Mark Wiens

For decades, world-class athletes have conditioned their feet—and upped the speed at which they shift from one foot to the next—by leaving their shoes at home. Nike gets barefoot-running religion with the Free, which distills the training shoe to its very essence. For an ultra-minimalist platform, this year's Gear of the Year winner is an astonishing performer.

1. Try out the Nike Free sans socks. Even sockless, there's no chafe: Soft synthetic suede covers a seamless elastic-mesh upper. On both longish runs and quick neighborhood trots my feet felt solidly encased—yet were free to move where they pleased.

2. Most running shoes are designed to flex underfoot in front of the laces. The Free, scored on the underside like a chocolate bar, can be squished down to the size of a mango, and the shoe moves and bends every direction your foot would naturally.

3. Forget rock-solid heel plates locking your dogs in place. The Free instead offers a millimeter of elastic mesh. Thus liberated, my feet found a neutral, ultra-comfortable zone—instead of one dictated by multiple layers of material.

4. Acknowledging that every foot has its own idiosyncrasies, Nike sells the Free with two sculpted inserts. Start with the thicker one and, as you strengthen the muscles in your feet, move on to its thinner counterpart.

5. The midsole and arch support are much thinner and softer than those in conventional shoes, but there's still enough lift and protection to guarantee some stability without compromising freedom of movement.