Besides being one of the smartest pieces of new playwriting the New Playwrights' Theatre has uncovered, "Practice" may be the only play ever written about street hockey.

Its skaters -- a 1950 playground team in Queens, N.Y. -- are not the sort who go careering across the intersection of 19th and M streets these days. But the play, like those born-again skaters, risks falling on its face a dozen different ways.

For starters, it asks a great deal physically of the New Playwrights' Theatre. Most of the notable sports plays have shied away from depicting events in the arena itself (e.g. "That Championship Season," "The Changing Room," "Androcles and the "lion"). "Practice" is actually set on a playground hockey rink, with its skate-borne characters wielding sticks and shooting pucks.

Even without any provision for an audience, the dimensions of New Playwrights' cozy space on Church Street would not meet NHL specifications. But designer Russell Metheny has ingeniously managed to create a plausible miniature rink in three-quarter-round, with wire mesh overhead for atmosphere and short wall to keep loose pucks from injuring the audience.

Then there is, or was, the problem of casting. Washington is not known for an abundance of tallented young actors who can (a) deliver reasonable approximations of a Queens accent, (b) look respectable on roller skates, and (c) while doing both of the above, shoot a puck in the general direction of a goal. Director John Hertzler must have located just about everyone within a 100-mile radius who filled this esoteric bill, or worked extremely hard to whip his company into line -- or perhaps a little of both.

Wherever the credit lies, the 17 members of the "Practice" cast carry this demanding performance off in high style. Stoney Richards, in particular, throws himself expertly and utterly into his role as the team bully's salty, unthinking sidekick. Eric Zengota and Reed Harvey make full-blooded characters of two serious fellows who could easily be turned into ponderous mouthpieces for the author.

Jack O'Donnell's play runs as many risks as does the production. Its subject matter -- the allure of hanging out with the gang as a substitute for plunging into the larger world -- has been treated in countless novels, plays and movies from "A Separate Peace" to "Dean End" to "The Last Picture Show." tr for ad 5

But "Practice" is more interesting than many of the works it shadows thematically, at least up to its violent and rather too familiar denouement.

O'Donnell sets up his conflict carefully and gracefully. Hayes, the team leader, has kicked an opposing player in the groin, sent him to the hospital and thus created a state of war between the "Senecas" and the "Blades."

The Senecas are warned to stay out of Corona, and a few of them seem perfectly willing to heed the warning. But Hayes urges his teammates not to back down, recalling for inspiration his father's one great stand in life -- abandoning school at 14 rather than addressing a black teacher as "Sir."

"Practice" has evidently gone through a good deal of rewriting, and it could stand more yet. But O'Donnell knows how to capture an audience and he has a sharp memory for juvenile banter -- the kind rooted in one particular time and place and the kind that is universal.

"Hey, Maureen!" one of his characters shouts at a passing girl. "What are you doing hanging around the library at seven? You wanna get brain fever?"