NATURAL FEEL. POWERFUL STABILITY.The Nike Free TR Versatility Amp Men's Training Shoe gives you both lightweight lockdown and premium comfort thanks to Flywire cables and no-sew overlays on a breathable knit upper. A Nike Free midsole expands and contracts in every direction for the ultimate in natural flexibility.BenefitsWarp-knit upper for breathable comfort and supportFlywire cables for a dynamic fitNo-sew overlays offer support and durabilityDual-density Nike Free midsole expands in every direction for natural movementReinforced rubber on the outsole for durability in high-wear areasNike 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. The team spent eight years studying the biomechanics of runners' feet in motion. 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.