The Nike Free Viritous Print Volt/Dark Grey of Women's Nike Shoe features a breathable textile upper inspired by the Nike Huarache, and deep flex grooves for a natural ride.FLEXIBLE AND BREATHABLEBenefits Breathable textile upper helps keep your feet cool Bootie construction for a snug fit and easy on and off Flywire cables offer lightweight support and lockdown Nike Free IU midsole/outsole for incredible flexibility Rubber pods over high-wear areas for durabilityNike 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....The Nike Shoes more colors