There's nothing more devastating to an avid exerciser than having to stop his or her routine to let an injury heal.

So many times, people won't stop. Paul Mossa, a personal trainer with the Cooper Fitness Center in Dallas, says a good percentage of the people he treats after an injury "have a very hard time not working out." Sure, there are some clients who use their pain "as kind of an excuse for them to stop working out," but in his experience, they're in the minority.

One way he helps devotees get back in the game is through Greg Roskopf's Muscle Activation Techniques (MAT).

"It works on muscles and muscular imbalance, which is probably about 80 percent of what people's injuries are from," says Mr. Mossa, one of about 70 people in the country who are certified to perform MAT.

How it works: Mr. Mossa first checks the patient's range of motion to determine if the muscles are tight or weak. He then tests the muscle for strength, and afterward performs manual therapy on the problem area. The treatment includes "muscle palpation," similar to massage, which works the soft tissues to stimulate the muscles to become stronger.

The cost of treatment begins at $100 for the first hour, Mr. Mossa says, adding that one of his clients had tremendous back pain before MAT, but recovered after three or four sessions.

"It doesn't happen with every single person," he adds, "but we can eliminate a majority of people's pain."

But patients also must be willing to let the injury heal, he says: "If they let it rest, it's going to get better 10 times faster."

Still, it can be an active form of rest, says Ken Locker, a certified athletic trainer at Presbyterian Hospital in Dallas. "Say you're an active jogger and you're in a car wreck and hurt your knee. It doesn't mean you can't lift upper-body weights, or use an upper-body bike, or get in the pool and do the American crawl. Active rest is exercising the other parts of the body and giving the injured part a break."

That's what the pros do, adds Mr. Locker, who once helped train the Cowboys.