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, try to lift your elbows as high up into the sky behind you as you can. Keeping your elbows high, bring your elbows up and down like drawing an upside-down snow angel.
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.