Is it possible to jump so high

that you hurt yourself landing? Massive foot-floor coordination fuckups aside, is it possible to amass such velocity on the way back down from a vertical leap that you're sure to do yourself injury? Obviously not on Earth, but what about in lower-gravity situations?

only if you don't know how the fuck to land properly.  I've seen someone go off the side of one of those folded up giant stacks of bleachers at the side of my high school gymnaseum (approx 20 feet up) with not much ill effect.