Handstand Push-up
From a handstand position, lower the body until the head touches the ground, then push up until the elbows are locked. If you can’t hold a freestanding handstand, then use a wall for support.
Scaling and Substitution
Handstand push-ups can be scaled by reducing the incline of the body. Place the feet on a box, or other raised surface and do push-ups with the hands on the ground.
Rubber stretch bands can also be hung from a pull-up bar or other raised location to provide assistance. If you have a partner, you can also have them hold your legs and help pull you up.
If none of the above scaling methods are feasible, then similar strength can be developed from a shoulder press. However, actually moving your body as in a handstand has tremendous benefits in coordination and kinesthetic awareness that cannot be duplicated by moving a barbell.