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.
Those aches and pains, that annoying inflexibility, that injury that flares up whenever you try to deadlift a number that's higher than your IQ – all of it could be the result of tight or inflamed fascia.