Nike Free iD MAKE IT PERSONAL The ultra-flexible Nike Free iD combines the feel of barefoot running with cushioning, traction and underfoot protection. Customize the colors and add a personal message to your shoe with NIKEiD. Customize Your Colors Choose the colors of every part of your shoe, from the mesh to the midsole. Choose Your Laces The Nike Free iD offers many different colors of laces, so you can make them pop or match them to the rest of your design. Leave Your Mark Add your name or favorite number to the tongue tops. Flexibility Nike Free flex grooves extend the length and width of the outsole, allowing the foot to move naturally, enhancing the flex and grip of the toes and increasing the foot's range of motion. The minimalist design helps strengthen the foot and ankle by working core muscles that aren't activated in firmer shoes. Nike 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, just like 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.