What Agonist Muscles Are Used in Bench Press Exercises?

The science of strength training exercise classifies the muscles involved in an exercise according to what they do in that exercise. The agonists in an exercise are those muscles directly involved in moving the weight. For the bench press, there are three main agonist muscles: the pectoralis major, the anterior deltoid and the triceps brachii.

The bench press usually involves free weights, such as barbells or dumbbells, but can also use a machine designed for the movement, the lever bench press machine. This exercise is a compound strength training exercise, which means it involves the movement of multiple joints. In the case of the bench press, you are moving both your shoulder joints and your elbow joints as you move the weight from your chest and up into the air. Because of its compound nature, the bench press involves three agonist muscles.

The pectoralis major is the largest group of muscles in your chest. The pectoralis major consists of two main muscles, one attached to the sternum and one attached to the clavicle. These muscles are the main muscles worked during the exercise. It may seem counterintuitive, because it is your arms that move the most during a bench press, but the pectoralis major muscles act as arm movers, despite being in your chest. The upward movement of the weight is due to the force that stems from your chest muscles.

The anterior deltoid is at the front of your shoulder. This muscle is involved in movements that push your upper arm away from your torso. In many outward movements such as the bench press, the anterior deltoid works as a synergist, or assisting muscle, to the pectoralis major. In the bench press, when your elbows are wider apart than are your shoulders, your anterior deltoids are engaged.

The triceps are upper arm muscles opposite the biceps, on the outside of your upper arms. The triceps muscles are important players in a bench press, because they control the movement of the forearms as the elbows begin to lock. The triceps become more involved in the action when your grip on the barbell becomes narrower.