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.
Every good trainer has that moment of clarity when something he thought was true is brought into question. Alwyn calls these mini-epiphanies "Ah-ha" moments. Here are five "Ah-ha" moments that might just change the way you think, too.