Rollerblade Marathon Structure Technology Rollerblade's new Marathon Structure is a breakthrough in shell and cuff designs. This new, high-performance shell includes a carbon shell and a refined cuff design for a more precise fit, reduced weight, and additional forward flex for a more efficient stride. The marathon Structure is the perfect skate for distance skaters who prefer a little added lateral support over the traditional race boot design, yet still require absolute freedom of movement. This is a closer, more streamlined design.