Tattoos are optional, but Punk Rock Aerobics exercisers are required to "beat on the brat with a baseball bat."

That's just one punk anthem aerobics instructors Hilken Mancini and Maura Jasper blast during their edgy new workouts.

They choreograph moves usually seen at rock shows, play music by The Ramones and Iggy Pop, and encourage air guitar as part of their class.

"This is for everyone who pushed back the coffee table, cranked up music and danced around," said Jasper, 36.

Wearing 1980s gym shorts and cotton knee socks, the ladies encourage participants — who pay $7 a class — to skank and pogo not at sports clubs, but at such famous punk rock clubs as Boston's Middle East and CB's 313 Gallery, sister venue to CBGBs, in New York.

At a recent class, the floor was sticky from the night before and participants occasionally had to dodge cigarette butts as they jumped around.

Mirrors were intentionally missing from the darkly lit club.

"This way participants can do moves like air guitar and not worry about what they look like," said Mancini, 32.

The "super lunge," done for the duration of a very long J Mascis (Dinosaur Jr.) guitar solo, works the glutes and thighs. The windmill, a wind-up for air guitar, works the arms. And the skank, a standard move at rock shows, has elbows meeting opposite knees, which works the stomach and calves.

Instead of weights, bricks from Home Depot are used for strength training. They're tough to grab at first, but Mancini makes sure everyone has correct form. And punkaerobicizers are reminded to be themselves and rock out like they are in their living rooms.

"This class is for someone who is disenfranchised with typical images of beauty," Mancini said. "It is for those who think for themselves."

Guest DJs, who add to the party vibe, spin Sex Pistols and The Real Kids. The music provides inspiration for exercisers who are tired of the remixed Cher, Pointer Sisters and Enrique Iglesias tunes heard in many gyms.

"I always get turned off by the crappy music and the whole gym culture," said participant Jill Weidman, a 34-year-old graphic designer. "The whole point of this class was to have fun and be a goofball. I found it empowering."

John Cantwell, who teaches Aerobagogo! at Meridian Sports Club in Los Angeles, Calif., considers rock music an untapped aerobics outlet.

"My class could be called 'How to Be a Rock Star 101,'" Cantwell said.

He plays Jane's Addiction, Red Hot Chili Peppers and Blondie, leading students in swaggering Mick Jagger poses and sexy moves from the film Showgirls.

And while the Punk Rock Aerobics duo's moves are less traditional than some, Mancini studied ballet at the Boston Conservatory. Jasper, a visual artist, created album covers for Dinosaur Jr. and Sub Pop in the early 1990s.

The two unlikely instructors said they never dreamed of teaching an aerobics class and described the instructor certification process as grueling.

"But in true punk rock fashion we went to Burger King on our certification lunch break, " Jasper said. "All the other instructors were eating salads."

Aiming to reach an audience beyond Boston and New York, Jasper and Mancini are making a Punk Rock Aerobics video. But even if the style develops mainstream success, the women promise it'll always have the do-it-yourself vibe.

"If we are not having fun, we get bummed out," Jasper said.

After the class ends, as a reward for a job well done, Mancini and Jasper pass out "punk junk": free candy.