Place your hands on a secure chair or bench either side of your bum with fingers facing forward. Have your legs out in from of you (the further your feet are away from your chair the harder the exercise). Lift your bum off the chair and gradually lower your bum towards the ground, keeping your back close the face of the chair (resist drifting too far away from the chair) whilst keeping your elbows in tight. Return to the start position. Repeat.