The actor told E! News he had to ride his horse day after day so the animal could learn to get used to the rider.
"It got rough. It got really rough," he said Friday. "There was some chafing. You're bouncing up and down, you have to ride [the horse], so you really learn. So, my butt just got raw."
"I got some scars on it and I had to be on the horse the next day, because the horse needs to learn that you are the rider, so you can never miss a day," he continued. "So, I learned my lesson to listen to the experts and I will always do that from now on."
"I had my trusty beast -- my horse -- to work on my legs with every time I rode him and then also working with a sword -- it works your shoulders and your chests quite well, so I love it," he said. "Also, I'm topless in most of the scenes so it gave me the opportunity to do push-ups whenever I wanted to."