Seated Dumbbell Shoulder Rotation

The dumbbell shoulder rotation is a rotator cuff exercise that trains internal and external rotation in the same set. Sitting tall on a bench with a dumbbell in each hand, you bend the elbows to 90 degrees and hold the upper arms parallel to the floor, then turn the forearms outward as far as they go, pause, and turn them inward as far as they go. The upper arms never move. Four small muscles run from the shoulder blade to the head of the humerus and keep it centered in the socket while the big pressing muscles do their work; when they are weak, the head drifts and impingement follows. That is why this shows up in rehab plans and in the warm-up of anyone who benches or throws. Load stays deliberately light, 5 to 10 pounds is plenty, and 15 slow reps do more for the joint than 8 heavy ones ever will.