Freedom. We all crave it to our very souls. Or is it soles? Nike Free technology has revolutionized the athletic world and has offered the opportunity for a more barefoot running experience to the many who still desire the protection and structure of a shoe. The Nike team ran numerous tests in which men and women ran barefoot on grass and monitored the biomechanics of the runners' feet and joints. What they found was that without the constriction of traditional running shoes, the foot went through a greater range of motion. The whole foot was being used in a much more natural way which exercised and strengthened muscles that were typically neglected, muscles that aided in stabilization and helped prevent injuries. Using these muscles could potentially enhance an athlete's performance. The challenge then was to create a line of shoes that would allow the same freedom of movement and therefore provide the same benefits that barefoot running did. And Nike Free was born. Nike designers took a traditional running shoe and cut deep sipes, or grooves, into the bottom. These grooves allowed for a much greater amount of flexibility through the heel-to-toe transition, much like barefoot running did, but the shoes still provided protection from poor landings and potentially injurious surfaces. Nike then took the Free model and made varying degrees of thickness to the highly flexible soles. Thus the numerically named Free shoes. The higher numbers corresponded to the thickness of the sole - the lower the number, the thinner the sole. Cushioning, flexibility and comfort - women's Nike Free running and training shoes have become a popular choice for athletes of every degree. Available in multiple colors and designs, Nike Free shoes are also desirable as a stylish option to perk up any workout wardrobe.