From short-distance sprints to interval training around the track, the Nike Men's Free RN Running Shoe allows your foot to flex naturally as you train. Nike engineered the sole and midsole to flex with your foot with each step and kept cushion to a minimum to give the shoe a responsive, natural feel so your feet are able to react to the surface you're running on. The upper, which is composed of a breathable mesh material, allows cool air to pass through the shoe as you run, so you don't finish your workout with sweat-saturated socks--if only you could say the same thing for those sweaty pits.