Your rotator cuff works in every upper body exercise. It keeps your shoulder stable during pressing, pulling, and overhead work. Weak rotator cuff muscles lead to impingement, pain, and injury. Train them with external and internal rotations using bands or light dumbbells. Include rotator cuff work in every warm-up. Consistent, light work is better than occasional heavy work. Shoulder health is built in the small muscles, not the big ones.