The InfinityRN 4 offers supportive cushioning for a smooth ride and helps you hit the ground running. Made with soft, comfortable Nike ReactX foam and updated with Nike Running's best-fitting Flyknit yet, this road running shoe helps you take off anytime, anywhere. Thanks to the high foam content and intuitive, supportive design, you can run faster and further in this shoe. The more cushioning you have underfoot, the softer and more comfortable your running experience will be. The cushioning helps to soften the impact when your feet hit the ground. The ReactX foam provides an incredibly soft ride and helps you to push your limits. The more supportive the shoe is, the more stability it can add to your natural running style. A combination of tuned support and deliberately placed cushioning ensures that you feel secure with every step. The curved outsole ensures that your foot rolls smoothly from heel to toe and through the entire stride to the footprint. This makes every step feel more natural and ensures greater running efficiency as less energy is wasted on impact. A new internal Flyknit fit band (like an elastic band around the middle of the foot) provides elastic, secure support. The more responsive a shoe is, the more energy you can recover with each stride. Whether you want to run a little faster or with a little less effort, responsive shoes give you a little more oomph so you can get more out of your run. ReactX foam offers 13% energy return compared to React foam, helping you stay fresh and bouncy during your run. What's new about the Nike InfinityRN 4? This version of the Nike InfinityRN 4 continues to offer a soft and smooth ride, with the new ReactX foam providing more support. The redesigned Flyknit upper and wider toe box give your foot a stable and secure feel. The waffle outsole offers durable traction. The Flyknit tongue is adjustable and soft. The foam collar feels soft and supportive. More rubber on the outsole provides traction and durability.