Could be! With this one I was considering how humans can build muscle beyond whatever they get from a hunting/gathering lifestyle, which I take to be equivalent to a wild animal's level of fitness; just enough to get food and not die, but not so much that it becomes a detriment with energy burn/time wasted maintaining it. Animals can get fat and weak when overfed/underworked, so maybe they can build excess muscle with a proper diet and exercise.