The facts on backs. (Health and Fitness For Life).

TODAY IS A GOOD DAY FOR PRINCIPAL dancer Muriel Maffre. Her lower back isn't giving her too much trouble. She's able to move with good range of motion and extension during her classes and rehearsals with the San Francisco Ballet. That isn't always the case, though. On the bad days, her muscles spasm and the pain kicks in.

Next to the foot and ankle, the back is the sore spot for dancers. Back injuries "are a human condition," says physical therapist Michael Leslie of the San Francisco Ballet.

Getting educated is the critical first step. The spine is divided into the cervical, thoracic, and lumbar areas. Discs are pads of cartilage between vertebrae that act like cushions. Dancers typically have problems in the lower (lumbar) back, though sometimes the middle (thoracic) back can get into trouble.

Which back injuries sideline dancers often turns on age. Strains and sprains in the ligaments of the lower back often plague dancers in their early to mid-20s, Leslie says. In their mid- to late 20s their discs may start to degenerate. That can continue into their mid-30s, when their joints may start to go. Overuse contributes to many lower back problems. But body wear and tear also has to do with the demands of different styles of dance. In the United States, ballet companies offer a mix of styles that require different motor patterns. Dancing a variety of styles all in one night may put more strain on the lower back, Leslie says.

Other rimes, dancers push their bodies beyond what they are prepared to do, says Boyd Bender, physical therapist for the Pacific Northwest Ballet in Seattle. Experienced dancers, he notes, can often spot subtle problems, like the feeling of being off balance. Certain red flags--like stiffness on only one side--can tip physical therapists to trouble in a dancer's lower back, Leslie says.

Bender says dancers tend to be hypermobile in certain parts of the lower back. (Proper training and awareness of body position helps minimize stresses dancers put on their lower backs, especially from movements like arabesque.) But think of an ankle that has been sprained; over time, it becomes looser. Similarly, discs, ligaments, and the tissues surrounding the joints can become irritated and very painful. That, in turn, can affect the tone of the muscles and cause pain. Sometimes if a dancer has stiff hips, the body will compensate for that by using the back more.

Some injuries (like disc protrusions) are severe enough to require surgery. If not, physical therapists work closely with dancers to get them healthy again. Their treatments include stretching exercises, massage, and active release techniques to work the soft tissue and joints, and the familiar ice, heat, electrical stimulation, ultrasound, and taping.

Stretching is a mainstay. When Leslie works with dancers with low back problems, he often has them do the "swastika" stretch: sitting upright on the floor, in fourth position, with knees bent at ninety degrees. This move stretches the groin, or the "turn-in" muscles, which often get short shrift. To stretch the "turn-out" muscles in the hip joints, he has dancers lie on their backs with knees bent and feet on the floor, then place one ankle on the opposite thigh, reach under the supporting leg, and pull forward.

Another therapeutic stretch is the cobra pose, a fundamental yoga stretch. Leslie has dancers lie on their stomachs and gradually push up on their hands, working to extend their elbows while keeping the pelvis on the floor.

Strong abdominal muscles are critical to a strong lower back. Bender often instructs dancers to do modified curl-ups to work the deeper abdominal muscles. Other times, he puts them on a balance ball or wobble boards, which work their core muscles and promote balance and coordination.

Maffre, who was born with scoliosis, is no stranger to injury and cross-training. The 5' 10" dancer has always been extremely limber, which she says may have made her more susceptible to back injuries. Five years ago she had problems with hypermobility in the sacroiliac joint at the base of her spine. She received sugar-based injections, which created scar tissue to stabilize the joint.

For eight years, Maffre, 35, has coped with the degeneration of the joints in her lower back. The moment she arches her back, she's in pain. She works with a physical therapist twice a week, but she won't take painkillers. "I would rather feel my body and the pain as it is and deal with that," she says.

To cope, Maffre has changed how she trains and dances. She dances six days a week and on the seventh day, she goes to the gym or does some nonballet activity, like power-walking. She stretches for half an hour before classes, rehearsals, and on her days off. She'll start with the cat stretch, followed by lunges and hip stretches. When she does arabesque, she lifts and lengthens her torso to create room for her vertebrae and relieve pressure on her spine. She's learned to use her abdominal muscles more instead of relying solely on the flexibility of her spine.

"If I had had a better understanding sooner of how much length and strength I needed in my body, I probably could have prevented it," Maffre says. "The injury has helped me develop my dancing--the quality of being more in length, in control, and more aware."

Rhoda Fukushima covers health and fitness for the St. Paul Pioneer Press. Her work is circulated in the Midwest by Knight Ridder.