"I take a lot of pride over the fact that owing to me gymnastics became very popular in the United States. I would like to tell you that I receive a lot of letters from San Francisco and Los Angeles. Responding to these letters, I describe to them my future plans and tell them about my life."

Olga Korbut

Olga Korbut sat, pert and smiling, at a long table in a conference room underneath Lenin Central Stadium this week. She was on display, along with other sporting heroes and heroines of the Byelorussian and Moldavian Soviet Socialist Republics.

Her scarlet blazer was adorned with seven medals and ribbons, including one identifying her as a "merited master of sport." She looked relaxed, sitting next to her husband - pop singer Leonid Bartkevich - but her fidgeting fingers, playing nervously with her rings underneath the table, betrayed a touch of anxiety. It looked as if she would chip all the red polish off her fingernails within the hour.

Olga Korbut...as a teen-ager in the 1972 Olympics, she turned millions of television viewers in the United States and around the world on to gymnastics with her grace, her strength, her marvelously expressive face. She revoluntionized her sport with the intricacy and difficulty of her routines, and won four gold medals despite a tearful slip from the balance beam.

Everyone loved little Olga, and the world seemed to be her oyster forever.

Olga Korbut...in the 1976 Olympics at Montreal, the magic of Munich was somehow gone. The Soviet prite was upstaged by Romanian Nadia Comaneci, only 14 years old and spellbinding in her perfection. Next to tiny Comaneci, Korbut looked washed out and washed up, a mere shadow of our memories from four years earlier.

But even so, she was recalled fondly. Even though plentiful stories surfaced of how temperamental she had been, a prima donna resented by other gymnasts and coaches in comparison to her less gifted but more even-tempered and diligent teammate Lyudmila Turischeva, Olga Korbut was revered in America.

And what of Korbut today, at age 25?

A photograph of her, soaring through a routine on the uneven bars, graces the gymnastics poster for the current Spartakiade, the National Games of the Peoples of the U.S.S.R. But her star has rather sadly and dramatically faded. In comparison with other retired Soviet world class athletes, little is heard from her in her homeland.

Her husband is the lead singer of a top Soviet soft rock group called "Pesynary." They have a son, born this spring. But a recent visitor to her home in Minsk, capital of Byelorussia, found her living in modest circumstances in a three-room apartment above a store on the corner of Karl Marx Prospekt and Young Communist League Street.

It hardly looked like the residence of a national treasure, according to the visitor. The living room contains expensive Romanian renaissance furniture, but that is the only hint of affluence. Korbut drives a 1974 green Volga sedan, which except for the absence of identifying checkered bands on the hood and doors, could pass for a taxi.

Photographs of her past triumphs, including two world championships, surround her, and she is reportedly unhappy in the role of housewife and mother. She hopes to coach gymnastics next year, but is not working now and is said to be given to fits of depression. A neighbor, asked by the curious visitor what Korbut does now, replied: "She dusts the furniture."

A rather haunting photograph of Korbut breast-feeding her son, looking old and haggard and troubled, was taken by a cameraman from the London Daily Mail, and was widely republished in newspapers around the world. This led to rumors that her marriage was on the rocks and that she was near a breakdown.

Certainly Korbut is much less visible and much less celebrated than her erstwhile teammate Turischeva, who married Olympic champion sprinter Valery. Borzov and now is a member of the Supreme soviet, the figurehead legislature here, and the 1980 Olympic Organizing Committee. A respected coach of Soviet Olympic gymnasts Turischeva is frequently cited in the magazine "Soviet Woman" and other propaganda publications as the ideal Soviet woman - stable, reliable, industrious, energetic and popular. Korbut, whose flashiness always overshadowed Turischeva in competition, is almost never mentioned.

One Muscovite described Korbut as being "in eclipse," but last week, at least briefly, she was back at the center of attention.

Every day during the Spartakiade, one or more of the cities or individual Soviet republics competing in the festival is designated for special attention, its leading past and present athletes spotlighted at a press conference. Now it was Byelorussia and Moldavia's turn.

Of the 19 sportsmen and officials who formed the delegations of these republics, Korbut by far received the most attention.

She had gymnastics eagerly the gumnastics competition at Spartakiade on television, she said. She had not seen any of it live, but had accompanied her husband to Moscow when he played a concert date this weel at the Hermitage Theater in the capital.

: :It is in my blood, and I like very much to watch gymnastics," she said. "I am sorry that I cannot already participate. I am missing it very much.

"Leaving the competition was actually something like a happy occasion, because when you leave you are very, very tired after so many years of work and you really want to put an end to it. But just having left it already, I am again sorry that I am not competing."

Asked what is her occupation, she said merely, " I am bringing up my son."

Having now witnessed both first hand, Korbut was asked, which would she say was more difficult: the life of a famous athlete or that of a famous singer?

"I can tell you that being popular is very demanding," she said through an interpreter, but with conviction that needed no translation. "When you are popular, you are supposed to behave yourself all the time because you know that everyone knows who you are. They look at you if you don't do what they expect you to do. However, when you are not popular anymore, you can really be free, you can lead the life you should. The real problems are to take care of your family, your husband, and a lot of housechores."

Informed that she is still immensely popular in the United States, Korbut was asked if she could tell us a little more about her marriage, her family, her life now.

"I believe that I have already answered this question," she said, which she actually did not.

"In about a year I hope to resume my work and become a coach. I have to prepare myself for this career because being a good athlete does not necessarily imply being a good coach. But anyway, I believe I will prepare myself thoroughly for the job.

"About my family, I will say something about balance," she continued, pausing to allow listeners to recall that she is a ranking expert on balance. "I really was a little bit unlucky at the beginning, but I am very lucky at the end. The balance of the scales is now in my favor."

Olga Korbut desperately wants the world to think that she is rapturously happy. The world would desperately like to think it is true. CAPTION: Picture, Ex-gymnast Olga Korbut meets with newsmen during Spartakiade in Moscow. AP