背景與目的：快速目標取向動作主要受主動肌以及拮抗肌的調控，在肌電圖上的特徵為三相模式，過去研究認為三相肌電模式的主動肌第一時期與拮抗肌作用可能受到來自脊髓上層的動作前程式化控制。本研究目的在探討健康成人執行快速與慢速目標取向動作之前，主動肌與拮抗肌之中樞興奮性在時序和強度上的改變，以及與三相肌電模式的關係。方法：本研究共徵召10位健康成年人(6男4女，23.1±1.85歲)，以橈側屈腕肌作為主動肌與拮抗肌角色，使用經顱磁刺激在執行快速目標取向動作前測量動作前興奮性強度。結果：研究結果發現，橈側屈腕肌為主動肌時，執行快速與慢速動作前60毫秒、80毫秒時動作誘發電位波振幅上升開始達顯著差異，若為拮抗肌時，執行快速動作前50毫秒時動作誘發電位波振幅即顯著上升，但慢速動作前則無顯著上升，且快速主動肌與拮抗肌動作前興奮性誘發起始時間差與三相肌電模式中主動肌與拮抗肌開始作用時間差有高度相關。結論：本研究證實快速目標動作中主動肌與拮抗肌時序受脊髓上階層之控制。(物理治療2014;39(1):42-49)

A ballistic goal-directed movement is controlled by a triphasic EMG pattern of agonist and antagonist muscle activation. This is considered as “preprogrammed supraspinal control”. The supraspinal modulation before initiation of rapid goal-directed movement is unknown. The purpose of this study was to investigate the timing and amplitude of motor evoked potential (MEP) in agonist and antagonist muscle before initiation of rapid goal-directed movement in healthy individuals. Ten healthy subjects (10 young subjects, 23.1±1.85 y/o, 6 males) participated in the study. MEPs of flexor carpi radialis were elicited at various time points before performing fast goal-directed wrist flexion and extension movements. The timing of agonistic and antagonistic muscle of premovement facilitation was 60 ms and 50 ms, respectively. The premovement MEP timing was correlated significantly with the triphasic EMG timing. We concluded that rapid goal-directed movement is controlled by central drive in healthy individuals. (FJPT 2014;39(1):42-49)