Hi guys, I'll try to keep the question as concise as possible.

So I'm reading Arnold's book "The Bodybuilding Encyclopedia" and in the book he has a few sample workouts for beginners and some sample workouts for advanced bodybuilders. In one of the workouts plans you need to train chest and back on the same day.

my question is whether it is recommended to work two huge muscle groups or one big muscle and one small one (e.g. chest/triceps or back/biceps)