When I ran the Seattle Marathon in 2005, a handful of guys wearing ponytails and matching green t-shirts — but no shoes — sped past me. The shirts advertised their membership in the Barefoot Running Society, which I made a mental note to Google when I got home. In the meantime, I was worried about these people. I expected a bloody scene at some point down the (urban) course. Instead, they were grinning and adjusting their ponytails when I finally crossed the finish line well after them.
In the next few years, as the barefoot tribe grew, many running traditionalists like me thought they were, well, wackos. “It takes more than recommendations from… a Runner’s World forum to convince me to lose my shoes,” Megan Gambino, a former cross-country runner and current marathoner, wrote in a post on Smithsonian’s site in 2010. But by then, Christopher McDougall had waxed enthusiastic about barefoot running in his bestseller Born to Run, and the tide was starting to turn in barefooters’ favor.
The scientists analyzed the foot strikes of a group of lifelong barefoot Kenyan runners and noticed that they landed on their forefeet, rather than their heels. “Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners,” the researchers concluded. (The below video shows a shoe-less forefoot-striker.)
If humans had evolved to land on the forefoot rather than the heel, then using traditional running shoes—which tend to reinforce rear-foot running—was definitely not the way to go anymore. Soon bare feet were everywhere. In a 2011 article in the New York Times Sunday magazine, McDougall reported that barefoot shoes had skyrocketed into a $1.7 billion industry.
But to a group of researchers at George Washington University, this whole barefooting phenomenon, and the fact that an entire industry had sprung up around a single study of a single group of runners, didn’t sit well. They decided to conduct their own study using a different set of Kenyan runners.
Of the Harvard study, they wrote, “[T]his research was conducted on a single population and we know little about variation in running form among habitually barefoot people, including the effects of running speed, which has been shown to affect strike patterns in shod runners.”
The new GW study was published last week in the journal PLos ONE, and the results contradict the central piece of now-conventional wisdom about barefoot running established in the Harvard study — namely that habitual barefoot runners don’t land on the rear foot.
The researchers had 38 volunteers run down a hard-packed track with a pressure sensor located midway down the route. Each runner crossed the pad at least three times at a their own endurance pace, and then at least three more times at a faster sprint pace. The results showed that the majority of barefoot runners in the GW study were actually rear-foot strikers.
“Our results indicate that not all habitually unshod people prefer a [forefoot strike] or [midfoot strike] at their preferred endurance running speeds,” the scientists wrote.
Yet some of their other findings were in line with the previous research. “Our data support the hypothesis that a forefoot strike reduces impact loading,” they noted in the study. But, they added, that doesn’t really matter when it comes to long distances. “[T]he majority of subjects instead used a rearfoot strike at endurance running speeds.”
Where does this leave the barefoot converts among us? Probably exactly where we were two weeks ago. The GW study doesn’t claim to be definitive. “It is not clear which experimental sample, if either, represents a better ‘model’ for the distances and frequencies of running in early humans,” the researchers wrote. No doubt the debate will rage on anew.