Fukunaga T, Ichinose Y, Ito M, Kawakami Y, Fukashiro S
Department of Life Sciences, University of Tokyo, Japan.
J Appl Physiol (1985). 1997 Jan;82(1):354-8. doi: 10.1152/jappl.1997.82.1.354.
We have developed a technique to determine fascicle length in human vastus lateralis muscle in vivo by using ultrasonography. When the subjects had the knee fully extended passively from a position of 110 degree flexion (relaxed condition), the fascicle length decreased from 133 to 97 mm on average. During static contractions at 10% of maximal voluntary contraction strength (tensed condition), fascicle shortening was more pronounced (from 126 to 67 mm), especially when the knee was closer to full extension. Similarly, as the knee was extended, the angle of pennation (fascicle angle, defined as the angle between fascicles and aponeurosis) increased (relaxed, from 14 to 18 degrees; tensed, from 14 to 21 degrees), and a greater increase in the pennation angle was observed in the tensed than in the relaxed condition when the knee was close to extension (< 40 degrees). We conclude that there are differences in fascicle lengths and pennation angles when the muscle is in a relaxed and isometrically tensed conditions and that the differences are affected by joint angles, at least at the submaximal contraction level.
我们已经开发出一种技术，通过超声检查在体内测定人体股外侧肌的肌束长度。当受试者从110度屈曲位置被动地将膝关节完全伸直（放松状态）时，肌束长度平均从133毫米减少到97毫米。在最大自主收缩力量的10%进行静态收缩时（紧张状态），肌束缩短更为明显（从126毫米到67毫米），尤其是当膝关节接近完全伸直时。同样，随着膝关节伸直，羽状角（肌束角，定义为肌束与腱膜之间的角度）增大（放松时，从14度到18度；紧张时，从14度到21度），并且当膝关节接近伸直（<40度）时，在紧张状态下观察到的羽状角增加幅度大于放松状态。我们得出结论，当肌肉处于放松和等长紧张状态时，肌束长度和羽状角存在差异，并且这些差异受关节角度影响，至少在次最大收缩水平是如此。
