The toe-spring section of a cycling shoe plays a key role in supporting efficient pedaling. Too high, and it causes increased tension in the plantar, calf, and hamstring muscles. Too low, and you get a bowlegged, inefficient pedaling form. Extensive research by Shimano's R&D experts has produced a superior shoe last design with an optimized toe-spring section that promotes a smoother, more energy-efficient upstroke. Built based on feedback from pro riders, Shimano Dynalast helps reduce energy loss on long rides, letting you keep more in the tank for that final sprint to the line.