PHILADELPHIA -- Two teams battling it out while racing around a track on roller skates can only mean one thing -- roller derby.

Video: Roller Girls Burn Up Rinks
This aggressive sport is bringing out serious skaters, with unusual styles and looks, NBC 10 News reported on Thursday. Roller Derby is back and the participants are letting loose their wild side, with names such as "Darth Vader No. 13" and "Betty Machete No. 3"

From head to toe, the women stand out, but what drives them to scrape skin and bruise bones while whipping around on wheels?

"I'm a punk rocker at heart. I love the mosh pit, I love slammin' around, (to) do it on skates -- all the better," said a woman who identified herself as Betty Machete.

"I don't drink or smoke. I do Roller Derby," said Goody Two Skates.

Believe it or not, most of these women are moms. Gentle by day, but by night, they push, shove and kick -- all in the name of fun.

The participants said their biggest fans are their children.

"Our daughters are here all the time," said Darth Vader No. 13.

"They want to cheer me on," said Dynamite.

Both mothers and professionals are in the mix, NBC 10 News reported. Dynamite teaches preschool, Goody Two Skates wears a lab coat and Candy Ka-Boom does body piercing.

If anyone is thinking of lacing up, the Penn Jersey She Devils and the Philly Roller Girls are gearing up for their season, which kicks off in late summer/early fall. They practice several times a week, preparing to play other leagues and even other cities.