Designed as an up-tempo shoe, it’s quickly proven itself as much more, equally capable during long, moderate training sessions and sprints to the finish. Energy efficient PWRRUN PB foam bounces back with every step combined with a winged nylon plate that provides torsional rigidity while maintaining flexibility in the forefoot, making for a sure footed, snappy ride SPEEDROLL technology for effortless speed and addictive forward motion you can rely on daily Increased amount of rubber coverage in the heel, extending further up the shoe and to the edges for added durability Full length longitudinal groove to add increased flexibility for a more natural, smooth transition in your gate cycle