SOMERVILLE — As the students planted their feet and raised their heads while coming forward in a high plank pose, the yoga instructor told them to do something unconventional.
“You’re going to scream,” said Black Widow Yoga founder Tina Moroney, nearly shouting to be heard over an Ozzy Osbourne song that blared through a pair of concert speakers.
On any other night, the venue — with its “no stage diving,” signs and a floor that smells like stale beer — would host bands like Cattle Decapitation.
But on this evening, it’s a makeshift studio for Metal Yoga, a typical yoga class set to double-bass drums and heavy guitar riffs, with a liberal dose of swear words and middle fingers.
Everywhere you look, it seems someone is adding a unique twist to the centuries-old practice. For starters, there’s glow-in-the-dark yoga, which fuses black lights and glow sticks with power yoga; the highly popular “Beer Yoga,” where students sip craft brews in a tap room after stretching; and “Goat Yoga,” where sun salutations are interrupted by frolicking baby goats.
Oh, and don’t forget Marijuasana, a workshop coming to the area that mixes marijuana and “asana,” the word for a yoga pose.
Teachers and industry analysts say this sudden phenomenon of experimental yoga is directly correlated to yoga’s surge in popularity. And although it’s true that some of these quirky offerings eschew tradition, they also give newcomers who might otherwise steer clear of those posh Back Bay studios a portal into the stretchy-pants community.
“This isn’t, like, a way to distract from the yoga,” said Brian Aldred, a self-proclaimed “metal head” and one of the many students who shelled out $17 for the recent Metal Yoga class. “It’s a way to get into the yoga.”
Moroney agreed, noting that men in particular seem more comfortable with the nontraditional spin.
“It opens up people who may feel like they can express themselves in a new way, and they might not feel like certain other ways of doing yoga really relate to them,” she said.
A study by the Sport and Fitness Industry Association found that in 2016, 26.2 million people tried at least one yoga class, up from 23 million in 2012. A separate report conducted by Yoga Journal and the nonprofit Yoga Alliance in 2016 showed even stronger growth: More than 36 million Americans reported trying a yoga class in the previous six months, compared with 20 million four years prior.
At the same time, that study found, people are spending more on yoga accessories, equipment, and on a variety of classes, some of which they might view as a place to socialize with like-minded people under the guise of getting fit.
Lucky for them, there are plenty to choose from. Whether it’s a one-time class for charity, like the upcoming “Bunny Yoga” taking place in Brookline to benefit the MSPCA, or an ongoing practice like Moroney’s Metal Yoga, which she typically teaches at the Satanic Temple in Salem, the options can seem endless.
Andrew Tanner, chief ambassador for the Yoga Alliance and a yoga teacher for 15 years, called it the “postmodern era of yoga.”
“Over the last 20 years, more and more people have started to break away from the traditional system and add their own modern, Westernized views into what they are teaching. And then those [students] started teaching, and their students have added even more layers of complexity,” he said. “That’s why you see people who are able to do these workshops like Goat Yoga.”
Jason Chung, a senior research scholar at New York University’s Sports and Society, a think-tank that studies social issues through sports, said the emergence of these classes is a “very millennial thing to a certain extent.”
Anything that combines health consciousness and social interaction, he said, is particularly attractive to younger consumers.
“It’s desirable to people to be in shape and fit, so if you can fit in a social exercise activity, it’s the best of both worlds,” he said.
With greater access to yoga teacher training and less overhead for dedicated studio space as classes are held at breweries and parks, the influx of offbeat yoga styles isn’t surprising.
Chung said at this point, it’s difficult to know whether it’s a fad or more of a sustained trend, but as long as people are going out and exercising safely, “There is really no downside.”
“If you can add bunnies to it, why not?” he said.
But some traditional yogis still prefer the basics.
Rebecca Pacheco, a yoga instructor and author of “Do Your Om Thing: Bending Yoga Tradition to Fit Your Modern Life,” said she fully supports getting creative when it comes to personal yoga journeys, but given the choice, she’d skip the animal antics and pass on all the bells and whistles.
“I don’t think anyone is confusing these experiences for sustainable or deeply meaningful yoga practice, which ultimately doesn’t need anything extra,” she said in an e-mail. “One of the best and most enduring aspects of yoga is how simple it can be. All you truly need is a mat.”