Major Muscles and Actions Involved
Variant 1: Military press
The term military press is not in common use today but the exercise is still used extensively. In the shoulder joint the major muscles are the anterior deltoid, the pectoralis major (upper portion), and the coracobrachialis. They are involved in shoulder joint flexion in which the upper arm travels in the anterior-posterior plane from a position in front of the body upward to an overhead position.
In the shoulder girdle the major muscles are the serratus anterior and the upper and lower fibers of the trapezius. They are involved in upward rotation of the scapulae, in which the right scapula turns counterclockwise and the left scapula turns clockwise when viewed from the rear. In addition, the scapulae are elevated (move directly upward) during execution, which involves the uppermost trapezius and the levator scapulae.
In the elbow joint there is extension which involves the triceps brachii. In this action the forearms move away from the upper arms which move away from the shoulders until the arms are straight and directly overhead.
Variant 2: Press from the shoulders with the elbows out
The shoulder joint muscles involved in this variant are the middle and anterior deltoid and the supraspinatus. They perform shoulder joint abduction, in which the arms move from an out-to-the sides position to an overhead position. In the shoulder girdle and elbow joint, the same muscles and actions occur as in Variant 1.
The combination of actions involved in the overhead press is used in a multitude of sports. These actions play a major role in weightlifting (clean and jerk and snatch), in gymnastics (vaulting push off the horse, handstand press), tumbling (pushing off the floor), hand balancing (pushing and holding the top performer), and in the recovery strokes in swimming.