It's hard to observe a Zumba Kids class without being overtaken by the urge to sway your hips and tap your feet.

That's what I discovered as I sat in the corner of an exercise studio at Shelburne Health & Fitness, watching my 6-year-old daughter, Mira, and four other elementary schoolers shimmy and shake to rhythmic Latin music.

Zumba is a trademarked dance-fitness workout that has exploded in popularity since it was created in 2001; Inc. magazine named Zumba Fitness Company of the Year in 2012, noting that an astounding 140,000 locations in 150 countries offer Zumba classes.

It's not surprising, then, that the craze is catching on with the kiddie set. Zumba instructors must get additional certifications to be able to teach Zumba Kids for ages 7 to 11 and Zumba Kids Jr. for ages 4 to 6. Until recently, the kids classes were called Zumbatomic.

Mira's Zumba Kids class began with a warm-up. Spurred on by the enthusiastic whoops of instructor Jennifer Niles, the group powered through a series of step touches, bicep curls, hand waves, and movements that mimicked jump roping and driving a car.

"Why don't you get a drink quickly?" Niles suggested when the song ended.

Adult Zumba and Zumba Kids classes use a lot of the same music, Niles says, ranging from salsa to merengue to cumbia to reggaeton. But while the grown-ups' class is a 60-minute nonstop fitness dance party, the kids' version lasts just 45 minutes, and there are frequent water breaks.

Another difference is that many of the adult Zumba moves are a bit racy, so Niles tones them down for kids. She also simplifies the steps. "It's not expected that a 4-year-old would do salsa steps like an adult," she says.

On the day I visited, kids were learning new steps to a song with a samba rhythm. Niles started by instructing kids to shift their weight from one foot to another. Then she asked them to embody their favorite superhero. Kids vogued dramatically with arms splayed and pretended to shoot webs like Spiderman.

At one point, the song lyrics instructed, "Take it back to the old school / let me see you Cabbage Patch." It was hard to maintain my composure as Mira and her fellow exercisers attempted the '80s dance move, churning their fists in circular motions.

After the kids imitated monkeys, babies and elephants in a rousing game of Freeze Dance, Niles put on a cool-down song from the movie Rio. Kids stretched their legs, rolled their shoulders and waved their arms in fluid, flying motions.

"You did a super-fantastic job," Niles enthused. "Come on and get your sticker."

Zumba not only encourages physical fitness in kids, Niles says, but also fosters creativity and confidence.

After class, I asked the kids what they like about the workout.

Nine-year-old Sam put it simply: "You get to dance!"