BREATHABILITY AND A NATURAL RANGE OF MOTION.The Nike Free 5.0 (2c-10c) Toddler Girls' Running Shoe is made with breathable mesh and deep Nike Free sipes for a smooth, comfortable ride and maximum flexibility.BenefitsLightweight mesh with dynamic quarter creates a snug, flexible fit that moves with the natural motion of the footInjected Phylon midsole for lightweight cushioningDeep Nike Free sipes for excellent range of motion and a natural, barefoot-like feelVELCRO ® brand fastener strap for an adjustable fit and supportReinforced outsole rubber on 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.