New Harvard research casts doubt on the old adage, “All you need to run is a pair of shoes.”

Scientists have found that people who run barefoot, or in minimal
footwear, tend to avoid “heel-striking,” and instead land on the ball
of the foot or the middle of the foot. In so doing, these runners use
the architecture of the foot and leg and some clever Newtonian physics
to avoid hurtful and potentially damaging impacts, equivalent to two to
three times body weight, that shod heel-strikers repeatedly experience.

“People who don’t wear shoes when they run have an astonishingly different strike,” said Daniel E. Lieberman, a professor in Harvard’s new department of human evolutionary biology and co-author of a paper appearing this week in the journal Nature.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.”

Here are videos of runners with and without shoes, and other extensive information about the findings.

And here’s a video interview with Daniel Lieberman, produced by Nature.

Working with populations of runners in the United States and Kenya,
Lieberman and his colleagues at Harvard, the University of Glasgow, and
Moi University in Kenya 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 a striking pattern.

Most shod runners — more than 75 percent of Americans — 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 toward 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,” said co-author Madhusudhan Venkadesan, a postdoctoral
researcher in applied mathematics and human evolutionary biology at
Harvard. “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.”

The differences between shod and unshod running have evolutionary
underpinnings. For example, said Lieberman, our early Australopith ancestors had less-developed arches in their feet. Homo sapiens, by contrast, has evolved a strong, large arch that we use as a spring when running.

“Our feet were made in part for running,” Lieberman said. But as he
and his co-authors write in 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, warned 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,” said 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.”

In the future, he hopes, the kind of work done in this paper can not
only investigate barefoot running but can provide insight into how to
better prevent the repetitive-stress injuries that afflict a high
percentage of runners today.

“Our hope is that an evolutionary medicine approach to running and
sports injury can help people run better for longer and feel better
while they do it,” said Lieberman.

The Nature paper arose out of the senior honors theses of two
Harvard undergraduates, William Werbel ’08 and Adam Daoud ‘09, both of
whom went to Africa with Lieberman to help collect data for this study.

Lieberman’s co-authors on the Nature paper are Venkadesan and Daoud
at Harvard; Werbel, now at the University of Michigan; Susan D’Andrea
of the Providence Veterans Affairs Medical Center in Providence; Irene
S. Davis of the University of Delaware; and Robert Ojiambo Mang’Eni and
Yannis Pitsiladis of Moi University in Kenya and the University of
Glasgow in Scotland.

The research was funded by the American School of Prehistoric Research, the Goelet Fund, Harvard University, and Vibram USA.