Nike Free Run+ 2 Premium EXT Women's Shoes - Black, 5 The Nike Free Run+ 2 Premium: Barefoot-like feel, shoe-like benefits The Nike Free Run+ 2 Premium EXT Women's Shoe is designed to maximize the foot's natural range of motion while providing protection and cushioning for a smooth ride. Benefits Numerous flex grooves for a more natural, barefoot-like stride Dynamic upper for a perfect glove-like fit Asymmetrical lacing system to help reduce pressure over the top ridge of the foot Waffle lugs at the outsole for impact absorption and traction Nike+ ready Weight: 7. 2 ounces (women's size 8) 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 and flexible running shoe from the inside out.