RIZE — *** — Documentary feature about street dancing; rated PG-13 (vulgarity, drugs, profanity, brief nudity).

The dancers in "Rize" are so impossibly muscular, so preternaturally athletic and limber from the rigors of krumping and clowning, you could easily imagine them inspiring a new workout trend.

It would spread from classes at the elite, overpriced clubs — where it sort of exists now under names like "Raw Groove" and "Street Crunk" — until it reached every gym in every town across America.

That's how cathartic and enticing and, yes, fun David LaChapelle makes this arduous dance style look. And with the surreal lighting and hypnotic pacing that have become his trademarks, he makes you feel as if you, too, could be this good.

But you can't — because what they do cannot be taught. No one taught them how to do it. As the acclaimed fashion photographer and music video director shows in his documentary, the moves sprang naturally on the streets of South Central Los Angeles as a means of expression after the 1992 Rodney King riots.

Participating in this style of dance, with its extraordinarily fast hip thrusts and arm flagellations, also serves as an alternative to gang membership and a backlash against the commercialized hip-hop culture that glorifies it.

Having said that, the clowners and krumpers have certainly formed gangs of their own, albeit nonviolent ones. Think of it as a raw, extreme version of the Sharks and the Jets.

Either you are a member of a clown group — painted disciples of Tommy Johnson, or "Tommy the Clown," the longtime community activist who's touted as a ghetto celebrity — or you krump, with moves that evolved from clowning into something very different, an almost violent mix of popping and locking, tribal rituals, stripper choreography and moshing.

LaChapelle tries to wrap his arms around all of this and put it in artistic, historical and socio-economic perspective, though his approach feels a bit cursory. He introduces us to talented, focused young people with street names like Tight Eyez and Lil C. A guy who goes by Dragon gives an eloquent soliloquy on krump as "ghetto ballet." And one beautifully edited segment juxtaposes images of kids slamming into and maneuvering around each other on the playground with footage of African tribesmen performing in the same way.

But LaChapelle's strength is as a visual stylist, not as a historian. This is the man who brought us the videos for Christina Aguilera's "Dirty" and Britney Spears' "Everytime."

"Rize" often feels like a music video, too — one that may never end. There are four or five natural stopping points, which makes the whole endeavor seem a tad repetitive. But LaChapelle's images remain lush, vivid and wondrous to behold, even after seeing them repeatedly.

"Rize" is rated PG-13 for suggestive content, drug references, language and brief nudity. Running time: 84 minutes.