Scientists studying barefoot runners have found that there are biomechanical advantages to leaving your shoes at home. But if you decide to try jogging with nothing between your feet and the ground, you should ease into it and retrain your running style. Otherwise, if you overdo barefoot running, you may increase your chance of injury.
“People who don’t wear shoes when they run have an astonishingly different (foot) strike,” says Daniel E. Lieberman, professor of human evolutionary biology at Harvard University and co-author of a paper about barefoot running. “By landing on the middle or front of the foot, barefoot runners have almost no impact collision, much less than most shod runners generate when they heel-strike. Most people today think barefoot running is dangerous and hurts, but actually you can run barefoot on the world’s hardest surfaces without the slightest discomfort and pain. All you need is a few calluses to avoid roughing up the skin of the foot. Further, it might be less injurious than the way some people run in shoes.”
Working with populations of runners in the United States and Kenya, Lieberman and colleagues at Harvard, the University of Glasgow and Moi University looked at the running gaits of three groups: those who had always run barefoot, those who had always worn shoes and those who had converted to barefoot running from shod running. The researchers found an interesting pattern.
Most shod runners — more than 75 percent of Americans who run — heel-strike, experiencing a very large and sudden collision force about 1,000 times per mile run. People who run barefoot, however, tend to land with a springy step towards the middle or front of the foot.
“Heel-striking is painful when barefoot or in minimal shoes because it causes a large collisional force each time a foot lands on the ground,” says researcher Madhusudhan Venkadesan. “Barefoot runners point their toes more at landing, avoiding this collision by decreasing the effective mass of the foot that comes to a sudden stop when you land, and by having a more compliant, or springy, leg.”
“Our feet were made in part for running,” Lieberman says. But as he and his co-authors write in the journal Nature: “Humans have engaged in endurance running for millions of years, 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.”
For modern humans who have grown up wearing shoes, barefoot or minimal shoe running is something to be eased into, warns Lieberman. Modern running shoes are designed to make heel-striking easy and comfortable. The padded heel cushions the force of the impact, making heel-striking less punishing.
“Running barefoot or in minimal shoes is fun but uses different muscles,” says Lieberman. “If you’ve been a heel-striker all your life you have to transition slowly to build strength in your calf and foot muscles.”