HOW: Get a band set-up at shoulder height. While starting with your elbows straight, elbows at shoulder height, and palms facing down, drive your elbows back by squeezing your shoulder blades together until your elbows are in line with your shoulder. Hold this position for a moment, then slowly return to starting position and repeat.
FEEL: You should feel the muscles on the outside and the back your shoulders working as well as your shoulder blade muscles. Think about squeezing a pencil between your shoulder blades as you perform this movement.
COMPENSATION: Do not shrug your shoulders, do not move your head/neck, do not lean backwards, do not flare your elbows. Try to isolate this exercise to shoulder and arm movement only.