Justin Gelband, 42, spends his days crafting the types of bodies seen on billboards, in magazine advertisements and on the big screen. For the past nine years, Gelband has worked with models, many of them employed by Victoria’s Secret, providing them with personalized physical training before they strut down the catwalk. Early last year he expanded this training to the general public with the opening of his own gym, called modelFIT, located in a Bowery studio that some of his clients already recognize: it was previously used by photographer Terry Richardson. And last Wednesday, he launched a new branch of modelFIT, this one exclusively for men — called, predictably, MANFIT.

Gelband got his start as a trainer in Los Angeles at 24 Hour Fitness. He was drawn to fitness because of his passion for changing people’s lives, especially women. “My whole philosophy is built on empowering women to be the best that they can be with the body they’ve been given,” said Gelband, sharing a philosophy instilled by his mother.

In modelFIT, Gelband focuses on low weight and a narrow range of movements to tone models’ already-thin bodies. He isolates specific muscles, working each just a little to avoid building bulky muscles, but enough to keep the models firm and toned. Despite the fact that the classes specifically avoid a traditional gym body in favor of something more symmetrical and sleek, ever since its founding modelFIT has attracted the attention of men. “While some do [participate], most are intimidated to work out in a class full of women,” said Vanessa Packer, cofounder of modelFIT. Packer and Gelband decided to create their own class for men, which they call a completely new approach to men’s exercise. “We also wanted to see who was manly enough to take the class,” Packer added.

To do this, Gelband hired Angelo Grinceri, a movement specialist. “Everything we do, besides sitting down, requires our arms and legs to move simultaneously together,” said Grinceri. “So we base our resistance training program around that same principal.” Grinceri said that instead of breaking muscles down with traditional repetitive weight training that lends an explosive build and big bulky quads or shoulders, MANFIT works to keep the body symmetric and toned.

“Imagine bench-pressing a barbell. In a MANFIT exercise, we want to replicate a chess press,” said Grinceri. “But instead of lying on your back, you’re standing, and when you press forward, you step forward. This moves the entire body and uses your hips,” thus strengthening your core. The MANFIT exercises directly mimic movements in running, skiing, rock climbing and snowboarding, the type of activities found in the lifestyle of the class’s target audience, said Grinceri.

Grinceri has been a physical trainer for a decade, but he was on hiatus the last two years to write a fitness book outlining 60 basic exercises that have been adapted to include the dynamic, movement-based resistance training that he uses in the MANFIT class. The book is due out in February, giving him a few months to observe his new moves in a real setting.

“100 percent I believe that this is going to kick off a revolutionary way to promote general exercise,” said Grinceri. For men sitting in an office all day, Grinceri said the core training in MANFIT is one of the best ways to relieve lower back pain, which close to 80 percent of adults will experience at some point in their lifetimes, according to the National Institute of Health.

Besides being practical for the sedentary lifestyle of the 21st century man, new fitness regimens that look to capitalize on the dynamic movements we use in our day-to-day life, rather than a static focus on individual muscle groups, have been gaining ground. New York’s famous Gleason’s Boxing Gym, once stocked with semi-professional boxers, now trains a clientele comprised of 75 percent business men and women, according to owner Bruce Silverglade. The rise of dynamic workouts for both men and women has also come in the form of full-body workouts disguised as competitions, like Tough Mudder, or in clothing choices, like the popularity of athleisure and wearable fitness trackers made to help wearers capitalize on their active lifestyle throughout the day.

At the first MANFIT class, held in September, Grinceri hosted a few male models alongside some “active dudes.” They worked their entire bodies with the use of step motions, resistance bands and free weights while listening to a “very bro” playlist of Lloyd Banks, Gucci Mane and Ludacris. Every participant signed up for another class.