Setup: A reverse hyper table or other apparatus that will allow you to bend at the waist and where your feet do not touch the floor.
Position: Lay face down with a suitable anchor for your hands to grasp. Lay off of the equipment so that you can bend 90 degree at the waist.
Movement: Keeping the upper body flat and still, straighten one leg, activating the glutes and low back. The other leg is hanging down. Keep the knees straight at all times. Lower the leg under control, pause, and raise the other leg. Repeat.