A CUSHIONED, NATURAL RIDE.More cushioned than the 3.0 and closer to the ground than the 5.0, the Nike Free 4.0 Flyknit Men's Running Shoe is designed to unleash your natural stride with a low-profile midsole and a lightweight, supportive Flyknit upper.Enhanced Movement Hexagonal flex grooves offer six points of flexibility to let your foot move naturally in every direction. Secondary cuts in the midsole enhance natural range of motion.Natural Stride With a 6mm offset between heel and forefoot height, the Nike Free 4.0 Flyknit features a very low-profile midsole and a rounded heel to encourage a more natural footstrike.Support The strong, lightweight Flyknit upper provides a contoured, supportive fit with stretchy polyester yarn. Flywire integrated with the laces delivers added support and an adaptive fit.More Benefits Asymmetrical lacing reduces lace pressureNon-stretch heel material for structure and supportMolded sockliner mimics your foot's shape for added supportSolid rubber under the toe enhances traction and durabilityWaffle outsole pistons absorb impact and add responsivenessProduct Details Weight: 7.55 ounces (men's size 10)Midsole offset: 6mmNIKE FREE ORIGINS After learning that Stanford athletes had been training barefoot on the university's golf course, three of Nike's most innovative and creative employees set out to develop a shoe that felt natural and weightless, similar to bare feet. In 2002, they examined a group of men and women with pressure measuring insoles taped to their feet, using high-speed cameras to capture images of each foot in motion. The team spent eight years studying the biomechanics of shoeless running. The results yielded a profound understanding of the foot's natural landing angle, pressure and toe position, allowing Nike designers to build an unconventional running shoe from the inside out.FLYKNIT ORIGINS Nike Flyknit technology was inspired by feedback from runners seeking a shoe with the snug (and virtually unnoticed) fit of a sock. Nike embarked on a four-year mission with teams of programmers, engineers and designers to create the technology needed to make the knit upper with static properties for structure and durability. Then the precise placement of support, flexibility and breathability—all in one layer—was refined. The result is a featherweight, formfitting and virtually seamless upper.