The 'Tarahumara' use their legs 'as designed.' By running at a young age with minimal footwear, they naturally develop the best biomechanical use of their legs. Cushioned shoes restrict foot movements and allow for over-striding. Short strides are natural.

Way before we were scratching pictures on caves or beating rhythms on hollow trees we were perfecting the art of combining our breath and mind and muscles into fluid self-propulsion over wild terrain.

He was onto something. Something huge. It wasn't just how to run; it was how to live, the essence of who we are as a species and what we're meant to be.

For nearly 2 million years, our ancestors survived and thrived and spread across the planet because they could run other mammals into heat exhaustion.

But you can't muscle through a five-hour run that way; you have to relax into it like easing your body into a hot bath, until it no longer resists the shock and begins to enjoy it.

Everyone is built for running.

Faced with the almost inescapable conclusion that it had been selling lemons, Nike shifted into make-lemonade mode. Jeff Pisciotta became head of a top-secret and seemingly impossible project: finding a way to make a buck off a naked foot.