Nike Alphafly 2 Once you take a few strides in the Nike Alphafly 2, you’ll never look at your favorite pair of old racing shoes the same way again. A thick, lightweight support system marries the 2 worlds of comfort and speed in holy running matrimony. Enjoy the greatest energy return of all our racing shoes while you chase your personal bests. Zoom Air units and full-length ZoomX foam deliver Nike’s highest energy return cushioning system, adding more bounce into every step. A thin rubber outsole enhances traction and allows for more ZoomX under the Zoom Air cushioning. The additional foam not only adds more bounce, but also helps improve transition from heel to forefoot. Full-length ZoomX foam offers an ultra-lightweight and responsive ride. It’s built for speed but also provides cushioning to stay fresh even in the late miles of a marathon. It offers comfort where you need it. Full-length carbon fiber plate delivers a sort of roll-forward feel that makes you want to take on the next step. It gives you a propulsive sensation and helps you smoothly transition through your stride. Both the forefoot and heel offer slightly wider bases for a stable platform, so you can tackle turns on the course with confidence. Part of the Flyknit family—Atomknit material on the upper has a contoured fit while being lightweight and super-breathable. Specifically designed lofted heel pods use Flyknit yarns for secure, extended comfort and lightweight heel lockdown. Notched laces offer a secure, but soft lace-up. An integrated knit tongue with lofted padding make for a secure, repeatable fit that helps reduce lace pressure. The sole was designed using data from hundreds of runners. It has different angles of traction placed where you need it, providing grip from foot-strike to toe-off.