On the secret to injury-free running:

We were once the greatest endurance runners on earth. We didn’t have fangs, claws, strength or speed, but the springiness of our legs and our unrivaled ability to cool our bodies by sweating rather than panting enabled humans to chase prey until it dropped from heat exhaustion. Some speculate that collaboration on such hunts led to language, then shared technology. Running arguably made us the masters of the world.

So how did one of our greatest strengths become such a liability?