LIGHTWEIGHT FLEXIBILITY. ALL-AROUND CONTROL.The Nike Free Trainer 3.0 AMP Men's Shoe is made with hexagonal flex grooves and a low-profile Phylite midsole to give you a natural, flexible ride and premium lightweight cushioning. Flywire technology and no-sew skin overlays provide supportive lockdown and streamlined durability.BenefitsMesh upper gives you breathability and a lightweight feelFlywire technology in the midfoot wraps the arch to provide an ultra-light, locked-down fitNo-sew skin overlays in the midfoot and toe create durability and a clean finishPhylite midsole/outsole for durability, a resilient ride and reduced overall weightHexagonal flex grooves offer six different flex points for the ultimate in natural motionWaffle outsole pistons help absorb impact and increase responsivenessProduct DetailsMinimally-constructed tongue is lined with a thin foam layer for lightweight comfort against the lacesAbrasion-resistant carbon rubber outsole reinforcements enhance durability in high-wear areasAnatomical heel is rounded to roll with the ground to promote natural motionWeight: 8.0 ounces (men's size 10)Nike Free OriginsAfter 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 and flexible running shoe from the inside out.