仰臥推舉運動為一種常見的上肢及胸部肌群重量訓練方式，本研究以不同握寬(窄握、中握與寬握)與不同運動時期(槓鈴上升與下降期)，來探討上肢與胸部肌群在仰臥推舉的動態過程中，肌肉活化程度之變化。實驗中擷取仰臥推舉過程中，雙向運動方向動態即時肌電訊號進行分析，以推斷肌群的活化程度。本研究發現，在進行仰臥推舉運動時，在槓鈴上升時期，上肢各肌群在三種不同握槓寬度情況下，各肌群的活化程度並沒有太大差異；在槓鈴下降時期，上肢各肌群在三種不同握槓寬度情況下，各肌群的活化程度亦相近。因此握寬距離對肌肉的活化程度無明顯相對應關係。本研究藉由仰臥推舉運動時，測得動態即時肌電訊號，以SPSS 軟體進行各項統計分析，發現槓鈴上升期的各肌肉活化程度皆大於槓鈴下降期。在槓鈴上升期，胸大肌、前三角肌與肱三頭肌因對抗重力進行向心收縮，而增加肌肉活化；而闊背肌、後三角肌與肱二頭肌為了提供關節穩定度因而提高肌肉活化程度。

Bench press is a common weight training method for upper extremity muscle groups. In this research, real-time electromyogram (EMG) was used to detect upper extremity muscle activations on three grip widths (narrow, middle and wide grips) and two exercise phases (barbell ascent phase and descent phase) during the dynamic periods of bench press. In the study, it was found that there was no significant different in upper extremity muscle activations when changing grip widths during the ascent phase of bench press exercise. Also, there was no significant different in upper extremity muscle activations when changing grip widths during the descent phase of bench press exercise. Therefore, the activations of upper extremity muscle groups were not apparently related to the grip width of bench press. However, when comparing muscle activations during ascent and descent phases, upper extremity muscle activations were found significantly greater in the ascent phase than descent phase. In the ascent phase, the pectoralis major、anterior deltoid, and triceps increase the muscle concentric contraction activation to overcome the gravity. Latissimus dorsi、posterior deltoid, and biceps also increase their muscle activation to support the stability of joints.