Foot strike patterns and collision forces in habitually barefoot versus shod runners

The biomechanics of barefoot running Before the introduction of modern padded running shoes in the 1970s, and for most of human evolutionary history, humans ran either barefoot or in minimal shoes. A comparison by Daniel Lieberman and colleagues of the biomechanics of habitually shod versus habitually barefoot runners now suggests that the collision-free way that barefoot runners typically land is not only comfortable but may also help avoid some impact-related repetitive stress injuries. Kinematic and kinetic analyses show that modern shoes allow runners to land on the heel, as they do when they walk. Runners who don't wear shoes land more often on the ball of the foot or with a flat foot. This means that they often flex their ankles as they strike the ground and generate smaller impact forces than shod, rear-foot, strikers — compare the impact generated by landing from a jump on your heel versus your toes. Although humans have engaged in long-distance running either barefoot or with minimal footwear for most of human evolutionary history, the modern running shoe was not invented until the 1970s. Here, runners who habitually run in sports shoes are shown to run differently to those who habitually run barefoot, with the latter often landing on the fore-foot rather than the rear-foot. This strike pattern may have evolved to protect from some of the impact-related injuries now experienced by runners. Humans have engaged in endurance running for millions of years 1 , but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing