Five years ago, Angie Stewart, a Los Angeles-based personal trainer, suffered from iliotibial band (ITB) pain so severe she couldn't run longer than 40 minutes. "The outside of both of my legs would hurt to the point that I would have to sit down," says Stewart, who had been accustomed to logging 40 to 50 miles a week. "Once I even had to get someone to drive me home." For six months, she tried all the usual antidotes--icing, stretching, cutting her mileage, doing physical therapy, self-massaging with a foam roller. Nothing worked. Finally, Stewart tried yoga.

"I hated it at first," she says. "All I could think about while I was there was that I'd rather be running. I felt like I was wasting my time. I didn't see how something so noncompetitive and calming in nature could provide me with any athletic benefits."

But after two months of five sessions a week, Stewart says her ITB syndrome disappeared. And with the conviction of the converted, she founded Runner's Yoga 90210, where marathoners, beginner runners, and even members of UCLA's track team gather in Beverly Hills's Roxbury Park for a 20- to 30-minute run followed by 45 to 55 minutes of yoga in a nearby studio.