Shoes and running injuries – where are we today?

When Dr. Benno Nigg went into retirement this summer he used the occasion to organize a symposium where many of his companions, but also young researchers discussed the future of running and running shoe research. The "running-symposium" in the Canadian Calgary on 15 and 16 August 2014 thus was not a classical scientific congress, but it offered the option for exchange and determination of where running shoe research is today.

Dr. Benno Nigg

"This conference is different from all the other conferences I know", said Simon Lüthi in the middle of a discussion. He was Benno Nigg's first PhD. student when Nigg changed from the ETH Zürich to the University of Calgary in order to design an interdisciplinary research center there. This research center dealt with the research of human locomotion. A focus of the "Human Performance Laboratory" was: Running and running shoes.

Ten keynote lectures and five panel discussions looked closely at these two topics. Not only recent trends, but also false presumptions from the past were discussed with a frankness that is quite rare.

Benno Nigg himself talked in his lecture once more about the reasons why they did research about running shoes at all. Already in the 70s there had been statistics of a certain percentage of runners that were injured in the course of a season. "Our assumption was," according to Nigg, "that shoes do play a role here and you could lower the injury rate by using corresponding shoe or protection designs." This assumption was supported by first biomechanical measurements that showed a strong impact during the heel-strike and a pronation during the heel-strike phase that appeared unnaturally strong. That was the birth of modern sports shoe research.

Impact and pronation were to dominate research and the concepts of sports shoe producers for years. They still determine today big parts of their product line of many manufacturers. However, in biomechanics these concepts are no longer used. "There is no evidence, neither using an epidemiological nor a prospective study that one of these two could be the reason of injuries," Joe Hamill from the University of Amherst, USA, stated. Various studies had shown that impact forces cannot predict if someone gets injured, Benno Nigg explained. For example the forces in the joints were higher in the push-off phase than in the heel-strike phase. And if impact forces would indeed play a role here, according to Nigg, then faster runners would have to be injured more often, because the impact forces get bigger with speed. But this was not the case.

Also pronation that was intended to be curtailed with shoes for decades, has meanwhile be rehabilitated as a natural cushioning mechanism. This happened at the latest with the study of Rasmus Nielsen from Denmark, who examined the position of feet of 900 runners. His result: You can hardly find runners with a pronation exceeding 10 degrees. And runners with a normal pronation had the fewest injuries within the observation period of one year. "This is exactly the opposite of what we used to believe," Nigg exclaimed. "It looks like pronation is an advantage."