How the Little Swiss Brand 'On' Broke Every Rule to Become the Fastest-Growing Sneaker Brand in the U.S. It all started in the mountains of Switzerland, with some cut-up garden hoses.

One day in 2005, Olivier Bernhard, a superstar athlete sponsored by Nike, got a call from a stranger asking for his shoes. "Do me a favor and send them to me," the man said. He was an engineer. "I'll put something on them, and you go run."

Bernhard, a duathlon world champion and six-time Ironman winner, is famous in Switzerland, where he grew up running in the mountains. He's also a performance junkie; he loves tinkering and pushing to find an edge. Intrigued by the call, he mailed off a pair of his Nikes. "I got my Swoosh shoes back with cut-up garden-hose pieces on the bottom," Bernhard says with his Swiss-German accent. "So on a February night — even in my little village, I didn't want anybody to see me in the shoes; they were really ugly. And I went for a run. I felt, Wow, this is so cool. It's playful; it's different. I came back, and before even showering, I had a list of 50 things I would adjust to make it a really comfortable performance running shoe."

Bernhard spent the next three years building on the engineer's work — cutting hoses and gluing them on shoes to invent a wildly springy sole that turned feet into pogo sticks and made people feel like they were running on clouds. By 2008, he was thinking about launching a shoe company and went to see his former agent, Caspar Coppetti, now at a global marketing company, for advice. "Don't do it," Coppetti said. "Just drop it. ASAP."