Prone Shoulder Y's
How to: Lay on your stomach with both arms out in front in a Y position, arms are locked out at the elbow & thumbs pointing up. Keep the shoulders down & back, head neutral. Slowly raise the arms off the floor as high as you can without compensating by raising the chest off the floor, bending the elbows, dropping the head or elevating the shoulders.
Compensations: Watch for raising the chest off the floor, bending the elbows, dropping your head or elevating and rounding the shoulders forward.