Final answer:
During exercises that involve shoulder horizontal adduction, resistance is crucial to engage the pectoralis major and latissimus dorsi muscles, supported by the rotator cuff muscles for shoulder stability and strength.
Step-by-step explanation:
Resistance should be properly positioned to counteract shoulder horizontal adduction during certain exercises, particularly those targeting the muscles responsible for moving and stabilizing the humerus and shoulder joint. The resistance aims to engage and strengthen specific shoulder muscles, including the pectoralis major and the latissimus dorsi, which are axial muscles crossing the shoulder joint involved in horizontal adduction movements. The primary support for the shoulder during these movements is provided by the rotator cuff muscles, which consist of the supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles work synergistically to maintain the humeral head within the glenoid cavity, providing dynamic stability as their contractions help to counteract external forces during exercise.