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 one knee, pulling the heel in towards your buttocks.
Control the movement as you straighten the leg back out again.
Do not lower the hips back down until you have completed all repetitions.
