Taking a hint from “Flashdance,” Marcie Judelson is

a Jewish advertising copywriter by day — and

creative dance instructor by night.

A San Franciscan of 30 years who grew up on the East Coast, Judelson is the creator and instructor of Boomercize, a fitness class that uses the music

of their childhoods to get baby boomers up and moving.

The idea for Boomercize started to form five years ago, when Judelson realized that she was “a formerly thin person who hit middle-age and the pounds started packing on.” That’s when it came to her: There needed to be a way to shed the pounds while reminiscing with classic oldies.

“I was looking for a new exercise option that highlights low-impact aerobics,” Judelson said. She attended a few classes, but none felt like they were the right fit.

Judelson was no stranger to the arts: she grew up watching her father paint and her mother sing professionally, and she has training in ballroom dancing, ballet and tap. So her friends suggested she teach a class of her own.

It was Judelson’s love of music that fueled her passion to dance. As a child, she idolized the dancers she saw on TV: “When you’re 10 years old, the beauty, coolness and grace … it was something so exciting to me.”

And as a Reform Jew, Judelson also believes there’s a spiritual link between dance and Judaism: “To me, there’s a very spiritual and emotional side to dance and music, the power to transform your energy” and connect to the religion, she said.

Judelson’s music collection includes hits from the 1920s and ’30s, but like any good baby boomer, one of her favorite musical eras is the ’60s. “My first experience was dancing to Motown, the Four Seasons, the Beach Boys,” she said.

For Judelson, nostalgia combined with exercise “brings out a whole new definition on youth.”

In each hour-long Boomercize class, she borrows dance moves of the “American Bandstand” genre: “The twist, pony, swim, cha-cha, mashed potato, the monkey, the hitchhike — a legal one, mind you — they’re structured with simple, easy-to-follow choreographies,” she said.

The classes are currently taught at the Presidio Dance Theater in San Francisco, though Judelson says she intends to pursue local JCCs as well.

Having recognizable music has helped Boomercize appeal to its target audience. San Francisco resident Darlene Popovich raved about getting the chance to “exercise while singing.”

Judelson has always disliked aerobics classes because they are mostly loud and mechanical, rather than dance-oriented. “For the most part,

they are taught by younger enthusiasts, and these classes are getting harder on our bodies as we age,” she said.

The intensity sometimes comes with a price:

“Too much wear and tear for our age.” Judelson emphasized that she is not a “super-high-energy hyper instructor” and that comfort is crucial in her class. “People don’t want to be in an environment that is intimidating.”

And for middle-aged baby boomers, that comfort makes a big difference. Boomercize is “a place where I can do aerobics without being surrounded by super human 20-somethings and, without killing myself to keep up,” said attendee Fran Hulse of Mill Valley.

Boomercize welcomes women and men, though Judelson’s regulars are mostly women, their age ranging from 40 to 70, with a few exceptions: “There was an 82-year old woman who was just a pistol of energy. She wore me out!”

For more information about Boomercize, call (415) 608-4503 or visit www.boomercize.com for information on upcoming classes.