The Overhead Press (OHP) is a foundational exercise that involves pressing a weight directly above the head, primarily targeting the shoulder muscles. This movement requires significant stability and coordination from the entire shoulder girdle. Many lifters question whether the OHP provides meaningful stimulus for the development of the trapezius muscle, or “traps,” which span the upper back and neck.
The Trapezius Muscle: Structure and Function
The trapezius is a large, flat muscle covering the upper back and neck. Named for its trapezoid shape, it extends from the base of the skull down to the mid-back, connecting to the shoulder blades and collarbone. This muscle is functionally divided into three distinct segments: the upper, middle, and lower fibers.
The upper fibers elevate the shoulder blade, the movement associated with a shrug, and assist in neck rotation. The middle fibers primarily retract the shoulder blades toward the spine. The lower fibers depress the shoulder blade and work with the upper fibers to rotate the scapula upward. These combined functions allow the traps to stabilize the shoulder and move the head and neck.
Overhead Press Mechanics and Scapular Movement
The OHP is defined as shoulder abduction and flexion, moving the arms from a rack position to a fully extended position directly overhead. To achieve this full range of motion safely, the body requires a coordinated movement known as the scapulohumeral rhythm. This rhythm dictates that the shoulder blade must move in a specific ratio relative to arm movement.
As the arm moves past 90 degrees of elevation, the shoulder blade must rotate upward to create space for the upper arm bone. Without this upward rotation, the shoulder joint is forced into a compromised position, limiting range of motion and potentially leading to impingement. This necessary rotation is a key component of OHP biomechanics, distinguishing it from movements like the bench press, where the scapula is fixed. The upward rotation of the scapula is the mechanism that directly involves the trapezius muscle.
Trap Engagement During the Overhead Press
The trapezius muscle is active during the overhead press, primarily serving as a dynamic stabilizer and assistant to the deltoids. Scapular upward rotation is met by the synergistic action of the upper and lower trapezius fibers working alongside the serratus anterior muscle. The upper traps elevate the shoulder while the lower traps pull it down, and this coordinated effort rotates the shoulder blade upward.
The traps are also involved in the final, locked-out position of the press. To fully secure the weight overhead, many coaches recommend actively shrugging the shoulders toward the ears. This powerful contraction of the upper trapezius helps create a stable column of support from the hand down to the shoulder girdle. The middle trapezius fibers also contribute by retracting the shoulder blades, maintaining a rigid upper back structure throughout the lift.
While the traps are active, their role is stabilization and assistance, rather than being the primary mover. Electromyography (EMG) studies confirm that the deltoids, particularly the anterior head, receive the highest activation as the muscles responsible for pressing the weight. Therefore, the OHP provides a significant stabilizing stimulus for the traps, particularly the upper and lower sections, but it is not considered the most effective exercise for inducing maximum mechanical tension and hypertrophy.
OHP Versus Dedicated Trap Exercises
To understand the practical application, the OHP’s effect on the traps must be compared to exercises specifically designed for them. Traditional barbell shrugs, for example, involve a heavier load and a shorter range of motion focused entirely on scapular elevation. This direct mechanical tension and heavy loading is considered superior for maximizing upper trapezius size compared to the OHP’s stabilization-based stimulus.
The OHP is a superior movement for shoulder strength and health due to the demands it places on coordinated scapular motion and stability. For individuals seeking maximum trap development, the OHP serves as a valuable supplementary exercise, especially when incorporating the final shrug to lock out the weight. However, pairing the OHP with dedicated exercises, such as heavy shrugs for the upper traps or face pulls for the middle and lower traps, will provide a more comprehensive stimulus for overall trapezius growth. Ultimately, the overhead press works the traps in a functional capacity, but dedicated isolation work is required to maximize their size.