1. Lie on your back on the floor and wrap the band around the arches of your feet.
2. Cross the ends of the band over each other to make an “X” and grasp the ends with opposite hands.
3. Bend your hips and knees so that your knees are near your chest and then crunch your torso off the floor. Extend your legs while you raise your arms overhead—keep your shoulder blades off the floor. That’s one rep.