In the late 2000s, two French mountain athletes set out to build a running shoe that captured the feeling of flying. Jean-Luc Diard and Nicolas “Nico” Mermoud had spent decades inside the innovation engine at Salomon—where product was obsession. In 2007, as Nico recovered from a brutal ultramarathon around Mont Blanc, the founders fixed on a problem that Big Footwear didn’t care about: downhill running was destroying bodies. Their solution: make the shoe bigger, softer, and shaped like a rocker. At first, their prototypes looked like clown shoes. Runners who preferred minimalist footwear laughed at them. ...