Beyond the tree-lined, narrow gravel road that leads to the weathered stable, a 9-year-old girl mounts a black horse. Her small, gentle hands quickly brush his hay-like hair.

To those who don't know her, Nicole Fini is just a child atop a horse, a common scene here, where the silence is pervasive, save the occasional whinny of the animals or the twitter of the children. It is where these children come once a week for what would otherwise take place in a sterile hospital room.

But the physical therapy they receive from the equestrian activities at Rainbow Center in Prince William County repairs the emotions and minds of children with disabilities, those who harbor negative self-images, who think they are anything less than normal.

"This type of therapy is out to give them a sense of well-being and self-confidence, and there's definitely the therapeutic benefits, too," said Bob Fini, Nicole's father.

Eight months after Nicole was born, a doctor diagnosed the Manassas youth with cerebral palsy.

"And we began her on physical therapy right away, even before we knew for sure," said Beth Fini, her mother. "This has been a really, really great thing for Nicole. Emotionally, it's been wonderful, as well as physically."

For Nicole, and hundreds like her with physical impairments or mental and emotional setbacks, Rainbow Center is the best thing about the necessary daily and weekly therapy sessions they must receive. The Catharpin center has logged more than 35,000 hours of therapeutic riding instruction and hippotherapy since its founding in 1985.

"I like it best because I've got a horse with me," said Nicole, who has been a student at Rainbow Center since she was 3. "I'm a lot more familiar with them now."

Rainbow Center, which operates under the auspices of the North American Riding for the Handicapped Association, offers three equestrian programs: hippotherapy, in which the movement of the horse affects the action and reaction of the student; therapeutic riding, in which the action of the student affects the movement of the horse; and therapeutic driving, in which the student uses an adapted driving cart to facilitate the same therapy to affect the movement of the horse.

Hippotherapy has been used as a form of treatment in Europe, particularly Germany and Switzerland, for more than 15 years. In hippotherapy, the action of the horse, coupled with traditional therapy, strengthens muscle tone and muscle action.

"It's really about patterning," said Trish Redmond, Rainbow's program director. "The horse is the only creature that mimics man stride for stride, so, for instance, with hippotherapy, if you have a child who has difficulty balancing, then you can teach them with the horse moving forward in a rolling motion and then hopefully build that response for the children.

"With therapeutic riding, what you're really doing is taking riding lessons and adapting them to a child's needs," she said.

The center, on 20 acres of leased land, has a three-year waiting list. Because of local advertising, the program has become too popular and there just aren't enough instructors, trainers, horses, acres and hours of sunlight to accommodate all those who wish to attend, Bob Fini said.

A new center, to be built on 44 acres in Nokesville in a couple of years for about $2.5 million, will ease the problems. The new center, for which Rainbow is still raising funds, will allow about 200 students to participate in the program, which now accommodates only about 30 to 50 Prince William residents each session, held twice a week.

Also, the new center will be open year-round. An indoor, year-round arena will be part of the future center, along with far more sessions. Thursday was Rainbow's last day of therapy sessions before closing for the winter.

"Because we're a seasonal place, we're limited in the number of instructors we have, and to attract really qualified instructors, most are going to want full-time or year-round employment," said Fini, who serves as vice president of Rainbow Center, a nonprofit organization. "It's hard to attract those when they can only work one day a week in the warm weather."

Rainbow Center relies on public and private funding, including about $17,000 annually from Prince William, other government grants, donations and fund-raising. It also charges tuition of $129 to $180 for six one-hour lessons. It has about 100 volunteers who feed and groom the horses and help students ride.

Last year, more than 26,000 volunteer hours were logged for the two sessions per week, the equivalent of 13 full-time employees, according to a Rainbow Center brochure. That resulted in 762 hours of therapeutic riding instruction to 50 students and nearly 100 hours of hippotherapy treatments to 11 students.

"We really want to have that year-round operation because we'll have dramatically more clients, and to do that we have to grow as an organization," Fini said. "And then we'll be able to have considerably more volunteers."

The volunteers have varied backgrounds. Peg Siegenthaler works as a hippotherapist on Saturdays and a physical therapist for Prince William during the week. Jane Wilson trains guiding eye dogs for a living. Jane Steele, a full-time physical therapist assistant, said she would volunteer full time if she could.

"It's just so rewarding, to see what I see," Steele said.

It is what Redmond calls "indescribable."

"I don't know how many times I've heard parents say to me, 'I never thought my child could do this,' " she said. "There's just this avenue of therapy, emotional or physical or both, and it's unique in that. And the kids have fun."

And the emotional, self-esteem rewards are beyond anything initially imagined, Beth Fini said.

"This is Nicole's activity; it's something she can really call her own," she said. "She has a sister who dances and another who sings, and this is what she does to make her feel better about herself."

On Thursday, Nicole sat atop King, her black beauty. Together they performed exercises that stretched Nicole's legs and muscles. After 30 minutes, she slid off King's back and into the arms of Bill Mills, a retired Marine who volunteers at the center.

"That's my girl," he said, carrying her over to her mother's minivan.

The instructors packed the place away. The afternoon sun glinted on King's back as he was led back to his stall. Mills, clad in boots, bluejeans and a denim shirt with a handkerchief wrapped around his neck, walked over to a white plastic chair and, removing his cowboy hat, sat down. He breathed deeply.

"Really, what it is, is that I love to see them grow older and do as well as they do. It's just the most rewarding thing."