Do you ever wonder how dancers perform such seemingly impossible feats as bending backwards while balanced on one toe or leaping so high they appear to hand in mid-air?

"The secret," says movement therapist Glenna Batson, "is often fantasy. Dancers who want to hold a precarious balance may pretend they've got strings attached to parts of their body, holding them up like a puppet.

"Or if they want one leg to make huge circles in the air they might imagine a laser beam shooting out of their big toe, slicing big holes in a far wall."

This type of imagery is at the root of Batson's work as a movement therapist, an emerging specialty that combines medical knowledge with the dancer's art to help people -- dancer or not -- eliminate chronic pain and injury.

"When you go to a doctor with an injury," she says, "they usually just deal with the symptoms. If you've got back pain, for example, you'll get hot packs and muscle relaxers.

"The pain goes away all right. But a few weeks later it's back again. That's because you've healed the symptom, but haven't cured the cause. So you set up a chronic pain-injury cycle that you'll stay trapped in unless you uncover why it's happening and correct it."

That's where the movement therapist comes in.

"I start by looking at the person's stance and alignment," says Batson. "No one's body is perfectly symmetrical, so I look for small anatomic imperfections -- like one shoulder lower than the other, or one leg shorter -- that can add up to big problems.

"Then I have them do a few preliminary diagnostic movements to see how their structure affects their movement. When I figure out what may be the source of the problem, I set up 'imagine work' to help them discover where they need to relax and release."

Batson, who holds several degrees in dance, spent three years working with a New York osteopath before accepting a position last fall as assitant professor at the University of Maryland.At the New York clinic she worked both with professional dancers, including the New York City Ballet's Patricia McBride, and with "weekend athletes."

"A lot of the injuries lay people experienced were due to weakness and lack of conditioning. Some were even breathing wrong -- sucking in their gut when they inhaled and expanding it when they exhaled.

"Back pain was often a result of standing improperly, hyper-extending the spine with the tail sticking out. Dropping the tail-bone, learning to sit and sleep properly (on the back or side) often ended the problem."

Batson learned about movement therapy in 1976 while trying to make it as a dancer in New York -- which included a stint as a belly dancer. "I tore some ligaments in the back of my pelvis," she recalls, "and the only advice doctors had was rest. That healed, but then I started getting horrible back pain.

"I went everywhere -- from orthopedists to chiropractors -- but they all treated the symptoms. Finally I heard about movement therapy and went to see one of the pioneers, a woman named Irene Dowd."

Dowd discovered that alignment problems were putting undue strain on Batson's back -- a problem that was exaggerated when she danced. Dowd gave Batson some images and exercises to use in correcting the problem. Within a few months the pain faded and never returned.

"It was amazing," Batson says, "like I had a new body. I discovered I had talent for creating the images that helped alter body movement, so I began studying movement therapy with Dowd."

Of the several techniques, practiced within the growing field, probably the best known, says Batson, are the Feldenkrais technique, developed by a former physicist from Israel, and the Alexander technique of "movement re-education."

Batson uses a lesser-known method called ideo-kinesis, which literally translates to imagined action. "It works on the same principle as biofeedback," she says. "Since the body and the mind are linked, you can imagine yourself moving in a certain way and you'll actually move that way.

"If you tell your back muscles to let go, they probably won't respond to that type of instruction. But if you try to imagine a sunburst radiating across your lower back, your muscles will release."

One small change in body alignment, she says, can affect the whole body. "It's like when you go to a psychotherapist and they introduce a new concept. You begin relating that idea to other aspects of life, and everything starts changing around you.

"One small shift in your posture, like relaxing your shoulders, can ease neck tension, headaches and make you move easier and appear taller."

Word of movement therapy is "slowly spreading," says Batson, "usually by word of mouth from people you've helped. If you work with a doctor, like I did in New York, patients are referred to you. Depending on the problem, the therapy may require biweekly sessions over the course of a month, or -- for professional dancers and athletes -- may be an ongoing process."