oss Marte used to be one of the biggest drug kingpins on the Lower East Side of Manhattan, making upwards of $3,000 a day. He started selling drugs when he was just 13 and realized how easy it was to turn $100 into $300. He continued throughout high school and college, eventually getting kicked out.

After returning home, Marte picked up right where he left off, selling weed, coke, crack and ecstasy. After taking over the business from a fellow drug dealer, he was a millionaire. The perks of living like a high roller were numerous — cars, Jordans, clothes — but at the same time, Marte stopped moving. He sat in a car for most of the day with someone else handling drop-offs, and the number on the weight scale rose.

In 2009, a partner double-crossed him, and Marte was sentenced to 12 years. When he entered Ulster Correctional Facility, the doctors told him that in five years he’d likely die of a heart attack. He knew something had to change. He started working out in his 9′ x 6′ cell, running every day and doing whatever moves he could in that space “I built myself up to running around two hours a day basically seven days a week,” Marte says. “Sometimes I would be running in two to three feet of snow.” He lost 70 pounds in six months.

“It became a routine, an addiction, I just needed to get up and run,” Marte explains when asked if he ever got bored. Other men started running and working out with him in prison after they saw the changes he made. He was the group leader. Eventually, Marte received an early release from prison — walking out with everything he did to lose the weight.

“I put this whole 90-day workout plan together while I was in the system,” Marte says. He started training friends in the neighborhood, eventually expanding to classes in rented ballet studios, but he wanted to do more. “My whole idea was to build a facility to look like a prison, and I spoke it out into the existence,” he says. Marte’s Lower East Side studio is now complete with prison bars, 3-minute shower rules and no locks on any lockers. “We tell people to trust ex-cons with your shit,” he says.

The workouts have expanded from the 90-day plan Marte wrote in prison, and you can always expect a different bent depending on which trainer you have leading class. “The whole mission of the company is to hire formerly incarcerated individuals to teach fitness classes,” Marte explains.

Part of Marte’s 90-day program is excerpted below, but we also asked what he does now to stay in shape. Beyond training for the New York City marathon (The goal is to lose 15 pounds in the next two months,” he quips), he regularly teaches Monday through Thursday classes at his studio and then puts in the time. “I’ll do 300 push-ups; depending on the day, I’ll do up to 500 push-ups. I’ll do 200 bodybuilders (they’re burpees with a plank jack) and then I’ll do a lot of pull-ups. I do 24 sets and max them out, working from the widest position [on the bar] inwards.”

Coss Marte’s ConBody Workout

Warm up with a jog, then rotate the following exercises, doing 2 sets of 10 to 25 reps of each. For an added challenge, run a lap around the track between each set.

Jumping jacks: Keep your feet together, hands by your side. Jump and spread feet so that you land with your feet shoulder-width apart. At the same time, raise hands so that they touch over the top of your head as you land. Jump again, bringing feet together so that they are next to each other when you land. At the same time, bring your hands down to your sides. Repeat quickly.
Calf Raise: Stand up straight. Bring your heels up off the ground about five inches. Go up and down.
Assisted dip (bench dip): Use something like a chair, bench, or ledge. Sit on it. Bring your butt off the ledge, to the side. Keep your hands on the edge of the surface. Bring your arms to a 90-degree angle as you dip down. Your butt should almost touch the ground but not quite. Then push yourself back up.
Pull-up (wide/close/regular): Grab the pull-up bar at shoulder width, palms facing away from you. Thumbs either wrapped around the bar or tucked under the bar. Pull yourself up until your chin goes past the bar. Lower yourself until your arms are straight. Repeat. Beginners: I recommend practicing by doing one pull-up and then holding for 10 seconds. Build up to doing more reps.
Chin-up (wide/close/regular): Same as a pull-up, except instead of grabbing the bar with your palms facing away, grab with your palms facing yourself.
Push-up: Lay down belly on the ground. Place your hands at your shoulders. Position your arms so that your elbows are at roughly a 90-degree angle and tucked against your side. Push up. Your entire body should leave the ground. Keep your back flat. Keep your elbows tucked in to your sides instead of letting them spread out sideways. Go up and down, chest to the ground, then back up.
Gravity push-up: On your knees. Place your hands directly over your shoulders, palms facing the sky. Push up against the air. Fully extend arms. Then bring hands back down to shoulders. Repeat.
Arm spin: Fully extend arms to your sides, and do small circles to the front. When rotating them backward, place your palms facing up to the sky and rotate. Fully extended, keep elbows locked.
Sit-up: Sit down. Lie with your back flat to the ground. Tuck your feet back so your knees are up. Place your hands at your temples. Crunch up until your elbows touch your knees. (Do not lock them behind your head — this tends to make people pull against the back of their skull, which puts strain on the neck and the spine.)

Buy the Book

The workout above appears in ConBody: The Revolutionary Bodyweight Prision Boot Camp, Born from an Extraordinary Story of Hope, by Coss Marte, published by St. Martin’s Griffin. Buy Now: $17