New research is good news for athletes and fitness enthusiasts who favor thick, heavily cushioned running shoes. Although these shoes are increasingly popular because they provide comfort and a high degree of shock absorbing protection, those benefits were thought to come at the expense of increased overall leg stiffness, which alters a runner’s normal stride and could increase muscle fatigue. Plenty of research suggests just such a result when running on a compliant surface, like a synthetic rubber track, but no one had actually tested how the cushioned midsole of a running shoe affects overall leg stiffness. Until now. “Our results show that runners do not need to worry about the amount of cushioning,” says Nicholas Holowka, an assistant professor of anthropology at the University at Buffalo and first author of the study in the Journal of Biomechanics. “That element of shoe design is not interrupting your normal running style in any significant …