Improvisation, for all its supposed freedom, is a tricky and demanding venture. There's got to be some semblance of structure lurking behind all that spontaneity. Repetition's okay, but predictability's a no-no. And there must be surprises!

Free Association, Washington's oldest and best-known dance improvisation troupe, seems to have fallen prey to the demons that surround the art form. A first-time spectator at their performance yesterday afternoon as part of the Renwick Museum's 10th anniversary celebration might have found them agile, but painfully unfunny and aimless in their routines. To a veteran Free Association-watcher, the dancers seem to have run out of creative steam. They depend far too heavily on wacky costumes and props, and on certain roles: frazzled, catatonic wife, dopey husband, prattling infant, bored sophisticate. Though all are trained dancers, they rely on a severely limited movement vocabulary of sloppy falls, loony prancing steps, static poses, huddles, rolls and crawling.

There were some arresting moments in the group's shenanigans, and Jack Guidone, the true clown among them, always managed to pick up the shards of a failing routine and bring it back to life, Sadly, this was his last performance with the troupe. David Frievogel's musical improvisations on piano strings, a piece of metal, kettle drums, keyboard and radio provided a constant, witty commentary on the lackluster proceedings.