The last thought I have before I throw up in the bathroom of the CrossFit box is, Oh, what a cliché. I’m about to throw up at CrossFit. Then I throw up. I had rushed to the toilet after Coach Kevin remarked that I looked a little green, which he said just moments after yelling at me to “Give it all you’ve got!” That directive came during the intervals on the assault bike, which followed the quarter-mile sprint with the medicine ball, which followed the sets of squats, burpees, lunges, crunches, and elastic band–assisted pull-ups.

The exercise class I’m barfing through is at CrossFit City of Angels, just one stop of many on my quest to find the most intense workout class in Los Angeles. I set out on this journey after a monthlong sojourn at a vertical-climbing machine studio called Rise Nation. I reluctantly signed up for the classes after a running injury. However, I ended up enjoying the classes so much that I went from a curmudgeonly distance runner—skeptical of any form of exercise that required a fee greater than the shoes on my feet—to a full-on boutique gym convert. I started to wonder: Was there some silver-bullet fitness class where, if I followed the instructor’s impassioned plea to give it all I’ve got, I would push myself to the edge of my physical limits and determine how tough I really was? I wanted to find out.

I really didn’t want the answer to be CrossFit, though. I mean, how cliché can you get?

Stationary Bikes in a Dark, Crowded Room

I begin my quest with the trailblazer of the boutique gym movement: SoulCycle.

“OK, now tap it back!” the instructor intones.

In unison, my classmates “tap it back.” The movement involves reaching your butt behind the back of your seat and bobbing downward while continuing to spin the pedals. For some reason, it reminds me of a bird attempting to quickly lay an egg without anybody noticing.

I attempt a tap-back or two, and then stop. I don’t like it. The candles in the studio smell nice, but the New Agey dance vibes are not for me. My quest continues. I try other spin studios: FlyWheel, Peloton, and YAS (Yoga and Spin).

FlyWheel emerged as my spin class of choice. Slate called FlyWheel “SoulCycle for uber-competitive sadists,” on account of the TorqBoard, a ranked display of each rider’s power output. In effect, you can “win” at exercise, which, as an aspiring uber-competitive sadist, I found to be highly motivating.

I left FlyWheel feeling comfortable with the idea of adding the classes to my weekly running regimen. However, I was suspicious of my comfort. How intense could it be if I enjoyed it? I felt the urge to try something outside my comfort zone: weightlifting.

“These Shoes Feel Like Ski Boots!”

In my daily life, I’m as awkward as a baby giraffe in a bouncy castle, so to avoid decapitating myself while doing a bench press, I looked into my options for lifting with a personal trainer.

A friend recommended a trainer who, to keep prices lower, worked out of his garage rather than a corporate gym. This seemed sketchy as hell, which sounded like it would be potentially great for my mission. Enter LIFT, a private gym on L.A.’s east side.

My trainer was Dirk (the Platonic ideal of a personal trainer name), who owns LIFT along with his wife, Chenell. Dirk’s website bio: “Dirk is 50. 6 feet, 215 lbs. He’s been strength-training for 20 years. He hasn’t done cardio in 10 years.”

I left FlyWheel feeling comfortable with the idea of adding the classes to my weekly running regimen. However, I was suspicious of my comfort. How intense could it be if I enjoyed it?

When I arrive for my session, Dirk and I talk about the cardio I’ve been doing in spin classes. He scoffs. Dirk condemns cardio with the same intensity that precocious kindergartners announce to their classmates that they don’t believe in Santa Claus.

“We don’t do cardio here. Can you do a pull-up?” he asks.

“Nope!” I say, a little too enthusiastically.

“OK. You got weightlifting shoes?”

“What are…I mean, I’m wearing running shoes. So, no? I’ll say no.”

“You can borrow a pair of mine,” Dirk says, tossing me a pair from around the corner.

I put them on. “These feel like ski boots!” I say, again improperly modulating my enthusiasm.

Squats. Lunges. Deadlifts. Biceps curls. Jump press. Bench press. Negative pull-ups. Ab-wheel rollouts. Dirk is attentive throughout, correcting my form and giving me encouragement. The shoes are incredible. I feel bolted to the ground and like I’m doing squats properly for the first time.

Ultimately, though, since the weightlifting road seemed to lead to a body that was, while super-jacked, not exactly ideal for distance running, I wasn’t sure it was a road I wanted to keep going down. Plus, I like cardio. It was time to move on.

Learning How to Hurt People

“Easy!” my Muay Thai instructor shouts. “We’re not trying to knock anybody’s head off. Yet.” My classmates chuckle.

It’s my first class class at the Echo Park Boxing and Muay Thai Gym. My partner has more tattoos and more experience than I have, and he is not bothering to hide his annoyance at the piss-poor job I’m doing holding pads for him.

“No, not like that,” he says for the fifth time. “Meet my punch with the glove, otherwise I’ll knock your hand back like a flipper.”

To illustrate his point, he hits the pad I have strapped to my forearm, and, as he prophesied, it knocks my hand back into my face. In effect, I’ve punched myself.

The studio offers a variety of martial arts instruction. The jiujitsu class is the most outside my comfort zone. The instructor, Gavin, looks and sounds uncannily like Sting, if Sting spent a few decades of his life fighting for a living. We dive right into practicing armbars and choke holds.

“Let’s review the guillotine!” Gavin croons.

The guillotine, otherwise known as the Mae Hadaka Jime, is a choke hold performed from the front in which you encircle your opponent’s neck with both arms, thereby compressing the trachea and blocking airflow.

We practice the move. I am timid. Gavin notices and tries to get me to be more authoritative. I demure. Gavin leans in and whispers in my ear, in what must be the only time when this is an appropriate thing for a teacher to tell a student: “Choke him like a motherfucker.”

Those words do the trick. I choke him. My partner taps out. I release. He coughs and gives me a nod of approval. “That’s it!” Gavin says enthusiastically. “OK, now do it again.”

Adventures in Sticky Socks

“First time doing barre?” the cheery woman at the counter asks me.

“How could you tell?” I reply with a grin. I am the only man in this Pure Barre studio, and judging by their Instagram feed, I am also the only man who has ever taken a Pure Barre class in the history of the world.

“Do you have sticky socks?” she asks.

“What are…I mean, I’m wearing running socks. So, no? I’ll say no.”

I buy a pair of $12 sticky socks.

The micromovements of barre were taken from ballet and adapted into a general fitness program, popularized nationally by studios like Pure Barre, FlyBarre, Pop Physique, and others.

I was skeptical that barre could be intense. In its own words, “Pure Barre fitness studios offer the safest, most effective way to transform your body.” Safest? That sounded easy.

Turns out, safe can be hard. Excruciatingly hard.

Barre uses isometric movements. Planks, static lunges, or hovering a leg just above the ground, then pulsing that leg up and down an inch. It’s easy to do once. It’s difficult to do for a minute. By the end of the hour-long class, you wonder how you got a full-body workout while apparently doing so little.

Around 40 minutes in, my legs began to shake during a wall squat.

“I’m shaking,” I say apologetically to the instructor as she walks by.

“The shake! Yes. That means this muscle group is reaching fatigue. That’s good! It leads to long, lean muscles! It will make your butt look like the peach emoji!”

Impressed by the surprise intensity of barre, I took my sticky socks and decided to see where else they could grip me.

Any class that didn’t end with me in a puddle of my own sweat and a chance to experience at least a mild case of DOMS was not going to fill my Exercise Holy Grail.

When I arrived for my free intro class at Club Pilates, I was surprised by what I saw: a whole bunch of gear. I think that I pictured Pilates to be like yoga, except maybe standing, and with waving your arms around. OK, I guess I was picturing tai chi. I was not picturing the feng shui torture chamber of devices that I saw, the centerpiece of which was a series of coffin-sized machines built from wood, pulleys and cushions: the reformer. The reformer looks nearly identical to the rack, a medieval torture device consisting of a rectangular wooden frame and straps used to pull a person’s limbs off. Interesting coincidence.

If barre is excruciating, Pilates is agonizing.

“Stretch your legs out straight, to a 45-degree angle. You want to make a V with your body,” the instructor tells me. I attempt to make my body into the V. I briefly attain Pilates perfection. Then my abs start to shake. I look over to see if my instructor is watching to get her approval, but she has already moved on. The shake becomes too much, and I let my body collapse from a perfect Pilates V to a dour, dilapidated O.

I was intrigued by the “safe yet hard” concept, and I was curious how much more intense it could get it. I tried the Supraformer at Lagree Fitness. The Supraformer is on a hydraulic suspension system that adjusts the pitch, tilt, and yaw of the platform to intensify the sought-after shake. Next, I tried the PowerPlate at Plate Fit, where Pilates-style exercises are performed on a small platform that vibrates 25 to 50 times per second to utilize “the body’s natural reflexive response to vibration.” In other words, it’s like doing crunches on top of a dryer with a boot inside.

These classes all exceeded my expectations for how challenging “safe” could be, but any class that didn’t end with me in a puddle of my own sweat and a chance to experience at least a mild case of DOMS was not going to fill my Exercise Holy Grail. Would I ever find what I was looking for?

A HIIT to the Gut

What has the cardio intensity of spin, the targeted resistance training of Pilates, the musculoskeletal benefits of weightlifting, and the intensity of choking strangers? High-intensity interval training.

I took a variety of HIIT classes, and each left me sweaty enough that I felt like a public health nuisance taking the city bus afterward. Now I was getting somewhere. Mile High Run Club, Sweat Garage, Basecamp Fitness, LIT Method, Barry’s Bootcamp, and Orangetheory Fitness—they all involved some combination of alternating between intense cardio for a short burst (treadmill, spin bike, or rowing machine) and strength training.

They were all fantastic, but Orangetheory Fitness struck me as the chosen one. In addition to top-notch equipment, skilled instructors, and well-designed workouts, the feature that sets Orangetheory apart from other boutique HIIT gyms is its incorporation of customized heart rate monitoring. With more than 700 locations and nearly half a billion dollars in annual revenue, I’m not the first person to deem it the fitness class of choice.

At Orangetheory, they have effort level down to a science: Individual heart rate monitors project data in real time onto a monitor. An algorithm converts the data into “splat points,” or minutes spent in an anaerobic zone. A typical class goal is 12 splat points. Students can adjust their pace to achieve their splat goal by following personalized, laminated pace cards that are distributed at the start of each class. An improvement in precision over a spin instructor shouting, “Give me all you got!”

As it turns out, I was on a fool’s quest all along. Orangetheory was great, but it wasn’t the hardest exercise class I took in Los Angeles. CrossFit was. Sorry, the cliché is true. Don’t tell Coach Kevin, but I think I might just stick to running.