Violet Temper likes to joke that the wing tattoos on her calves help her skate.

"I'd probably be in jail if it wasn't for roller derby," says Philly teammate Cycrone, right after declaring, "It makes me a better mom."

The EMTs and the ambulance will be ready starting today at the Convention Center, as a dozen roller derby teams - including Philadelphia - begin their league's version of the World Series.

The Liberty Belles are hot. They beat last year's champs, the Gotham Girls All-Stars, to earn a first-round bye.

Take that, Big Apple!

That means fans will have to wait until tomorrow morning to see this collection of amateur all-stars from the three teams that usually play at the 23d Street Armory - the Philthy Britches, the Heavy Metal Hookers and the Broad Street Butchers.

It's a rare opportunity for fans and nonfans alike, said Temper, who's really Mishel Castro, 34, a Web code engineeer for an ad agency.

"The City of Sisterly Shove" may not host this event again for a long time, because the Women's Flat Track Derby Association represents more than 60 towns and cities, she said.

The bouts, as the matches are called, are totally legit, with genuine suspense and injuries - no whacks with folding chairs, explained Cycrone, actually Jocelyn Jenik, 46, a medical transcriptionist from Queen Village.

Basically, a team scores a point whenever its "jammer" - look for the star on the helmet - passes a skater on the other team.

Jammers can be any size - Annie Christ is about 4-foot-11, while Summer Assault might be a 6-footer, Jenik said.

"You want them to be fast," Jenik said.

The squad has a bunch of jammers ready, including Mo Pain, Shenita Stretcher and Gloria Grindem, Castro said.

Scores get high. The Belle's 90-89 victory over the New Yorkers would be called a defensive struggle, Jenik said.

Today's bouts begin at 3:30 p.m. with the Boston Derby Dames vs. Mad Rollin' Dolls of Madison, Wisc. Also scheduled: Rocky Mountain Rollergirls vs. Houston Roller Derby; Kansas City Roller Warriors vs. Denver Roller Dolls; and Gotham Girls Roller Derby vs. Detroit Derby Girls.

That's right, the New Yorkers lost in the battle for a bye, but they still made the tournament.

The winners will be matched up, starting at 10 a.m. tomorrow, against Texas Rollergirls, Philly Roller Girls, Windy City Rollers of Chicago, and Oly Rollers of Olympia, Wash.

The survivors will play again tomorrow evening to determine who'll be in Sunday's championship bout, which will follow a consolation contest between the third- and fourth-place teams.

"Any of the 12 teams in this tournament could take it," Castro said.

Tickets, which range from $40 for one-day general admission to $115 for a three-day VIP pass, are available at the event, which will be in Hall A, up the escalator from the main entrance to the Convention Center.

Yes, it's a rough-and-tumble sport, as the nicknames - how about Robin Drugstores and Felony Griffith? - and the Roller Girls website itself suggest.

Take the "bio" for Olivia Face at www.phillyrollergirls.com: "Once upon a time i was a fetus, some stuff happened, and now i beat up girls on roller skates."

Or Violet Temper's favorite quote: "I shot a man in reno, just to watch him die."

But spectators should also find the competition quite entertaining, Castro said.

"People who think that roller derby is a bunch of girls with tattoos beating up on each other will hopefully be pleasantly surprised to learn that it's extremely athletic, competitive, legitimate, amazingly captivating and fun," she said.

As for Jenik's remark about staying out of jail, she explained the sport's a great way to work out tensions and aggressions, some of which come from being a single mom raising a couple of young boys.

Contact staff writer Peter Mucha at 215-854-4342 or pmucha@phillynews.com.