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Monday, January 28, 2013

Barefoot running doesn’t guarantee strain reduction

Many studies have shown that barefoot running is both more energetically efficient and better for one’s joints. If it weren’t for hot pavements and gravel, more people would probably take it up. However, thanks to the work of Kevin Hatala from George Washington University and his colleagues, it now seems that barefoot running isn’t necessarily a cure-all for running problems. This is because, contrary to conventional wisdom, running barefoot doesn’t guarantee a more healthful foot strike pattern.

It was thought that during a normal stride, an unshod runner would strike first with the fore or midfoot whereas a person wearing running shoes would tend to land first on the back of the foot. Among other factors, it’s this impact on the heel that causes the greater foot and joint strain associated with shod running. Prior studies with habitually barefoot runners such as the Kalenjin people of Kenya showed that they did land on their forefeet as they ran.

Hatala and his colleagues looked at a different barefoot community: the Daasanach of northern Kenya. The scientists recruited 38 habitually unshod adult Daasanachs (half men and half women) and asked them to run at varying speeds along a 15 meter trackway containing a pressure pad at the midpoint. Each volunteer ran across the pad at least three times for a total of 133 trials.

At endurance speed, the barefoot runners landed each stride on their forefeet only 4% of the time. 72% of the time, they used a rearfoot or heel strike as they ran. Avoiding the heel strike was supposed to be the unshod runner’s claim to fame, and yet these normally barefoot people were using the same stride as people wearing Nikes. A few of the subjects did revert to a forefoot strike as they increased speed, but most people landed on the middle or back of their feet regardless of speed.

This doesn’t mean that it isn’t better to land on your toes than on your heels as you run, but it does seem to indicate that landing on one’s toes is not necessarily the way that humans evolved to run. I should note that the Daasanach people do not spend as much time running as other barefoot populations that have been studied. For example, the Kalenjin, who do land on their toes, spend a lot more time running than the Dassanach do. So, it could be that the Daasanach have lost the knack of injury-free long distance running.

In any case, I've decided to give those minimalist five-toed running shoes a try. Wish me luck!

Kevin G. Hatala, Heather L. Dingwall, Roshna E. Wunderlich, & Brian G. Richmond (2012). Variation in Foot Strike Patterns during Running among Habitually Barefoot Populations PloS ONE : doi:10.1371/journal.pone.0052548.