HOW: Start by lying on your side with your knees bent. Bend the top arm’s elbow to make a 90 degree bend or an “L” shape. Support your head with your other arm or a pillow. Your palm should be facing flat against your stomach. Rotate the arm up and out while keeping that “L” shape in your elbow. Your thumb should be pointing up as the arm comes off of your stomach. Pretend there is a rod going from your shoulder through the bottom of your elbow and that rod has to stay still. Keep that elbow at your side as you rotate that arm up and back down to the starting position.
FEEL: You should feel the muscles in the back of your shoulder and shoulder blade working.
COMPENSATION: Don’t let the elbow come up or back as you rotate your arm up. Don’t lean back with your body, stay on your side.