Kellan Lutz works hard to get that Hercules 'pop' The skinny guy doesn't get cast as Hercules. Conversely, you can't just go down to the Gold's Gym in Venice Beach and hire some muscle head to play the lead in a big-budget 3-D movie. Acting chops to go with the bulging biceps and rippling midsection are required. "The Legend of Hercules," opening Jan. 10, has Kellan Lutz leaving "Twilight" vampires behind and returning to Greek mythology. The actor who played Poseidon in "Immortals" goes from god to demigod, but with added muscle. It's obvious fitness is a big part of your life now, but were you like this as a child? I grew up in the Midwest and lived on a farm, and having older siblings, it was a rowdy house. I remember always being outside because I loved the animals. I tried to live like Mowgli from "The Jungle Book." I made up my own fantasy worlds, cut swords out of cardboard boxes, climbed trees, tried to ride my golden retriever.... I lived a pretty fearless childhood. Did you feel pressure to make your physique live up to a certain ideal for Hercules? No one ever told me I needed to look a certain way. ... For playing Poseidon in "Immortals," they hired trainers and nutritionists, but for Hercules there was a phone call that I got the part and then we started shooting soon after, so I really had to push myself. The only thing said about my physique was from Renny Harlin, the director, who said because it's 3-D they wanted to be sure my abs popped out. It sounds like you must have already been in great shape. I wasn't working out much before that because I didn't know what my next job was going to be, so as soon as I heard I started working out really hard. I was also really careful about what I was eating to stay in top shape. I had my own vision of Hercules from when I was a boy as to what he looked like. But it was more about telling the story we wanted and making some magic. Once filming began, what kind of training regimen did you engage in? The movie itself was a workout because they had me killing gladiators every other day. Sword fighting is very much a cardio exercise. Plus, you're swinging heavy pieces of metal, and you do take after take after take. I did a lot of running in the movie as well.... We did bow and spear training; there was a lot of stunt work. With all that action, were injuries an issue? Every action movie I do I get a new scar. One horse bucked me off, then almost landed on me, and I just barely rolled out of the way. And I was like, "Did you get that on camera?" It's funny that I'd rather ride a horse than go to the gym. I hate doing legs in the gym, and riding a horse is a great leg workout. You're squeezing your legs and using your abs too, and it was a really fun way to exercise. You don't even think about doing it, but afterwards you're sore. Fell is a certified strength and conditioning specialist and founder of sixpackabs.com. Dr. Hooman Melamed's tips for avoiding workout injuries In Bronson Canyon, the tai chi energy has flowed for 45 years Girlz Gone Riding club carves out a place for women in mountain biking