We called her barefoot Bonnie. She showed up at a training run in Earth Shoes and clobbered most of the guys. Then she ditched even that minimal footwear for a summer on the track, beating several of the local elites. At the time, less than two years ago, most people didn't even know it was permitted to race without shoes. Today, we're in a minimalist running craze. The untraditionally shod are, if not everywhere, vociferous enough that they certainly seem to be. Is there anything actually to it, or is it just noise, inspired by Born to Run, Christopher McDougall's New York Times bestseller about the sandal-wearing ultramarathoners among Mexico's Tarahumara Indians?

Proponents of minimalism speak with the zeal of the recently converted. Opponents spout dire warnings: you'll ruin your arches, step on an HIV-contaminated needle, pound your feet to hamburger. "If you talked to people in podiatry a decade ago, nobody would have said that barefoot activity had any benefit," says Ray McClanahan, a Portland, Ore., podiatrist. "But now, a few people are starting to say it might be good for you."

Away from the hype and the extremes, the minimalist movement is rightly correcting decades of drifting in the other direction when it comes to running shoe design. At its core, minimalism asks the runner to look for the least amount of shoe he or she can safely wear now, and to work toward reducing the amount of shoe necessary through strengthening the foot and improving one's stride. It assumes that running is a natural movement of the body, rather than an unnatural act that requires pads and braces to perform safely. Putting it plainly, the movement embraces the notion that the beefier the shoe, the more a runner's natural stride is inhibited.

After 30 years of making shoes with large amounts of cushy foam and structured stability, shoe companies have gradually gotten into the act -- starting with Nike's Free in 2004. Although most brands have always had some type of lightweight trainer or racer in their line, this spring many manufacturers are offering some type of shoe specifically designed to promote a natural running gait. "More people are shifting toward this type of product, or at least trying it," says Sean Murphy, manager of advanced products engineering and sports research for New Balance. "I think this movement is going to start to affect even the training shoes you see on the wall [in running stores]."

In fact, Murphy says, we may be on the verge of a sea change similar to the one that spawned today's "traditional" shoe in the late 1970s and early '80s.