The Insane Training Brie Larson Had To Do For Captain Marvel

As a de facto member of the Avengers — and the first female superhero to get her own Marvel movie — Carol Danvers (aka Captain Marvel) has done quite a bit of heavy lifting. The same could be said for Brie Larson, who's run the gauntlet for her role in Marvel's Cinematic Universe since her casting in 2016. Back then, the actor was something of a novice to the world of fitness, telling Insider that she only started training for her MCU debut "out of sheer panic."

"I affectionately called myself 'an introvert with asthma' before I got to play Carol Danvers," she recalled, since she could scarcely walk up a hill "without being out of breath." All that changed once her training actually began. By the end of her months-long regimen, Larson could do far more than walk up a hill without assistance. She could also push a 5,000-pound Jeep up an equally-steep incline.

Larson has since become "kind of obsessed" with the process of training, but getting to that point was definitely a trial by fire for the actor. Her role in the MCU was a big pivot from her early days on independent films, which typically demanded more emotional work than physical. Her first go as Captain Marvel would call for nine grueling months of training — and building up her strength was only half the battle.

When Larson was cast as Carol Danvers all those years ago, she teamed up with celebrity trainer Jason Walsh, who's spent years forging actors into action stars. Walsh turned Emily Blunt into a post-apocalyptic crusader for "Edge of Tomorrow," and got Matt Damon into stellar shape for "Jason Bourne," so he's well able to produce a night-and-day transformation in his clients. For "Captain Marvel," though, Walsh was looking for a different result. Rather than bulking Larson up to play a superhero — like her "Avengers" co-stars had been doing for years — Walsh was more focused on building the superhero mentality. He told Men's Journal about the process, and how he aimed to build Larson's confidence as much as her strength:

"What we tried to establish in the training was also part of character building: What's the psychology of a character who's basically invincible? I wanted to get as close to that as possible. Having that physical strength helped her become the character."

Walsh and Larson's training routine is pretty well-documented — and just as daunting as you'd think. Walsh swears by hip thrusts and dead lifts, and those two movements became the foundation of their regimen. Paired with conditioning exercises and loads of ab work, the pair began to build towards those superhuman goals. "We got deep into heavy progression," Walsh explained. "We'd go from mobility into activation work, which we considered a warmup, then into the primary strength exercises."

The pair would actively train four days out of the week — sometimes five, "unless Brie was feeling destroyed" — but the goal was always to keep risk of injury to a minimum. Big budget Marvel flicks often keep to tight schedules, so injuries are often synonymous with delays. Fortunately, Larson was dedicated to every part of the process, including getting ample nutrition and sleep.

Of course, there were bad days as well as the good. The "mental aspect" that required Larson to push herself to such limits was just as important as the physical. "There were some moments where I made her cry in the gym," Walsh admitted, "but she was able to push through that because of how dedicated she was to this."

That dedication paid off for Larson in a major way. By the end of her nine-month program, Larson could deadlift over 200 pounds, hip thrust 400, and of course, pull off that viral Jeep maneuver. Larson admitted later that the workout was more of a joke between her and Walsh throughout their training process, but Walsh eventually made it a reality. "I was like, 'Well, she can move planets,'" Larson told /Film. "'The least I could do is move a car.'"

"There was a lot of talk about the Jeep workout," Walsh recalled. While he admits that the feat was "superhuman in a way," he also stressed that it wasn't an every day occurrence. "It was something fun and cool for her to do just to see she could do it."

Walsh was adamant in building Larson's confidence as much as her strength, and that confidence really shines through in her portrayal of Carol Danvers. From her wire-work stunts to her more intimate scenes, everything she does looks effortless. It's likely because Larson had become so aware of her own strength in the process, which helped her further connect to the character. "It's really become a huge part of how I learned more about her, and became her, and embodied her," Larson explained.

It's also a process that Larson has continued in between her massive Marvel projects. The actor told Insider that training has since become a part of her daily routine, and she frequently updates fans about her progress in the gym through her social media. And now, with a "Captain Marvel" sequel on the horizon, Larson has been sharing her new goals — and new milestones — with even more frequency. The forthcoming film, titled "The Marvels," will see Carol Danvers reuniting with Monica Rambeau (Teyonah Parris) and teaming up with newcomer Ms. Marvel (Iman Vellani), aka Kamala Khan. 

Details, as usual, are being kept tightly under wraps — but director Nia DaCosta will likely be exploring Captain Marvel's vulnerabilities as much as her strengths. "I want to know more about Captain Marvel," DaCosta told Inverse in 2021. "How do you actually deal with being the most powerful being in the universe? How does that weigh on you?"

It sounds like the Marvels are in for a pretty epic adventure. Seeing how much work Larson has already put into the character, she's definitely up for the challenge.