When Conner Mantz recently broke the American record in the marathon, the shoes he wore made him faster. Super shoes improve running economy, a measure of the energy cost to run at a specific speed, by about 4%, leading to a 2% performance improvement in distance events. Super shoes have a curved carbon-fiber plate embedded in a thick midsole of bouncy, light foam. Runners have broken all world records in distance events since super shoes were released in 2016. How do super shoes make runners faster?