Dennis Duff is a self-described historian of Roller Derby. He’s loved the sport ever since his sister’s boyfriend came over one day when he was young and tuned the television set to a roller derby bout. For his day job, he’s a chef at Southview Senior Living in St. Paul, but whenever the Minnesota Roller Girls have a bout, Duff can be found in the entrance way, presenting homemade timelines of roller derby and jerseys, as well as scores of related magazines dating back to the ’70s. Even the boxes he uses to carry his memorabilia from bout to bout have yellowed newspaper clippings and photos taped to them.

He’s followed roller derby through its various inceptions and its battles for television ratings.

“I never liked any of the conventional sports,” he said. “I can’t really say why I like it so much.”

Denny Duff is only one of the many individuals visitors will see at a Minnesota Roller Girls event. Groups of middle-school-aged girls line up to have black eyes painted on their face. Proud families come wearing the colors of their daughter’s team. From bachelor parties to die-hard derby fans, the audience is wide-ranging.

The vendors selling $6 beers and soft drinks resemble any sporting match but with the ambiance of a rock concert. The lights are low. The crowd surrounds the flat track on three sides, outlined with lit-up plastic tubes, taped to the floor of the Roy Wilkins auditorium.

Some members of the Minnesota Roller Girls come out to the flat track before the first period begins to re-enact what a “jam” looks like in slow motion, as the announcer explains the still ambiguous sport to the crowd.

The skaters in derby are as diverse as their audience. Rachel Hunter, who skates with the Garda Belts and is better known as Ann E. Briated, is a law and molecular biology student at the University.

“It’s great to come after a frustrating day at school and just hit people,” she said, “in a controllable fashion.”

This year marks her second year on the team. She, along with the other roller girls, practice for two hours, three times a week. She admits it’s a huge time commitment, especially because the organization is completely skater-run. No one is paid and all of their leftover money at the end of each season goes to charities.

“Effectively, our balances go to zero,” Hunter said.

The Minnesota Roller Girls consist of four home teams – the Atomic Bombshells, the Garda Belts, the Dagger Dolls and the Rockits – but they often skate against teams from all over the country. The teams are introduced to classic fight songs, like “Eye of the Tiger,” as their skater names are introduced and they warm up with a skate around the track. Uniforms vary, but are often individualized to the skater’s tastes. One girl’s butt reads “Derby or Die.”

Carrie Fisher, who works two waitressing jobs and also works for a clothing designer, is known as Sparkle Ninja and skates with the Dagger Dolls. Fisher has been skating most of her life – 12 years as a figure skater and four years in women’s hockey. Two of her friends were the captains of the Dagger Dolls and she went along to a bout.

“I fell in love,” she said. “I couldn’t calm down.” This is now her second season skating. She too loves the people, she said, for their youth, vitality, friendship and strong femininity.

With all the females in the room, Fisher said there’s only a little drama.

“It’s pretty impressive,” she said, “With stuff like that, you get it out on the track and leave it there.”

Competition to even be a roller girl is fairly strong. When Fisher tried out, of the 70 girls that tried out, only 30 were taken.

Andrea Martin has been with the Roller Girls since its inception in November 2003. Known as Trixie Whipsum and skating for the Rockits, Martin is a full-time mother. She has a 5-month-old baby at home, and she’s getting back into shape with the Roller Girls after having her baby. When she was younger, she worked at a skate shop, so when she saw an ad in the City Pages, she thought it might be a good idea to try it out. She said it also helps that she’s competitive.

The sport is known for its injuries. On Martin’s Web site profile, for instance, she lists a torn ligament and “bruises in the shape of skate wheels in very curious places.” Injuries are just part of the sport, along with fishnet stockings, punny aliases, and strong friendships.

Martin counts some Roller Girls as her best friends. “It’s a lot of fun. I like the friendships, the competitiveness,” Martin said, “and 4,000 people screaming your name.”