For 15-year-old Casey Bryan of Woods Cross, his two main activities, gymnastics and academics, feed off each other.

"I don't know if I enjoy studying, but I like getting good grades," says Bryan, a 3.9 student last term with a 3.77 cumulative GPA at Woods Cross High School."It comes with the discipline from gymnastics - just the idea that I have to get my homework done so I can go to the gym," he says. "I don't dink around when I come home from school; I study."

Academics will help him stay in sports long after the conclusion of his gymnastics career - which is on target for him to make the 1996 Olympics - because Bryan hopes to get into a sports-medicine profession like physical therapy, a highly competitive field.

"I'm fascinated with the body, why it does (what it does), and how to fix it when it goes wrong," Bryan says.

Bryan's body has a leg up on most.

He is the newly crowned U.S. Gymnastics Federation's national Class II (15-under) men's all-around champion, a title he took last weekend against 216 competitors at Cal State University-Fullerton, and he has already won his first international competition, in a meet in Portugal last month.

He's in training now, at USA Gymnastics World in Woods Cross, for the July Olympic Festival in Los Angeles, an optionals-only, fun type of meet that pits the juniors against the seniors and lets the youngsters know where they stand. "I'd probably come in behind them," Bryan surmises, based on his experience at the Olympic Festival last year when he couldn't perform properly because of injury.

Following the Olympic Festival, a national meet and a national training camp this summer, Bryan will probably move into the elite program by next spring. He looks forward to that: It's both a step up and a chance to break up the boredom by learning a new and more difficult set of compulsories. The qualifying meets are nearly a year away, but "It goes fast," says Bryan.

Coach Chris Leech describes Bryan as a powerful, aggressive, charismatic athlete. Bryan says he doesn't like to lose but knows how to accept it. He hasn't lost a meet this year. He hates cockiness and considers compassion a strong personal trait. "He's very much ahead of the game for his age," Leech says.

Bryan doesn't recall much about his start in gymnastics. He was all of 4 then, and parents Marsha and Doug Bryan put him in classes for safety's sake - he'd seen some gymnasts on TV and started imitating them. "I can't remember," he says. "I'm sure I wanted to do it because I tried it on my bed and stuff."

He can't remember if it was easy for him at first, either. Gymnastics was tough for him, however, when he was 9 and trying to learn a stutz on the parallel bars. That's a swinging, reversing move with a change in grip, and it was the highlight of Bart Conner's 1984 gold-medal routine in the Olympics, but it was also a required element for Class II boys' compulsories, and Casey had gone directly from Class IV to Class II.

"I almost quit because of the stutz," says Bryan, who can't even recall why it was such a problem, just that, "I'd think about it all day and almost hate to go to the gym because I knew I'd have to throw them."

That solved, nothing keeps him out of the gym now, though he manages to make room for just about everything a normal 15-year-old enjoys. He left scouting after attaining Eagle Scout status because he couldn't quite fit it into his schedule, but he does find time for basketball, football, racquetball and mountain biking with his friends, as well as movies and dates. "I don't like being unorganized," Bryan admits.

"People ask, `How can you stand going into the gym for four hours a day?"' Bryan says. "It's just fun," is his answer.

And satisfying. Humbly, Bryan says, "Not many people are the best in the nation at one thing in their life - at least in their age group."