This article originally appeared in the June 25, 2012 issue of Sports Illustrated.

The angry pop-pop-pop-what-what whap of a fighter punching padded mitts echoed off the walls like gunfire, competing with the screech of AC/DC on the stereo. Nearby another fighter is on his personal Highway to Hell, grinding out miles on a treadmill, trying to melt 11 pounds off his 166-pound frame before a weigh-in days away. An older gym denizen known affectionately as Crazy Steve poses in front of a mirror and spins butterfly knives as if they were nunchucks. The resident pit bull, Maximus, gnaws on balls of athletic tape.

The fight gym is an iconic and beloved institution in the Republic of Sport, and on this warm Monday in May the Jackson/Winkeljohn Gym in Albuquerque has all the essential qualities. Air thick with the musky perfume of sweat, testosterone and industrial cleaner? Check. A rich and diverse cast of characters? Grit and romance? Tragedy? Check, check and check.

But the centerpiece at Jackson/Winkeljohn is not a ring with turnbuckles, as it was at the Kronk Gym in Detroit or Gleason's in Brooklyn. Rather, it's a chain-link octagon, one more indication that mixed martial arts (MMA) is surmounting boxing as the nation's combat sport of choice. Beyond that, the gym has an air of ... what, mysticism? It's less a battlefield than an ashram. Coleader Greg Jackson is a gentle goateed man who speaks in aphorisms, often in a voice so soft that you have to lean in to hear him. He's as likely to refer to a military tactician, a Renaissance painter or a jazz musician as he is to a sports figure.

On a wall at the gym's entrance, the obligatory autographed glossies of the many resident MMA stars bear inscriptions such as these:

I owe everything to you. - Nate Marquardt

You Are Creating a Whole New Me. - Cub Swanson

I am honored to be part of your team - Georges St-Pierre

Steel is only as strong as those who forge it.- Rocky Ramirez

Cage fighters express themselves like this?

The messages lay bare one of the great ironies of an ascending sport. The Ultimate Fighting Challenge (UFC), the leading MMA organization, is a Vegas-based juggernaut, wildly successful in part because of its relentless hype. Cards are slickly packaged events, all neon and bright lights, the front rows filled with celebrities -- Shaq! The Biebs! Fitty! Bryce Harper! There's a UFC reality show. You can watch undercard bouts live via Facebook. Fighters are given cash bonuses for building their Twitter followings.

Yet the soul of the sport? It resides largely at a low-slung 7,000-square-foot building -- defiantly unslick, classically old school -- sandwiched between a storefront church and an auto-body shop on a featureless Albuquerque side street. It is here that most of the best fighters on the planet converge to train, seeking instruction from the sport's ultimate (and unlikely) one-two combination: a onetime pacifist (Jackson) and a one-eyed hardass (Mike Winkeljohn). "Honestly," says Jon Jones, currently the brightest star in the UFC cosmos and a Jackson/Winkeljohn disciple since 2008, "I don't even think of it as a gym."

No? What is it then?

Jones pauses, strokes his chin. Finally he says, "It's a place where you learn wisdom."

There's a good reason why the debauched AMC show Breaking Bad is based and shot in Albuquerque. A poor city in a poor state, ABQ is a colorful town but a tough town. Tempers tend to run short; lines at bars tend to run long. Greg Jackson grasped the local vibe at a young age, having grown up in the city's south valley� where, as he puts it, "some of the greatest people in the world are living with some of the worst people."

Jackson's parents were transplanted Quakers from the Midwest. "They were hippyesque," he says, "and they had this idea that happiness came from helping people." His mom, Kris, was a nurse, and his father, Jim, still advocates for the state's disabled population when he isn't singing tenor with the New Mexico Philharmonic. The Jacksons were ardent believers in nonviolence. Which was virtuous and noble, but left Greg conflicted. Much of his childhood was spent balancing pacifism and reality. "There were times when I should've fought but didn't, because I didn't want to get into trouble and go against what my parents taught me," he says. "There were other times I got in fights I had no business getting into and got suspended."

After he graduated (barely) from Rio Grande High School, Jackson opened a small self-defense school based on Gaidojutsu, a martial art of his own creation that combines wrestling and judo locks with kickboxing. When Jackson wasn't teaching, he was devouring books on philosophy, religion, history, science, math. He incorporated much of this into his instruction. "What I've always tried to do is study everyone smarter than me, which, lucky for me, is most people," he says. "Any good trainer is using music to train fighters. He's using chaos theory, game theory, fractals. It's a lot of science and a lot of art."

A decade ago, as Jackson's gym was gaining traction, so was MMA, a sport that married the ground fighting of jujitsu and wrestling with the striking of boxing, kickboxing and Muay Thai. One second you could be upright, eating punches; the next you could be on the ground, on top of your opponent, squeezing him like an anaconda. Fine by Jackson. He'd always been interested in blending combat styles. "All fighting is contextual to a time and place," he says. "Karate was [a response to] fighting a samurai. If he pulls out a sword, you have one chance to get him or he'll chop your head off. That's great. But it's basically irrelevant if you're fighting a boxer."

Jackson first took local athletes and trained them to become UFC stars. One was Diego Sanchez, a New Mexico state-champion wrestler, who won the middleweight division on the first season of the popular reality show Ultimate Fighter and has been in the UFC ever since. Another was Keith Jardine, a local tough guy who'd done some boxing and martial arts; he began training with Jackson in 2001 and, within a few years, was in the UFC beating fighters on the order of light heavyweight champion Chuck Liddell.

Word of the mystical, cerebral trainer rocketed around the UFC subculture. Soon, like filings drawn to a magnet, fighters from all over converged on the stucco gym in Albuquerque. The full list of Jackson-trained UFC fighters is so long that it would need to be serialized. But it would include St-Pierre, a French-Canadian who became one of the most decorated welterweights in UFC history; Rashad Evans, an African-American and a former light heavyweight champion; Diego Brandão, a compactly built Brazilian featherweight and one of the UFC's brightest prospects; and Clay Guida, a Rafael Nadal lookalike and top lightweight from outside Chicago who headlines this weekend's UFC card in Atlantic City.

The current alpha dog in the kennel, though, is Jones. "It's so much more of a mental experience than a physical experience," the 24-year-old light heavyweight champion says of his training. "People see you punch or kick. They don't see the visualization, the meditation, the breathing� the things that really give you the warrior spirit."

For all the established fighters at the gym, Jackson and his partner often let dreamers in the door, figuring that Darwinism will winnow out the weak. For $500 a month prospects can bunk at the Dorm, a crash pad above the gym, and discover how long they can stick it out. This spring they include Jared Bailey, 24, an introverted oilfield worker who left his wife and three kids in northern Alberta and drove 32 hours to central New Mexico to follow his bliss. "It's an individual sport," says Jones, "but it's a team sport. You need to learn from others, spar with others, so why not be with the best?"

During a typical Tuesday-morning sparring session, a barefoot Jackson, wearing a green T-shirt and shorts, yells out general instruction but spends most of his time pulling fighters aside for brief tutorials. Even in these microsessions there are bits of wisdom ("Don't always think you need to avoid someone's strength; if you expose his strength as being not that strong, you'll break him spiritually") peppered with Latin aphorisms and Zen references.

Reconciling the team and the individual is an enduring riddle for Jackson. He says, "We have a competitive-cooperative dynamic: You cooperate. And you compete. You can't go too far in either direction, or you don't improve. If it's all cooperation and no one is pushing you, when the fight comes, you won't be comfortable, you'll break mentally. If you're hypercompetitive and worried about dominating, you won't train with courtesy, and you don't belong here."

The other great challenge is having a few organizing principles for the gym while tailoring instruction to individuals. Some fighters relate to historical figures, so Jackson will cite his heroes: Lincoln, Washington, Genghis Khan, the polar explorer Ernest Shackleton. Some fighters respond to authority, in which case Jackson takes a more autocratic approach. Others, like Jones, need to feel as though they're part of the process, in which case Jackson is more inclusive and collaborative with the fighter. "It's like the best of [ancient] Athens, where you have a democracy and it's give-and-take," says Jackson, "but it's also the best of Sparta, where you have dogmatic leadership. [Winkeljohn and I] have the final say."

While Jackson's parents have grown comfortable with his line of work, he still wrestles with what it is that he does so well. This undeniably violent, undeniably popular and undeniably evolving sport, what does it stand for? "It can't just be two guys fighting in a cage� that doesn't have a lot of social value outside of entertainment," Jackson says. "This sport should be taking kids that [might] be a detriment to society and teaching them to use those skills in a better way. It should take kids who don't want to compete and teach them martial arts: respect, discipline, courage."

To a person -- yes, there are a few women in the stable -- the Albuquerque fighters talk about the balance in the gym, "the yin-and-yang thing," as Keith Jardine puts it. The foil for Jackson is his partner, Mike Winkeljohn. Also a native of Albuquerque, Winkeljohn spent almost two decades as a professional kickboxer and Muay Thai fighter, winning international championships in both disciplines. If you tune in to ESPN Classic on the right night, you can see him kicking ass -- sometimes literally -- in the '90s.

Winkeljohn, who met Jackson in 1992 through a friend, was his partner's complete opposite from the start. Politically, Jackson leaned to the left; Winkeljohn leaned to the right. Jackson's expertise was in the geometry of ground fighting; Winkeljohn excelled when both fighters were on their feet. "We are who we are," says Winkeljohn, now 49, Jackson's senior by 11 years. "We like and respect each other. We like and respect fighting. So it works. If we came from the same place, it would limit us."

In 2007 they joined forces to found Jackson/Winkeljohn MMA. Independently, the partners characterize their relationship as "little brother, big brother." (Physically they could pass for siblings.) To the fighters it's more good cop, bad cop. Jackson encourages the fighters to talk through their feelings. Winkeljohn doesn't need to hear it; he needs to see it. "Coach Wink doesn't put up with anybody's anything," says Guida. "In a good way."

Jackson recommends books to his fighters. Winkeljohn gives them a lift to the Sandia Mountains for notoriously brutal training runs. While the Albuquerque camp is known as "Jackson's gym," the resident fighters will tell you it's an equal partnership: Winkeljohn's bluntness is just as effective and motivating as Jackson's nuance. "They are different in every aspect of their approach to fighting," says Isaac Vallie-Flagg, a lightweight, "and we're all better for it."

One day in the fall of 2009, Winkeljohn was holding pads for a fighter who was snapping off kicks. On one kick the fighter's toenail raked Winkeljohn's right eye, which "shriveled like a little grape" (his phrase), and he lost his sight in it. Winkeljohn now wears protective goggles when he works with fighters, which is up to 12 hours a day. "It sucks, but people have suffered a lot worse," he says of losing the eye.

Adds Jackson, "I would read George Washington, his men bleeding in the snow and not eating, and that would be a slap to me. I get that in little doses looking at Mr. Winkeljohn." (Out of respect, they refer to each other as Mister.)

A vivid illustration of the two trainers' dynamic: Earlier this spring Jones defended his light-heavyweight title against Rashad Evans, a longtime Jackson/Winkeljohn fighter and Jones training partner. Before the fight Evans had become upset with Jones for so readily agreeing to the bout. (UFC matchmakers try to avoid pitting stablemates against each other, but sometimes it's inevitable.) Evans also accused Jackson/Winkeljohn of creating a divide between the two fighters. The theme of all the prefight hype was loyalty. "Judas Jones," Evans called his opponent. Jackson tried to stay neutral, often asserting, "I have no animosity toward Rashad." Winkeljohn was less conflicted. Jones is part of the team; Evans no longer is. What's the problem?

Jones told Winkeljohn to "play me like a video game," and the coach obligingly devised a brilliant fight plan that exploited Jones's 10-inch reach advantage. Spending virtually the entire fight on his feet, Jones dominated each round with an array of knees, kicks, elbows, spinning backfists and straight punches. If the fight was a 25-minute demonstration of Jones's lavish skills, it was also an infomercial for Winkeljohn's stand-up style of fighting.

If there's a drawback to running the most prominent training facility in a growing sport, it's the time commitment, with which Winkeljohn and Jackson -- both husbands and fathers -- have struggled. When upward of 40 elite fighters anchor their careers to your gym, you pull some late hours to make sure they get individual attention. You also spend most weekends accompanying fighters to events and working their corners. One Saturday night you're in Virginia Beach; the next, in Atlanta, San Jose or Boston. (Often the destinations are not reachable by direct flight from Albuquerque.) When Winkeljohn isn't home with his family, he spends his precious free time working as a general contractor. The man is nothing if not an unapologetic capitalist.

This is, not surprisingly, at odds with Jackson's choice in leisure activity. He once wrestled reptiles Down Under with his friend Steve Irwin, the late Crocodile Hunter, who flew Jackson to Australia for private training sessions. These days Jackson's hobby is "ghost-towning." When he gets the chance, he takes a map and roams the desert in search of boomtowns that went bust. "I love that you can have an adventure, you can be a detective," he says. "But I also love that it's a diversion, that it doesn't have anything to do with fighting."

Then the Philosopher King of MMA reconsiders. "A ghost town reminds me to appreciate what I have when I have it," he says. "It reminds me that we're all on our way to the grave� no matter how big we make the buildings, no matter how strong we are. So you might as well fulfill your potential and do everything you can, right now."

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