Kawakami Y, Ichinose Y, Fukunaga T
Department of Life Sciences (Sports Sciences), The University of Tokyo, Tokyo 153, Japan.
J Appl Physiol (1985). 1998 Aug;85(2):398-404. doi: 10.1152/jappl.1998.85.2.398.
Architectural properties of the triceps surae muscles were determined in vivo for six men. The ankle was positioned at 15 degrees dorsiflexion (-15 degrees) and 0, 15, and 30 degrees plantar flexion, with the knee set at 0, 45, and 90 degrees. At each position, longitudinal ultrasonic images of the medial (MG) and lateral (LG) gastrocnemius and soleus (Sol) muscles were obtained while the subject was relaxed (passive) and performed maximal isometric plantar flexion (active), from which fascicle lengths and angles with respect to the aponeuroses were determined. In the passive condition, fascicle lengths changed from 59, 65, and 43 mm (knee, 0 degrees; ankle, -15 degrees) to 32, 41, and 30 mm (knee, 90 degrees ankle, 30 degrees) for MG, LG, and Sol, respectively. Fascicle shortening by contraction was more pronounced at longer fascicle lengths. MG had greatest fascicle angles, ranging from 22 to 67 degrees, and was in a very disadvantageous condition when the knee was flexed at 90 degrees, irrespective of ankle positions. Different lengths and angles of fascicles, and their changes by contraction, might be related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses.
对六名男性的小腿三头肌的结构特性进行了活体测定。踝关节分别处于背屈15度（-15度）以及跖屈0度、15度和30度，膝关节分别处于0度、45度和90度。在每个位置，当受试者放松（被动）并进行最大等长跖屈（主动）时，获取内侧腓肠肌（MG）、外侧腓肠肌（LG）和比目鱼肌（Sol）的纵向超声图像，由此确定肌束长度以及相对于腱膜的角度。在被动状态下，MG、LG和Sol的肌束长度分别从59毫米、65毫米和43毫米（膝关节，0度；踝关节，-15度）变化到32毫米、41毫米和30毫米（膝关节，90度；踝关节，30度）。肌束长度越长，收缩导致的肌束缩短越明显。MG的肌束角度最大，范围为22度至67度，并且当膝关节屈曲90度时，无论踝关节处于何种位置，MG都处于非常不利的状态。肌束的不同长度和角度及其收缩变化，可能与肌肉产生力的能力以及肌腱和腱膜的弹性特性差异有关。
