You think your trainer has it tough? It's Jason Walsh's job to get celebrities in shape for blockbuster roles. He prepped Matt Damon for the “Bourne” movies, Bradley Cooper for “American Sniper,” and most recently, John Krasinski for “13 Hours.”

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“It’s a huge responsibility,” Walsh tells us. “You never know how things are going to end up and if you hurt someone or stall the process of production, that’s millions of dollars lost.” But good news for anyone who has something about their body they want to fix: Even celebrities have body issues. Walsh tells us that 100 percent of his celeb clients come to him with an issue that needs addressing. Yes, including Bradley Cooper. We got Walsh to reveal what really works:

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Skip the bootcamp
Years ago, Walsh noticed that his clients kept coming to him with the same problem: their bodies were overworked from group workout classes — especially trendy bootcamp style ones.

He went on a mission to find a way to provide an intense workout without overworking any one area of the body and found the solution in a versaclimber, a vertical climbing cardio machine that works the upper and lower body.

“The crawling motion — which we’ve progressed from as babies — balances the body out,” Walsh explains. “It’s low impact and super effective.” It’s also not easy. Climbing requires a lot of oxygen and energy, which Walsh says makes people burn twice as many calories as they would doing another type of workout.

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Making it fun
After his “a-ha” moment with the versaclimber, Walsh created routines and group classes utilizing the versaclimber. He opened a fitness studio, Rise Nation, in Hollywood and is hoping to open a New York City location within the next couple years.

Music plays a huge role into Rise Nation. "I was at a concert and just blown away by the visuals," Walsh says. "I was jumping around and having a good time and by the end, I was soaking wet with sweat. I didn't even realize it was a workout because I was having such a good time."  

To mirror that in his Rise Nation classes, the versaclimber routines he uses in the class are timed to music and he also uses various lighting concepts to create a club-like environment that can serve as a distraction to the intense workout.

How to get the same results
Versaclimbers take up a lot of room, are expensive and not many gyms have them, but the same concept can be applied with indoor rock climbing, which is available in most cities. (New Yorkers, Brooklyn Boulders is a great one.) With so many celebrities turning to these climbing-based moves, we predict rock climbing to be one of the year’s biggest fitness trends.

Follow Emily on Twitter: @EmLaurence