Lay on your back with your hands behind your head. Press your hands into your head, and your head into your hands. Raise your legs straight into the air, so your body forms an “L”. Crunch from your abdomen, keeping your core tight and raising only your shoulders off the ground. Stabilize your neck if necessary to keep yourself from straining it. Look ahead and reach your left hand to touch your right foot. Release the crunch, bringing your hand back behind your head. Crunch up again, reaching your right hand to touch your left foot. Repeat, relaxing the crunch, but maintaining straight legs in the air between each repetition.