It’s not often that a decades-old workout fad resurges with cult-like fervor.  Boutique spinning classes, however, have thousands of people nationwide eager to sell their souls.  

SoulCycle, an industry-leading indoor cycling company that incorporates music, dance and therapy into its classes, embraces its obsessive community. “[SoulCycle’s] definitely a cult,” said Northeastern senior and SoulCycle enthusiast Katie Wong, “They literally advertise it on their merchandise with phrases like ‘posse, gang, cult.’”

Founded by Elizabeth Cutler and Julie Rice in New York City in 2006, the company now has more than 50 locations countrywide and sees over 13,000 riders every day, including famous names like Oprah, Madonna and Bradley Cooper, according to a press release provided by the company.

Some view SoulCycle with skepticism, however, as concerns have been raised about the safety of the company’s style of spin, as well as questions about the effectiveness of the workout.

So how does SoulCycle differ from the spin classes popularized in the late 1990s?

With therapeutic, mental components of motivation and spirituality added to their 45-minute workouts, SoulCycle claims to offer a unique, meditative fitness experience.  According to the company’s website, “SoulCycle doesn’t just change bodies, it changes lives.”

“SoulCycle is more than just exercise,” said Wong, who first attended a class six months ago while on co-op in Palo Alto, Calif., and now goes to the studio in Back Bay two to three times a week. “I see it as my therapy. If I’m not feeling well or I’m upset, if I go to SoulCycle, I’ll feel so much better, not just physically but emotionally and mentally. Ten times out of ten I walk out of SoulCycle and feel ready to conquer the world.”

Wong, an international business major with a concentration in finance, attributes most of this inspiration to SoulCycle’s staff of young, beautiful and charismatic instructors. “They don’t just yell ‘go harder, go faster!’ Instead, it’s more like ‘if you don’t push yourself harder, then change doesn’t happen.’ It’s more motivational stuff that makes me actually want to push myself and make myself better,” said Wong, adding that the insights translate fluidly to all aspects of her life.

Luckily for Wong, she didn’t have to suffer a period of SoulCycle withdrawal after finishing her co-op in California. The first SoulCycle studio in downtown Boston opened in Back Bay in late October, 2015, just two months before she returned to Boston. A studio in Chestnut Hill has been open since 2014 and, according to the Daily Mail, has attracted New England quarterback Tom Brady and his wife, Brazilian fashion model Gisele Bündchen.

Aside from providing encouragement, SoulCycle instructors also cultivate a fun and energetic atmosphere. “It feels more like a dance party than a workout,” Wong said.

The instructors curate unique playlists and craft specific choreography, designing an exercise program that “focuses on rhythm and the energy of the pack” to make “riders feel like they are partying in a healthy nightclub,” the company stated in the press release.

Caroline Earle, a spin instructor at Turnstyle Cycle, an indoor cycling boutique in Cambridge that employs a similar style of spin as SoulCycle, said the dance-party environment keeps people engaged with the exercise. “The choreography is to keep the class entertained and excited. People love the patterning of the choreography so continually doing that throughout the class makes it exciting for people to come in and do.”

The inclusion of choreography and upper body exercises, such as push-ups on the handlebars, abdominal twists and high-repetition lifting of 1-pound weights, differentiates SoulCycle’s style of spin from more traditional indoor-cycling classes, which aim to emulate a typical outdoor ride, according to Earle.

While it may mean a more entertaining ride, the incorporation of dancing and upper body exercises may also mean a weaker workout.

“You can’t burn matches in two areas,” explained Tom Scotto, an indoor cycling master instructor of 14 years, “so you’re either stressing one area or you’re stressing the other.”

“They’d be better off riding harder for half the time on the bike and then getting off and doing the other half as an upper body workout,” Scotto continued. “Since you’re doing both [upper and lower body exercises] at the same time, you’re reducing the effectiveness of both.” Scotto is an elite-level USA Cycling coach based in Boston with more than two decades of experience.

More than the effectiveness of the workout, though, Scotto is concerned about the safety of SoulCycle’s style of spin. After taking one SoulCycle class, Scotto said “the workout was great for an activity just to get people off of the couch, but there were definitely a lot of what we term as contraindicated movements,” meaning a movement that is contrary to the mechanics of the bike and puts the body at an angle or position where the joints and muscles can be harmed.

According to Scotto, these types of movements tend to show up as overuse injuries over time. “Unfortunately, it’s the people who are having a lot of fun now that somewhere down the line, depending on what movements they did and what they were accustomed to, will wind up with overuse issues,” explained Scotto, “and by the time they notice it, it will be too late. That’s what most fitness professionals get up in arms with [SoulCycle] about – or I guess I should say up in legs.”

When confronted with the safety concerns, Wong wasn’t too worried about the long-term effects. At $30 per class in Boston (not including the $3 cost of shoe rentals), Wong said the classes aren’t sustainable, or even accessible, for the average person.  “[SoulCycle’s] something I choose to invest in because I know I wouldn’t work out as hard without it, but, to be honest, I’m not sure if it’s worth what it costs,” Wong shared.

With no memberships or student discounts offered, Wong predicts the studio will stay popular with only those that can afford it.