緒論：足球比賽中，邊線投擲（throw-in）通常與戰術搭配執行，因此投擲距離與穩定性十分重要。由於不同層級球員，在經驗與身體特質上本具有差異存在，可能導致擲球距離與準確性產生差異。故釐清投擲過程中各肌群所扮演的角色，與不同層級球員間各投擲分期肌肉活動狀況，便能執行適合的訓練，以利提升運動表現。方法：招募優秀組與一般組各10名為受試者，以無線表面肌電系統（BTS FREE EMG 300, 1200 Hz），收取慣用手橈側伸腕肌、尺側屈腕肌、肱二頭肌、肱三頭肌、斜方肌與闊背肌肌肉活化訊號，並以攝影機（BTS VIXTA, 300 Hz），同步記錄所有動作過程，每人投擲5次取3次最遠之有效球，以利分期比較。以獨立樣本t考驗（t-test, independent samples）確定受試者投擲距離達顯著差異後，再以混合設計二因子變異數分析（two-way ANOVA, mixed design）比較各分期之肌肉活化參數，統計水準訂為α = .05。結果：優秀組投擲距離顯著遠於一般組。肌肉活化部分，優秀組在後擺期肱二頭肌與加速期斜方肌皆顯著大於一般組；減速期各肌肉則皆未達顯著差異。結論：執行邊線投擲時，後擺期主要作用為肌斜方肌與肱二頭肌，加速期主要作用肌為斜方肌與肱三頭肌，減速期主要作用肌為肱二頭肌與橈側伸腕肌，故教練可加強該肌群的訓練以利增進運動表現。

Introduction: The throw-in combines different attacking movements which usually used in the soccer games. Therefore, the throwing range and stability are important. Due to different levels of players have difference in experience and physical characteristics, it possibility affect throwing distance and accuracy. Clarify the character of muscle group and muscle activity situation in the throwing process will be able to implement targeted training to improve the athletic performance. Methods: We recruited ten soccer players to join superior group and ten participants to be the normal group. The wireless EMG system (BTS FREE EMG 300,1200 Hz) was used to collect the muscle activity of extensor carpi radialis, Flexor carpi ulnaris, biceps, triceps brachii, trapezius and latissimus dorsi. Every participant needed to execute 5 times throw-in movements and used one camera (BTS VIXTA, 300 Hz) to record their movements simultaneously. We chose the farthest three times movements of each participants to analysis. The data collected were compared by using t-test and mixed design two-way ANOVA, the statistical significant level was set at α = .05. Results: The throwing distance of superior group was significantly farther than normal group. In muscle activity, the Biceps of superior group was significantly higher than normal group in cocking phase, the Trapezius of superior group was significantly higher than normal group in arm acceleration stage and there was no significant difference in the arm deceleration phase. Conclusion: There were significant difference in the muscle activity of throw-in movement. The reason why the superior group were farther of throwing may because they had more muscle activity than normal group of Biceps in cocking phase and both of trapezius and latissimus dorsi were also more than normal group in arm acceleration stage. Additionally, the superior group used the triceps brachii to be the buffering agonist in arm deceleration, when the moment of ball leaves, the muscle of extensor carpi radialis had more activities to increased the stability of the ball, to increased the distant throwing distance. Consequently, coaches can increase the training the extensor carpi radialis muscle group to improve the exercise performance.