JJ's chest is thick as can be, shape is not as good as Arnold, but size is about the same think.
I had a BETTER chest in my late teens, early 20''s than I do now. It would pump up thick as shit-but as I got lder I could not get the same pumps and my chest is not as big today.
Bac then I had a very basic chest routine-10 sets of 10 reps on the bench press, usualy hanging at 225#. I could not do that routine today because it is too damn boring (plus my shoulders make all sorts of weird sounds on flat bench when I do them-rarely), but back then I loved it.
my chest looks like a bag of dicks...tho it is improving rapidly.
on german volume training im sure that it was massive.
i dont respons at all to high reps. sucks