不同投擲距離肌群作用時序之比較

The study of throwing pattern under different target distances from the perspective of firing sequences of upper extremities muscles

目的：本研究目的為比較參與者上肢肌群「肌電起始」與「最大肌電值」在不同目標距離下激發時間及次序是否有差異。方法：10名男童參與3種目標距離投擲（10公尺、15公尺、20公尺），利用表面肌電儀器（Mega ME3000P8，1000Hz），配合「Mega Win Version 2.4軟體」及高速攝影機（Mega Speed MS10K CCD B／W，100Hz）利用同步紀錄器加以記錄分析，比較不同距離下各肌群參與作用時序差異，並以相依樣本單因子變異數分析上肢各肌群在「肌電起始激發時間」及「最大肌電值激發時間」之差異，統計水準定為α＝.05。結果：在三種不同距離的擲準投擲動作中，肱二頭肌、斜方肌、闊背肌在目標距離為20公尺時激發時間顯著早於10公尺，各肌群起始激發順序會因為距離改變而產生部分肌群次序變化，起始激發時間則有隨著距離增加而提早激發的現象；伸橈肌、斜方肌為較早開始活化的肌群，闊背肌隨著距離的增加，活化的次序有提前激發的現象。各肌群產生最大肌電值和各肌群起始激發的順序具有相類似的情形，且較遠距離比較近的距離提早產生最大肌電值，但均未達顯著差異，在肌群不同激發次序方面，三種距離均呈現斜方肌、肱二頭肌及後三角肌最大肌電值較早激發的現象。結論：本研究結果顯示20公尺的「肌群活化時序」比其他目標距離更符合動力由下肢產生經由轉腰、肩關節、肘關節到腕關節的動力鏈傳遞過程。Purpose: The purpose of the study was to compare differences of firing sequences for beginning and peak values of EMG signals among three different target distances of over-arm throwing. Method: Ten subjects who were asked to throw to the target from three different distances (10m, 15m, 20m) voluntarily participated in this study. In order to obtain athlete performances, present study used high speed camera (Mega Speed MS10K CCD B/W, 100Hz) and adapted EMG measurement system (Mega ME3000P8, 1000 Hz) to collect data simultaneously. The study adapted the dependent One-way ANOVA (a = .05) to compare the differences among three different target distances of over-arm throwing. Results: The results indicated that firing sequences of beginning for the biceps brachii muscle, trapezius muscle and latissimus dorsi muscle of 20m were earlier than those of 10m significantly. The firing sequences of beginning were changed by different target distances. These muscles that started firing earlier were extensor carpi radialis muscle and trapezius muscle. The firing sequences of beginning for latissimus dorsi muscle were moving ahead as the target distance increased. The firing sequences of peak values for upper extremities muscles were also changed by the different target distances. But the firing timing of peak values among three target distances weren't different significantly. The firing timing of peak values for the trapezius muscle, biceps brachii muscle and deltoid muscle were shown earlier than those of the others. Conclusion: It was concluded that firing sequences of beginning and peak values of upper extremities muscles for 20m target distance were better than those of the others'. Because the process of energy transfer for 20m target distance which was from the hip, shoulder joint and elbow joints and then to the wrist joint matched the principle of the kinetic chain.