The new midsole in the Epic React shoes don’t need this 24 hour recovery period and they also don’t start to lose their effectiveness after the 250 or so hundred miles mark. Though their midsoles are made from a completely new type of synthetic rubber, the Reacts aren’t the first running shoes to make this claim. Just last year, Brooks’ Running debuted its new shoe Levitate, which holds the same two longevity claims. The Levitate midsole is also brand new, but its technology (Brooks partnered with BASF to create it) is no secret: Instead of EVA, its made of a different rubber called PU, which is housed inside a stronger formulation of the rubber called TPU. That combo, Brooks claims provides the Levitate with a super high energy return, and allows it to bounce back between workouts and remain springy for endless miles.