Sit on the floor with your knees bent and feet together. Wrap the band around your feet, holding the ends between your knees. Lie back with your knees open, sides of your feet touching the floor, arms straight and fingers reaching toward your knees. Bend your elbows as you curl your head and shoulders off the floor into a crunch, bringing your fists toward your chest in a biceps curl [shown]. Slowly straighten your arms as you curl your torso down to the floor. Do 5 to 10 reps.