Arnold was not one of those guys who was on all the time after his bodybuilding career ended. For a while he was for example into running a lot and got pretty skinny. Then he gained size for conan. And from then on it has gone up and down depending on his priorities (if he is filming a movie and how much of his body is shown in the movie), health status, political career etc.
But he has an incredible response to drugs and training and many have noted how quickly he can add size and get in shape. Padilla was another freak who could grow almost visibly day by day.
