Having a little bit of trouble lifting those free weights today? From big and buff stars like Dwayne “The Rock” Johnson to petite and toned models Miranda Kerr and Karlie Kloss, many celebrities rely on weight training to keep their physique in fantastic form. They weren’t born like this—most celebrities have to do some kind of resistance training like the rest of us. Here is a little celebrity inspiration to get you pumping iron like a pro…