The elastic heel strap separates the Adidas Terrex Free Hiker Primeblue Hiking Shoe from most mid-cuff hiking boots. It has a bit more heel support without inhibiting freedom of movement. Rocky, technical sections of the trail feel a whole lot easier, and there's still plenty of stability for the long stretch. Underfoot, this shoe uses Adidas's Boost midsole for maintaining soft cushioning and shock absorption.