It was one of those well-meaning programs that must have looked good on paper when a do-gooder thought it up in 1987: an aerobics class for women in prison.

"This was a population that was not in a position to say, 'I want to get my body in shape,' " says Rhodessa Jones, the would-be Jane Fonda of the San Francisco jail.

But out of that misbegotten venture of 1987 came her one-woman show, "Big Butt Girls, Hard-Headed Women," which Ms. Jones will perform tonight and tomorrow at Center Stage. The show is based on female prisoners -- murderers, drug abusers and prostitutes -- that Ms. Jones met through the class she was hired to teach.

In the show, Ms. Jones takes audiences into the prison to meet these women and hear their stories. It's been well-reviewed in Los Angeles ("masterful"), New York ("a physical bang, crack, boom") and Boston ("powerful and haunting").

"Her work is very personal and autobiographical," says Jill Morris, the curator of Center Stage's "Off-Center" series, who selected the show after seeing tapes of Ms. Jones' work. "That's how she connects with other people. There is no fourth wall at all."

The show plays on the absurdity of going into prison to teach aerobics to women with larger concerns than cellulite. And indeed, Ms. Jones shifted the focus of the class from exercise to communication, and she and the inmates started sharing their experiences. Ms. Jones, a longtime performing artist in the San Francisco area, realized the wall separating her from her class was a thin one.

"These people looked like me," says Ms. Jones, 45, a striking woman with freckly, burnished skin, close-cropped reddish hair and the kind of energy that makes even a seated conversation seem like theater. "I had a daughter at 16. I've been in abusive relationships. I've done my own dance with drugs. What was it that saved me from falling through the cracks the way they did?"

Her discovery of the arts saved her, she says. A brother -- she's the eighth of 12 children born to migrant farm workers who settled near Rochester, N.Y., in the 1950s -- brought her to a "hippie-commune-theater" he was working with at the time that she became a young mother. It was as if a light flicked on.

"It was like entering another world," she says.

The theater bug stayed with her, even though her life took some detours. She did the hippie, dropout thing, leaving the United States in 1971 with her own merry band -- her daughter, a "wild Irish man" she was living with and another friend -- and headed south in a truck.

They made it as far as the Panama Canal -- where the guards waved them off, crying "no heepees, no heepees" -- and ended up settling in Costa Rica for about a year until her daughter got sick and a friend in California sent her money to return. She settled in the Bay area, where she lives today, co-directing a theater company, Cultural Odyssey, with a one-time live-in companion, Idris Ackamoor. He is in Baltimore as well, directing Ms. Jones in her show.

Working as an artist, though, has its dry spells -- once, for about 1 1/2 years in the early 1970s, Ms. Jones worked as an exotic dancer. "Hey, I was gorgeous!" she says with a bountiful laugh and total frankness. "I had a great body!" Even then, though, she was gathering material for her art -- her experiences led her to create a one-woman show and eventually link up with Mr. Ackamoor's Cultural Odyssey.

She is still drawn to incarcerated women, however. She created the Medea Project, named after theater's baddest of bad girls, several years ago to continue working with women in prison or out on parole. These women, as well as professional actresses, develop shows based on their experiences.

Even as the current, three-strikes-you're-out tide of public opinion seems to call for prisoners to be locked up for good rather than rehabilitated and released, Ms. Jones remains unrepentantly supportive of the incarcerated, especially women.

"For me, it gets back to why I do what I do," she says. "A woman has to find a voice to express her rage, her desires, her fears.

" 'Be nice,' we're told. But nice is a rip-off," she says. "I say to women, those brave, outrageous girls you used to be afraid of in school -- the ones who would jump on the back of motorcycles, the ones who would smoke and curse -- this is courage."

Her admiration of women who refuse to bend to societal norms led to the title she selected for her show.

"It's a collective memory in African-American society. We grew up being told, 'Sit your big butt down, don't be so hardheaded,' " she says.

The title first came to her when she was at the San Francisco jail, waiting for her class to begin, and a large, shackled woman was being taken somewhere by a guard. As the woman was led by, Ms. Jones timidly said something like, "Take care of yourself," and the woman responded, "Girl, don't worry about me." Ms. Jones watched her walk away, thinking how strongly and confidently this particular "big-butted" woman marched onward.

At this point in her life, she finds herself part of a family of women: Her mother is still alive. Ms. Jones' daughter is now 29, a widow, a full-time college student in Brooklyn, and herself the mother of a 4-year-old girl.

"It's magical to have lived to be someone's grandmother," Ms. Jones marvels. "She's wilder and crazier than my daughter. My daughter tells me, 'When I'm your age, I want to have a Porsche and my own house.' My granddaughter is my soul mate -- she's already writing her own songs."

When she tours, Ms. Jones tries to conduct some sort of program for women in each city. On Wednesday in Baltimore, she led a group from the Ripken Learning Center in an often emotional workshop, during which the women told about their lives and participated in acting exercises and other modes of expression.

Carolyn Jenkins, 36, a Ripken Center student, says she wasn't sure what to expect from the workshop but soon found herself comfortable enough to share some of her poetry and stories. "People wrote out their experiences, and other people acted them out. I wrote about the first time I rode a bike," she says.

"It was very, very creative. She created something in just a little bit of time," says Falesa McCall, 25, another student who participated in the workshop. "She was very patient, listening to us, and she seemed very caring. To her, everyone has a talent."

Such workshops are a way to build and diversify audiences for her work, and that of theater in general, but it's also a way for Ms. Jones to find commonality with women outside her own sphere.

"As I look forward to workshops like this," she says, "I think, 'How many places will we be able to connect?' "

ONE-WOMAN SHOW

What: Rhodessa Jones

When: 8 tonight and tomorrow night

Where: Head Theater, Center Stage, 700 N. Calvert St.

Tickets: $15

Call: (410) 332-0033