Lie face up with your arms overhead and your legs extended, resting on the floor.
Lift your hands and feet a few inches off of the floor into a hollow position, and keep your abs engaged by pulling your belly button into your spine and pressing your lower back into the floor.
With control, lift your upper body and lower body simultaneously, reaching your arms toward your feet. Think of your body folding in half.
Lower your arms and legs toward the floor to complete one rep. The more you bring your upper back off of the ground during the "V" part of the exercise and the lower you bring your arms and legs at the end of each rep, the harder the move will be.