This is a great variation of shoulder press instead of using dumbbells or a barbell. This is a great body weight exercise for divers, gymnasts and wrestlers.
Start the exercise in the "A" position shown. Bend your elbows til your nose is cose to the ground, then push back to the top.
You make the exercise more difficult by elevating your feet. The higher your feet, the harder it is. The next progression could be knees bent w/ knees on a stability ball, then legs up on a high box (so body is at a 90 degree angle) and finally in a fully vertical position.