Science & technologySports equipmentGetting a leg upNew running shoes could help smash a string of Olympic recordsPlatform shoes are back in fashion, at least in athletics.Many of the long-distance runners at the Tokyo Olympics, which begin on July 23rd, will arrive at the starting line sporting footwear with a distinctive chunky-looking heel.It will be more than just a fashion statement. The new shoes offer such a big performance advantage that critics have described them as "technological doping".Running-shoe makers have long tried to boost athletic performance, observes Geoff Burns, a biomechanics expert at the University of Michigan.In olden days, a 1% improvement in "running economy"―the energy taken to travel a given distance―would have impressed.But in 2016 Nike released the first version of its "Vaporfly" model, which improved running economy by 4%.If that percentage were to translate directly into performance, it would knock about five minutes off an elite male's marathon time.In practice, as Dr Burns observes, it wouldn't quite do that.A marathon improvement of around 90 seconds would be a more realistic expectation.But Vaporfly and its successors have helped athletes smash a string of records.On June 6th Sifan Hassan, a Dutch runner, completed a women's 10,000 metres race in 29 minutes and 6.82 seconds, beating a record set in 2016.
