Lie on your back with your legs hip-width apart, feet flat on the floor, and with a towel under your heels.
Keep your arms relaxed on the floor by your sides.
Tuck your tailbone between your legs and lift your buttocks up until your hips are straight.
Slide your heels away from you so that your knees straighten and hips stay high.
Then lower your buttocks on the floor and bend your knees back to the starting position.
You can also use a sliding disc for this exercise.
