Figure 1
From: Shoulder muscle EMG activity during push up variations on and off a Swiss ball
EMG linear envelopes during a push ups with the hands on an exercise bench and a Swiss ball. EMG activity is non-normalized and is therefore in arbitrary EMG units. A bias was added to the activity of the pectoralis major, rectus abdominis and external oblique for ease of viewing to prevent overlap of the muscle's linear envelopes. Three pushups occurred over the course of 30 seconds.