For many students, summer vacation means sleeping late, spending days at the pool or heading for the beach.

Lily Lee of Alexandria got up at 4:15 a.m. each weekday to go ice skating.

By 5:10 a.m., 12-year-old Lily was at the Fairfax Ice Arena, practicing jumps, spins, figure eights -- all the intricacies of figure skating.

She was one of more than 100 youngsters in an annual eight-week training program at the Fairfax Ice Arena. For most of them, it wasn't just a cool way to spend the summer, but part of a competitive career that may last for years.

Last fall, Lily placed second in the intermediate ladies' category in the South Atlantic Regional figure skating championships, and third in the Eastern championships.

Most skaters in the program started at the rink's group lesson program, which is offered year-round for beginning to experienced skaters. The group program opened about 10 years ago with about 200 students and now has about 1,000 youngsters. As the group program has grown, the summer training sessions have grown with it, said rink owner and manager Henry Weisiger.

"Every year we're turning out people who want to go higher and higher," he said.

Students in this year's summer program ranged from 6-year-olds just starting in competitive skating to 19-year-old Leslie Shackelford of Arlington, the rink's most advanced skater, who was the 1981 South Atlantic senior ladies' champion.

Students in the program got intensive instruction from the rink's 11 professional skaters. Older, more advanced skaters practiced about five hours a day Monday through Friday, and some put in a few hours at other rinks on weekends. Some of the younger skaters practiced 1 1/2 hours a day, while the youngest usually came in only two or three days a week.

In addition, many students took exercise classes two afternoons a week and trampoline classes another two days a week to help improve their skating skills and strengthen their muscles.

"All the people who are doing this have to really love it," said Weisiger's wife Audrey, a former junior ladies' national bronze medalist and a pro at the rink. "Otherwise, it's not worth it."

Each day was divided into 45-minute practice sessions to work on school figures, jumps, spins and freestyle routines.

Someone who wandered into the rink during a freestyle session was likely to see skaters in bright clothing racing around the ice, jumping, spinning -- and sometimes falling.

Ken Class, a former national silver medalist in the novice men's category and bronze medalist in the junior men's category, stood at rinkside filming one of his students, a young girl in a green dress, as she did a double-toe loop jump. To a casual observer, the jump may have looked perfect, but as teacher and student came off the ice to see an instant replay, Class suggested she could accomplish a lighter, more graceful landing.

"You could have done much more on that," he told her. "Why be lazy? Why look like a sack of potatoes?"

After analyzing the replay, they returned to the ice to try the jump again.

Meanwhile, Darin Hosier, 16, of Falls Church, worked on a double axle, one of the most difficult jumps in figure skating. He began his competition routine, opened with a smooth combination of two double jumps in a row, then raced to the other end of the rink for the double axle. He missed, and began again. This time he landed perfectly, and other skaters stopped long enough to cheer.

The training program, which ended Sunday, is "eight long, grueling weeks," said Audrey Weisiger, "but they go by fast."

The program cost each skater $400 to $750, depending on how much practice time was scheduled. In addition, there were the costs of lessons, skates, blades and costumes. Some skaters spent as much as $100 a week on lessons alone.

For most of the students, skating is a year-round effort, with long practice hours and little time for the kinds of things other youngsters enjoy. But the young skaters have few complaints.

"Skating's worth it," said Hosier, who spent his fourth summer in the Fairfax program. Like Lily Lee, he skates about five hours each weekday and has begun to taste competitive success. Last fall, he placed third in the intermediate men's category in the South Atlantic Regional championships and second in the Eastern championships.

"This year, my major . . . goal is just to be lucky enough to make it to nationals, because this year, the competition is going to be stiff," he said.

Leslie Shackelford has been on the competitive circuit 10 years. Last winter when she started college she hung up her skates for six months.

"It was a good change," she said. "I enjoyed school. I got to be a teen-ager, which I missed when I was skating."

But she will be back in action this fall, once again at the Fairfax Arena.