Set Up: Floor space, foot anchor.
Position: Lay flat on the floor with your feet anchored under a piece of equipment or a partner holding your feet at the ankles, knees bent at 90 degrees, arms crossed in front of your body so that your hands are on the front of your shoulders.
Movement: Situp so that you come up and touch mid-thigh or higher with your elbows, lay back so that the shoulder blades are on the ground and the back of your head almost touches the ground, repeat. When the hands start coming off the shoulders to assist with momentum, the set is over.