NIJINSKY -- At the Dupont Circle Theatre

Ballet movies are a marvelous idea. You get all the backstage excitement of the standard show business story with more stylish glamour. Besides, all the daily sweat dancers put into stardom makes the standard crack-up ending -- the My-Public-Finally-Demanded-My-Life bit -- more convincing than it is for, say, rock singers.

But people who are going to tap that burgeoning audience of balletomanes must learn to trust in the power of dance. Those people are Hubert Ross and his wife, Nora Kaye, the dancer, who made "The Turning Point" and now "Nijinsky." It's stupidfying that they haven't included in the new film one decent example of what it was that made Nijinsky the sensation of his day. Would anyone do a film biography of a musical comedy star without one full dance number?

We see George de la Pena, who plays Nijinsky, wearing the hokey arrangement of languid rose petals that was his costume for the art nouveau shocker, "Le Spectre de la Rose," and the even wilder get-up for "L'Apres-Midi d'un Faune." We see his eyes nearly corss in an orgiastic expression that creepily duplicates a photograph of Nijinsky.

But we don't really see him dance. Instead, the truncated views of performances have been hyped up with blinding lighting effects, slow motion, facial closeups, stop shots and long cuts to the appreciative glances of Leslie Browne as the future Mme. Nijinskaya. Washington audiences who saw Rudolph Nureyev recreate Nijinsky parts with the London Festival Ballet at the Kennedy Center have an idea of what the sensual impact must've been, but the "Nijinsky" audience won't.

Two more minutes of the "Petrouchka" sequence would have done it. No one expects the movie to be a documentary of a ballet, but a comprehensible excerpt from this one would have done double service, illustrating Nijinsky's attractions and adding some stunning symbolism about the fate of a puppet who is discarded by his puppeteer. The powerful opening shot of Nijinsky, flopping inert on an asylum floor, is surely intended to suggest Petrouchka.

Actually, just one good leap could have done it. According to Nijinsky, as quoted by his partner Karsavina in her autobiography, this would be "not difficult" to do. "You have just to go up and then pause a little up there." In any case, films can fake such things.

As biography, "Nijinsky" has some oddities. The violent public reaction to "Le Sacre du Printemps" is blamed sqaurely on Nijinsky's choreography, for example, as if Stravinsky's music had had nothing to do with it. The great choreographer Fokine is presented as a petty has-been.

But the fictionalized version of Nijinksy's relationship with the creative genius of the Ballets Russes, Diaghilev, who is played by Alan Bates, is interestingly done. There are few "La Cage aux Folles" cliches about homosexuality, which is portrayed with enough dignity to suggest that Nijinsky's choice of partners was between two individuals -- a brutally demanding artist and an uncritically supportive worshipper -- and not just between the representatives of different sexes.

That isn't the film's only worthwhile contribution. The sumptuous style, both of Edwardian society and of ballet as it burst into the 20th century, is beautifully done. American Ballet Theatre's Leslie Browne hasn't panned out as an actress, but George de la Pena, also from the company, looks divine, and a geniuine ABT star, Carla Fracci, is enchanting as Karsavina. Another fine touch is Anton Dolin, who was with the Ballets Russes as well as ABT, playing his own teacher, Enrico Cecchetti.

Then there are the witty lines dryly delivered bv bates in his sleek, mannered interpretation of Diaghilev.

On his last attempt at heterosexuality: "I suddenly said to myself in the middle of it, "This is ridiculous,' and I got up and went home."

Justifying his firing of Nijinsky for having married: "You think only the young have the right to be ruthless."

And admonishing Nijinsky for eating sweets: "Nobody loves a fat fawn."

Not that, alone, is worth the admission. Even without any dance.