If you spend in the neighborhood of $100 per pair of running shoes like I do, you may find the following statement by Dr. Daniel Lieberman, a professor of biological anthropology at Harvard University, disconcerting:

“A lot of foot and knee injuries that are currently plaguing us are actually caused by people running with shoes that actually make our feet weak, cause us to over-pronate, give us knee problems,” says Lieberman in Born To Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen, a book by Christopher McDougall.

“Until 1972, when the modern athletic shoe was invented by Nike, people ran in very thin-soled shoes, had strong feet, and had much lower incidence of knee injuries.”

Lieberman’s study and McDougall’s book are fueling a debate within running circles (and shoe companies). Are running shoes not only not helping us, but actually hurting us? Is running barefoot safer?

“We were born to run, but maybe not with shoes on,” says The Boston Globe. “New research … 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. That’s very different from most shoe-clad runners, who crash down on their heels with every bound.”

Or as Popular Mechanics asks, “Could shoes — and shoe companies — be part of a $25 billion snake oil industry, covering hundreds of thousands of perfectly able bare feet?”

Lieberman explains on his study’s web site that “runners who forefoot or midfoot strike do not need shoes with elevated cushioned heels to cope with these sudden, high transient forces that occur when you land on the ground.”

McDougall isn’t quite so gentle. One full chapter of his book is an indictment of Nike and other running shoe manufacturers that he believes know their shoes are causing injury and continue to sell them anyway.

At least one shoe company, New Balance, addresses the issue head on: “After hundreds of years of walking with shoes on, is it time we relearn? There’s a movement going on that challenges the very foundation of sneaker wearers (not to mention sneaker companies) everywhere, around running barefoot. This broad grouping of perspectives includes some runners who are finding they prefer to run exclusively barefoot, some who prefer to run with minimally cushioned shoes, and others who like to vary their runs between shod, minimally shod, and shoeless.”

Nike, the inventor of the modern high-tech, highly engineered running shoe, doesn’t miss a trick. Or a marketing niche. It has introduced a new shoe, Nike Free, that for all the world looks like the flat-soled Keds, PF Flyers, and Chuck Taylor All Stars I wore as a kid. The Nike Free slogan? “Run Supernatural.” Back to the future, I guess.

In his book, McDougall builds the case that humans are built — not to run fast — but to run long. He tracks down and studies the mythical Tarahumara Indians who run for extreme distances in lightweight sandals in the remote and deadly Copper Canyons of Mexico.

And he’s a convert. Since running in Vibram FiveFingers, a neoprene sock-like foot covering, he’s seen his running injuries disappear.

Though I’m not quite ready to hit the pavement barefoot, especially in the winter, the idea of lacing up the old Chucks from high school is kind of appealing. As I remember, I was faster back then.

How about you?