MOSCOW'S EAST SIDE STORY: TEEN-AGE TOUGHS.New York Times 1988

In a jerry-built gymnasium hidden beneath an apartment building in this eastside Moscow suburb, a half-dozen teen-agers are pumping iron. White, well-muscled young bodies strain at the homemade squat bars and leg weights, to the beat of pop music from a boom box.

These young men and their suburb have become a Moscow sensation since a popular weekly magazine, Ogonyok, asserted that a fearsome gang of teen-age vigilantes had arisen from Lyubertsi's underground weight-lifting rooms.

The Ogonyok article described groups of young body-builders, calling themselves Lyubers, who roam Moscow, sporting an informal uniform of baggy checked pants, white shirts and skinny black ties, terrorizing hippies, punks and other young nonconformists. An Idol: Schwarzenegger

Authorities condemned the article as sensationalism, and the young body-builders say they are up to nothing more menacing than emulating the pictures of Arnold Schwarzenegger pasted to their basement walls.

But in a city where the rumor is a highly developed mass medium and suspicion of the official version of any story is habitual, the Lyuber story is widely believed. It has provoked, among other reactions, fascination and social introspection.

''Throughout Moscow, there is a rustle of rumors: Lyubers, Lyubers.'' said Yuri Shchekochikhin, a commentator on youth affairs for the weekly cultural newspaper Literaturnaya Gazeta.

On at least two occasions in recent weeks, officials say, hundreds of Moscow teen-agers have gathered near reported Lyuber hangouts, spoiling for a fight.

''We will defend Moscow,'' declared a notice that was circulated in Moscow secondary schools, calling on students to gather for a showdown. Local devotees of the spikes-and-leather rock music genre known as heavy metal signed a petition saying: ''We, Moscow metalists, declare war on the Lyubers throughout the city and district. The press has already given the Lyubers their due. Now it's our turn.'' Averting a Fight

The police prevented a clash Feb. 22 ''only with great difficulty,'' Maj. Gen. Viktor V. Goncharev of the police told the newspaper Sovetskaya Rossiya this week.

Again last Sunday evening, dozens of uniformed officers patrolled the area in front of Gorky Park with walkie-talkies, turning away any group of young people that did not seem bound for the park's ice-skating rink.

In response to worry caused by the Ogonyok article, one newspaper has set up a telephone hot line for teen-agers to call and discuss their problems. The Communist Party has organized peace parleys among different groups of young people and has begun a campaign to provide more acceptable outlets for youthful energy, such as new sports clubs and discotheques.

The controversy has also lent new urgency to an anxious debate about what is happening to a restless generation of Soviet youth, and where the official system failed to satisfy their needs. Cleaning Out the Capital

Ogonyok, which is affiliated with the Communist Party daily newspaper Pravda, published the Lyuber article in early February. Weaving together interviews with members of various young cliques - both the Lyubers and those who said they had been victimized - the writer, Vladimir Yakovlev, painted a portrait of a vigilante movement with unmistakable neo-fascist leanings.

''Hippies, punks and metalists shame the Soviet way of life,'' one of the Lyubers reportedly told the Ogonyok writer. ''We want to drive them from the capital.''

The author, in the end, was uncertain whether the Lyubers were right-wing ideologues, bored teen-agers, or hooligans manipulated by Fagin-style grownups grooming the youngsters for criminal activities. But he suggested that the conformist Soviet authorities had turned a blind eye to the victims. Who's to Blame? ''Let's think about this,'' he wrote. ''Didn't we ourselves create the situation where certain groups of teen-agers don't believe they are entitled to apply for the protection of the law?''

Soviet officials at first contributed to the spread of Lyuber lore. When police plainclothesmen attacked Jewish demonstrators on a Moscow pedestrian mall last month, a Soviet Government spokesman cited the Ogonyok article and asserted that the violence was the work of suburban vigilantes.

But in the last week, Soviet newspapers have attacked the Lyuber article with a ferocity that is extraordinary even by the current standards of journalistic debate.

In Sovetskaya Rossiya, in an interview under the headline ''They Created the Myth of the Lyubers,'' General Goncharev denounced the Ogonyok article, saying it was ''all based on rumors, conjectures, exaggerations, juggling of the facts.''

''Unfortunately, there have been some skirmishes between these people and Muscovites,'' he said. But these arose from normal frictions among adolescents, not from a violent cult of vigilantes. ''In that sense, these Lyubers don't exist,'' he said.

Mr. Shchekochikhin, the Literaturnaya Gazeta commentator, suggested that the myth was promoted by people who are unhappy with the liberalization of Soviet society.

Here in Lyubertsi, a group of young body-builders who had been interviewed earlier by Ogonyok said they were embittered by the article. From One, Indignation

''They made us out to be a band of hooligans,'' said Gennadi Mikheyev, an 18-year-old electronics student at a technical school. ''We rarely go to Moscow at night, and in any case we don't go in for beating people.''

In the city, he said, ''sometimes a quarrel may lead to a fight.''

''It's just life,'' he said. ''Fights happen. But I've never heard of a person who is such a fanatic that he wants to clean up the city, beat all the metalists. Maybe there is some truth in it, but I think it's just invented.''

He and his friends conceded that they do not have a high regard for hippies and punks. But they said the concept of a vigilante squad had been fabricated.

''We never set out to humiliate anyone,'' Mr. Mikheyev said. ''To humiliate people when you know that you are stronger than them is not good.'' Judo Workouts in a Cellar

Mr. Mikheyev is one of a dozen youngsters who work out regularly in a makeshift gym in the basement of a five-story apartment building. The police say they have counted more than 50 such clubs involving about 500 young enthusiasts in this working-class suburb of 360,000 people.

This particular club, reached by clambering 50 feet through a rubble-strewn cellar, includes two rooms of weight-lifting equipment and a third room for table tennis, boxing and judo workouts.

The young men who use the club say it was started three years ago because the government-run gymnasiums had long lines and inconvenient hours, and because the founders wanted a place of their own.

Last year, the young men said, officials raided many of the unofficial gyms and shut a number for unsanitary conditions. But the general official view is tolerant, they said. A Change in Official Attitudes

Since the Ogonyok controversy, they added, officials have hastened to offer weight-training classes at local gymnasiums, and to improve the quality of concerts, discotheques and video cafes.

In Moscow living rooms, parents theorize variously that the problems of Soviet youth are the result of permissiveness, spoiled youths, cynical attitudes toward authority, or envy of suburban youths toward those who live in the livelier center.

The official view seems to be that the problems are the product of idle hands. In several newspaper articles, official groups like the Komsomol youth league have been taken to task for failing to give youngsters healthy and entertaining diversions.

After the Ogonyok article appeared, hundreds of teen-agers from Lyubertsi and eastern Moscow were gathered at a youth center for a discussion. Then they were invited to stay for a dance performance and discotheque.

''Out of several hundred teen-agers, only dozens stayed,'' the suburban newspaper Leninskoye Znamya reported with an air of discovery. ''It's boring, it turns out, at the youth center.''