在大鼠内侧腓肠肌（MG）的亚结构中，以及当MG通过关节旋转拉伸时，MG肌节伸长如何与跖屈阻力相关。我们以16种膝关节和踝关节角度组合（55°、90°、125°和160°）固定48只大鼠后肢，每种组合固定3只肢体。我们测量了近端和远端肌腹长度和穿刺角。我们从近端、中端和远端肌腹区解剖了四到五条肌纤维，并测量了纤维和肌节的长度。我们比较了不同区域纤维和肌节的长度，并评估了膝关节或踝关节旋转引起的肌肉腹部延长对纤维长度、肌节长度和笔触角度的影响。最后，我们测量了12只大鼠在踝关节角度从120°到70°范围内的跖屈曲扭矩，膝盖固定在90°。我们发现，随着肌肉腹部的延长，笔角减小，纤维和肌节在MG区域均匀延长。肌节延长的开始（超过2.1µm）比被动跖屈曲力矩的开始早了大约20°。与膝关节旋转相比，踝关节旋转引起的肌腹延长对平均肌节长度、纤维长度和笔触角度的影响更大。综上所述，肌节在MG区均匀延长。

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引用次数: 0

Development and validation of a deep learning markerless system for lower-limb kinematics in hip and knee osteoarthritis population 髋关节和膝关节骨关节炎患者下肢运动学的深度学习无标记系统的开发和验证。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-03 DOI: 10.1016/j.jbiomech.2026.113238

Junqing Wang , Tengfei Li , Wei Xu , Bo Hu , Fashu Xu , Bin Song , Yong Nie , Yubo Fan , Kang Li

With the advancement of deep learning technology, markerless systems have emerged as a cost-effective and user-friendly alternative to marker-based systems. However, most existing markerless systems are developed using datasets from healthy individuals, which limits their generalizability to patient populations. Therefore, this study developed a four-camera markerless system using a dataset of patients with osteoarthritis and validated its measurement accuracy in lower-limb kinematics. A total of 150 patients with hip or knee osteoarthritis were allocated to a training set (n = 120) and a test set (n = 30). Kinematic data during gait were simultaneously collected using both markerless and marker-based systems. We developed a four-camera markerless system on the training set. In the test set, the kinematic differences between the markerless and marker-based systems over the gait cycle were assessed using root mean square error (RMSE) and intraclass correlation coefficient (ICC). The grand mean position difference and ICC for the keypoints predicted by the markerless system were 13.4 mm and 0.93, respectively. Additionally, the mean RMSE for all joint angles was 4.1°. The ICC for the joint angle waveforms between the markerless and marker-based systems in the sagittal, frontal, and transverse planes were 0.93, 0.50, and 0.34, respectively. Our four-camera markerless system, developed using data from patient populations, shows high accuracy in keypoints and sagittal plane joint angles prediction. This indicates that our markerless system is suitable for osteoarthritis populations and offers a cost-effective and convenient tool for disease-related biomechanical research.

随着深度学习技术的进步，无标记系统已经成为基于标记系统的一种经济高效且用户友好的替代方案。然而，大多数现有的无标记系统是使用健康个体的数据集开发的，这限制了它们在患者群体中的推广。因此，本研究使用骨关节炎患者数据集开发了一个四摄像头无标记系统，并验证了其下肢运动学测量的准确性。共有150例髋关节或膝关节骨关节炎患者被分配到训练组（n = 120）和测试组（n = 30）。采用无标记和基于标记的系统同时收集步态过程中的运动学数据。我们在训练集上开发了一个四摄像头无标记系统。在测试集中，使用均方根误差（RMSE）和类内相关系数（ICC）评估了无标记和基于标记系统在步态周期中的运动学差异。无标记系统预测的关键点的大平均位置差和ICC分别为13.4 mm和0.93。此外，所有关节角度的平均RMSE为4.1°。无标记和基于标记系统在矢状面、额状面和横切面的关节角波形的ICC分别为0.93、0.50和0.34。我们的四摄像头无标记系统使用患者群体数据开发，在关键点和矢状面关节角度预测方面具有很高的准确性。这表明我们的无标记系统适用于骨关节炎人群，并为疾病相关的生物力学研究提供了一种成本效益高且方便的工具。

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引用次数: 0

Spatiotemporal mapping of plantar shear forces during human walking using a flexible thin-film sensor 基于柔性薄膜传感器的人体行走过程中足底剪切力的时空映射。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-03 DOI: 10.1016/j.jbiomech.2026.113239

Kohei Nishizawa, Naomichi Ogihara

During walking, the foot is subjected to complex vertical and shear ground reaction forces, which play critical roles in gait mechanics and the development of foot pathologies. However, plantar shear stress has been less investigated due to measurement difficulties. This study aimed (1) to evaluate the accuracy of a newly developed thin-film shear force distribution sensor in measuring plantar pressure and shear stress during walking, and (2) to characterize the spatiotemporal features of plantar shear loading throughout the stance phase. Five healthy male adults participated in walking experiments using the thin-film sensor affixed to a force plate for reference. The sensor measures normal and shear forces with a resolution of 24 × 24 sensing points over a 312 × 312 mm area. Force outputs were sampled at 100 Hz and compared with the ground reaction forces obtained from the force plate. The integrated vertical and shear components from the thin-film sensor showed good agreement with the force plate data, confirming its accuracy and reliability. Spatiotemporal shear maps revealed dynamic changes in magnitude and direction across stance: posterior shear beneath the heel during early stance, medial rotation at mid-stance, and anterior propulsion beneath the forefoot during push-off. This sensing system enables continuous mapping of plantar shear and pressure distributions, providing a practical tool for gait analysis and the prevention of foot disorders such as diabetic ulcers and hallux valgus.

在行走过程中，足部受到复杂的垂直和剪切地面反作用力，这在步态力学和足部疾病的发展中起着至关重要的作用。然而，由于测量困难，足底剪切应力的研究较少。本研究旨在(1)评估新开发的薄膜剪切力分布传感器测量行走过程中足底压力和剪切应力的准确性；(2)表征整个站立阶段足底剪切载荷的时空特征。5名健康成年男性参加了步行实验，使用贴在力板上的薄膜传感器作为参考。传感器测量法向力和剪力，分辨率为24 × 24个测点，测量面积为312 × 312 mm。在100 Hz下采样力输出，并与从力板获得的地面反作用力进行比较。薄膜传感器测得的垂直分量和剪切分量与测力板数据吻合较好，证实了其准确性和可靠性。时空剪切图揭示了跨站姿在大小和方向上的动态变化：站姿早期脚跟下方的后部剪切，站姿中期的内侧旋转，蹬离时前脚下方的前部推进。该传感系统能够连续绘制足底剪切和压力分布，为步态分析和预防足部疾病（如糖尿病溃疡和拇外翻）提供实用工具。

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引用次数: 0

The segmental dynamics of the lower leg in the side-volley kick in male soccer players 男子足球运动员侧抽射时小腿的节段动力学

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-08 DOI: 10.1016/j.jbiomech.2026.113249

Tsuyoshi Iitake, Hiroyuki Nunome

The present study aimed to clarify the differences in interaction torques acting on the kicking limb by expressing them as functions of the relative linear accelerations in a linked lower leg system. Twenty experienced male university-level soccer players (19.5 ± 1.1 years, 1.75 ± 0.06 m, 69.2 ± 5.5 kg) were instructed to perform the side-volley and instep kicks as forcefully as possible. The kicking motions were captured using a 12-camera optoelectronic motion capture system at 500 Hz. To describe the differences in the detailed mechanics of the interaction torques between the two kicks, the acceleration of the lower leg centre of gravity was decomposed into the relative accelerations of adjacent body landmarks from the support leg’s hip joint, which allowed us to calculate the interaction torques due to accelerative actions of these body landmarks. The side-volley kick generated significantly smaller total interaction torque and the interaction torque due to the support leg’s hip in the final phase of kicking than the instep kick. There was a distinctive difference between the two kicks in the practical accelerative actions at the support leg’s hip. In the side-volley kick, while the interaction torque due to the vertical acceleration of the support leg’s hip was negligible during kicking, that due to the horizontal acceleration (towards the left from the back-view of right-footed players) had the most considerable magnitude. The horizontal acceleration is most likely derived from the support leg’s hip adduction joint torque, apparent in the latter part of kicking.

本研究旨在澄清相互作用扭矩的差异，通过将其表达为连接的下肢系统中相对线性加速度的函数。选取20名有经验的男大学生足球运动员（年龄19.5±1.1岁，身高1.75±0.06米，体重69.2±5.5公斤），指导他们尽可能用力地进行侧截击和脚背踢。踢腿运动采用12个摄像头的光电运动捕捉系统，频率为500 Hz。为了描述两种踢腿之间相互作用扭矩的详细力学差异，将小腿重心的加速度分解为来自支撑腿髋关节的相邻身体标志的相对加速度，从而使我们能够计算这些身体标志的加速作用所产生的相互作用扭矩。侧截击踢腿在踢腿的最后阶段产生的总相互作用扭矩和由支撑腿的臀部产生的相互作用扭矩明显小于脚背踢腿。两种踢法在支撑腿臀部的实际加速动作上有明显的区别。在侧截击踢中，由于支撑腿臀部的垂直加速度而产生的相互作用扭矩在踢腿过程中可以忽略不计，而由于水平加速度（从右脚球员的后视镜看向左）产生的相互作用扭矩具有最可观的幅度。水平加速度很可能来源于支撑腿的髋关节内收关节扭矩，这在踢腿的后半部分很明显。

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引用次数: 0

Numerical modelling of airflow and aerosol particle delivery in cats with bronchial and non-bronchial disease 患有支气管和非支气管疾病的猫体内气流和气溶胶颗粒输送的数值模拟。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-02-26 DOI: 10.1016/j.jbiomech.2026.113233

Carla Zamora-Perarnau , Mauro Malvè , Rocío Fernández-Parra

Feline lower airway disease comprises a spectrum of inflammatory conditions, including asthma, which is commonly treated with inhaled glucocorticoids. This study employs computed tomography (CT)–based computational fluid dynamics (CFD) models to characterize airflow dynamics in feline lower airways with and without bronchial disease (BD and NBD), evaluating velocity, pressure, wall shear stress, and airway resistance under different flow conditions. In addition, deposition patterns of two aerosol particle sizes (1 µm and 10 µm) were assessed within the trachea and bronchi.

Geometrical reconstructions of the trachea and lobar bronchi were generated from CT scans of 24 cats, classified into BD and NBD groups. Simulations were performed using two airflow conditions and two particle diameters. Airflow parameters and aerosol particle deposition were calculated for each model.

A trend toward higher values of most airflow parameters was observed in the NBD group, except for expiratory resistance and velocity. However, no statistically significant differences in airflow parameters were identified between groups. Particle deposition analysis showed a higher deposition fraction for larger particles, with 10 µm particles depositing more frequently on bronchial walls than 1 µm particles in both groups.

Overall, CT-based CFD analysis revealed no significant group differences in resistance, pressure, wall shear stress, or velocity. Nevertheless, particle size influenced deposition patterns, with larger particles showing increased bronchial trapping. Although the initial hypothesis was not confirmed, this feasibility and characterization study establishes a methodological framework for future in silico investigations of feline lower airway disease providing preliminary physiologically and clinically relevant insights.

猫下气道疾病包括一系列炎症，包括哮喘，通常用吸入糖皮质激素治疗。本研究采用基于计算机断层扫描（CT）的计算流体动力学（CFD）模型来表征患有和不患有支气管疾病（BD和NBD）的猫下气道的气流动力学，评估不同流动条件下的速度、压力、壁面剪切应力和气道阻力。此外，还评估了两种气溶胶粒径（1µm和10µm）在气管和支气管内的沉积模式。将24只猫分为BD组和NBD组，通过CT扫描生成气管和大叶支气管的几何重建。采用两种气流条件和两种颗粒直径进行了模拟。计算了每个模型的气流参数和气溶胶颗粒沉积。除呼气阻力和呼气速度外，NBD组大多数气流参数均有升高的趋势。然而，两组之间的气流参数没有统计学上的显著差异。颗粒沉积分析显示，大颗粒的沉积率更高，两组中10µm颗粒在支气管壁上的沉积频率高于1µm颗粒。总体而言，基于ct的CFD分析显示，各组在阻力、压力、壁面剪切应力或速度方面没有显著差异。然而，颗粒大小影响沉积模式，较大的颗粒显示支气管捕获增加。虽然最初的假设没有得到证实，但这项可行性和表征研究为未来猫下气道疾病的计算机研究建立了一个方法学框架，提供了初步的生理学和临床相关见解。

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引用次数: 0

Modes of centripetal ground reaction force application in curved sprinting on an athletic track in male athletes 向心地面反作用力在男子运动员弯曲跑道短跑中的作用模式

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-02-06 DOI: 10.1016/j.jbiomech.2026.113186

Yasuko Hirono, Norihisa Fujii

Curve sprinting requires a centripetal ground reaction force (GRF) impulse, causing biomechanical leg asymmetries. However, the strategies for modulating this impulse, its primary determinants (contact duration versus GRF magnitude), and specific joint kinetic and kinematic contributions remain unclear. This study investigated these impulse determinants and identified lower-limb factors associated with the magnitude of the GRF to elucidate asymmetrical leg modes in curve sprinting. Fifteen experienced male sprinters performed submaximal sprints on a 42-m-radius curve. Three-dimensional kinematic data and GRFs were recorded, joint torques were calculated, and partial least squares regression (PLSR) was used to assess key relationships. The centripetal impulse was strongly correlated with the mean centripetal GRF for both legs but not with the contact duration. Thus, the mean centripetal GRF, rather than the contact duration, was the primary determinant of the centripetal impulse during curve sprinting for both legs, supporting our first hypothesis. The PLSR results revealed functionally distinct asymmetrical modes: the left leg engaged in a complex turning and stability mode, defined by specific hip/ankle torques, and suppressed outward push. Conversely, the right leg relied on a dominant whole-limb inclination of the knee and ankle joint axis, along with a contribution from the ankle plantarflexion torque. These findings highlight distinct asymmetrical mechanisms of GRF application, thereby advancing our understanding of curve-sprinting biomechanics.

曲线冲刺需要向心地面反作用力（GRF）脉冲，导致生物力学腿部不对称。然而，调节这种冲量的策略，其主要决定因素（接触持续时间与GRF大小），以及具体的关节动力学和运动学贡献仍不清楚。本研究调查了这些冲动决定因素，并确定了与GRF大小相关的下肢因素，以阐明曲线短跑中不对称的腿部模式。15名有经验的男性短跑运动员在半径42米的弯道上进行了次极限冲刺。记录三维运动学数据和grf，计算关节力矩，并使用偏最小二乘回归（PLSR）评估关键关系。向心冲量与两腿平均向心GRF密切相关，但与接触时间无关。因此，平均向心GRF，而不是接触时间，是两条腿在曲线冲刺期间向心冲量的主要决定因素，支持我们的第一个假设。PLSR结果显示功能上明显的不对称模式：左腿参与复杂的转弯和稳定模式，由特定的髋关节/踝关节扭矩定义，并抑制向外推动。相反，右腿依赖于膝关节和踝关节轴的全肢倾斜，以及踝关节跖屈曲扭矩的贡献。这些发现突出了GRF应用的不同不对称机制，从而促进了我们对曲线冲刺生物力学的理解。

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引用次数: 0

Knee and hip joint dynamics differ between sprinting and Nordic hamstring exercises 在短跑和北欧腿筋运动中，膝关节和髋关节的动态是不同的

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-03 DOI: 10.1016/j.jbiomech.2026.113236

Kristen Steudel , Nicos Haralabidis , Reed Gurchiek , Jennifer Hicks , Scott Delp

Sprinting and the Nordic hamstring exercise (NHE) are common training modalities used to reduce hamstring injury risk, but the differences in the biomechanical demands of sprinting and the NHE are unclear. We conducted an exploratory analysis comparing knee and hip joint kinematics and kinetics, and biceps femoris long head (BFLH) muscle–tendon unit length and velocity during the flight phase of sprinting and the NHE. We collected motion capture and force data from fourteen athletic participants (8 males, 6 females) running (4–8 m/s) and performing the NHE. We used this experimental data and musculoskeletal modeling to compute joint kinematics and kinetics and estimate the BFLH muscle–tendon unit length and velocity for all running speeds and the NHE. Sprinting, for all speeds, puts the BFLH at longer lengths (p < 0.001) and higher lengthening velocities (p < 0.001) than the NHE. The NHE requires participants to generate peak knee flexion moments that are smaller than for running at 6 m/s and above (p < 0.001), and peak negative knee flexion powers that are less than 5% of all running speeds (p < 0.001). However, the duration of each NHE repetition is approximately 60 times longer than the BFLH lengthening portion of the flight phase of running, resulting in greater negative knee work for running at 6 m/s and below (p < 0.001) but less at 7.5 m/s and above (p < 0.001). The results of this study provide necessary quantitative information to compare the biomechanical demands of sprinting and the NHE.

短跑和北欧腿筋运动（NHE）是减少腿筋损伤风险的常用训练方式，但短跑和NHE在生物力学要求上的差异尚不清楚。我们进行了一项探索性分析，比较了在短跑和NHE的飞行阶段，膝关节和髋关节的运动学和动力学，以及股二头肌长头（BFLH）肌肉肌腱单位长度和速度。我们收集了14名运动参与者（8名男性，6名女性）在跑步（4-8米/秒）和进行NHE时的动作捕捉和力数据。我们使用这些实验数据和肌肉骨骼模型来计算关节运动学和动力学，并估计所有跑步速度和NHE下的BFLH肌肉肌腱单位长度和速度。与NHE相比，在所有速度下冲刺时，BFLH的长度都更长（p < 0.001），延长速度也更高（p < 0.001）。NHE要求参与者产生的峰值膝关节屈曲力矩小于6米/秒及以上（p < 0.001），峰值膝关节负屈曲力小于所有跑步速度的5% （p < 0.001）。然而，每次NHE重复的持续时间大约是跑步飞行阶段BFLH延长部分的60倍，导致以6米/秒及以下的速度跑步时膝关节负功更大（p < 0.001），而以7.5米/秒及以上的速度跑步时膝关节负功更小（p < 0.001）。本研究的结果为比较短跑和NHE的生物力学要求提供了必要的定量信息。

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引用次数: 0

Kinetics of the trunk in association with the attenuation of upper body acceleration during walking 行走时躯干动力学与上半身加速度衰减的关系。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-03 DOI: 10.1016/j.jbiomech.2026.113235

Toru Sakuma, Kensaku Kimura

The acceleration amplitude of body segments during walking is reduced from the ankle to the head. The primary function of shock absorption is performed by the legs, with the trunk also contributing. The aim of this study was to investigate the capability of the trunk to absorb shock during walking. Twenty healthy participants walked at their preferred and unnatural walk ratio (WR) (step length/cadence) at a constant speed. The unnatural WRs comprised 6 cadences (±10%, ±15%, and ± 20% of preferred cadence). Shock absorption was evaluated using the root mean square acceleration at the head (RMS_H) and lower trunk (RMS_T), the coefficient of attenuation from RMS_T to RMS_H, as well as the trunk joint torque and power. RMS_H and RMS_T in the anterior-posterior direction (AP) showed a significant increase (p < 0.05) in high WRs (slower cadence) and a significant decrease (p < 0.05) in low WRs (faster cadence) compared to the preferred WR. The attenuation coefficient in the AP was significantly decreased in high WRs than in the preferred WR (p < 0.05). The average negative power of the flexion–extension torque at the trunk joint had a significant negative correlation (p < 0.001) with RMS_T in the AP. These results suggested that trunk flexion–extension torque played a role in the shock absorption, and this negative power increased in response to an increase in RMS_T in the AP. However, given the limitation of the trunk’s shock absorption capacity, the RMS_H in the AP was more pronounced at high WR.

行走时身体各部分加速度振幅从踝关节到头部逐渐减小。主要的减震功能是由腿完成的，躯干也有贡献。本研究的目的是研究行走时躯干吸收冲击的能力。20名健康的参与者以他们喜欢的和不自然的步行比（步长/节奏）以恒定的速度行走。非自然WRs包括6个节奏（±10%，±15%和±20%的首选节奏）。减震评估采用了车体头部和下躯干的均方根加速度（RMSH）、从RMST到RMSH的衰减系数以及躯干关节的扭矩和功率。前后方向的RMSH和RMST均显著增加（p T）。这些结果表明，躯干屈伸扭矩在减震中起作用，并且该负功率随着躯干RMST的增加而增加。然而，由于躯干减震能力的限制，在高WR时，躯干的RMSH更为明显。

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引用次数: 0

Articular chondrocytes from the knee and ankle have different sensitivities to shear strain 膝关节和踝关节软骨细胞对剪切应变的敏感性不同。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-05-01 Epub Date: 2026-03-03 DOI: 10.1016/j.jbiomech.2026.113237

Steven Ayala , Michelle L. Delco , Lisa A. Fortier , Itai Cohen , Lawrence J. Bonassar

Traumatic injury to synovial joints results in focal defects and proinflammatory changes in cartilage tissue, eventually leading to post-traumatic osteoarthritis (PTOA). Additionally, disparate incidence rates of PTOA occur between joints, particularly the knee and ankle. We hypothesize that differences in PTOA rates between knee and ankle cartilage are related to inherent differences in mechanical properties and chondrocyte sensitivity to mechanical loads. Our objective was to compare the effect of injury on the spatial patterns of cellular response between knee and ankle cartilage and relate these responses to changes in tissue mechanical properties. Cartilage explants of neonatal bovids from the talar dome of the ankle and femoral condyle of the knee were subjected to our ex vivo combined injury model which combines rapid impact injury and repetitive cartilage articulation. Explants were bisected and fluorescently stained to assess global and depth-dependent cell death, caspase activity, and mitochondrial depolarization. Explants were tested via confocal elastography to determine the local shear strain and shear modulus profile. Results showed that chondrocyte response differed between joints, with knee cartilage showing greater damage within the surface region. Additionally, ankle cartilage experienced a greater decrease in shear modulus post-injury compared to knee, causing depth-dependent shear strain to significantly increase (p < 0.0287). Furthermore, regression analyses relating cellular response to local shear strain revealed joint-specific differences in chondrocyte sensitivity, defined as the slope of cellular response versus shear strain, for cell death (knee: 873 vs ankle: 551), apoptosis (knee: 7779 vs ankle: 3577), and MT depolarization (knee: 848 vs ankle: 535).

滑膜关节外伤性损伤导致局部缺损和软骨组织的促炎改变，最终导致创伤后骨关节炎（pta）。此外，在关节之间，尤其是膝关节和踝关节之间，pta的发病率也各不相同。我们假设膝关节和踝关节软骨之间的PTOA发生率的差异与机械特性和软骨细胞对机械负荷的敏感性的内在差异有关。我们的目的是比较损伤对膝关节和踝关节软骨之间细胞反应的空间模式的影响，并将这些反应与组织力学特性的变化联系起来。采用快速冲击损伤和重复性软骨关节结合的离体联合损伤模型，选取新生儿牛骨距骨穹窿和膝关节股骨髁软骨外植体。将外植体一分为二并进行荧光染色，以评估整体和深度依赖性细胞死亡、半胱天蛋白酶活性和线粒体去极化。通过共焦弹性成像测试外植体，以确定局部剪切应变和剪切模量剖面。结果显示，不同关节的软骨细胞反应不同，膝关节软骨在表面区域表现出更大的损伤。此外，与膝关节相比，踝关节软骨损伤后剪切模量下降更大，导致深度相关剪切应变显著增加(p

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引用次数: 0