In New York City, you can hardly walk a block without stumbling upon a yoga studio, CrossFit “box,” barre workout class or any of a dozen other specialty workout studios. So we asked the brains behind MyFitnessPal, an app which tracks the workouts and calories of some 75 million users, if the rise in these specialty fitness trends were replacing big box gyms.

“We are seeing exactly what you’re talking about, all of these new, specialized, niche sort of group workout studios really exploding in popularity,” said Tara-Nicholle Nelson, Marketing Vice President for the app. She credits the shift away from big box gyms on a changing attitude toward fitness. “I talk a little bit about this trend I call supernatural. And it just breaks down… that people are looking, they literally want to defy nature. They want to live healthier and look better and be fitter as they get older, but they want to do so with all-natural means.”

That means there’s a growing focus on all-around health and fitness. Companies that are plugged into this shift stand to make big bucks.

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“These workout [studios] from a business perspective are a very major signal of consumer interest. Consumers are out there and they want to find the latest workout that works.”

That’s translated into big growth for these studios. MyFitnessPal users reported a 17% increase in CrossFit workouts last year and a 71% jump in 2013. Soul Cycle, another high-profile, specialized gym that involves intense cycling in a dark room with loud music, saw a 78% jump. Even yoga – which has been slowly growing in popularity since it was introduced to the U.S. in the '70s – cracked the top 10 exercise list for the first time.

Still, the biggest trends in workouts aren’t really trends. MyFitnessPal tallied the top exercises for users in 2014 and walking was number one. (Full list in video above.) “I’m not really prone to making sweeping predictions, but I can’t imagine a year in which walking is not at the top of that list,” said Nelson, noting that walking is an exercise that appeals to everyone from serious athletes to senior citizens. Plus, growing use of devices like Fitbits, Jawbones and other wearable devices have led to an increase in tracking, so we’re more aware of walking as exercise. That trend is likely to increase with the introduction of devices like the Apple Watch (AAPL). Even Microsoft (MSFT) now has a fitness band.

The rise in specialized exercise, though, isn’t always clear cut, and it may not be all bad news for big gyms. Many sports clubs offer their own cycling and yoga classes, as well as “trendier” exercises like Zumba and even high intensity training that mimics CrossFit. “The smart big box gyms are starting to evolve," Nelson said, “To develop more of their square footage to really innovative classes.” Gym chain Equinox, for example, bought a majority stake in spinning studio Soul Cycle.

There are only a couple of publicly traded big box gyms. Town Sports International (CLUB), which owns New York Sports Club, Boston Sports Club and others, has seen share prices fall 39% over the past year. Lifetime Fitness (LTM), meanwhile, has seen a 22% increase in its stock.

But big box gyms aren’t the only trade affected by a shift in fitness trends. Apparel makers are keenly aware of the stratification of fitness.

Brooks, which makes shoes and clothes for runners, noted several years ago the drive towards specialized fitness and chose to focus just on running at the exclusion of other sports shoes. It was a strategy successful enough to earn the company an investment from Warren Buffett in 2012.

Running was the second most popular activity among MyFitnessPal users in 2014. While running and walking used to be considered free exercises, that’s not necessarily the case any longer. Sneakers regularly retail for $100 or more. Race entry fees have jumped. In 2012, the New York City marathon famously hiked its entry fee to $255 from $196 (though it’s lower if you’re a member of the New York Road Runners running club.) Plus, there’s line after line of running-only apparel. The usual suspects like Nike (NKE), Adidas (ADS.DE), Under Armour (UA) all have lines dedicated to running. But other retailers are picking up on the trend. Gap (GPS) as well as its Old Navy and Athletic brands offer running-specific gear.

And that’s clothing dedicated specifically to running. If you want to focus on yoga, you’re talking a whole separate line of clothes. Cue LuluLemon (LULU) which, despite a well-documented set of transparency issues and public relations gaffes, has still seen some 317% growth in its stock over the past 5 years versus just 140% for the S&P 500 (^GSPC).

It’s no wonder research firm IBISWorld reports the fitness industry is valued at $27 billion, encompassing nearly 30,000 businesses.

But what if you’re trying to lose pounds, not invest cash? There are ways to keep costs down, says Nelson. With individual classes at yoga and cycling studios ranging from $20-$40, entire businesses are popping up to try and keep costs in check.

“Things like ClassPass and FitMob evolved to allow participants to buy one pass to get a much lower cost per class, and they also do a sort of double duty for helping studios reach new audiences and fill unfilled slots.” Those services offer a bundle of classes for a fixed price, and customers can use them at a variety of studios. There’s even a yoga-only version called Yoga PassBook.

Bottom line: Fitness trends are becoming less trendy and more lifestyle-oriented. Nelson told Yahoo Finance that 64% of MyFitnessPal users are teaming up with people around health and fitness goals and more than 50% of their users say they prefer group workouts to solo. Even people who prefer solitary exercises like running, are becoming more likely to share their workouts and training schedules with friends. Plus, no one is staying loyal to one exercise anymore. “They want to do Zumba one day, they want to do CrossFit another day. They want to do high intensity interval training (HIIT) one day and a barre class or a Soul Cycle class another day. So we think these are some of the trends that are colliding.”

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