Gyms and the people who work for them have a nearly impossible mission. Think about it: First they have to get you in the door. Then they have to convince you to shell out money for a membership you almost certainly won’t use enough to justify its cost. Finally, they have to make you feel comfortable with the inherently uncomfortable situation of looking sweaty and disgusting in front of strangers. And yet somehow, they manage to do it.

Still, big-box gyms are having an identity crisis. Smaller studios catering to niche preferences are elbowing into their territory. More than 40 percent of gym members dump their full-service membership every year, according to the International Health, Racquet & Sportsclub Association. Meanwhile, boutique studios like SoulCycle or Pure Barre are the fastest-growing part of the fitness industry, leaving the chain gyms shaking in their boots. 

“All major chains are in major financial disruption,” says Thomas Plummer, author of How to Make More Money in the Fitness Industry. “They know what they do is not working but many are afraid to go to the next step.” While they figure out their next move, here are a few behind-the-scenes insights into how the big gyms work. 

1. THEY COUNT ON YOU NOT SHOWING UP.

“If you are not going to the gym, you are actually the gym's best customer,” writes Planet Money’s Stacey Vanek Smith at NPR. Many big clubs make their money by recruiting as many members as possible, which ends up being far more than they can actually accommodate. So they’re banking on you slacking on your workout goals. According to Smith, Planet Fitness has about 6500 members per gym but can only hold about 300 people at a time, max. 

Kevin Fowler, who directs a relatively small 400-member gym in Mississippi, says “if I had all of them in here even just through the day we wouldn’t be able to keep up with everything. We want the memberships and we want them to pay but we don’t necessarily want them to all come at one time.” 

2. THEY PUT THE CARDIO EQUIPMENT WHERE YOU CAN SEE IT ...

It’s in the big box gyms’ best interest to attract people who want easier, less frequent workouts rather than those with serious fitness goals. One way to do this is by hiding the equipment to avoid intimidating potential new customers. “Instead of displaying challenging equipment like weight benches and climbing machines in plain view, gyms will often hide weight rooms and other equipment in the back,” writes Smith. 

If they show any equipment at all, it’s usually the cardio machines. Ellipticals are the most popular machines because they’re easy to use, but they’re arguably not very efficient at getting your heart rate up. “Sure, the gliding motion of the elliptical burns calories, but that’s about it,” says fitness guru Jennifer Cohen. “It is also easy to slack off on the elliptical.” And who do the big gyms want to attract? Slackers. 

3. ... AND THEY PACK IN AS MUCH EQUIPMENT AS POSSIBLE.

Many large franchise operations get a cut of whatever equipment their franchisees buy—so the more equipment a gym is required to have, the more money the parent company gets. Rudy Fabiano, an architect who designs gyms through his firm, Fabiano Designs, uses the example of Planet Fitness: “They get maybe 10 percent to 15 percent of that package and the typical Planet buys half a million worth of equipment if not more. That’s $75,000 in profits. So it’s a little self-serving.” 

4. THOSE SIGN-UP FEES? YOU DON'T HAVE TO PAY THEM.

A lot of gyms have a one-time fee that comes with a new membership—and those fees are often negotiable. “The gym I worked at before this had a $200 sign-up fee, but I’m not sure anybody actually paid that $200 sign up fee,” Fowler says. Aside from extra money in the gym owner’s pocket, those fees exist mainly as a way of running promotions. If a gym wants to get a bunch of new members, it uses the rule of scarcity and drops the fee for a short amount of time to make new members feel like they're getting a bargain. 

If the only thing preventing you from signing up is that one-time fee, the salesperson will often lower the fee or skip it completely. They’re salespeople, after all, and they’d rather lose that fee and gain a year-long paying member than get nothing at all. “If that fee was a deal-breaker, I would wave it,” says Mo Hall, who spent six months doing membership sales at a fitness chain on Long Island. “If you say you’re not gonna pay it, they’re not gonna let you walk out the door.” 

Also, you’re more likely to get a bargain near the end of the month. “Salespeople work on commission,” one gym employee said on Reddit. “Therefore, they are much more likely to give you a better deal at the end of the month, when they may be below goal or getting a big commission from your sale.” 

5. GROUP EXERCISE RETAINS MEMBERS.

According to Plummer, fitness clubs lose about 50 percent of their members on a year-to-year basis. “In the past, club operators have resorted to fairly sleazy tactics to keep these people going, such as letting the members slip from a contractual obligation at the end of the first year into a month-to-month option with the hopes that he won’t notice and will just keep making those payments or just let the club keep drafting his credit card or checking account,” he writes in How to Make More Money in the Fitness Industry. 

There’s no doubt many clubs still use shady practices to retain members (the Better Business Bureau received more than 6000 complaints about gyms last year, many citing such practices), but other clubs realize there’s an easier way to keep members: get them involved in group exercise like yoga, spin classes or kickboxing.

“I have seen group exercise become very attractive to a large number of people because it offers accountability,” says Jeff Presley, a fitness instructor in Kentucky. “If I don’t show up, people are gonna miss me. If I do, I’m gonna be challenged because I’m working out with other people.” 

According to a Nielsen Global Consumer Exercise survey, gym members who participate in group exercise stay longer and are more likely to recommend their gym to family and friends. 

“You wanna encourage people to interact,” Fabiano says. He incorporates areas for socialization into his gym designs, whether that’s in the lobby, outside the locker rooms, or even on staircases where people have a tendency to gather anyway: “Those social engagements become important in terms of why you would keep going back.” 

6. THE YOGA MATS ARE PROBABLY FILTHY. 

Nothing turns off a customer like filth, and most clubs are aware of this. “Dirty clubs cost you more female members than any other issue,” Plummer writes. He even recommends owners hire “ghost shoppers” to visit the gym and report back on cleanliness. At Hall’s gym, one of the biggest recurring complaints was the strong smell of bleach in the air. 

But, according to Kim, a former fitness instructor in Alabama, the yoga mats are bacteria breeding grounds: “Even if the gym cleans the equipment ‘regularly,’ the regular cleaning may have been a week ago. At our gym, the mats were cleaned once a week. Yuck. Someone else's bare feet and sweaty back has been on that mat.” 

7. YOUR INSTRUCTOR MIGHT NOT BE CERTIFIED. 

When Kim became a group fitness instructor, all that was required of her was a three-day training course. “Personally, I have no background in any kind of physical education, fitness, or health,” she says. “Don't get me wrong—we do genuinely care about helping you get in better shape and keeping you from injuring yourself, but just because I can show you how to do a move doesn't mean it's a good move for you to be doing. Remember that the contract you signed when you joined the gym almost certainly released both the facility and its employees from any liability at all if you get hurt.”

8. PERSONAL TRAINERS KNOW WAY MORE THAN THEY WANT TO ABOUT THEIR CLIENTS. 

“You’re also their life coach and psychologist,” Fowler says. “When they get to know you, they’ll start telling you a lot. They’ll open up to you about their family, their kids, even their bathroom situations. It’s fine with me. I just listen to them and that’s all they want I guess.” 

9. EVERYONE WANTS BETTER ABS.

“The most popular thing people want to know when they come in is how to lose their stomach,” Fowler says. “Probably 90 percent of the people who come in want to know how to lose their stomach. But I’m always the bad guy because I have to tell them you can’t just do sit ups.” 

10. THE SAUNA IS PRIME REAL ESTATE.

“A lot of the older clientele, especially men, love the sauna, and God forbid that thing goes down for even one day,” says Patrick Miller, a former gym employee. Inevitably, though, the sauna does go down because it gets abused. “Whether it's from pouring water on the rock, which you are not supposed to do, to peeing on the rocks, when that sauna does go down, you may as well have just kidnapped their first born child,” Miller says.  

11. GYMRATS LOVE CRIME SHOWS.

For some reason, people tend to watch crime TV when they’re working out. “It’s lot of Law and Order,” Fowler says. “I haven’t quite figured it out yet.” Someone even created a Law & Order: SVU workout. It calls for 10 squats every time Elliot loses his cool. 

Even Emily Nussbaum, the TV critic for the New Yorker, likes watching crime shows on the treadmill. And this is a woman who watches TV (often really good TV) for a living. “Generally, this lineup consists of reruns of Law & Order: SVU and NCIS, which is a show I have actually never watched outside of the gym,” she writes. “I watch using captions, with headphones plugged into Pandora, and since I don’t follow the plot closely, watching the show has evolved into an experimental and soothing experience, all about people glaring and breaking down doors. It’s nearly avant-garde, or like one of those meditation DVDs.” 

12. YES, THE EMPLOYEES ARE WATCHING YOU.

Work in a gym and you’ll notice all kinds of human quirks that go way beyond just grunting and excessive sweating. For example, there are some members who show up regularly but don’t use the gym to work out at all. 

“There was this really sweet lady who would come in and shower at the gym and then leave,” Presley says. “No one would see her work out. It was really strange.” 

Others drop in just to please their employers. “There are still members to this day who come in, scan their cards, and leave five minutes later just so their employer can see they hit their quota for the month and pay for their membership,” Miller says. 

And the locker rooms are like treasure troves of strange human behavior. Presley tells the story of a regular at his gym who everyone called "the ladies man." “He would flirt with all the women and the front desk workers,” he says. “I walked into the men’s locker room one day and he had his toupee off and was combing it and blow drying it.”