This exercise primarily works your rotator cuff muscles, which are deep within your shoulders. Perform this move on a ball and you will also be working your abdominals and back muscles, which help you balance during the movement.

1 Lie down with your chest over a large stability ball. Move your legs shoulder-width apart, with your knees bent and your toes curled under for better stability. Hold a dumbbell in each hand. Bend your elbows at 90-degree angles, with your wrists below your elbows. Your palms will be facing your feet.

3 Keeping your elbows at shoulder height, slowly raise the dumbbells so that both palms face the floor and your elbows point toward your feet. Be sure to tighten your abdominal muscles and keep the tops of your shoulders pressing down away from your ears. Do not lift the dumbbells higher than shoulder level.

This article originally appeared in the Los Angeles Times in the "Good Form" feature of the Health Section. "Good Form" is updated with a new Karen Voight article each Monday.