Movement related EMGs become more variable during learning of fast accurate movements.
Movement related EMGs become more variable during learning of fast accurate movements.
复制标题
在学习快速准确的运动过程中，与运动相关的肌电图变得更加可变。
DOI：
10.1080/00222895.1987.10735415
复制
发表时间：
1987
影响因子：
1.4
通讯作者：
J. D. Cooke
中科院分区：
文献类型：
--
作者：
Warren G. Darling;J. D. Cooke
人类受试者以视觉步进跟踪范例进行简单的肘部弯曲和伸展运动。运动自行终止。指导受试者在练习过程中提高运动速度，同时保持终点准确性。研究了练习对二头肌和三头肌肌电图活动模式和变异性的影响。初始运动是通过表面肌电图所示的主动肌和拮抗肌的相互阶段性激活来进行的。通过练习，移动速度的增加与更大的激动剂和拮抗剂爆发以及拮抗剂爆发的更早发生有关。在练习过程中还观察到运动前拮抗剂沉默的持续时间减少。练习期间运动变异性的减少并没有伴随相关肌电图变异性的同等减少。令人惊讶的是，在更快、熟练的动作中，主动肌电图和拮抗肌电图的变化更大。联合激动剂-拮抗剂肌电图变异性取决于运动速度和轨迹变异性。由于主动肌和拮抗肌活动的相关变化，在相关肌电图存在较大变异性的情况下，运动的变异性较低。第一次激动剂爆发的变化通常被拮抗剂和晚期激动剂爆发的相关变化所补偿。尽管第一次激动剂爆发存在很大变化，但这些相关的变化使肢体轨迹保持相对恒定。因此，需要对脉冲变异性模型进行修改，以通过减速脉冲（由拮抗剂和晚期激动剂爆发产生）的相关变化来解释对加速脉冲（由第一次激动剂爆发产生）的变异性的补偿。
Human subjects performed simple flexion and extension movements about the elbow in a visual step-tracking paradigm. Movements were self-terminated. Subjects were instructed to increase movement velocity while maintaining end-point accuracy during practice. The effects of practice on the pattern and variability of EMG activity of the biceps and triceps muscles were studied. Initial movements were performed using reciprocal phasic activation of agonist and antagonist muscles as indicated by surface EMGs. With practice, increases in movement speed were associated with larger agonist and antagonist bursts and an earlier onset of the antagonist burst. Decreased duration of the premovement antagonist silence was also observed during practice. Decreases in variability of movements during practice were not accompanied by equivalent decreases in variability of the associated EMGs. Surprisingly, both agonist and antagonist EMGs were more variable in faster, practiced movements. The combined agonist-antagonist EMG variability depended on both movement speed and trajectory variability. Lower variability in movements in the presence of greater variability in the related EMGs occurred because of linked variations in agonist and antagonist muscle activities. Variations in the first agonist burst were often compensated for by associated variations in the antagonist and late agonist bursts. These linked variations maintained the limb trajectory relatively constant in spite of large variations in the first agonist burst. Modifications to impulse-variability models are therefore needed to explain compensations for variability in accelerative impulses (produced by the first agonist burst) by linked variations in impulses for deceleration (produced by the antagonist and late agonist bursts).