HOW: Get set-up standing in front of a wall with your arms supported on a foam roller that is also supported on the wall. With your thumbs facing towards you and putting pressure into the wall through the foam roller so that it doesn't drop, roll the foam roller up the wall into your arms are fully overhead. As your arms move overhead, let your chest move closer towards the wall. Return to starting position and repeat.
FEEL: You should feel your shoulder and shoulder blade muscles working with this exercise. You may feel a stretch behind and below your shoulders and in between your shoulder blades at the top of the movement.
COMPENSATION: Do not arch your lower back to get your arms overhead, do not lose pressure into the foam roller.