Lie on your back.
Bend both knees and place your feet flat on the floor.
Place a ball between your knees and gently squeeze it to keep it in place.
Lift your buttocks from the ground so that your knees, hips and shoulders are all aligned.
Squeeze your knees together against the ball, then release.
Gently lower your hips and back down to the ground, returning to the starting position.
