[Stay Comfortable: The updated Innovarch arch feature encourages better foot placement in each step and the Altra EGO Max cushioned midsoles are light luxurious and responsive Lock In: The sock-like engineered knit upper keeps your foot comfortable and locked in Propel Yourself: Our rocker shape geometry is designed to give the feeling of being propelled forward with each step and provides an efficient toe-off without taking away from your natural stride]