Dani Heckman loses her name when she laces up her roller skates and clops onto the flat track.

Hanging up the doe-eyed, cheery 29-year-old R.E.I outreach specialist in the locker room, Heckman becomes Dee Troit, a flash of black spandex, silver stars and knee pads, the number 8 inked on her arms.

“When we put our uniform and makeup on, it’s a chance to be somebody different for a little while,” Heckman said.

Heckman, who lives in Ballard, has skated with the Rat City Rollergirls, Seattle’s premiere roller derby league, since 2006.

The sport has soared in popularity in recent years, especially in Seattle. Just last week, the Rat City Rollergirls filled 5,703 seats in the Key Arena, shattering a national roller derby record.

All the rollergirls adopt alter egos, morphing into wheeled warriors that push, knock and mow down their opponents in a blend of sport and spectacle.

“Nothing is acting or theatrical," Heckman said. "The hits you see are real hits. The uniforms are just an added bonus. It gives you a little bit more character. Every girl has their own little flair.”

Each game, called a bout, is played by two teams of five players. Three pivots and one blocker from each team form the pack, zooming around the track when the first whistle blows. At the second whistle, two jammers, marked by the stars on their helmets, take off.

The jammers score points during each two-minute jam every time they legally pass an opposing girl’s hips.

Heckman wasn’t always Dee Troit. Before moving to Seattle, she lived in Michigan, where she was a member of the Detroit Derby Girls.

Back then, she was called Skittle. But when she moved, she decided she wanted something a little more similar to her own name—and a little more intimidating. Plus, given her home state, Dee Troit fit.

Within six hours of landing in Seattle, she was already testing her wheels at her first practice.

“I’ve never moved out of Michigan, so I knew if I didn’t go right away, I wouldn’t go because I was so nervous,” Heckman said. “I don’t know how I would have met people if I didn’t have roller derby.”

Like most children, Heckman skated as a child. But, she didn’t dust off her skills until she was snowed in one day in Michigan and caught the Texas roller derby documentary on TV.

Heckman’s first reaction: “Oh my god, people still use roller skates?”

A Google search yielded an open call for roller girls two days later. Heckman begged her friends to go with her, but she wound up going alone.

The woman conducting the meeting wore a cast on her arm.

“I thought, ‘What am I getting myself into?’” Heckman said.

But as she watched the girls skate, she started to think that it wouldn’t be too tough to get back into after all.

They let in a bunch of skaters that year, training them and sorting them into teams, Heckman said. It was the start of the Detroit Derby Girls.

In Seattle, she was sorted again. The Rat City Rollergirls are divided into four home teams: Grave Danger, Derby Liberation Front, Sockit Wenches and Throttle Rockets, which Heckman is part of. She’s usually a jammer.

It’s definitely a full-contact sport. There are no time-outs if someone tumbles out of bounds or knocks another girl down, and almost all the girls’ limbs are stained with green-blue bruises.

“We have a lot of knee and shoulder injuries in the league," Heckman said. "It’s just the nature of the sport. You have to be focused on doing a lot of cross-training so you don’t get hurt.”

Though she practices around three times a week and skates Green Lake some of the other days, earlier this month Heckman slipped during practice and fell on her right shoulder, tearing her rotator cuff.

She’s benched until April 23, when her doctor will evaluate whether she can compete in the May 1 bout.

She said she’s been lucky. The worst injuries she’s seen are broken collarbones, she said.

But even when nursing an injury, Heckman is still at practice, cheering on her team. Being a rollergirl is something like having a second job, and some girls practice five times a week.

Then, of course, there are the bouts. There are five this season, which began in January and ends in June.

“To go to the game and see the stands full—it’s just so wild,” Heckman said. “But, I don’t really hear the crowd. I’m just thinking about not getting hit.”

She revealed one of her nervous habits: talking out loud as she jams. She’ll commend a teammate’s hit or even giggle to herself.

Heckman credits the team’s marketing strategy, complete with bus ads and spots on Jack FM, with the surge in game attendance. Playing at the Key Arena probably doesn’t hurt, either.

“I think it’s become even more popular because it’s a sport for everyone,” Heckman said. “We have kids who come with their parents, older people, younger people—it’s such an eclectic mix of people.”

And, the Rat City Rollergirls take the time to interact with those fans. They sell their merchandise, sit in the stands and hand people their programs when they walk in the door.

For Heckman, the social aspect is what continues to draw her to the game, and she admitted she sometimes spends more time with the derby girls than with her girlfriend.

Even if they don’t have anything in common during the daytime—some of the girls are married, some have children and some are still in school—at night, they shed those identities, shimmy into their wheels and become someone else for a few hours.

“Roller derby allows girls to have an outlet for their nonprofessional lives,” Heckman said. “We have so many different types of girls with really professional jobs. It’s their opportunity to let loose and have a different personality.”