Which primary muscles are engaged during a push-up?

The primary muscles engaged during a push-up are crucial for understanding the movement mechanics involved in this widely practiced exercise. The anterior deltoid, which is located on the front of the shoulder, plays a significant role in the initiation and stabilization of the shoulder joint during a push-up. However, it is important to highlight that the pectoralis major is the most significant muscle being engaged in this movement.

The pectoralis major, a large chest muscle responsible for horizontal adduction and flexion of the shoulder, is heavily activated to push the body away from the ground. In addition, the triceps brachii, which are located on the back of the upper arm, contribute to elbow extension, aiding in the pushing movement. The biceps brachii, while involved, primarily work in stabilizing and controlling the movement rather than being a primary mover in this exercise.

Thus, while the anterior deltoid does contribute to the push-up motion to some extent, it is the pectoralis major that is chiefly responsible for the primary action of pushing against gravity, making it the most important muscle involved in this exercise.