Nike Free is a great concept, but let’s face it: with so many different Free models out there, sometimes it can be hard to differentiate between the various numbers, whether it’s a Free 3.0 or a 5.0. But if you break it down, the idea’s quite simple. The lower the number, the lower the shoe is to the ground for the most natural ride possible.

In a recent video, Nike Running Footwear Designer Rob Williams talks about the technology to shed further light on the Nike Free Ecosystem. Check it out.

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