Editing Push-up (section)

=== Triceps brachii ===
While the anterior deltoids and pectoralis major muscles work to horizontally adduct the upper arms during the upward phase of a push-up, the [[triceps brachii]] muscles, or triceps for short, are also hard at work extending the elbow joints so the arms can be fully extended. The triceps also control the speed of elbow-joint flexion during the downward phase of the exercise. The closer together the hands are placed during a push-up, the harder the triceps work. The muscle is divided into three heads — the lateral head, long head, and medial head. The lateral and medial heads attach to the back of the humerus bone, and the long head attaches just behind the shoulder socket on one end; all three heads combine and attach to the back of the elbow on the other.<ref>{{cite web|url=http://www.livestrong.com/article/341958-which-muscles-does-a-push-up-work/|title=Which Muscles Does a Push-Up Work?|author=Schirm, Matthew |work=Live Well - Jillian Michaels}}</ref>