Dancers in a new documentary have a lot to say about an inner-city craze called krumping (search) that's transformed their lives, but when asked to describe how it's done, they get tongue tied.

They call it clowning, stripper dancing, ghetto ballet — a form of therapy to help them cope with the struggles of growing up in crime-ridden South Los Angeles.

But words aren't enough to capture the anguish and exuberance displayed with every rapid bounce or fist punched in the air.

While still mostly unknown beyond the L.A. neighborhoods of Compton (search), Inglewood, Watts and Long Beach, dancers hope that krumping will become more familiar with this weekend's release of "Rize." (search)

The documentary by photographer and music video director David LaChapelle (search) explores the phenomenon started by Thomas Johnson, a former drug dealer who turned to religion and clown dancing after the 1992 Rodney King riots.

Nicknamed Tommy the Clown, Johnson would wear clown makeup and a rainbow afro wig to entertain at children's parties. As part of his act, he would dance a style often seen in hip hop music videos that blended his spontaneous, goofy version of strip dancing. As demands for his service grew, Johnson hired and trained a group of children to clown dance, too.

"It was fun, and it turned out to be something bigger than what I thought it would be," recalled Larry Berry, 21, who started working with Johnson when he was 12.

Berry and others who are featured in "Rize" say that Johnson's dancing provided an escape from their troubled homes and saved them from the potential pitfalls of growing up in the 'hood, where there were little options beyond playing sports or joining gangs.

The Johnson crew's growing popularity inspired dozens of imitator clown groups. So Johnson created the Battle Zone, reminiscent of break dance competitions that were popular in New York in the 1980s. In Battle Zones, kids compete to outdo each others' moves and win trophies and bragging rights. The competitive nature of the showdowns evolved into the more intense and aggressive krump style.

In a krump session, dancers in warriorlike makeup, baggy pants and combat boots meet inside a circle and show off athletic yet balletic moves. In scenes from "Rize," they appear to be in mock fights as they grab each other's T-shirts, pump their arms and thrust their hips in furious motion to the tunes of hip-hop music.

The winner is determined by audience response.

Krumpers began to get noticed and dancers appeared in music videos by Missy Elliott and the Black Eyed Peas.

LaChapelle discovered the dancers in 2002 while filming a music video for Christina Aguilera's hit song, "Dirrty." Brought in as extras, they struck up a spontaneous krump session in a waiting area.

"I was awe-struck when I saw it first," LaChapelle said. "I felt I had to do a documentary. I want people who watch the film to feel what I felt when being in a krump session, which is completely inspired."

"Rize" is LaChappelle's affectionate portrait of a crew of youngsters who, despite their hardscrabble circumstances, emerge as talented artists determined to shape their own destinies. They speak eloquently about their tough realities and the emotions that surface when they "get krumped" and dance in a trancelike state.

"These kids are from the hardest families, yet they're creative instead of destructive," he said.

"This dance is therapy — it allows you to free yourself," said Marquisa Gardner, 23, known as Ms. Prissy and the First Lady of Krump.

Gardner, who is dancing on rapper The Game's world concert tour, said krumping is a hit in Japan and Europe and fans often approach her. "They'd go, 'Are you Ms. Prissy?'" she said, feigning a British accent. "This is a craze. There's kids in Glasgow, Scotland, who are into this."

For years, Gardner said that she and her friends believed that they invented krumping until LaChapelle showed them a segment from "Rize" that astonished her. It juxtaposes images of kids maneuvering around each other with old footage of dancers in an African country performing in the same way.

"We didn't know we were doing the same thing," Berry said. "Nobody told us, OK the Africans used to do this. Yet here we are trying to take full-on credit."

LaChapelle was impressed with the "incredible riches" he found in the kids' neighborhoods and homes.

"There's this sense of camaraderie, of creating families, kids taking care of each other. The joy, the sheer joy of dancing on the streets," he said.

"These are heroes because of their talent, their fierceness, their krumpness."