One of the most difficult running injuries to defeat is recurring plantar fascitis, a sometimes-crippling pain in the heel, traditionally associated with excessive forces on the plantar fascia, the strong ligament-like structure that helps provide curve to your arch.

Since the 1980s the search for solutions has focused on motion control, either in shoes or via orthotics. And for much of that time, Portland podiatrist Ray McClanahan lined up with tradition. "For 12 years," he says, "I did what everybody says. But it didn't cure that many people. People kept coming back for cortisone shots. People kept coming back for orthotic modifications." Meanwhile, he was suffering the same problem himself, and the treatments weren't working for him, either.

Then he read a 2003 study by Temple University podiatrist Harvey Lemont in the Journal of the American Podiatric Medical Association. Lamont had looked at tissue samples from 50 patients undergoing heel-spur surgery for chronic plantar fascitis. Like many, Lemont had been taught that plantar fascitis was the result of inflammation of the plantar fascia. "In fact," he wrote, "the suffix '-itis' inherently implies an inflammatory disease."

But that wasn't what he and his colleagues saw under the microscope. Not a single sample showed signs of inflammation. Rather, the tissues appeared to have been damaged from repeated micro-tears and associated cell death. Lemont concluded that this called into question the widespread treatment of plantar fascitis with cortisone shots and anti-inflamatories. If there's no inflammation, such treatments won't work.

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His conclusion: reduced blood supply caused by the fact that our feet aren't supposed to be shaped like modern running shoes. We certainly aren't born that way, he adds. "Both of my daughters' feet were widest at the ends of the toes, not at the balls of the feet." In addition, he notes that modern running shoes pull the toes upward, in the rocker-like sole bottoms that angle your toes upward into the air, even at rest.

All of this, he says, puts stress on muscles that help you wiggle your toes. That, in turn, pinches an underlying artery, impeding blood flow right in the vicinity of the region where plantar fascitis pain tends to occur. "So the junk never gets flushed out," McClanahan says.

By not realizing this, he argues, people have long treated the condition by focusing on the wrong parts of the foot, "instead of [doing] what they need to do, which is putting the toe back where nature meant it to be."

Richard A. Lovett Massage & Bodywork Magazine, Michael Young, a massage therapist from Evergreen, Colo., reported success in treating plantar fascitis by working on calf muscles linked to the foot and toes, including ones that McClanahan says are never truly allowed to relax in modern shoes.

McClanahan himself focuses on footwear, with a strongly minimalist bent. "I still do make some orthotics," he says, "but for 2 to 3 percent of my population, as opposed to 80 or 90 percent.

His goal is to get people running in shoes that allow their toes to spread naturally. Often, that means Crocs, though he also likes racing flats with slits cut in the forefoot to give the toes more wriggle room. And he's invented a device he calls Correct Toes, which looks oddly like a set of brass knuckles (for toes). But instead of being a weapon, it's made of a soft, gelatinous plastic whose purpose is to help toes that have been crushed for too many years into narrow toe boxes to spread naturally. Socks with toes, like those made by Injinji, create a similar effect.

"This fixed my problems," he says. "I haven't had knee or foot pain in five years. I'm running 70 miles a week, up to 30 on weekends."

One of McClanahan's patients is Julie Thomas, a masters runner who suffered recurring bouts of plantar fascitis until she let McClanahan put her in Crocs, four years ago. Since then, she's taken up ultramarathoning, including her first 50-miler, last year, all without a recurrence.

"I haven't had a really big flare up since 2006," she says. "I can't even fathom going back to shoe with a high heel or a lot of cushioning."