In almost every group exercise class, there’s one person who is turned toward the back of the room while everyone else is facing forward — one person who prompts the instructor to call out: “Yoo-hoo, over there, your other left.”

That’s me.

So I wasn’t optimistic about taking an aerobics class in which signature sequences have names such as “heel hop, flick kick, knee lift, attitude, side angle.” But, ever curious, I decided to give Jazzercise a try.

Yes, Jazzercise: the jazz dance-fitness phenomenon that hit its stride in the early 1980s, spawning exercise classes (and knockoffs), best-selling books, workout videos, and a line of athletic gear. Until recently, I figured that Jazzercise had been supplanted by newer fitness crazes such as trampoline aerobics, and Indian-inspired Bollywood dance workouts. But Jazzercise is not only surviving; it’s thriving. And even amid New York’s competitive, fad-loving fitness landscape, the 39-year-old exercise movement is growing.

“I try hard to keep it current, and not to jump on any bandwagons,” the founder of Jazzercise, Judi Sheppard Missett, said in an interview. “I’ve never believed that something that hooks the customer base for only a short period of time does the trick. That’s like disco: hot for a while, and then gone.”

Disco, it’s not. Founded in 1969, Jazzercise now offers more than 32,000 courses a week and has franchises in all 50 states, as well as in 32 foreign countries. The company, which Ms. Missett runs from Carlsbad, Calif. with her daughter Shanna Missett Nelson, last year reported its strongest fiscal year ever, with revenues exceeding $85 million.

Here in New York, a certified Jazzercise instructor, Jeanne Zingaro, started a franchise five years ago; prior to that, classes hadn’t been available in the city for more than a decade, according to a Jazzercise spokewoman. Today, a stable of instructors offers a dozen Jazzercise classes at the Roy Arias Studios & Theatres on West 43rd Street, where the average class size is 12 to 15 students, Ms. Zingaro said.

It had been many years since I had heard anything about Jazzercise. So the first time I walked into the sixth-floor studio, I was half-expecting to hear “Walk Like an Egyptian” pouring out of a cassette player, as a leg warmer-clad instructor (whom I had imagined would look like Judith Light of “Who’s the Boss?”) led students through a series of intricately choreographed dance moves.

In reality, the music was contemporary: Rihanna, Justin Timberlake, Feist. And during the two Saturday morning classes I took, the leg warmer-less instructor, Pamela Savage, 29, never once singled out any of her dozen students, who represented a wide range of ages — twenty-somethings through fifty-somethings — and body types.

She took the complicated-sounding dance sequences and, from a small platform set up in the front of the room, broke them down into familiar movements (pliés, grapevines, cha-chas). By the end of the hour, I had gotten the hang of many of the routines, if not all of the corresponding arm movements.

“The first few times, you’re not going to do everything right,” one of my classmates, Sarah Rhine, 24, said, gently encouraging me to download the free instructional videos at the Jazzercise Web site.

Standing aerobic exercises, done without props, made up about three-quarters of the session. Light hand weights, used during the last few routines, added some additional resistance. But the workout, which wrapped up with a short series of mat-based abdominal exercises and some light stretching, never required more than moderate exertion.

It’s an ideal workout for dance-floor aficionados looking for a fun way to get in their cardiovascular exercise. However, it won’t likely appeal to those who favor more hard-core boot camp-style workouts, or more Zen ones that incorporate meditation.

After a class, Ms. Savage said that prior to taking her first Jazzercise class in Massachusetts six years ago, she, too, had thought Jazzercise had gone the way of the crimping iron.

“I said, ‘Really? It’s still around?’ But I was sold from the first class, which was fun, and over before I knew it,” she said.

Ms. Savage, who has been teaching Jazzercise in New York for more than a year, acknowledged that, especially in New York, the fitness regimen is still struggling to shed its 1980s image. “Some people still associate it with sweatbands and Olivia Newton-John,” she said.

Yet Jazzercise is continually evolving. Every 10 weeks, Ms. Missett provides instructors with a new soundtrack — Amy Winehouse is featured on the next one — and new routines that even the coordination-challenged among us can follow and enjoy.

Classes are $21.75 each; unlimited classes, $100 a month. For more information, call 212-374-1175 or visit jazznewyork.net. For additional locations in the New York metropolitan area, visit jazzercise.com.