From the day in 1970 that legendary University of Oregon track coach Bill Bowerman poured rubber onto his wife’s waffle iron to create a new running shoe sole, Nike has been a company dedicated to pushing the technological envelope in search of shoes that cushion, support and protect athlete’s feet.

Which is why its emphasis on running barefoot is so unexpected.

Of course, Nike is still a shoe company, so it isn’t suggesting literally running barefoot. Instead, it’s marketing a line of running shoes and trainers called Nike Free. The footwear is designed to emulate the motion of running au naturel.

The shoes had their genesis in a design brief submitted to Nike’s “Innovation Kitchen” by the company’s product people, who were asking for a new, lightweight training shoe for serious runners. The cooks in the Kitchen, Nike’s incubator for new projects, took that limited description and started asking around to see what sort of shoe people might be looking for.

During the course of their conversations with athletes and coaches, some Nike designers ended up talking to Vin Lananna, who was then the track coach at Stanford University. While discussing the Stanford program and his success there (Lananna’s 2002 men’s track and field team won the school’s first NCAA outdoor title since 1934), Lananna mentioned the unusual training he did with his athletes: He had them run on grass without shoes.

“He said that it kept his athletes stronger and healthier, and prevented injuries,” recalls Tobie Hatfield, senior engineer for advanced products at the Nike Innovation Kitchen. “And since they were injured less, they could train more. He was sure this training was giving them an edge.”

There was just one problem.

“We said, ‘That’s great, coach, you’re taking our shoes off to get better,'” says Hatfield.

Tossing aside the shoes wouldn’t work for Nike’s business. But Lananna’s observations stuck with Hatfield and his team, and eventually spurred an extensive biomechanical research project to see exactly what happens when we run barefoot.

More here.