The madness is about to begin.

Fifteen men stand against a wall in a 6,000-square-foot converted warehouse in Salt Lake City. They’re anxious, and it shows in their unconscious movements—shifting feet, tapping fingers, darting eyes. The punk music blasting from overhead speakers adds an almost palpable intensity as Gym Jones’s splendidly profane, superhero-size fitness director, Rob MacDonald, saunters up and down their ranks.

“You, 48. You, 54. You, 63,” says MacDonald, jabbing a finger at three men in turn. “That’s how many calories you have to burn—in one minute. If you don’t make it, you’ll keep trying until you fucking do.”

Muffled curses filter through the music as each man considers the immensity of his task. To reach his calorie goal, which MacDonald calculates using body size and fitness level, each man must give everything. Pain is a promise, suffering guaranteed. (Are you ready to enter the pain cave? Try the full Gym Jones Workout. It'll make you sweat, yell, and curse.)

The first victim saddles up on the AirDyne, a stationary bike with movable handles and a giant fan for a front wheel. It’s a remarkably innocent-looking torture device; the harder you pedal, the harder pedaling becomes, thanks to the exponential nature of air resistance. MacDonald smiles diabolically. “Go!”

The man pedals like Mark Cavendish on bath salts—a blur of whirling, spinning, revolving legs and pushing, pulling, flailing arms. His grimace hardens and his breathing becomes increasingly frantic as each second ticks by. Then it’s over. His minute is up and he’s off the bike and on his back, gasping for air and jabbing at his quads. “Next!” shouts MacDonald.

One by one the men take the test, dropping to the floor or hobbling about on spasming legs when it’s over. Some fail. A guy in his 20s who was assigned 48 calories finishes with 47. “The only thing that makes Rob happier than people hitting their mark is when they miss it by a calorie,” says Mark Twight, Gym Jones’s founder, who’s known as much for sculpting some of Hollywood’s most chiseled bodies as he is for eschewing the fame that comes with it. “He loves throwing them back into the fire.”



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As deranged as the Air Dyne test seems, it isn’t an exercise in fitness sadism or a blitzkrieg attempt to build lung capacity. It isn’t even designed to train the body. It’s a sweaty baptism into Gym Jones’s foremost principle: The mind is primary.

Benjamin Lowy

In a state known for religious zeal, Gym Jones fits right in. Members are called disciples, and half-assed effort leads to excommunication. Many of the workouts—which range from crushing, hourlong circuits to vicious intervals on the rower or AirDyne—are insanely intense. “Each workout is designed to be a mental crucible, an exercise in the art of suffering,” Twight says. “Through suffering, you discover your true potential.” (Push your limits with these 4 Brutal Fitness Tests from Gym Jones.)

Twight has practiced what he preaches. A celebrated mountaineer, he forged his mind-first fitness dogma while setting alpine speed records and claiming a first ascent on a notoriously treacherous frozen waterfall in the Canadian Rockies. “There were guys who were fitter and better technical climbers than I was,” says Twight. “But I did more transformative things because of what I had on board mentally.”

Twight founded Gym Jones in 2003 to help fellow climbers “unfuck their heads.” For years it existed on the fringes of hardcore fitness, gradually adding Special Forces recruits and MMA fighters to its ranks as news of Twight’s successes spread.



Then, in 2006, everything changed. The movie 300 hit theaters, and Twight, who’d been tasked with transforming the film’s doughy actors into a phalanx of hardened warriors, found himself in the limelight. Overnight, Gym Jones went from underground muscle factory to iconic fitness temple. (Want to crush fat and transform your body? Try The Anarachy Workout—one guy lost 18 pounds of fat in just 6 weeks.)

“Until that point, I ran the gym on the Fight Club model—it was invitation only, but if you were invited, I trained you for free,” says Twight. But after the movie was released, it was impossible to stay off the public’s radar. “The traffic it created nearly crashed our website,” he says. “We went from a few hundred hits a month to almost 13 million.”

The buzz was a curse, in a way. “It gave people the wrong idea. Aesthetics are actually our last concern,” says Twight. Gym Jones focuses on building true fitness, not the appearance of it, he explains. “And true fitness comes from training the muscle that sits in your skull: your brain.”

Most people aren’t prepared for what that entails. “They don’t know what all-out is because they’ve never been pushed to experience it,” says Twight. “Take the one-minute AirDyne test. If someone gave absolutely everything he had on the first try, it would be impossible to log a higher score on the second attempt. What holds people back? Maybe it’s fear. Maybe it’s laziness. But whatever it is, it’s 100 percent in their head.”

Those mental barriers also hinder performance in the weight room. Twight recalls a disciple who was fixated on pulling a double-body-weight deadlift, a Gym Jones fitness benchmark. “For him, that was 360 pounds,” says Twight. “He could lift 345 no problem, but put 360 on the bar and he couldn’t budge it. He thought 360 should be hard, so it was.” Twight’s solution: “We had him do a bunch of sets, switching up the plates each time until he lost track of them. Without knowing it, he did a couple of reps at 375.”

Benjamin Lowy

In 1924, the Nobelist Archibald Hill, Ph.D., became the first physiologist to propose that the brain regulates the heart during exercise. That regulation, he theorized, was meant to protect the heart from overexertion. But Hill’s idea took more than 70 years to gain traction, having been overshadowed by the more popular theory that physical exhaustion is purely a matter of cellular supply and demand.

Timothy Noakes, M.D., Ph.D., director of the Exercise Science and Sports Medicine Research Unit at the University of Cape Town, was taught the prevailing theory. When he started studying exercise physiology, he says, he was told that your muscles get tired—either because they run out of fuel or build up too much lactic acid—and that’s why you stop. But no one had ever proved that muscles were getting too little oxygen or fuel. What’s more, studies showed that people never recruited more than 50 percent of their muscle fibers—even during intense exercise, says Dr. Noakes. The theories just didn’t seem to match reality.



Related: 6 Brutally Tough Workouts You Can Do on Your Lunch Break

Eventually it occurred to Dr. Noakes that because you activate muscle by way of your brain, your brain must also be responsible for determining how long, hard, and fast you push yourself. While Hill had been on the right track, the more research Dr. Noakes conducted on his own “central governor theory,” the more the supporting evidence mounted.

To what degree can the governor in your head influence performance? Suppose you were told to pedal to exhaustion on a stationary bike while being timed by a clock. “You’re also told that it would be great if you could go for an hour,” Dr. Noakes says. What you’re not told is that the clock is slow. “You’ll find that when the clock reads an hour and five minutes, you’ll stop, even though you really did an hour and a half,” says Dr. Noakes. By taking this cue, your mental governor established a performance limit that in no way reflected your actual fitness level.

“Your brain sabotages your performance,” says Dr. Noakes. “When you feel fatigued [during exercise], it’s just an emotion. It has nothing to do with your physical state at all.”

Others agree. When Brazilian researcher Eduardo Fontes, Ph.D., analyzed cyclists’ brain activity on an fMRI machine as they pedaled to exhaustion, he showed that emotion plays a fundamental role in performance. “We saw that the limbic lobe—the emotional center of the brain—lit up as the intensity increased and the cyclists became more exhausted,” he says. “The more active the limbic lobe became, the more emotion they tied to exertion and the more they slowed.”

Your mental state, Fontes says, is behind much of the variation in your day-to-day performance. “Anyone who works out knows that training performance can differ drastically from one session to the next,” he says. “Physiologically you might not have changed; what may have changed substantially is your mental state.”

Benjamin Lowy

Fontes has found that people who are able to detach from their emotions during exercise—for example, not thinking about their panting breaths or burning legs—almost always end up performing better. “When you exercise or compete, you have to mentally process what’s happening to your body,” he says. “But the key is to not judge it as positive or negative; that’s when your brain sets limits.”

Dr. Noakes tells the story of a woman running an elite 5,000-meter race. She was about 20 meters behind first place and had mentally committed herself to coming in fifth or sixth. But as she began her final lap, she saw the clock and realized that if she could run that lap in less than 64 seconds—something she had done before—she would qualify for the Olympics. “All of a sudden her thinking shifted and she didn’t care about the race,” Dr. Noakes says. “She had a new goal that mattered on a much deeper level, a goal she believed she could achieve.” She hauled off, won the race, and qualified for the Olympics.

“Your biology sets your true limit, of course, but how close you get to it is determined by what you believe,” says Dr. Noakes.



Related: 10 Exercises That Burn More Calories Than Running

MacDonald specializes in that kind of focus shifting, which starts with goal setting. “If someone tells me they want to get fit, I ask, ‘Fit for what?’” he says. “Fitness is task dependent; you need to map things out and set a goal, whether that’s to finish a triathlon or simply to look and feel healthier.”

Everyone who walks into Gym Jones—Navy SEAL or sales rep—receives a customized training program. Nothing is arbitrary. Nothing is left to chance. And the commitment must be total. “You might work hard in the gym, but are you also sleeping eight hours or more a night, eating healthfully, and foam-rolling as you watch TV?” says MacDonald. “Constant attention to your goal is how you reach the next level. And recovery is half the battle: Don’t do the work if you don’t have the balls to rest.”

Such devotion—what disciples sometimes refer to as drinking the Kool-Aid—affects what MacDonald calls a “deep chemical change” that guarantees success both in the gym and beyond. “The swagger that comes from reaching a fat-loss target, crushing a half marathon, putting up a record lift, or passing an endurance test doesn’t wash off with your postworkout shower. It lingers,” he says. Indeed, a man who gives his all to break a barrier in the gym may also be fighting with the same obsessive determination in other aspects of his life: building a happy family, closing a deal, inspiring change in others.

“A breakthrough here can lead to someone being a totally different, more confident, improved person,” says Twight. “We see it every day. We’re seeing it right now on the AirDyne.”

The 20-something guy is back on the bike, pedaling savagely in another attempt at 48 calories. The seconds tick—43, 42, 41—as his face gets redder and his breathing harder.

Eighteen, 17, 16. . .with 15 seconds to go, his face twists in agony and his eyes close as he digs deeper into the pain cave.

Three, two, one.. .the timer finally reaches zero and then goes blank. The man collapses heavily on the handles, gasping for air. And then, victory: “49 calories” flashes across the screen. He staggers away from the bike, smiling broadly despite the leg cramps he’s probably feeling as he accepts high fives from everyone in the room. (Want to challenge your own grit? Then give The Hardest One-Exercise Workouts You Will Ever Do a shot.

“If you don’t push your mental limits, you’re just going through the motions and you will stay at a certain level mentally and physically for life,” says Twight. “But if you get comfortable with discomfort, if you put yourself in a dark place and come out the other side, you can accomplish anything.” You just have to believe.

Michael Easter Michael Easter is a health and fitness writer and a visiting lecturer at UNLV.

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