Actually, nobody in boxing ever had Joshua's size of biceps or deltoids :think Only Bruno and Wlad came close, but they're both smaller than Joshua And they were smaller than him at 26, they didn't reach those sizes until their early 30s
I would say that Briggs now or Briggs in years past had muscles that size and his stamina is terrible
he is 6.6 and cut , he is not bigger shoulder /legs /biceps wise than loads of black heavys or yesteryear, maybe he has a smaller waist thats it. bruno was a lot wider and a lot thicker through the chest and arms and that slowed him, joshua looks to have a lot more fast twitch muscle, albeit in athletics that mnakes a explosive athlete and not a distance runner.
Watch the whole video about Joshua,intresting stuff in there:https://www.youtube.com/watch?v=FKIthHNmZ74.Skp to 2.39
I see that's why all modern HW s are all far better than the ones from the 70s to the 90s so David haye was better than Ali foreman was a wimp those guys went 15 rnds but aren't very fit .sprinters lift weight how would they do in a 5000 m race ? Power is fine but what happens if the fights go long ? Power is no use without stamina.