Late one Friday night when Bertina Lee was a senior at the University of Virginia, she could not drag herself to the computer lab. The work, she decided, could wait until morning. The next day she learned that a haunting, violent crime had taken place.

A female student had been assaulted on campus right outside the lab where Lee would have been had she gone back to work.

Lee couldn’t shake the feeling that she could be next. She worried about her job at the library where she often walked home after midnight, alone.

Lee, who is 5 feet tall and weighs 130 pounds, was not particularly athletic. She had never imagined fighting in self-defense. But after the assault she thought of little else.

The kick-boxing classes she had taken from time to time to get in shape quickly became an obsession.

She fixated on a style of kick boxing called muay Thai. It is more aggressive than other forms and allows kicks, knees and punches. More than the workout, Lee sought its combative techniques, leg thrusts and fist jabs that might improve her chances if she were ever attacked. So she learned to fight.

That was three years ago. Today, Lee is one of the 30-member U.S. amateur kick-boxing team. While kick boxing is not an Olympic sport yet, it has caught the attention of the International Olympic Committee. And kick boxing could be billed as an exhibition sport at the Olympic games in the next decade.

Last month Lee surprised friends and even her coach when she won first place in the low-kick division of the amateur World Kick Boxing championships in Vienna, Austria. She qualified for the international event June 30 at a match in Fort Lee.

Lee didn’t hold back against her German opponent in the championships.

“At first I was like, ‘We’re going to play nice,'” recalls Lee. But then the weeks and months she spent training an hour and a half a day to prepare for the fight distilled into one thought: She was there to do a job.

“It was the first time I really got aggressive,” she says. “I hit her and she cried.” And for a moment, Lee says, she felt the blow herself, as if she were standing in her opponent’s shoes. Her coach, Brian Crenshaw, calls it humility. In kick boxing, he says, humility is more important than strength.

What is rare about Lee’s story isn’t how she got there, exactly, but that she got there at all. In a sports-crazed culture where much of an athlete’s success is accompanied by pomp and circumstance, Lee shuns fanfare. She hates an audience. By day, Lee, 25, works as a computer programmer and analyst for Dominion Resources. Many of her co-workers, she says, still don’t know she kick boxes.

At night she trades her corporate clothes for ankle braces and boxing gloves. But she avoids attention so much that when she first started kick boxing at Prodigy Martial Arts on West Broad Street, she attended the school’s smallest classes. She had no ambition to become an instructor or to compete seriously. Now she does both.

Long after becoming a regular at the school, Lee kept to herself, says Crenshaw, owner of Prodigy and coach of the U.S. amateur kick-boxing team.

“Bertina was very quiet,” Crenshaw recalls. “The amazing thing was she was always there.” Her second year at Prodigy she held the record for best attendance. Even so, it seems that Lee blended in.

“I wouldn’t say she came in being this prize student,” says Crenshaw. Four of his other students competed in Austria, too, he says; two ranked first in their divisions like Lee. But Lee was different, more patient than most. In time, her persistence made Crenshaw take notice.

“Bertina wasn’t the most flexible, wasn’t the strongest, but she was consistent with a keen ear,” Crenshaw says. “Even more than a good competitor what impresses me the most is she’s a good student.” That’s why, he says, he started testing her limits to become more aggressive. He took her to the city gym and threw her in the ring. Gradually Lee gained the confidence she needed to compete. And a little more than a year ago, she started fighting in matches.

For Lee, it was a matter of making up her mind to cut loose and let go mentally. “I pushed her buttons,” says Crenshaw. “The next thing you know she was coming after me and not holding back.”

And Lee didn’t start off with blazing great matches, Crenshaw remembers.

Her parents learned this firsthand. They didn’t know their daughter had planned to compete until the day of her first fight at the University of Maryland last year.

Naturally, they made the trip. It was the first time they had seen her in a boxing ring. “When they call your daughter’s name, your heart starts to pound,” says Lee’s mother, Arlene Lee. It wasn’t the most encouraging introduction to the sport, though: “She didn’t do well at all,” Arlene Lee says. “She didn’t win that match.”

Although Lee’s parents were nervous and concerned, her mother explains, they were even more proud and supportive. Lee’s father suffers from seizures and has spent much time in hospitals. Lee, the oldest of four girls in the family, has been kind of a pseudo-son to her father. They weren’t able to make the championship fight in Austria. But Lee’s father watches it on videotape. “He’s gets really excited and talks about it all the time,” Lee’s mother says with a laugh.

At Prodigy on a recent Tuesday night a class is ready to begin. In a room lined with mirrors and black punching bags, 16 young men and women gather on a buffed wooden floor. Lee is the smallest among them. She wears a blue bandana, her hair in a braid and yellow gloves.

After the warm-up exercises, Lee flashes a girlish smile to the group and tells them to pair up for sparring. The couples trade off wearing Thai pads — thick pads strapped over wrists and forearms that absorb kicks — and boxing gloves. Each takes a turn alternating kicks to the right, throwing cross-over punches, then kicks to the left. Leg, fist, fist, leg. Smack, pop, pop, smack. It’s the sound that takes Lee back to the ring.

“I go through a transformation,” she says. “I don’t remember anything or hear anything but a hum and me and my opponent.”