Mojica J A, Yamada Y, Nakamura R
Institute of Rehabilitation Medicine, Tohoku University School of Medicine, Narugo, Japan.
Tohoku J Exp Med. 1988 Apr;154(4):375-80. doi: 10.1620/tjem.154.375.
Using a reaction time (RT) task, the biceps brachii muscle was investigated in five healthy subjects to determine whether EMG in the initial phase of activity is dependent upon the direction of movement, i.e., elbow flexion and forearm supination, and/or influenced by the presence or absence of warning signal. Results showed that in the presence of warning EMG-RT of forearm supination was faster than that of elbow flexion, and that the reverse occurred in the absence of warning. The warning signal significantly reduced EMG-RT of both movements and the reduction of EMG-RT was larger in supination than flexion. Compared to forearm supination, large amplitude potentials were observed during elbow flexion. The warning suppressed EMG activities of both movements within 30 msec after their initiation. The present study indicates that the biceps brachii muscle exhibits a motor response program specific to the direction of movements and that preparatory set conditioned by warning shortens RT and also suppresses EMG activities.
利用反应时间（RT）任务，对五名健康受试者的肱二头肌进行了研究，以确定活动初始阶段的肌电图是否取决于运动方向，即肘部屈曲和前臂旋后，和/或受警告信号的有无影响。结果表明，在有警告的情况下，前臂旋后的肌电图反应时间比肘部屈曲的快，而在没有警告的情况下则相反。警告信号显著缩短了两种运动的肌电图反应时间，且旋后运动的肌电图反应时间缩短幅度大于屈曲运动。与前臂旋后相比，肘部屈曲时观察到较大幅度的电位。警告在两种运动开始后30毫秒内抑制了它们的肌电图活动。本研究表明，肱二头肌表现出特定于运动方向的运动反应程序，并且由警告所调节的准备状态缩短了反应时间，同时也抑制了肌电图活动。
