Department of Kinesiology, Biomechanics Laboratory, The Pennsylvania State University, University Park, PA, United States of America.
PLoS One. 2024 Aug 29;19(8):e0309406. doi: 10.1371/journal.pone.0309406. eCollection 2024.
The production of triceps surae plantarflexion moment is complex in that the Achilles tendon moment arm affects the Achilles tendon force by determining the muscle length change and shortening velocity during ankle rotation. In addition, there is evidence for associations between the sizes of muscles and their moment arm at the joints they span. These relationships between muscle architecture and tendon moment arm ultimately affect the muscle's force generating capacity and are thus important for understanding the roles played by muscles in producing locomotion. The purpose of this study was to investigate in vivo the relationship between architecture of two plantarflexors and the Achilles tendon moment arm in a healthy adult population. Ultrasound-based measurements were made of the architecture (fascicle length, muscle volume, physiological cross-sectional area, and anatomical cross-sectional area) of the lateral and medial gastrocnemius and the Achilles tendon moment arm was assessed using a technique that combined ultrasound imaging and motion analysis. Positive correlations were observed between the length (r = 0.499, p = 0.049) and size variables (muscle volume r = 0.621, p = 0.010; ACSA r = 0.536, p = 0.032) of the lateral gastrocnemius and the Achilles tendon moment arm, but correlations were only observed for size variables (muscle volume r = 0.638, p = 0.008; PCSA r = 0.525, p = 0.037; ACSA r = 0.544, p = 0.029), and not the length, of the medial gastrocnemius. These findings suggest lateral gastrocnemius adapts to moment arms to maintain force production throughout the range of motion across individuals, while the medial gastrocnemius does not and is thus better suited for static force generation.
一项健康成年人的横断面研究
比目鱼肌和跟腱的跖屈力矩的产生非常复杂，因为跟腱力臂通过确定在踝关节旋转过程中的肌肉长度变化和缩短速度来影响跟腱力。此外，有证据表明，肌肉及其在跨越关节时的力臂大小之间存在关联。这些肌肉结构与腱力臂之间的关系最终会影响肌肉的产生力的能力，因此对于理解肌肉在产生运动中的作用非常重要。本研究的目的是在健康成年人中研究两种跖屈肌的结构与跟腱力臂之间的关系。使用一种结合超声成像和运动分析的技术，对外侧和内侧比目鱼肌的结构（肌束长度、肌肉体积、生理横截面积和解剖横截面积）进行了超声测量，并评估了跟腱力臂。观察到外侧比目鱼肌的长度（r = 0.499，p = 0.049）和大小变量（肌肉体积 r = 0.621，p = 0.010；横截面积 r = 0.536，p = 0.032）与跟腱力臂之间存在正相关，但仅观察到大小变量（肌肉体积 r = 0.638，p = 0.008；PCSA r = 0.525，p = 0.037；横截面积 r = 0.544，p = 0.029）与跟腱力臂之间存在相关性，而与内侧比目鱼肌的长度无关。这些发现表明，外侧比目鱼肌适应力臂以在整个运动范围内维持力的产生，而内侧比目鱼肌则不适应，因此更适合产生静态力。
