Winter Samantha L, Challis John H
Department of Sport and Exercise Science, Aberystwyth University, Aberystwyth, Ceredigion, UK.
J Appl Biomech. 2010 Feb;26(1):45-51. doi: 10.1123/jab.26.1.45.
For a physiologically realistic joint range of motion and therefore range of muscle fiber lengths, only part of the whole muscle force-length curve can be used in vivo; that is, only a section of the force-length curve is expressed. Previous work has determined that the expressed section of the force-length curve for individual muscles can vary between subjects; however, the degree of intersubject variability is different for different muscles. This study determined the expressed section of both the rectus femoris and gastrocnemius--muscles with very different ratios of tendon slack length to muscle fiber optimum length--for 28 nonspecifically trained subjects to test the hypothesis that the value of this ratio affects the amount of variability in the expressed section. The force-length curves of the two muscles were reconstructed from moment-angle data using the method of Herzog & ter Keurs (1988). There was no relationship between the expressed sections of the force-length curve for the two muscles. Less variability was found in the expressed section of the gastrocnemius compared with the rectus femoris, supporting the hypothesis. The lack of relationship between the expressed sections of the two muscles has implications for motor control and for training muscle for rehabilitation.
对于生理上现实的关节活动范围以及因此肌肉纤维长度范围而言，在体内仅能使用整个肌肉力-长度曲线的一部分；也就是说，仅表达力-长度曲线的一段。先前的研究已确定，个体肌肉力-长度曲线的表达段在不同受试者之间可能有所不同；然而，不同肌肉的受试者间变异性程度有所差异。本研究针对28名未经特殊训练的受试者，确定了股直肌和腓肠肌（肌腱松弛长度与肌肉纤维最佳长度比值差异很大的两块肌肉）的表达段，以检验该比值会影响表达段变异性大小这一假设。使用赫尔佐格和特·凯尔斯（1988年）的方法，根据力矩-角度数据重建了这两块肌肉的力-长度曲线。两块肌肉力-长度曲线的表达段之间不存在相关性。与股直肌相比，腓肠肌表达段的变异性较小，这支持了该假设。两块肌肉表达段之间缺乏相关性对运动控制以及康复训练肌肉具有启示意义。
