肘関節伸展動作における素早い動作方向切り換え時の筋活動

概要

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In this study, we investigated a motor strategy for changing the direction of movement in rapidextensions at the elbow joint． This study focused on the changes in a triphasic electromyographic （EMG）pattern, i.e., the first agonist burst （AG I), the second agonist burst （AG2） and the antagonist burst（ANT）, for changing the direction of movement required after the initiation of movement． Subjects extended 40 degrees （Basic task） and then returned to the starting position after reaching a target of the Basic task（Return task）. These tasks were performed under two conditions； performing a predetermined task （SF condition） and performing a task in response to a visual stimulus after movement commencement （ST condition）． Kinematic parameters and EMG activity from the agonist （triceps brachii） and the antagonist（biceps brachii） muscles were recorded． As a result, in both conditions, the onset latency of ANT and AG2 in the Return task increased compared with those in the Basic task． In all bursts, the duration in the Return task was longer than in the Basic task, while only a－EMG in ANT was the difference between two tasks． It is concluded that the motor strategy for changing the direction of initiated movement was to increase the duration and amplitude of ANT in order to stop in the target and flex continuously．
2009-03-31