When one thinks of gymnastics, one often thinks of youth — wee toddlers rolling and performing cartwheels on soft mats, adolescent girls whirling through the air above impossibly thin beams, and fresh-faced teenage boys walking upon their hands with the ease of strolling through Central Park. But for those in their 20s, 30s, 40s — or even 50s — it may be time to fulfill a long-buried dream of becoming the next Mary Lou Retton or Bart Conner. (Well, it may be too late for that. But it’s not too late to learn how to nail that back handspring or aerial.)

Despite the growing number of universities across the country dropping their gymnastics programs due to a lack of funding or interest, gymnastics classes geared toward adults are more popular than ever in New York City. Most of these classes start by emphasizing the fundamentals.

CHELSEA PIERS FIELD HOUSE

“A lot of the stuff we teach people is how to stretch the right way and how to roll without injuring themselves,” an instructor at Chelsea Piers Field House, Andrew Pacho, said. Mr. Pacho — a gymnast with more than 30 years of experience and a performer who has appeared in six Broadway shows — said the gymnastics classes he teaches attract adult students of many backgrounds. “We have all kinds here at Chelsea Piers,” he noted, citing dancers, martial artists, capoeiristas, and skiers.

With seven “all-levels” sessions and one beginners-only slot offered every week, Chelsea Piers has the largest number of classes for novice adult gymnasts and is also by far the most popular of the city’s options for grown-up tumblers, with each 1 1/2-hour drop-in session drawing between 10 and 25 students.

Each class starts with a warm-up exercise: Typically, that includes a jog around part of the facility’s 23,000-square-foot space and a variety of stretches, push-ups, sit-ups, and other calisthenics. Next come handstands, rolls, and cartwheels — with instructors there to offer helping hands to those who need it and watchful eyes over those who don’t.

That leaves about an hour to focus on tumbling, with students learning (at their own pace) round-offs, front and back handsprings, bounders, and, when they are ready, front- and back-tucked somersaults, aerials, and other handless maneuvers. Apparatus classes are held separately on Wednesdays from 8:30–10 p.m. The learning process may require bouncing on a trampoline or leaping into an enormous foam pit. Gymnastics is “the big kids’ sport,” Mr. Pacho said.

Jeremy Weatherspoon, 23, a professional dancer with Eclectic Dance Theater, has been coming to the Chelsea Piers gymnastics class “every now and then” for about two years. “Chelsea Piers has the best facility for the amount of money that you are paying,” he told The New York Sun. It’s a “really good environment with knowledgeable instructors.”

But others, such as Ethan Baldwin, a 23-year-old technician at an Apple computer store, say the $27-a-class price tag is a bit hefty. “And the locker rooms are kind of sketchy,” Mr. Baldwin added. Still, he said, “the instructors were great and very skilled at catering to a large group of adults at varying skill levels.”

(23rd Street and Hudson River Park, between Piers 61 and 62, 212-336-6500, chelseapiers.com, $27 a class, $190 for 10 classes, $360 for 20. Beginners-only class: Wednesday, noon–1:30 p.m. All-levels classes: Monday, noon–1:30 p.m., Tuesday, Thursday, and Friday, noon–1:30 p.m. and 7–8:30 p.m.)

NYC ELITE GYMNASTICS

For those who prefer a downtown Manhattan location or who get stir-crazy in a crowd, NYC Elite Gymnastics may be a good option: The maximum size of an adult class is 14, with the average being about 10, instructor Kim Petros said.

Those with no gymnastics experience should note that the “Wednesday class tends to be a little more of a beginner class.” Ms. Petros added: “The Tuesday-Thursday class is more advanced. They can maybe do cartwheels and handsprings, but they need help with back handsprings and tucks.”

The evening drop-in sessions focus on “a lot of conditioning.” Though the facility is equipped with a trampoline and a foam pit, one potential downside is its lack of apparatus. “It’s all floor tumbling,” Ms. Petros said.

(100 Sixth Ave., between Watts and Grand streets, 212-334-3628, nycelite.com, $26 a class, $260 for 10 classes, Tuesday through Thursday, 8–9:30 p.m.)

BROOKLYN GYMNASTICS CENTER

Female Brooklynites looking for a single-sex training environment may want to look into Brooklyn Gymnastics Center, which offers a free trial class that usually consists of between five and eight women in their 20s and 30s.

“The only class we have for adults is for women because the men don’t seem to be all that interested or able to handle it,” the gym’s owner, Barbara Manaro, told the Sun.

Also, she warned, though beginners are welcome, they are rare. “Mostly what we get are old gymnasts,” she said. “And it’s tough. That’s why we don’t get a lot of beginners, because it’s a lot of work.”

(1635 Bath Ave., between Bay 13th and Bay 14th streets, Bay Ridge, Brooklyn, 718-232-6444, brooklyngymnastics.com, $485 for 20 weeks, $55 to register. Adult classes [women only]: Thursday, 7–8:30 p.m.)

AVIATOR SPORTS & RECREATION

Unlike the heavily female classes at Brooklyn Gymnastics, here the students are mostly men, the receptionist, Catherine McLean, said. “A lot of guys come because a lot of guys actually excel in it,” she said. The typical class size at Aviator is between 10 and 12, but “the largest size we’ve ever had is about 30,” Ms. McLean added. Though quite a trek for a Manhattanite, the Aviator Sports gymnastics facility is well-equipped and state-of-the-art. It’s a “really nice studio, really nice space,” Mr. Weatherspoon, the Chelsea Piers gymnastics student, said of Aviator.

(5 Floyd Bennett Field, Brooklyn, 718-758-7575, aviatorsports.com, $22 a class, $150 for 10 adult all-levels classes: Monday and Wednesday, 8–9:30 p.m.)

LAVA STUDIO

Those looking for a slightly different approach might want to check out Lava, an arts organization that has been producing original acrobatic performances for 12 years. “Our classes grow out of the performance work,” the group’s artistic director, Sarah East Johnson, said. “It’s very much a social activity — people having fun together.”

The fun includes learning to stand and slide on one another, as well as to do cartwheels, somersaults, and even trapeze work. “We focus a lot on headstands, which really work to connect the body so your arms and your legs and your middle all move together,” she said.

The classes, which usually consist of 10–16 students, fill up quickly, so dropping in isn’t always possible. But for Joes and Janes wanting to try out tumbling for the first time, perhaps the best part is that most of the students at Lava have no particular dance or sports background. “They’re just regular people,” Ms. Johnson said.

(524 Bergen St,, between Sixth Avenue and Carlton Street, Prospect Heights, Brooklyn , 718-399-3161, lavalove.org, $165 for 10 weeks, $20 for a drop-in. Introductory course: Thursday, 6–7:30 p.m.)