When Joan Krauthammer of Potomac first heard about horseback riding for the handicapped in 1978, she thought to herself, "Well, here's one thing Jeffrey will never be able to do."

Her son, then 6 years old, was a victim of spina bifida, in which the spine fails to close completely at birth. It left his lower body virtually paralyzed. Jeffrey's legs did not bend--"not even a drop"--at the knees.

But Judy McGaughan, owner of Riding for the Handicapped Foundation Inc. in Clarksburg, was not so easily put off. Telling the Krauthammers to "just come and let us worry about it," she bought a bareback pad--Jeffery couldn't fit over a saddle--trained three volunteers to help him and started weekly riding lessons.

A year later, Jeffrey's legs began to bend, and the year after that he'd gained so much flexibility he was able to ride on a saddle. Today, at age 11, he walks with crutches or a walker, his mother said, "and here he is, still trotting around the ring."

"We can't be sure it was all due to horseback riding," she added. "But we really do attribute a lot of the movement to it. We were told his one knee would never bend and the other maybe a little. Now his legs bend so much he can put his feet in the stirrups."

At first, Jeffrey said, he was "kinda scared" when he was put on the horse, but now "sometimes I trot and sometimes I just walk." The best part, he said, is "the end--when we get the prize ribbons."

McGaughan, who teaches horseback skills to about 100 handicapped children from Montgomery and Frederick counties each week, said Jeffrey's victory with horses is one of many she has witnessed in the past six and a half years. She teaches riding to children with every kind of handicap, from severe physical and mental disabilities to emotional and learning problems.

There are five such programs in Maryland and about 225 in the nation. Among them is a large riding school for the handicapped in Upper Marlboro, Program for Equestrian Therapy, run by the 4-H, and another in Columbia called the Maryland Therapeutic Horsemanship Association.

"Recreational therapy is a new field of study in many schools," McGaughan said. "We don't do physical therapy as such, but we do have therapeutic procedures that we use. Being on horseback does a great deal for posture. It aligns your body."

She said a physical therapist goes to the school and recommends additional exercises.

Riding also "pushes the kids to do a little more than they ever thought they could," she said.

There was, for example, a group of active autistic teen-agers from the Montgomery County Association for Autistic Adolescents who "all weigh 175 plus," she said. "The first time I saw them I thought, 'What am I going to do with these kids?'

"One of them was literally in the dirt, just groveling. The first thing was to get him out. You wouldn't believe the minute little steps we do. But you can just see the progress being made. Eventually, there's something they care about."

The first step usually is not to get the child to ride the horse but only to touch it, to brush it. "Some are fearful, especially the retarded and the autistic," McGaughan said. But in time they adjust, and then--with the help of volunteers, who are the mainstay of the program--they begin to ride.

"For each physically handicapped child, we have three volunteers--one at the head of the horse and two on either side. Then we wean some of the volunteers away."

In the case of severely handicapped children like Jeffrey Krauthammer, the two side walkers are eventually reduced to one; more able-bodied children ride alone, McGaughan said.

But often the progress is subtle, she added: "One boy, one of the most severely disabled we have, has . . . an unusual syndrome: His arms stop at the elbows and he has two little thumbs. He's hearing impaired and visually impaired. He's 12 years old and weighs 36 pounds. "Basically, what we're doing--we're giving him pleasure. And at the same time he's learning to do things. We don't let the pony move forward unless he holds the reins."

For learning-disabled children, the rewards are as much psychological as physical.

"They look normal but a lot of them have great difficulty controlling themselves in a situation," McGaughan said. "Here they learn to control something else. And some of the kids--just their relationship to the horse. It's wonderful just to hear them talk to the horse."

Two of McGaughan's most advanced students, Michael Minnik, 17, who says riding is "my main hobby," and David Glick, 22, both Down's syndrome victims from Frederick, have learned to ride so well they handle the horses themselves and are learning simple jumps. Last spring, Glick placed first and Minnik was second in a competition for handicapped riders in Pennsylvania.

"What that didn't do for their egos!" McGaughan said. She said she believes the self-confidence gained from riding "carries over into other fields."

Today, Glick, who does janitorial work for a fast-food chain, proudly pays for his own lessons, and Minnik will work with the horses in the barn this summer--a job that McGaughan said may become full time when he finishes school.

But the increased skills that give her students their biggest lift are also a source of worry to McGaughan: "This is our seventh year and some of our kids are ready to take more risk," she said.

"You know how scary it is to let any child take a risk but a physically handicapped child . . . . We have to know if a handicapped kid falls, he won't be any more likely to hurt himself than anybody else would."

So far, she said, there have been no serious injuries, although insurance is her second biggest expense.

McGaughan's decision to become a riding therapist grew from a horse-oriented life style and a degree in psychology and special education.

McGaughan's three children grew up active in pony clubs, which teach horsemanship to youngsters across the nation, and she kept horses on the family property, Banbury Cross Farm, on the border of Montgomery and Frederick counties.

So in 1977, when she decided horseback therapy "might be the nicest way to use my skills," she built an indoor arena next to the barn, had one of her husband's business associates design a hydraulic lift that could raise students in wheelchairs to horseback level and established her nonprofit organization.

"I had the place, I had the ponies, I had the tack," she said. "All I had to find were the clients and the volunteers."

Some of her first clients came from Chestnut Lodge, a psychiatric hospital in Rockville where McGaughan had done an internship and had contacts. "Then the Montgomery County Department of Recreation got hold of me. That's what really got us started," she said.

Today, classes come from the Recreation Department, the Jewish Community Center and Montgomery and Frederick schools for the handicapped. McGaughan said she subsidizes the operation, estimating it costs her a minimum of $10 a lesson to feed the horses and for special equipment.

But "if an organization is not getting money, we don't charge. And parents are never charged unless the child wants to go into a more advanced program."

McGaughan owns five horses and ponies and hopes the foundation this year can afford to feed the horses on its own.

She finances the operation through horse show benefits; sales of Christmas ornaments at the International Horse Show at the Capital Centre; and an annual ride-a-thon, in which handicapped, as well as able-bodied students, participate, followed by a picnic and a balloon launch.

One reason McGaughan believes she has to work so hard for money to support the program--even though she does mail solicitation "and we beg"--is that "horseback riding for the handicapped is so far out, it's hard to convince people to contribute."

More important, she said, is keeping enough volunteers to run the program. There are about 64 now.