Shane Parrish

Millions of people watched this lean, determined man cross the finish line, and something shifted.

Running clubs popped up.

Joggers appeared on suburban sidewalks.

In the 1970s, the New York Marathon had 127 finishers.

By the end of the decade, it had tens of thousands.

Nike didn't start the running boom, but they were the only company ready for it.

They rode the wave.

The waffle trainer caught fire because it's better traction, better cushioning and a better price.

But what surprised everyone, including Phil, was what happened next.

People stopped taking them off.

And here's what Phil wrote in his book.

He said, watching the shoe evolve in 1976 from popular accessory to cultural artifact, I had a thought.

People might start wearing this thing to class and the office and the grocery store and throughout their everyday lives.

Until that moment, athletic shoes were for athletics.

You wore them to run, then you changed.

The idea of wearing running shoes to the grocery store was radical.

So Knight made a small decision that turned out to be enormous.

He ordered the waffle trainer in blue to go with jeans.

We couldn't make enough.

Retailers and sales reps were on their knees pleading for all the waffle trainers we could ship.