It was most comfortable near the fireplace, this being Florida but not Florida-like weather, and the girls soon relaxed and assumed their own special glow, as they would in the home they had left 18 months ago for athletic and academic challenges.

"I was used to being alone," said Robin, who in fact celebrated her, 16th birthday two years ago in New Zealand, "so the change was not all that frightening."

"When I first went back to Washington," said her sister, Donna. "I went back to my old school and showed my teacher my report card from down here. It was all As and Bs and I said: 'See'."

These are the Campbells - Robin, 18, a world-class runner at distances from 200 meters through a mile, and Donna, 15, with potential from a mile and upward but whose dramatic growth physically has hampered her progress.

Like an increasing number of athletes, they chose to snap family roots at a remarkably tender age to accerate more rapidly in sports. So far, the 1,500-mile move has gone splendidly, but not quite in the fashion anyone had imagined.

Although they live with Brooks Johnson and his wife, Deanne, in a handsome house on a two-acre wooded lot just beyond town, the Campbells were not the only young Washington-area athletes who followed their coach south. Nor the only ones of experience transitional problems.

"I didn't know how to write a check," said Debbie Witt, 19, of Oxon Hill, who came simply because she wanted a year to consider her future after high school and now attends Santa Fe Community College here.

Lacey O'Neal came to coach the women's track and cross country teams at the University of Florida; Jackie Gordon because there was scholarship money available, through O'Neal, and Debbie pastel, Nancy Shafer and Rose Allwood for various other reason. LaRoya Huff returned home after a year.

"I'm not sure I could have done it, broken away to the extent Robin and Donna have, when I was their age," said Gordon, 20, who plans a career in law.

It was not a decision easily made, either for the girls or their parents or their coach, who has helped train them for nearly half their lives, in fact since the day D.C. Stadium officially became RFK Stadium in 169 and Martha Watson spotted Robin during a playground clinic and mentioned her potential to Johnson.

"I gave Robin my card and told her to get in touch if she was interested in serious running, figuring that was the last I'd ever see of her," said Johnson. "She called the next day."

If athletics, the Olympian dream, was the major lure here for his daughters, academics was what finally convinced Francis Campbell, a post-office supervisor whose own athletic goals were blotted early in life by his having to work.

"When I ran in China, I missed 48 straight days of school (at Easter High)," said Robin hardly wa schallenged, grading well while running about in the Soviet Union, Jamaica, Germany, Poland, New Zealand and assorted other countries, Donna was not stimulated, barely passing her junior-high courses.

All of that has changed drastically, with Donna the scholastic frontrunner now that the girls and Oak Hall Private School have come to terms with one another.

Oak Hall is where the elite of Gainesville send their children, a school, according to Johnson, founded to avoid public-school integration and thus terribly unsettled with the arrival of its first black students, even two whose tuition was being paid by a special parent, Dr. Robert Cade, who concocted Gatorade.

"Mostly, they would stare at us," said Robin, "although sometimes it seemed like people would come to school just to see what we looked like. There had been just two whites at Eastern. I knew how they felt."

Gradually, everyone began mingling, to the point, Donna said, of students asking: "How do you feel being black?" To which Donna replied: "How do you feel being white?"

"When we'd come home, my friends would say, 'What are white people really like?' and I'd say, 'Well, they don't bite.'"

In their home away from home, where Robin has learned to drive, the girls are outgoing and candid, alive with energy and questions, not quite certain what the future holds, either in sports or school, but unafraid to face it.

Except for one puzzling aspect that Robin volunteers. For some reason she is able to perform exquisitely before thousands in the largest of arenas, Madison Square Garden and the like, but often is unable to respond to the simplest question in a small classroom among friends.

"When I run," she said, "I can pretend the crowd can't see me, like it's a one-way mirrow with me able to see them but they can't see me. I don't know why, but in school I sometimes just can't answer when I'm called on, even when I know the answer."

The situation hardly calls for panic, although Johnson has lightened Robin's tack schedule at times. Donna's pace also is less intense at times because she has has grown so quickly, almost to Robin's 5-foot-10. The area around her hip is especially troublesome.

Even after graduation from Oak Hall this year, Robin said she would like to remain in Gainesville "for maybe a year or two, because of Deanne." Like Robin, Deanne is a world-class athlete, in the hurdles, whose hopes for the Montreal Olympics were dashed by an injury.

"For both Robin and Donna, the buzz word is not that simply any more," said Johnson, assistant track coach at Florida and long-distance consultant to several of America's fine sprinters. "They are getting more complex.

"They now are experiencing very intense enjoyment for very short periods. Before, there was a new joy almost every day because they were running faster and faster. It was a constant carrot, continuous gratification.

"Once you become somewhat sophisticated, there is a tendency for the fun to go out of it, because better times become so difficult to achieve. You see running as work instead of recreation.

"People get vicarious pleasure from what you do, but they also put pressure on you. Sometimes they say: 'Hey, why did you let that girl beat you?' Hey, sometimes somebody is simply better.

"At some point, the fear of failure, not the fear of competition, becomes the biggest fear of all." But that is a lesson for another day.