本實驗目的在分析不同負荷瞬發動作形成的肌電訊號，以了解不同負荷爆發力動作的神經肌肉之激活形式的變化。受試者為體育系學生及校隊選手21名，每位受試者進行15%、30%、45%、60%、75%、90%及105%最大自主用力之快速向心屈肘動作。實驗以傳力器、關節角度計、Biovision肌電系統測量力量曲線、角位移及肌電訊號。收集的資料經過處理後，以簡單迴歸進行統計分析，檢查瞬發動作不同負荷下形成的肌電振幅(electromyography amplitude)與肌電中位數頻率(median frequency)，顯著水準為.05。結果顯示不同負荷下，神經肌肉激活狀態皆處於最大用力，誘發較為一致的神經肌肉激活強度，即肌電振幅並不會隨不同負荷而改變。另一方面，肌電中位數頻率隨負荷的增加而上升，此時，雖然高負荷瞬發動作的動作速度比低負荷瞬發動作慢，卻能激發較高的頻率，不啻為提升發力率的爆發力訓練法。
To understand the neuromuscular activation pattern of the elbow flexor muscle under different loads during explosive movements, the electromyography (EMG) signals were induced under different loads with movement. Twenty-one young male physical education students or collegiate sport players were voluntarily participated in this study. Each subject performed fast concentric movement of the elbow flexor muscle under 15%, 30%, 45%, 60%, 75%, 90%, and 105% of maximal voluntary contraction. A loadcell, goniometer and the Biovision EMG system were used to collect the signals for force, elbow angular displacement and EMG. After the data were processed, the SPSS software was used to calculate the values of the parameters, and simple regression was used to determine the relationship between loads and EMG amplitude as well as the relationship between loads and EMG median frequency (MDF). The significance level was set at .05. The results demonstrated that the EMG amplitudes of explosive movement remained high because of the maximal effort exerted when the loads were changed. In other words, the diversity of EMG amplitudes was independent of the variation in the loads. On the other hand, EMG MDF showed a linear positive correlation with load. These results suggest that explosive movement with a heavy load might be suitable for power training to improve the rate of force development by enhancing the efficiency of activation frequency, even though its movement velocity was not higher than that of explosive movement with a light load.
