Lee Child's action hero Jack Reacher is supposed to be a 6 foot 5 inch giant with "arms like tree trunks" and hands as big as supermarket turkeys. so the casting agents behind the Amazon hit TV series Reacher got lucky when they found Alan Ritchson to play the former U.S. Army military policeman who investigates murders; he's just two inches shorter than the real thing. But he looks just as big, thanks to an intense fitness regime. Here's how he and his co-stars stay fit.

Malcolm Goodwin played Oscar Finlay on seasons one and two. He opened up about his career, approach to acting, and favorite ways to stay in shape in an interview with Fit Chat. Goodwin likes to box to stay fit. "I love the workout," he says. "I'm an asthmatic, so I have to keep my cardio going."

Robert Patrick played Shane Langston on season two. He opened up about getting sober to Salon.com. "For a long time, I never thought I had a problem," Patrick said. "I thought I was just like everyone else. Everyone I was with was doing the same things I was, and I didn't realize that we all had a problem. It took me a long time to realize I was abnormal. I'm grateful you asked the question, because I would like to say that a lot of that behavior was tied into my insecurities, which were a lot more prevalent when I was a youngster. I'm 21 years sober, and my life has benefited greatly. I have a sponsor, and I try and live by example. I'm a devout Episcopalian, and it took me a long time to get honest and get to know myself. The thing that was really lacking in my life was spirituality. My brother is in the music industry, and he's sober. I know he wishes he could have those years back that he spent under the influence. He's lost a couple of really good friends lately."

Alan Ritchson plays Jack Reacher on the show. He talked about getting in shape for the role to Men's Journal. "I did an attack on all fronts to get ready for this one. I do what I can to stay healthy and in shape all the time since a lot of my projects are in that superhero genre. I try to stay lean, so I'm usually walking around at 205 pounds. For this I wanted to bulk up though, and I ended up putting on 30 pounds to end up at 235 pounds. I was grinding it out five days a week for the eight months that we had to prep. I don't usually use weights because I get big so quick but I pulled them out for this. I got to unleash in the gym. The real requirement is you need to get the calories, proteins, and macros, so it was a conveyer belt of food. It's a full-time job to get 4,500 calories and 300 grams of protein in your body. I was lucky that I had the help."

Willa Fitzgerald played Roscoe Conklin in season one. She shared her wellness secrets with The Bare Magazine. "I feel like my number-one need is sleep. I prioritize getting 8-9 hours above most things. But food is definitely a close second in informing how I feel. I don't eat land meat and only eat fish on occasion. I try to eat as many vegetables and whole grains as possible. But I am also a sugar junkie. My freezer is filled with ice cream and my pantry is stocked with cookies and chocolate. Everything in moderation, which for me means listening to those sugar cravings when they come."

Maria Sten plays Frances Neagley on the show. She is a former dancer, and tells Black Girl Nerds that this helps with her stunts and acting career. "I do all my stunts whenever it is safe, which is most of the time. And so it's exciting to be able to use that old background of learning choreography and being in your body in such a natural way on a big explosive show like Reacher. Being a dancer requires a lot of discipline. It requires pushing through fatigue, pushing through aches, and whatever is going on with you. I am grateful to love what I do. And I take it seriously."

Serinda Swan played Karla Dixon in season two. She likes to do yoga to stay in shape. Swan shared this video on Instagram of herself doing yoga poses while on a paddleboard. She captioned the post, "Upside down styles…Been trying to master this dismount for days lol."

Kristin Kreuk played Charlie Hubble in season one. She shared her fitness secrets in a video interview with Shape Magazine. "I do a lot of yoga," she said. "When I'm at work, because my hours are crazy, I do a gym routine. I have a friend who's a trainer, so she puts together workouts and I just cycle them through."

Shannon Kook played Tony Swan in season two. He opened up about getting in shape for the film Dark Places to Talk Nerdy With Us. "I was a vegetarian for eight months, because I was trying to fast-track getting into shape. I was just pretty frustrated trying to figure out how to get in shape as much as possible for this character because just the description of him in the book is just him working out for four hours a day. Just grunting and swearing to death metal and his body's always at an acute angle."