The standard pushup is a fundamental bodyweight exercise recognized globally for building upper body strength. This movement requires coordinating multiple muscle groups to lift and lower the body. Classified as a horizontal pressing movement, a question arises regarding the activation of the large muscles on the back, specifically the latissimus dorsi, or lats. Understanding the primary mechanics of the pushup and the specific function of the lats is necessary to clarify this confusion.
Primary Muscle Groups That Power the Pushup
The pushup is powered primarily by muscles on the front of the body and the back of the arms, responsible for pushing away from the floor. The Pectoralis Major, or chest muscle, acts as the main engine, controlling the descent and driving the ascent. As the body lowers, the chest muscles undergo an eccentric contraction, actively lengthening to manage the force of gravity.
The subsequent push back involves a powerful concentric contraction, where the pectoralis major actively shortens to extend the arms. The Triceps Brachii, located on the back of the upper arm, serves as a major synergist in this motion. This muscle is responsible for extending the elbow joint, necessary for completing the lock-out at the top of the pushup.
The Anterior Deltoid also contributes significantly to the pushing action. It works alongside the chest to flex the shoulder joint and helps push the upper arms forward and inward. Furthermore, the Serratus Anterior, located along the rib cage, plays a crucial role by protracting the shoulder blades. This action helps stabilize the shoulder girdle against the chest wall.
The Primary Actions of the Latissimus Dorsi
The latissimus dorsi is a broad, flat, triangular muscle that covers most of the lower back. Unlike the muscles that drive the pushup, the lats are designed to perform movements that involve pulling the arms toward the body. This muscle originates from the lower spine, the pelvis, and the lower ribs before inserting onto the front of the upper arm bone, the humerus.
The primary dynamic actions of the latissimus dorsi include shoulder adduction, pulling the arm down toward the side of the body. It is also a powerful shoulder extensor, pulling the arm backward, as seen in a rowing motion. The lats also contribute to the internal rotation of the shoulder joint.
These functions mark the latissimus dorsi as a muscle of the posterior chain, heavily recruited during pulling exercises like pull-ups, chin-ups, and rowing. When the arms are fixed overhead, the lats can pull the trunk superiorly. The muscle’s function is centered on moving the arm relative to the trunk in a pulling direction.
Why Lats Are Minimal Players in the Pushup
Lat engagement is answered by the biomechanical mismatch between the exercise and the muscle’s main function. A standard pushup is an open-chain pressing movement, where the body moves away from fixed hands, relying on the shortening of anterior muscles. The lats, however, are dynamic movers in closed-chain pulling movements. This difference means they cannot act as a primary muscle to move the body.
Despite not being a prime mover, the lats are still recruited in a secondary, static capacity as stabilizers. Their deep attachments to the spine and pelvis mean they must contract isometrically—without changing length—to maintain a rigid torso. This static tension prevents the lower back from hyperextending and arching toward the floor.
The lats also contribute to maintaining proper shoulder positioning by subtly controlling the upper arm bone. This stabilization helps keep the shoulder joint healthy and aligned during the pressing motion. If a person feels soreness in their lats after pushups, it is typically a sign that the lats worked hard in this stabilizing role. For individuals seeking to build size or strength in the latissimus dorsi, exercises that involve dynamic pulling, such as rows and pull-downs, are necessary.