Walter C B
Department of Kinesiology, University of California, Los Angeles.
Eur J Appl Physiol Occup Physiol. 1988;57(5):577-82. doi: 10.1007/BF00418465.
Agonist premotor silence (PMS), a brief period of relative quiescence in active skeletal muscle prior to phasic activation, was investigated in subjects performing maximal contractions. The frequency of occurrence and potential function of the silent period were examined for elbow flexions and extensions. PMS was evident for movements in both directions, indicating that the mechanism is not primarily limited to extensors as previously hypothesized. Flexions demonstrating PMS exhibited increased velocity and acceleration; however, kinematic facilitation was only evident on trials exhibiting the muscular stretch-shortening cycle (SSC). The SSC was present on trials lacking PMS, demonstrating that biceps and triceps silence are not the sole determinants of preparatory agonist lengthening for elbow flexions and extensions, respectively. Taken together, the data indicate that agonist PMS is a mechanism under apparent central control that acts concomitantly with mechanical factors to potentiate elbow flexor contractions.
激动剂运动前沉默（PMS），即在相性激活之前活跃骨骼肌中短暂的相对静止期，在进行最大收缩的受试者中进行了研究。针对肘部屈伸动作，研究了沉默期的出现频率和潜在功能。两个方向的动作均出现了PMS，这表明该机制并不像之前假设的那样主要局限于伸肌。表现出PMS的屈肘动作速度和加速度增加；然而，运动学促进作用仅在表现出肌肉拉长-缩短周期（SSC）的试验中明显。在缺乏PMS的试验中也存在SSC，这表明肱二头肌和肱三头肌的沉默并非分别作为肘部屈伸动作准备期激动剂拉长的唯一决定因素。综合来看，数据表明激动剂PMS是一种明显受中枢控制的机制，它与机械因素共同作用以增强肘部屈肌收缩。
