Lie on your back with your heels in the straps.
Tighten your abdominal and buttock muscles and raise your hips off the floor until you have a straight line from your head to your feet.
Keeping your core strong, bend your knees, pulling your heels in towards your hips.
Control the movement as you straighten the legs back out again.
Do not lower the hips back down until you have completed all repetitions.
