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Inside a small room on the Lower East Side of Manhattan, New York, a group of sweaty, grunting females attempts pullups on crude bars.

What appears to be the local county lockup — there are prison bars, a spot for mug shots and even occasional meals served on industrial trays — is actually hot fitness studio ConBody, which is drawing devotees of posh studios like SoulCycle and Pure Yoga.

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Classes are taught by ex-convicts, and pampered New Yorkers, who will most likely never see the inside of a jail cell, are flocking here.

“I found it on Gilt,” said class participant Katie Williams of the Lower East Side, referring to the luxury discount site hawking Christian Dior accessories and tennis lessons.

“I like the rustic feel of this,” adds Williams, a 24-year-old account executive, noting the contrast between ConBody’s bare-bones aesthetic to the typical mirrored studios she frequents.

ConBody is the brainchild of convicted drug dealer Coss Marte. After his release from upstate’s Greene Correctional Facility in 2013, Marte was unable to find employment.

He did, however, have an idea for a no-frills, prison-style boot camp, having lost 70 pounds serving his four-year sentence by using his own body weight to get toned and fit.

Initially, he gained a following by training groups in Sara D. Roosevelt Park and a rented space in a preschool.

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In January 2016, Marte, a charismatic 31-year-old father of one, opened up his own studio at Broome and Eldridge streets — the same corner where he once sold drugs — and began hiring fellow ex-cons as trainers and maintenance and customer-service workers.

The former drug kingpin has managed to tap into people’s morbid curiosity about prison, which has been stoked by shows like “Oz” and “Orange Is the New Black.”

The studio became a makeshift jailyard gym as seen through an ironic millennial prism.

In fact, when participants take their mug-shot selfies, they ask him for pointers.

“A lot of people ask, ‘Do I smile? Do I keep a serious face? Do I turn this way?’ They want to get the right position,” Marte said.

In April, Marte organized a 10K run dubbed the “Prison Break,” and this month he landed a marquee spot inside the Saks Wellery, Saks Fifth Avenue’s new wellness pop-up at its flagship store.

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There, ConBody is featured alongside classes from Gwyneth Paltrow favorite Tracy Anderson and Karlie Kloss’ haunt ModelFit.

“After I closed the deal with [Saks], I stepped out of the building and felt like crying,” said Marte, who walked the 50 blocks home to diffuse all of his emotions and clear his mind.

“I never would have imagined [finding myself in this position] four years ago sitting in a prison cell in lockdown.”

Jill Reinholt, a Greenwich Village resident who also found ConBody on Gilt, swears by the penitentiary-style sweat sessions.

“It’s the only place I’ve ever been where I’m motivated and inspired and I laugh,” the 28-year-old teacher said of the studio’s $30, 45-minute classes.

She’s given up on barre and pilates classes, and is happy to channel a trip up the river if it means a leaner, stronger frame.

“I used to do other classes, and then I saw the biggest difference in my body when I was coming here consistently,” she said.

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Williams is a yoga devotee but loves being doted on by the crew of ex-cons.

“I love the music,” she said. “I love how the classes are small, so you get personal attention.”

Marte has even launched monthly prison-food pop-ups where his chef pal Kelly Zavala cooks up Salvadoran grub for $10 a pop.

“We promote it as ‘prison food’ but it’s really good,” Marte said of the pupusa with rice and beans served on an industrial tray. “Hell, yeah, it’s much better than the food I had in jail.”

Beyond fetishizing the prison experience, ConBody has a laudable social mission, which is to employ those who can’t find a job because of their rap sheet.

“When I met Coss, I just fell in love with his story,” Reinholt said. “I’m a teacher in low-income communities, so I’ve always been aware of the school-to-prison pipelines.”

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To her, ConBody is also a story of redemption.

“In talking to Coss and hearing his backstory and upbringing, I’m very proud of them and happy for what they’ve done.”

Inside the modest LES studio, there are no locks on the lockers. People simply toss their belongings inside and trust that — in a room staffed by ex-cons — their bags will not be touched.

“It’s about trusting that we’re people and human beings. When people come in for the first time, they are nervous and don’t know what they are getting into. And they realize that we break down the stereotype and make everyone feel like human beings,” said Marte, who recently launched an online class subscription, for which he said more than 4,000 people in 20 countries have signed up.

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He also is in talks to franchise ConBody in cities across the country and even in Australia, which was once a British penal colony.

“People believe the product is good. It’s not like your bougie Barry’s or SoulCycle,” Marte said.
And it’s not just workout buffs who want a piece of Marte’s concept.

“It’s crazy. I get fan jail mail every week,” he said. “They say things like, ‘I have two years left and I want to join ConBody.’ ”

First published on the New York Post