- Lie :
on your back on the floor, place your arms on either side, bend your knees, and place your feet on the floor (with your ankles crossed) so that your knees are at a 90-degree angle. they do. Tighten your abdominal muscles, lift your pelvis and move it toward your chest to lift your tailbone off the ground.Hold for one to two seconds, then slowly lower your pelvic joint and return to the starting position.Repeat this movement 12 to 16 times. You can use your hands at first to help stabilize yourself, but the stronger you get, the less you rely on them.