New research has backed up the findings of another study we covered recently on Gizmag which found the average modern running shoe causes significant damage to the knees, hips and ankles compared to running barefoot. The new study found that people who run barefoot land on the ball or middle of the foot. This mitigates the potentially damaging impacts that can be equivalent to two or three times their body weight that shoe-wearing runners, who generally land on their heels, subject their bodies to.

“People who don’t wear shoes when they run have an astonishingly different strike,” Daniel E. Lieberman, professor of human evolutionary biology at Harvard University and co-author of a paper told the Harvard Gazette. “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”.

According to Lieberman running barefoot can allow runners to run on the world’s hardest surfaces without the slightest discomfort or pain. That is, once they’ve toughened up the soles of the foot with a few calluses.

The research team comprising scientists from Harvard, the University of Glasgow, and Moi University in Kenya worked with runners in the US and Kenya, looking 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.

It found that most shod runners struck the running surface with their heels, which resulted in a very large and sudden collision force about 1,000 times per mile run. In contrast, those who ran barefoot tended to land on the middle or ball of their foot with a springy step that alleviated the collision force, thanks to some clever Newtonian physics.

“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,” said study co-author Madhusudhan Venkadesan, a postdoctoral researcher in applied mathematics and human evolutionary biology at Harvard.

While the modern running shoe wasn’t invented until the 1970s, barefoot runners are now benefiting from millions of years of evolution. According to Lieberman, our early Australopith ancestors had less-developed arches in their feet. Homo sapiens, by contrast, have evolved a strong, large arch that we use as a spring when running.

But for runners who have grown up with footwear and are looking to throw away their running shoes and go barefoot, Lieberman warns it is something to be eased into. Because modern running shoes are designed with padded heel cushions to lessen the impact of heel-striking, runners switching too quickly could subject themselves to much greater impacts. Since running barefoot uses different muscles, runners need to transition slowly to build up strength in their foot and calf muscles as they change their running style, he states.

The team’s study, “Foot strike patterns and collision forces in habitually barefoot versus shod runners,” appears in the journal Nature.