Now there are other sounds: chains clattering to the floor in tempo, adding percussion to a rising cacophony of noise, the song under the song that's now blasting out of unseen speakers, vibrating the steel walls. Voices punctuate this wall of sound, and you can't decide if these are voices of support or voices promising violence.

Should you open the door and peek in? Maybe just a crack. A quick look inside...

And that's when the big garage door you hadn't noticed before bangs open with a sound of thunder. The two songs – one played by AC/DC, the other played by a dozen of the world's most elite powerlifters – hit you in the stomach like a fist.

The men who walk out into the sunlight look more like characters from a mature-rated video game, one where a portal to a dark dimension opens up and creatures with bad intensions stagger out into our world, blind and ravenous.

They are distinctly different, yet clearly part of the same tribe: shaven heads or mohawks, biker-gang facial hair, tattoos, necks completely engulfed by mountainous traps, EliteFTS logos on every item of clothing.

One of them pushes out a snarling two-pronged sled and loads it with 45-pound plates. They take turns pushing it across the parking lot: push it 40 yards, rest one minute, push it back. Repeat six times or until this weapon of mass destruction called the Prowler stops moving.

One lifter, a Columbus chiropractor in his real life, starts off at a run, but he's soon on his knees, gasping, sucking wind. He pushes it another two feet, takes five breaths, moves it an inch or two further, takes five more breaths, and tries again.

Nothing. Not an inch.

He's finished, today's first victim of the Prowler. Knees bleeding, he staggers off. That means it's someone else's turn.

The next one makes six rounds but it takes its toll on him, too. Hands on his knees, he can't catch his breath, can't speak. Then the coughing begins. Then retching and puking. You might call this rhabdomyolysis, but they call it the "Prowler Flu." He won't be functional again for another hour.

His fellow lifters give him no sympathy, only silent respect. They've all been there. You sweat, you bleed, you puke, and you do it again and again. If you didn't, then you wouldn't be allowed to train here.

Now a woman heaves into the sled. "Maybe just for one light set; I did hill sprints yesterday," she'd said five minutes before while you watched the other guy lose his breakfast. But one set turns into two, and two turns into three. Then she's down, screaming, clutching her hamstring.

"Get off the ground, Leanne, you're giving me a hard-on!" This from one of the Grim Reapers. Visualize a black-hooded reaper, no scythe, but sporting 250+ pounds of muscle. There are at least three of them in this crew, one of them being Dave Tate, owner of this secret training facility.

The hoodies won't come off until well into the workout, which will extend to three hours on this overcast Saturday morning. Some of the lifters flew in from other states for this training session, and they're going to get their moneys' worth.

Someone brings Leanne a cup of Plazma™ and she's up and around a few minutes later. "Not all women could thrive in this environment," she'd said earlier. "But I love being surrounded by the best people, guiding me and pushing me."

She won't get any pats on the back for wrestling with the Prowler, but her fellow lifters will know: Leanne is not dicking around.

Now a couple of the bigger lifters come out of the gym and watch the Prowler eat a few more of their pack. That's what the Prowler does: it eats people. And most of the crew here today for this UGSS or Underground Strength Session will sacrifice their bodies – and sometimes their breakfasts – on its altar in exchange for the unstoppable conditioning it provides them.

Just then, as you're wondering how you'd measure up on the Prowler, one of the biggest and widest men you've ever seen walks by you, glances over at the Prowler – which is now consuming another of his teammates as a mid-morning snack – and says, "No way, not me. That thing is for the fit people." He grins then and looks almost apologetic, but not quite. "Sorry, but I ain't about to push it!"

You decide to take the risk and step into the cavernous warehouse. Piles of metal, fat bars, monolifts, benches, racks, bands, chains. Music blares; chalk dust fills the air like nuclear fallout; the few pieces of cardio equipment have copies of Penthouse on their magazine racks.

Everything is oversized. The benches are wider than normal, the foot plates on the machines are enormous, allowing for sumo hack squats and leg presses. All of it is overbuilt. This stuff, you think, looks more like heavy-duty demolition equipment than exercise equipment.

The carriage on the leg press weighs 400 pounds before you add a single plate to it. This gym isn't built for people it seems; it's built for giants. If the God-King Xerxes owned a private gym, this would be it.

What is this place? you think. What have I stumbled into?

That's easy to answer. You've found the strongest gym on the planet.

You've seen it happening in gyms across the country. First the number of squat racks start to dwindle. If you're lucky, you might find a single rack in the brand-name gyms that once produced the world's biggest bodybuilders and strongest powerlifters. If you're unlucky, then your power rack will be replaced by yet another treadmill with a built-in TV and fan.

After the racks go, the dumbbells start disappearing. First dumbbells over 100 pounds go AWOL. Then anything over 65.

And deadlifting platforms, extra space for Olympic lifts, specialized bars, and rubber plates? Hell, your gym probably didn't have those to begin with.

What's going on here?

It's simple really. Commercial gyms are purposefully driving out the hardcore lifters. If you leave, who cares? They'd much rather have ten new housewives paying dues and never showing up than your sweaty, grunting, chalk-smuggling ass.

Sometimes this is done on the sly through the slow attrition of hardcore equipment. Sometimes it's overt. One chain, Planet Fitness, known for its "Judgment Free Zone" motto, openly castigates anyone who trains hard enough to make a noise, drops a weight, or carries a little too much muscle.

This judgment-free gym judges anyone who trains with effort, and dubs them a "lunk." Rumor has it that membership prices mysteriously increase when a well-muscled lunk tries to join.

The result is a movement, a movement of serious lifters away from commercial gyms and into warehouses or garages. These "underground" gyms are now home to some of the strongest athletes on the planet.

This one, as you've guessed, belongs to Dave Tate, founder and CEO of Elite Fitness Systems. In fact, the other two areas of this building house his stock, and the building across the way serves as his offices.

This under-the-radar gym's members and sponsored lifters include everyone from what Tate calls "strength enthusiasts" – people who love to train for strength but don't compete in meets – to elite powerlifters and state champion bodybuilders. (A two-time Mr. Ohio is here today.)

Hardcore training has gone underground and into nameless facilities in the commercial/industrial areas of cities. Tate and Biotest head honcho Tim Patterson have discussed creating a database of these gyms. Why? Because one day you might walk into your gym, look around, and realize that you're no longer welcome.

The exodus, it seems, has already begun.

JL Holdsworth is considering a run at bodybuilding. He's over in the corner, pounding away on the hack squat, bringing his already massive legs up to match his even more massive upper body.

Jeremy Frey, Josh McMillan, Mike Ruggiera, Matt "Kroc" Kroczaleski, Christian Mello, Ted Toelston... they're all here today. Even coach Christian Thibaudeau is joining in on the fun.

But the deadlifting... the deadlifting, you think, is unreal. You may have read that many top powerlifters don't train the deadlift all that much, focusing more on the bench and squat. Maybe, but today you're seeing something unexpected.

The average gym member has never seen this much weight on a bar. The average "fitness center" may not even have that many plates in the facility.

No one, it seems, trains with fewer than 12 plates on the bar, plus the thickest chains you've ever seen outside of those attached to anchors. The chains alone can add 120 or more pounds. Today, most of the crew is pulling from the shins for reps, ripping both chains off the floor and flesh off their legs with every rep.

Molly Edwards, the "beginner," works up to a 405 single. This on top of six sets of cam bar squats, six runs at the Prowler, high reps press work on three different machines, pulldowns, rows, face pulls, plus triceps assistance and extra ab work.

"I'm going to take this as far as I can, go as far as I can go," Molly says. "You can only have so many surgeries. After that I'll lift for health and have a family. And one day I'll be able to say to my kids, 'Look what I did.'"

It's a hard game to play and a hard life to live. Powerlifting icon Louie Simmons has been known to advise those lifting under his tutelage not to get married, not to have kids, because it might mess up their totals. At the highest levels, the sport is all-consuming. The word sacrifice doesn't even begin to describe it.

If the deadlifting is unreal, then the squatting is other-worldly. You stand there and gawk as lifter after lifter pounds out reps with 14 plates on the bar.

And then you realize that a couple of those plates are 100's, not 45's... not to mention a couple of 25's slapped on the ends for good measure.

The numbers get blurred in your mind. It's like listening to government bailout statistics: a billion, a trillion, three trillion... numbers so big you don't really even comprehend them anymore.

That's when Tate walks up to you and drops a bomb: "What you're seeing here today is what I'd call average or maybe medium," says Tate. "These workouts are really just normal stuff – no real crazy lifts. Most of the guys are tapered back and don't have meets for a few months."

You have to think about that for a minute. The most brutal three hours of training you've ever seen was... medium. Average. Nothin' special.

If the EliteFTS dial goes to 11 – and you know it goes to 11 – you just witnessed a 6 or a 7.

The message is clear, and a little painful: If you're the most hardcore lifter at 24 Hour Fitness or what passes these days as Gold's, well, you probably wouldn't last through the warm-up sets in this unmarked warehouse in London, Ohio.

There are no swaggering egos here, you realize. There's confidence and respect, yes, but no egotists. There's the good-natured nut-busting you heard during warm-ups, but there are no insults or cut-downs, not even toward the "small" guys and younger members of the crew. The stronger, more experienced members are mentors, not bullies.

There are no experts either. Yes, these men and women know more about training than anyone you've ever met, but they're always looking to learn more. They want their squats evaluated by as many eyes as possible. They seek knowledge, advice, and critiques. "It doesn't matter if these guys are convicts, lawyers, or coaches, it all stays outside," says Tate. "In here, it's about getting stronger, getting better, and nothing else."

And that's when the epiphany hits you: Before you walked through that unmarked door, you didn't even realize this level of strength and muscularity even existed. And if you didn't know that higher level existed, then you didn't know you needed to strive for it.

You can't reach the top of the mountain if you don't know there's a mountain in front of you.

"If you want to remain mediocre, then train with mediocre people and have mediocre friends," Tate says.

And that's when you begin to wonder if there are secret gyms like this in your city.

Maybe you don't want to compete in powerlifting, but you'd love to take a run at that Prowler or try out a yoke bar squat or reverse hyper. But most of all, you want to reach another level – that next level you just learned about today in this covert gym hidden in this quaint Ohio town.

You want that mental fortitude this type of training develops, and you want that body. A body built for strength. A body built for violence. A body built for just about anything.