Instructions
Place dumbbells on the floor and lie face down on a bench. Grasp a dumbbell in each hand with your thumbs facing each other (palms towards your feet). Maintaining a slight bend in your elbows, raise your arms until your elbows are approximately at the same height as the bench, hands can be out wider than your elbows. Lower to the starting position to repeat.
Tips
This exercise is great to work on shoulder/scapula stability. Make sure you keep each sides even and that you don't allow your elbow to tuck in or flare out. Use light weights and high repetitions to use this as a shoulder rehabilitation exercise.
