Instructions
Set up two flat benches so that you can sit on the edge of one, with your feet up on the other. Grip the sides of the bench you are sitting on, with your hands positioned tightly against your legs. Slide yourself off the bench so that you are just off the ledge. Lower your body by bending your elbows back behind you until your arms are in a 90 degree angle. Push yourself back up to the starting position.
Tips
Make sure your body lowers in a straight line with your back close to the bench and your elbows staying tucked behind you.