With a shirt on and a cup of hot cocoa in his hand, Peter Vidmar looks too small for the muscular part he played at the Olympics and too fresh faced for the traveling salesman role he's playing now. But the 23-year-old gold medal winning gymnast has a pretty fair pitch and a product that's not hard to sell.

"The pressure is going to be off us and we are going to be loose and ready to put on a show," said Vidmar, who spent yesterday in Washington acting as advance man for the first stop on a national victory tour by America's Olympic gymnasts. Mary Lou Retton, Mitch Gaylord, Bart Conner and the rest of the aerial acrobats who earned so much precious metal and national adulation in Los Angeles will perform at Capital Centre on Sept. 14 and 15.

Vidmar is not getting paid to play the huckster, but he seems eager. The blond-haired Californian, who cried on the medal platform with the rest of his team after upsetting the Chinese team for the gold, then won an individual gold on the pommel horse and a silver in the all around competition, sees himself as a modern Pied Piper, leading America's youth, especially the boys, to gymnastic glory.

"In 1972 all the little girls ran out and joined clubs after seeing Olga Korbut," he said. "In 1976 all the little girls did the same for Nadia. The ratio was 10 girls to every boy. Now we have six male gymnasts for the boys to look up to. I want to keep the momentum we gained from being lost."

For Vidmar and the rest of America's Olympic heroes, this is a time for selling both their sports and themselves. The commercial potential of the patriotic pride they aroused can be very lucrative. Especially if you have the right image and agent. Vidmar has both.

"The William Morris Agency is handling my public appearances and contract offers," says Vidmar, who has a face that would look good on a box of Wheaties, an intelligent congeniality and not a hint of the calculating ambition that soured the public on Mark Spitz. When Vidmar says a traditional, quiet family life is more important to him than fame and glory, that hard work is its own reward and his Olympic ambitions were primarily team oriented, it may sound hard to believe, but it rings true.

"Gymnastics is a sport where individual ego can come into play," he said over a breakfast of bacon and eggs at a Washington hotel with his wife Donna, a gymnast he met at UCLA. "But everybody on that floor during the Olympics was selfless. You just keep telling yourself, 'The team is the most important thing' and pretty soon you start to believe it."

Vidmar was one of the few boys in the crowd of little girls who were turned on to gymnastics by the 1972 Olympics. He was 11 at the time, short and skinny, living in the middle class comfort of Los Angeles. His father, a gymnast in high school, took him to the Culver City club coached by Makoto Sakamoto, a Japanese gymnast who had competed in the 1972 Games.

For the next six years, Vidmar and Sakamoto worked together with the secrecy of basement inventors. By the time Vidmar entered UCLA he had only been in half a dozen competitions. In 1978, he sprang full grown and master crafted onto the national scene and immediately made the U.S. team.

"He didn't care about winning local competitions," said Vidmar, who spent all those years in training without benefit of the normal feedback youthful athletes get by beating their peers. "He was preparing me for international competition.

"I guess I made the normal sacrifices -- dances, dating, that kind of thing. But I really did love everything about gymnastics, even the drudgery and dreary workouts. In retrospect, it doesn't seem like much of a sacrifice," said Vidmar, who has not had more than three days off in a row in 11 years.

Yesterday afternoon, during a visit to the MarVaTeens gym in Rockville, Vidmar could not have dampened the enthusiasm of the club's star struck gymnasts with any amount of sober talk of sacrifice. And he didn't try.

"I'm impressed," said 15-year-old David Pearlstein, after some personal coaching by Vidmar on the pommel horse. "I'm just happy he's a normal person. He doesn't act like any big-time movie star."

But a few yards away, another gymnast sat clutching a photo album in shy tribute to the power of handsome sports heroes.

"These are pictures I took at the Olympics; some of them are of him," said Susie Silverman, 13. She had inscribed the album to Vidmar. But now she was afraid to approach him.

"He probably already has a lot of pictures," said Silverman. "But maybe he'd like some more."