Neuroscience Research Australia, Randwick, New South Wales, Australia.
J Appl Physiol (1985). 2012 Aug 15;113(4):517-23. doi: 10.1152/japplphysiol.00111.2012. Epub 2012 Jun 21.
The plantarflexors of the lower limb are often assumed to act as independent actuators, but the validity of this assumption is the subject of considerable debate. This study aims to determine the degree to which passive changes in gastrocnemius muscle length, induced by knee motion, affect the tension in the adjacent soleus muscle. A second aim is to quantify the magnitude of myofascial passive force transmission between gastrocnemius and adjacent soleus. Fifteen healthy volunteers participated. Simultaneous ultrasound images of the gastrocnemius and soleus muscles were obtained during passive knee flexion (0-90°), while keeping the ankle angle fixed at either 70° or 115°. Image correlation analysis was used to quantify muscle fascicle lengths in both muscles. The data show that the soleus muscle fascicles elongate significantly during gastrocnemius shortening. The approximate change in passive soleus force as a result of the observed change in fascicle length was estimated and appears to be <5 N, but this estimate is sensitive to the assumed slack length of soleus.
下肢跖屈肌通常被认为是独立的执行器，但这一假设的有效性是一个备受争议的话题。本研究旨在确定膝关节运动引起的比目鱼肌长度的被动变化在多大程度上影响相邻的腓肠肌的张力。第二个目的是量化腓肠肌和相邻比目鱼肌之间的肌筋膜被动力传递的幅度。15 名健康志愿者参与了这项研究。在保持踝关节角度分别为 70°或 115°的情况下，被动膝关节弯曲（0-90°）期间同时获取了腓肠肌和比目鱼肌的超声图像。图像相关分析用于量化两块肌肉中的肌纤维束长度。数据显示，在腓肠肌缩短过程中，比目鱼肌的肌纤维束明显拉长。根据观察到的纤维长度变化估计了被动比目鱼肌力的近似变化，估计值似乎小于 5N，但这一估计值对比目鱼肌的假设松弛长度很敏感。
