Posted by Matt Juul @MattJuul
Digital Arts and Entertainment Writer at Boston Magazine
Matt Juul

Jason Bourne may be a man of few words, but he knows how to kick butt and look good doing it.

Matt Damon had to get into fighting shape in order to make his 45-year-old body look believable as the iconic superspy in the upcoming Jason Bourne film.

The hard work paid off, though, as people were pretty impressed with the actor's physique when producer Frank Marshall tweeted out a shirtless photo of Damon from the first day of filming. The rock hard abs were the end result of a lot of training and some serious dieting.

"Now I'm 45 and it's just brutal. We shot this bare-knuckle fighting scene on my 45th birthday and it was a lot of work to get there," Damon told the BBC in April. "I was on a very strict diet and spent a lot of time in the gym just making myself miserable."

For the action movie star, it sounds like the diet was the worst part of preparing to get back in the saddle as the amnesiac rogue agent. He told E! News in September that the process involved "a lot of no's and not one yes."

"I like to say yes too much. I like burgers and beer," Damon said. "It's been no burgers and beer for a while."

Staying off the junk food may have been torture, but his workout routine was no joke either. Damon got back into shape by working with trainer Jason Walsh, who also recently helped John Krasinski transform into an extremely ripped Navy SEAL in 13 Hours: The Secret Soldiers of Benghazi.

When Damon first started working with Walsh while making Elysium, he had issues with his back and shoulder. The trainer told Business Insider that the actor came to him because he had a reputation for correcting injuries.

"I helped him out with his shoulder injury and soon after we got his back cleared up and he was 100-percent feeling great so we continued from there," Walsh said.

After taking some time off, Damon went back to Walsh to get ready for the new Bourne sequel. The workout guru focused on giving the star a solid foundation of "mobility, flexibility, and overall strength."

According to Business Insider, this meant daily workouts consisting of pull-ups, push-ups, sit-ups, squats, and sled drags. Walsh told Men's Journal that he also had Damon use a VersaClimber machine frequently during training.

"The VersaClimber reinforces primitive movements, namely the natural crawl motion, which is superior for strengthening the body effectively and safely," Walsh said.

All the workouts and dieting may make Damon look buff, but it takes some extra effort to get all of those martial arts moves down.

Fight choreographer Roger Yuan deserves a lot of the credit for making the beatdowns look good on camera, although the actor isn't a total slouch in the fighting department.

During a recent Reddit AMA, Damon revealed that he took up boxing while working on the Bourne movies. However, he admitted that getting in the ring with anyone would probably be a bad idea.

"I was 29 and I fell in love with [boxing]. I never did it as a sport," Damon said. "I wouldn't put me in a ring against anyone. I'm an excellent movie fighter, probably wouldn't be in a real fight."