When you're a veteran of 15 half-marathons and six marathons, running through discomfort is familiar territory. So when Shirley Cornelius, 43, of Spokane, Washington, developed a painful tightness in her glutes, she didn't stop training--even when her stride began to shorten, her knees started to hurt, and her right leg felt numb. New shoes and orthotics didn't help, nor did six months of physical therapy. Desperate to get better, Cornelius turned to Active Release Techniques (ART), a rigorous and interactive form of massage therapy in which a practitioner applies pressure to the affected area while moving the surrounding muscles through a full range of motion.

Cornelius's breakthrough came when Kelli Pearson, an ART practitioner and chiropractor in Spokane, discovered that both of the runner's sacroiliac joints (which lie between the spine and the pelvis) were "locked up," meaning their range of motion was very restricted. She used her hands to search the muscles for "adhesions"--places where injury, repetitive motion, and inflammation had left dense, tight scar tissue. Pearson pressed into the scar tissue, and ran her hand along it in one direction as she instructed Cornelius to move her legs through a proscribed set of motions, including moving each leg forward and back. The next day, Cornelius was sore. The day after that, she felt better. And by the time her next half-marathon rolled around, the pain was gone. "After three months of weekly sessions, I'm 100 percent better," she says. "The difference is amazing."

While ART, which Colorado chiropractor Michael Leahy patented in 1988, remains virtually unknown to the general public, many elite athletes rely on it to heal their soft-tissue injuries. The NFL, NHL, and Major League Baseball have begun contracting ART practitioners to keep players healthy; ART booths are popping up at marathons and triathlons; and Olympic runners, such as Marla Runyon, credit ART for helping them recover from injuries such as plantar fasciitis.

At first glance, ART might appear similar to a standard massage. A key difference is the direction of the rubdown, says Bill Ross, M.D., a sports medicine specialist at St. Francis Memorial Hospital in San Francisco. "Other kinds of deep-tissue massage move in any direction," Dr. Ross says. "ART lengthens the tissue in the same direction as muscle fibers naturally move. That's what stretches out the adhesions and causes healing."

Being "active" also sets ART apart. You participate in an ART session by moving your limbs to help release tension. Unlike most forms of massage therapy and chiropractic care, ART isn't designed to be an ongoing treatment or preventive tool?it's done to heal a specific injury. The average recovery requires six to 10 sessions, though some patients feel an immediate change.

A key to ART's apparent success might lie in Leahy himself, a triathlete who has completed 31 Ironmans. His background as a chiropractor and an aeronautical engineer gives Leahy a unique understanding of the complexity of the soft-tissue system of muscles, tendons, ligaments, and fascia (overlying sheets of connective tissue). "You need to make the layers of tissue slide over one another in order to function correctly," says Leahy. "They all have to slide directionally or the runner feels weakness and tightness. ART has 500 specific protocols to address the ways these tissues slide across each other."

Learning these protocols takes three days of hands-on training and about $2,000. ART certification is open to all licensed healthcare providers, including physical therapists, massage therapists, and trainers. There are about 3,500 certified practitioners worldwide. If performed by a chiropractor or physical therapist, insurance will often cover the cost of treatment, which ranges from $50 to $100 a session.

Before you start looking for an ART therapist near you, know that so far, there's been only one published study on the method's efficacy. The research, published in 1998, was done at the University of California at San Diego, and found that 71 percent of patients reported improvement after four weeks of ART treatment. But only seven percent said their pain was completely gone, and the study wasn't randomized, nor did it use a control group--two precursors for scientific proof.

A random, controlled study with patients reporting their pain and functional levels would help scientifically back up what the anecdotal evidence on ART is suggesting. Such a study is planned for late this year at UC San Diego.

But seeing is believing, even for an M.D. like Dr. Ross. "I know that it works," he says. "ART is more effective for chronic inflammation than any other treatment available--and often a complete cure. I've been treating these problems for 25 years, and now I finally have something to recommend to my patients that works."