[QUOTE=Rob Furness;507310] The brain adjusts to run light in anticipation of hurting the foot, a bit like touching something hot and recoiling.

So the solution is just to get your brain to believe you are weightless (or massless) and you will have zero impact force and hence never be injured. No matter what my brain thinks I will still be hitting the ground with a force of roughly 740 Newtons as long as I'm on planet Earth.