Think of this exercise as a push-up that's mostly for your shoulders instead of your chest. It forces the shoulders to work hard to drive your body back using a natural arc and push angle.
The Push-Back Push-Up
Level 1: Drop down, explode straight back, and return to push-up position.
Level 2: Same basic movement, but put your feet up on a braced bench. Your abs will be screaming.
When you think of science, the first thing that probably comes to mind is images of atrophied, goggle-wearing weaklings in white coats. Bulging muscles and inhuman strength are certainly not part of your mental image!