Purpose : The purpose of this study is to examine the muscle activity of shoulder stabilization according to change of supporting base interval between push-up bend and push-up plus position and is to prevent or treat a shoulder injury by the most effective exercise for rehabilitation. Methods : This study analyzed the muscle activity according to change of supporting base interval between push-up bend and push-up plus movement. The participants without neuromuscular disease were 25 students - 12 males and 13 females - all twenty or over and the surface electrode of EMG attached on pectoralis major, triceps long head, middle trapezius, lower trapezius, serratus anterior and latissimus dorsi. The process has practiced 3 sessions of supporting base interval - narrowing interval, two shoulder interval, broad interval - by push-up bend and push-up plus movement. Result : 1. The muscle activity of pectoralis major was significantly increased according to narrow interval of supporting base on push-up plus movement and was significant difference(p<.05). 2. The muscle activity of biceps was significantly increased according to narrow interval of supporting base on push-up bend movement(p<.05). 3. The muscle activity of middle or lower trapezius was a difference according to change of supporting base on push-up bend and push-up plus movement but was not significant difference. 4. The muscle activity of serratus anterior was significantly increased according to broad interval of supporting base on push-up bend movement(p<.05). 5. The muscle activity of latissimus dorsi was significantly increased according to broad interval of supporting base on push-up bend movement(p<.05). Conclusion : These results lead us to the conclusion that push-up bend exercise have the effect of muscle strength of biceps on narrowing interval, of serratus anterior or latissimus dorsi on broad interval and push-up plus exercise have the effect of muscle strength of pectoralis major on narrowing interval of support base.