Lie on your back and reach your arms rigidly to your side, off the floor. Lift your legs off the floor, and point them, so they are at about a 45-degree angle. Lift your head, so your shoulders are off the floor as well.
When you're ready to begin, lift your upper torso off the floor, and bend your knees. You can lean back to make this move harder or come up more to make it easier. Slowly lower your upper body back down to the floor, straightening out your legs as you do so. Stop when your back is on the floor, but not your head, shoulders, or legs.
This completes one rep.
Complete for 40 seconds, and then take 80 seconds of rest before starting the second circuit.