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The website for CrossFit, the extreme fitness regimen that has become all the rage, displays an interactive map of the world that's almost hypnotic.

You could spend hours staring at it, scrolling from continent to continent, discovering CrossFit affiliates in every nook and cranny of the planet. Zambia. Namibia. Iceland. Cyprus. Lebanon. Israel. Malta. Morocco. South Korea. Thailand. Tasmania. United Arab Emirates. Bahrain. New Zealand. Australia. Virtually every country in South and Central America. Every country in Europe. They're even in places you can't possibly have heard of, like Rarotonga (South Pacific) and Khabarovsk Krai (remote eastern Russia). And, of course, they form a virtual blanket over the entire United States.

That mesmerizing map reflects how CrossFit seems to have literally conquered the world of fitness.

And it just keeps filling up with dots. Last October, CrossFit announced it had reached 8,000 affiliates. Three-and-a-half months later, the company hit 9,000. And four-and-a-half months after that, just a few weeks ago, came the 10,000th affiliate for the $40 million, privately held company.

This weekend's 2014 CrossFit Games are sponsored by Reebok, televised by ESPN and about $2 million in prize money will be awarded.

This, then, is the bitter irony about CrossFit, conceived as a renegade workout program that regularly portrays itself as the anti-gym. Yes, the truth is that CrossFit has gone mainstream.

None of which would be a problem except that, well, some people think it's a problem.

As the sport has gone to the masses, it seems to be drawing more attention from fitness and medical professionals concerned about safety. They say they are struck by the number of patients/clients who say they were injured doing CrossFit; they worry that with so many CrossFit facilities opening, there can't be enough qualified trainers to teach these kinds of intense workouts; they argue that some of these exercises are being misused under CrossFit's emphasis on doing as many reps as possible and/or racing the clock; they wonder whether all these people flocking to CrossFit understand that it's not like going to Starbucks, that this is not a franchise but rather a disparate group of 10,000 gyms. And it's not lost on them that some people who raise questions about CrossFit have faced a hostile response.

CrossFit workouts call for a varied set of exercises that, in many cases, are to be done as quickly as possible or within a certain time frame. The routines employ everything from Olympic lifts like the clean and jerk to box jumps to handstand pushups to pull-ups that call for you to bring your toes up to the bar. None of this was really an issue for CrossFit when it was primarily Navy Seals or first responders or assorted other fitness savants pushing themselves to extremes. Who better to be tested in the ultimate way than those people, and they surely knew what they were getting into.

Now, though, with CrossFit's precipitous growth, it's dominated by average men and women who want to be in great shape. Particularly women known as "soccer moms," according to Greg Glassman, CrossFit's creator, who explained in a 2011 video posted on YouTube: "They're running with the movement."

To be certain, given CrossFit's surging popularity, there are an endless stream of ad hominem attacks on it that are rooted in little more than jealousy, the pervasive bitterness of social media or, at the very least, parody. But beyond that, there are the folks who regularly come into contact with everyday CrossFitters and wonder about the sanity of it all.

This week, Reebok announced that it signed Rich Froning, the three-time champion of the CrossFit Games, to a long-term contract. A Reebok executive told "Men's Journal" that the deal made Froning one of the company's highest-paid athletes. Dario Cantatore/Getty Images

"There are a lot of people in this world who work with athletes and do really challenging stuff every day," says Tracy Fober, a strength and conditioning coach who has previously taught CrossFit weightlifting trainers courses and who recently was hired by U.S. Ski and Snowboarding. "And you can work people really hard and still understand there are limits, that sometimes you just gotta say, 'Nope, that's enough and any more is just kind of stupid human tricks.'"

Want to open a 'box'? Simple

CrossFit's rapid growth can be tied to several factors -- the emerging stature of the CrossFit Games, the community atmosphere of the training and the fact workouts are short and results come quickly. But perhaps nothing has spawned the company's growth more than the fact it's actually quite easy to open a CrossFit gym, or "box," as they're called in CrossFit's vernacular. A $1,000 weekend seminar, an essay and a $3,000 annual affiliate fee are all it takes to use the brand name.

"It was important to us that there wasn't a huge barrier to entry," said Lauren Jenai, Glassman's ex-wife, who helped grow the business organically out of the couple's initial box in the small California coastal community of Santa Cruz. In late 2012, amid a nasty divorce and a battle over the direction of the company, Jenai sold her half of the business to Glassman for $20 million. "There were not huge start-up costs; we made it easy just for normal people to open a business."

Indeed, because the Glassmans chose not to franchise, someone could open a box without having to come up with a six-figure payment before they even could consider launching. As well, many CrossFit boxes are in business parks or warehouses, so the rent is considerably cheaper than at traditional gyms.

Prospective box owners first sign up through headquarters, or HQ, for a two-day certification class -- known as the Level 1 Cert -- that costs $1,000 and introduces the "methodology and foundational movements" of CrossFit. At the end of the two days, there's a 55-question, multiple-choice test.

"We joke all the time that a CrossFit certification only certifies that you have a valid credit card," said Greg Everett, who was a partner in the fourth affiliate, which opened in 2003, and worked closely with HQ before an ugly and personal dispute led to HQ pulling his affiliation in 2009.

The Level 1 is one of CrossFit's primary sources of income. The classes often sell out, with as many as 50 people, and there are several offered throughout the country and world practically every weekend. For example, about a week before the weekend of June 21-23, the CrossFit website listed sold-out Level 1 Certs at eight spots in the United States; three in Europe (Germany, Sweden, England); and one each in Australia, Dubai, China and Brazil.

Beyond the Level 1 Cert, CrossFit has prospective owners file an application with an essay, which its website says should include, "what CrossFit affiliation means to you, why you want it, and what you want to achieve. It doesn't have to be long or formal, but it should be from the heart." There are no franchise costs, only a $3,000 annual fee.

"Outside the Lines" sought to learn more about the Level 1 Cert, but Dave Castro, one of Glassman's top associates, wrote in an email that reporters could neither observe nor film a class unless they participated in it. Castro wrote: "Approaching this with traditional methods of journalism will be what prevents this from happening. Nothing we do is traditional, nor should be your approach on covering us properly." Requests to interview Glassman or others from HQ also were denied.

Women work out at the Kent and Sussex CrossFit in England. Getty Images

In reality, there is no governmental regulation on personal trainers in any setting, be it a CrossFit box or a 24-Hour Fitness facility. Instead, private organizations like CrossFit or the National Strength and Conditioning Association offer courses that allow trainers to state they are certified through those organizations. Nor is there government oversight on gyms themselves, at least where the quality of the facility is concerned.

Everett says he and a few other early CrossFit disciples had begun to express concerns several years ago that, among other things, it was far too easy to become an affiliate and that quality control was emerging as a problem. HQ's position on this seemed clear, as articulated by Glassman's oft-stated Libertarian perspective: "The cream would rise to the top." It was not HQ's role to police the affiliates, this was not a franchise and the market would settle itself.

The tension over this came to a boil in late 2009 at a two-day seminar in Austin, Texas, titled, "The Black Box Summit: For Affiliates By Affiliates." Though the event was affiliate-driven, HQ was represented by Castro and one other official. There are several versions of what happened, but what's undisputed is that it got nasty between Everett and Castro -- with Castro at one point calling Everett a "fat f---" -- and not long after Everett had his affiliation rescinded. Robb Wolf, a business partner of Everett's and another of the very earliest followers, was ousted, too, and the event became part of CrossFit HQ lore.

Jenai, whose relationship with Glassman already was fraying at that point, says she was sympathetic to the concerns beginning to emerge from the affiliates but that Glassman and others were wary of the Black Box Summit from the start.

"There has always been an underlying fear of the affiliate community taking over," Jenai said.

Five years later, with nearly seven times the affiliates there were in 2009, the concerns about quality control have only grown louder. Indeed, if you look at that affiliate map now, it's not unusual to find one CrossFit box actually right down the block from another, in some cases barely more than a 10th of a mile apart.

"I think that's the biggest complaint," Jenai said, "that there's no territory, that you could have some a--h--- who just got his Level 1, has no certified trainers and no extra credentials offering their training super cheap, when you have a legitimate gym 400 meters away."

To Fober, the strength and conditioning coach and physical therapist, it's less about the fairness to the affiliates than it is about the safety of the consumers. For her, it raises the question of whether CrossFit users actually understand that despite the brand dominance, there's no guarantee on quality.

"My brother-in-law owns several McDonald's," she said. "He is held to strict standards by McDonald's. He makes a lot of money, but if they say, 'We want you to move our McDonald's across the street,' he has to do it. The quality control is so rigid. ... There were two CrossFits literally within two blocks of each other here. How much quality control is there? But I don't think they care [at HQ]."

Debates about safety

So, then, how safe is CrossFit?

"Contrary to a whole lot of bulls--- out there, it's really safe," said Jenai, who runs her own box in Prescott, Arizona. "It's really hard to get hurt doing functional movements."

Rachel Crass doesn't agree, at least not about the part that includes Olympic weightlifting. Crass' father was a 1984 and 1988 Olympian, and Rachel was just 7 when she took part in her first competition. She made four junior world teams, one senior world team and is currently a national coach for USA weightlifting.

"For every person who thinks it's the best thing to ever happen to weightlifting," Crass said, "there's one or two more people who really lament the technique and programming and how the Olympic lifts are being used."

CrossFit urges athletes to scale back workouts to fit their abilities, but Crass says it's common for technique to go out the window amid the call to do as many reps as quickly as possible. She works with CrossFit athletes and says she sees injuries from them far more often than from her clients who perform the lifts more traditionally.

"You'll see injuries [and say], 'You've only been in it three months, why in the world are you getting hurt?'" Crass said.

But then there's Mike Burgener, a well-respected veteran of the U.S. weightlifting community and a longtime coach for CrossFit's training clinics. In 2007, Burgener ran five clinics for CrossFit, all by himself, all in California. This year, he will oversee 115 in the U.S. and around the world, with some 75 coaches under his umbrella.

2013 CrossFit women's champion Sam Briggs. Courtesy of CrossFit Inc.

"I go to gyms unannounced, I go to a gym and there's not been one gym that I've ever been to in my 10 years of experience that I walked into and said, 'Oh, oh that is unsafe,'" Burgener said, adding that technique on the lifts has improved immensely through the years. He does admit, though, "Nine thousand boxes is a lot, and to assume that you're going to have all 9,000 of them be able to teach the snatch and the clean and jerk in a safe and efficient manner isn't going to happen."

One of the reasons nobody seems to have anything more than anecdotes to support claims one way or the other about the overall safety of CrossFit is because virtually no research on it exists.

In 2012, Dr. Joe Powers, a primary care sports medicine doctor, and some of his colleagues at the American Sports Medicine Institute, began to notice an increase in patients coming to them who attributed their injuries to CrossFit.

"It wasn't a massive influx," he said, "kind of out of the blue or anything like that, but I think it was sort of a steady stream over time where we became aware and said, 'OK, this is something that we should probably look at a bit closer.'"

Finding a dearth of studies on CrossFit, they decided to do some of their own. Powers and epidemiologist Kyle Aune say they're largely in the early stages of the work, and it's too early to draw conclusions about injury rates, but they hope to be able to reach that point. They presented two posters recently at a medical conference, and Aune says the thing that has struck him most so far is that 35 percent of the athletes who reported injuries cited overexertion, 20 percent cited improper technique and 7 percent cited fatigue for the cause. Aune says he doesn't know if those numbers would be any different for runners, weightlifters or any other activity common among recreational adults.

"These people know that they're tired, they're fatigued, they're overextended, using improper technique [from fatigue]," he said. "If you ask any Olympic weightlifting coach, they would tell you if you're not using weights right, or lifting too much, or tired, that's a problem." Said Powers: "I think maxing out to the point of exhaustion, for a lot of these exercises may not be the best thing."

If, in the end, their research raises questions around CrossFit, Powers and Aune might need to be prepared for some backlash. CrossFit HQ has developed a reputation for attacking anyone who would question the sport's safety, be it in the form of a lawsuit or through social media.

For example, Aune and Powers are both well aware that researchers at Ohio State University have been sued by a local CrossFit affiliate in Columbus, Ohio, while CrossFit HQ has sued the National Strength and Conditioning Association. The lawsuits stem from a study published in the NSCA's peer-reviewed journal, "The Journal of Strength and Conditioning Research."

The Ohio State researchers sought to examine the effects of CrossFit training on "aerobic fitness and body composition." And, in fact, they found that, CrossFit worked quite well, that it "significantly improves maximal aerobic capacity and body composition in individuals of all fitness levels and genders." So, why the lawsuit? Buried within the 17-page paper, in an overview of the study participants, was this sentence: "Of the 11 subjects who dropped out of the training program, two cited time concerns with the remaining nine subjects (16 percent of total recruited subjects) citing overuse or injury for failing to complete the program and finish follow up testing."

Soon, a representative of CrossFit HQ was contacting one of the Ohio State researchers and members of the box who had participated. What HQ said it discovered was that while the study "correctly found that CrossFit improved the athletes' fitness levels," the 16 percent figure was wrong. It was, CrossFit stated in its lawsuit, "at best the result of sloppy and scientifically unreliable work, and at worst a complete fabrication." CrossFit HQ stated it had contacted many of the participants, who denied reporting injuries as a cause for leaving the study. And, CrossFit asserted, the 16 percent dropout data was "contrived to dissuade people from using CrossFit" because the NSCA is a competitor.

Aune is concerned that the lawsuits could make researchers reluctant to study CrossFit.

"You just want people to make informed decisions," he said. "The majority of these athletes are not what you see in the CrossFit Games, they're sometimes pudgy, pasty, middle-aged people who just want to get healthy and not have hypertension."

CrossFit community very strong

Kevin Ogar does look like one of those athletes you might see at the CrossFit Games. And up until six and a half months ago, he had designs on competing in the event this weekend. Instead, he's now paralyzed from the waist down after failing to complete a 235-pound snatch lift and having the bar fall on his back as he tried to bail out.