David LaChapelle’s background in advertising and music videos is apparent in his first feature documentary, an exuberant, colorful, viscerally exciting but overly flashy and sadly disorganized treatment of krumping, a wildly athletic form of street dance that’s developed in L.A.’s South Central area. It’s hard to resist the energy on display in the film, or to fail to empathize with the youngsters for whom the dancing provides not just a mode of expression but a means to develop self-esteem (as well as an alternative to gang activity). Still, it has to be said that as movie “Rize” gets awfully repetitive, and that it raises some uncomfortable sociological questions.

After briefly situating the phenomenon historically by reference to the Watts uprising of 1965 and the Rodney King incident, LaChapelle introduces us to Tommy Johnson, a local man who transformed himself into Tommy the Clown, a birthday performer who became known (and beloved) for his dancing and anti-gang persona. Johnson’s popularity led to an outburst of “clowning,” in which youngsters formed into “chapters” that in effect challenged one another to contests that involved pumped-up dancing rather than violence (and included face-paint as well). That movement later morphed into what came to be called krumping, which dispensed with the whole clown motif and became more a virtuoso exhibition that often invited a sort of competition that, in an updated style, mirrored the balletic confrontations of “West Side Story.” The larger groups then became rivals as well, leading to a big Clowns-vs.-Krumpers stand-off at a local auditorium that became a major community event.

The focus of the film is on the dancing itself, but LaChapelle rightly sees it as a social phenomenon rather than just a cultural footnote. That’s why he uses it as a window into the lives of some of the characters–Johnson, of course (who suffers a personal tragedy on the very night of his victory in the final showdown that points up the fragility of his whole enterprise), but also Dragon, an amazingly dextrous krumper whose moves are convincingly interpreted, especially in a haunting seaside scene, as a statement of resolve against the forces that have so limited his options. Some of this contextual material generates considerable power, although one might wish it were expanded and deepened.

Moreover, while “Rize” certainly works as a celebration of the spirit that animates the whole movement, capturing the verve and abandon of the dancing with skill (although, some might say, a bit too much slickness at times), and though at one point it makes an interesting juxtaposition of its competitive moves with African tribal dance (something that could have borne amplification), the film never confronts the issue of “What follows?” Certainly one can appreciate the sheer physical stamina that goes into the maneuvers, as well as the fact that while it doesn’t literally keep kids off the streets, it does change what they’re doing there. But the question of how it might actually alter lives for the better, in terms of providing a foundation that will help the participants in future endeavors (unless they decide to try the hard road of performers or choreographers, of course) is never addressed. It may build self-esteem, but that, without other tools, is rarely enough.

Still, that’s asking “Rize” in effect to be something it doesn’t aspire to. Simply as a portrait of a social and cultural phenomenon most viewers won’t ever have been introduced to, it’s vibrant and colorful, and occasionally moving as well.