Zijdewind I, Kernell D
Department of Neurophysiology, University of Amsterdam, The Netherlands.
Muscle Nerve. 1994 Sep;17(9):1044-54. doi: 10.1002/mus.880170912.
We have studied the fatigue-associated behavior of surface EMG in two histochemically different muscles of the hand: first dorsal interosseous (FDI) and adductor pollicis (AP; relatively more type I fibers in AP than in FDI). During a fatigue test evoked by electrical stimulation of the ulnar nerve, the mean amplitudes of compound muscle action potentials (M-waves) exhibited the same overall pattern for both muscles: a rapid phase of potentiation followed by a gradual decline. However, if the group of subjects was subdivided on the basis of hand length, significant differences emerged in the reactions of AP: in large hands, no fatigue-associated M-wave decline was seen, whereas in small hands a distinct decline was observed. A possible explanation for this phenomenon might be the presence of a greater amount of EMG contamination from other muscles in smaller hands. In the supposedly "cleaner" recordings from larger hands, significant differences between FDI and AP were observed with regard to their fatigue-associated EMG reactions (M-wave depression in FDI but not in AP). The direction of these differences was in accordance with expectations on the basis of known differences in histochemical fiber type composition.
我们研究了手部两块组织化学性质不同的肌肉——第一背侧骨间肌（FDI）和拇收肌（AP；与FDI相比，AP中I型纤维相对较多）——与疲劳相关的表面肌电图行为。在通过尺神经电刺激诱发的疲劳测试中，两块肌肉的复合肌肉动作电位（M波）平均振幅呈现出相同的总体模式：先是快速增强阶段，随后逐渐下降。然而，如果根据手的长度将受试者分组，AP的反应就会出现显著差异：大手组中，未观察到与疲劳相关的M波下降，而小手组中则观察到明显下降。这种现象的一个可能解释是，小手中来自其他肌肉的肌电图干扰量更大。在大手组推测“更纯净”的记录中，观察到FDI和AP在与疲劳相关的肌电图反应方面存在显著差异（FDI中M波出现抑制，而AP中未出现）。这些差异的方向与基于已知组织化学纤维类型组成差异的预期一致。
