Ichinose Y, Kawakami Y, Ito M, Fukunaga T
Department of Life Sciences (Sports Sciences), University of Tokyo, Japan.
Acta Anat (Basel). 1997;159(2-3):78-83. doi: 10.1159/000147969.
The length and angles of fascicles were determined for the vastus lateralis muscle (VL) using ultrasonography in 6 subjects performing ramp isometric knee extension. The subject increased torque from zero (relax) to maximum (MVC) with the knee positioned every 15 degrees, from 10 degrees to 100 degrees flexion (0 degrees = full extension). As the knee was positioned closer to extension, fascicle length was shorter [116 +/- 4.7 (mean +/- SEM) mm at 100 degrees vs. 88 +/- 4.1 mm at 10 degrees (relax)]. The fascicle length of the VL decreased with increasing torque at each knee position [116 +/- 4.7 (relax) to 92 +/- 4.3 mm (MVC) at 100 degrees]. On the other hand, fascicle angles increased with an increase in torque. These changes reflected the compliance of the muscle-tendon complex which increased as the knee reached a straight position. The estimated muscle force of the VL was maximal (2,052 +/- 125 N) for a fascicle length of 78 +/- 2.7 mm (i.e. optimum length) with the knee positioned at 70 degrees of flexion. The relationship between muscle force and fascicle length indicated that the VL uses the ascending (knee < 70 degrees), plateau (70 degrees), and descending regions (> 70 degrees) of the force-length curve.
对6名进行斜坡等长膝关节伸展的受试者，使用超声测定了股外侧肌（VL）的肌束长度和角度。受试者在膝关节从10度屈曲到100度屈曲（0度=完全伸展），每隔15度定位一次的情况下，将扭矩从零（放松）增加到最大（最大自主收缩，MVC）。随着膝关节位置更接近伸展，肌束长度变短[100度时为116±4.7（平均值±标准误）mm，而10度（放松）时为88±4.1 mm]。在每个膝关节位置，VL的肌束长度随扭矩增加而缩短[100度时从116±4.7（放松）缩短到92±4.3 mm（MVC）]。另一方面，肌束角度随扭矩增加而增大。这些变化反映了肌腱复合体的顺应性，随着膝关节接近伸直位置，顺应性增加。当膝关节屈曲70度时，VL的估计肌肉力量在肌束长度为78±2.7 mm（即最佳长度）时最大（2052±125 N）。肌肉力量与肌束长度之间的关系表明，VL利用了力-长度曲线的上升段（膝关节<70度）、平台段（70度）和下降段（>70度）。
