Harvard University /Barefoot Runners Avoid Impact

By Carolyn Y. Johnson, Globe Staff

We were born to run, but maybe not with shoes.

New research led by Harvard scientists shows that people who run barefoot or with minimal shoes -- as people have done for millions of years -- often land on their feet in a way that avoids a jarring impact.

Bare feet slamming down on all kinds of terrain without cushioned soles or arch support may seem like it would be hard on the body. But the new work, published online today in the scientific journal Nature, finds that the way the majority of people run in shoes -- striking heel first -- is not gentle at all.

"It's as if every time you land on the ground, someone hits you on the heel with a hammer," said Daniel E. Lieberman, a professor of human evolutionary biology at Harvard University, who studies the biomechanics of running in the lab -- and himself runs with minimal or no shoes. "It's an amazing thing. Running barefoot can be less impactful."

Instead of striking heel-first, barefoot runners tend to land on the ball or middle of their foot. Researchers need to do followup studies to test whether less impact translates into fewer injuries, but the new finding may become yet another example of the way in which evolution has made humans ill-equipped to handle some of the luxuries of modern life. Millions of years of evolution created humans best adapted to an environment lacking recent inventions such as desk jobs, video games, abundant processed foods, and -- perhaps -- the modern running shoe.

Several scientists not involved in the research said the findings were intriguing, but that the critical next step will be to test whether landing differently decreases injuries.

"I think the contentious part will be whether wearing shoes and changing the pattern of running...actually has an impact on foot injury," said Brian Richmond, an anthropologist at George Washington University. "It's an idea worth examining, because basically what they found is how people would run in a more natural setting."

The new work builds on Lieberman's longstanding interest in humans' ability to run long distances. While walking on two feet is often seen as a hallmark of human evolution, so is endurance running, argues Lieberman, who has previously found fossil evidence of numerous skeletal traits adapted for running. But if humans have been running for more than a million years, what did they do before the running shoe came about in the 1970s?

Now, by studying runners in the US and Kenya who normally run barefoot and comparing them with people who run with shoes, he and an international team of researchers have detailed the differences. Lieberman's lab receives support from Vibram, a company that makes FiveFingers, minimal shoes that look like gloves for feet.

The vast majority of shoe-wearing runners strike the ground with their heel first, experiencing an initial collision with an impact two to three times their body weight. Shoes slow the collision, but barefoot runners avoid it by landing on their forefoot or midfoot with a more springy step.

"If it's true this kind of running could reduce stress injuries, that can help people," Lieberman said. "We can use evolutionary principles -- evolutionary medicine -- to help people run in a way that's less injurious."

That possibility still has to be tested, but many barefoot runners report anecdotally that shedding shoes helped with injuries.

Jeffrey Ferris, a Jamaica Plain resident, said he got his first taste of barefoot running four decades ago, during cross-country practice in high school in Coronado, Calif. In his 20s, he found himself dealing with knee problems that forced him to give up running until he accidentally discovered that when he ran barefoot his knees didn't hurt.

"It's fun, it's tactile, it's stimulating," Ferris said. "I run faster, it protects the knees and the joints, it's different. It kind of matches the notion that our body evolved to work as a runner ... that's really how the body is made to work."

Ferris now runs barefoot regularly and was an early research subject for Lieberman. While he has tried minimal shoes designed to mimic being shoeless, he prefers to protect his feet against cold or abrasive conditions by wearing socks with a protective layer of duct tape.

Benno Nigg, co-director of the Human Performance Lab at the University of Calgary, said that barefoot running seems to emerge as a fad on a regular basis. It got a lot of attention in 1960, when Abebe Bikila won the Olympic Marathon in a record time running barefoot. In 1985, South African Zola Budd broke the world record in the women's 5000 meters barefoot. The current interest is driven in large part by the 2009 book, "Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Ever Seen," which tells the story of a Mexican tribe who run long distances without running shoes.

Sean Murphy, manager of advanced project engineering at New Balance, said that for the past year the company has been testing some of the ideas of barefoot running in its biomechanics lab. The company is integrating what it is learning into products, but also has found that "barefoot or close to barefoot condition is not for everyone," Murphy said.

People who want to go barefoot or land in a different way should proceed cautiously, Lieberman stressed. Runners should transition gradually, because calf and foot muscles will need to build up to avoid injury. More information is available at barefootrunning.fas.harvard.edu.

Four-time Boston Marathon winner Bill Rodgers said that he tends to land on his forefoot, though he runs in shoes. He thinks people should use the shoe or stride that works for them.

"I am in favor of people becoming fit and I believe running and walking are the ultimate ways to do that -- I believe we are meant to move," Rodgers said. "Everybody's biodynamics are a little different."