An electromyography analysis of 3 muscles surrounding the shoulder joint during the performance of a chest press exercise at several angles.

This study compared the activation of the clavicular head and the sternocostal head of the pectoralis major and the anterior deltoid when performing the bench press at several different angles. Fifteen healthy male subjects participated in this study. Subjects performed the chest press exercise at 0 (flat bench), 28, 44, and 56 degrees above horizontal using 70% of their respective 1 repetition maximum for each angle. Electromyographic activity was recorded during each repetition. Activation of the clavicular head of the pectoralis major was significantly greater at 44 degrees compared to 0 degrees (p = 0.010), at 56 degrees compared to 0 degrees (p = 0.013), and at 44 degrees compared to 28 degrees (p = 0.003). Activation of the sternocostal head of the pectoralis major was significantly greater at 0 degrees compared to 28 degrees (p = 0.013), at 0 degrees compared to 44 degrees (p = 0.018), at 0 degrees compared to 56 degrees (p = 0.001), at 28 degrees compared to 56 degrees (p = 0.003), and at 44 degrees compared to 56 degrees (p = 0.001). Activation of the anterior deltoid was significantly greater at 28 degrees compared to 0 degrees (p = 0.002), at 44 degrees compared to 0 degrees (p = 0.012), and at 56 degrees compared to 0 degrees (p = 0.014). To optimize recruiting the involved musculature, it would seem that performing both the flat and incline chest press exercises is necessary.