HOW: Start with your chest against the swissball with your knees on the ground. You can also place your toes on the ground as well if you would like. With your thumbs up and start with your elbows are your side, lift your elbows up towards the sky. Maintaining the reach towards the sky, slowly lift your elbows/hands in front of you like you are making a snowangel in the ground.
FEEL: You should feel all the muscles in your shoulder blades working to lift your arms up.
COMPENSATION: Lift with your shoulder blades, not necessarily with your shoulders or arms.