A worker cleans up a shoe of the soccer shoes brand "Milemil" in a factory on September 23, 2015, in Romans-sur-Isere, southeastern France. Can technical sportswear do away with petroleum-based materials? This is the hope of designers who create swimsuits from wool and sneakers from whey and fruit, a challenge for sports brands faced with the imperatives of strength and safety. (Photo by PHILIPPE DESMAZES / AFP) (Photo by PHILIPPE DESMAZES/AFP via Getty Images)