Which action is performed via a bench press exercise?

The bench press exercise primarily involves the horizontal adduction of the humerus. During this movement, as an individual lowers the barbell to the chest and then presses it back up, the arms move in a manner that brings the upper arms closer to the midline of the body. This action effectively recruits the pectoralis major, the primary muscle responsible for horizontal adduction, along with the triceps brachii and the anterior deltoids assisting in the movement.

The other choices involve actions that are not the primary focus of the bench press. Extension of the elbow does occur during the pressing phase; however, it is not the defining movement of the exercise. Abduction of the shoulder, which involves moving the arm away from the body, does not happen in this exercise, as the arms are drawn together towards the midline. Flexion of the neck does not relate to the bench press action at all, as it concerns movement of the cervical spine rather than the upper limb and shoulder. Thus, the correct answer highlights the key movement characteristic of the bench press.