The Anatomy of a Push Up

Woman doing push-ups

Pushups are one of the most widely performed exercises in the world. Used by a range of people from elite athletes to school children, there are numerous variations of pushups; therefore, regardless of your fitness level, there is probably a pushup for you. Knowing a little about the anatomy of a pushup can help you get even more benefit from this popular exercise.


The agonist, or the prime mover muscle, is the target muscle and usually the reason for selecting a particular exercise. For the pushup, the agonist is the pectoralis major, or pecs. Your pecs are essentially your chest muscles. As you lower yourself toward the floor, the pecs lengthen and control the speed of your descent. As you push back up again, they shorten. The lowering and lengthening phase of the exercise is called an eccentric contraction while the lifting and shortening phase is called a concentric contraction.


Muscles are arranged in opposing pairs across joints. For movement to occur, when one muscle within the pair contracts, it's opposite must relax. This is called reciprocal inhibition. The muscle which opposes the agonist is called the antagonist. In pushups, there are a number of antagonists, but the main ones are the middle fibers of the trapezius muscle, the posterior deltoids and the rhomboids. These muscles are on the opposite side of the torso in relation to your pecs.


While it is possible to identify the muscle doing the majority of the work in a particular exercise, there is usually more than one muscle involved. These helper muscles are commonly referred to as synergists. Although not the target muscle of the exercise, these muscles are important as they assist the agonist. The main synergists in the pushup are the triceps and the anterior deltoids or front shoulder muscles. They assist with elbow extension and shoulder flexion, respectively.


Fixators help hold your body in a certain position so the agonists and sysnergists have a stable base from which to work. Small muscles in your shoulder, called your rotator cuff, keep the head of your humerus firmly located within your shoulder socket while your rectus abdominus, or abs, hold your spine straight. Other fixators of note include your latissimus dorsi muscles on the side of your upper back which aid in shoulder stability and your quadriceps, or thigh muscles which work to keep your legs straight and rigid.