Foreman was INSANELY strong. Watch this video of Foreman hitting a heavy bag. This content is protected Imagine being hit by this guy.
Marquez became superhuman (Roidquez) for the third and fourth fights. Crazy that of the 3 Mexican ATGs he fought, two of them were drug cheats.
Clenelo's got a very good chin, but you can just as much attribute his resiliency to his slick movement. He rolls with a lot of punches and it's hard to hit him clean repeatedly. For someone to have a super human chin, they have to be able to absorb an obscene amount of punishment or hard flush shots. I don't think Clenelo can eat a multiple flush shots as one seems to buzz him. Examples: Golovkin Inoue Pacquiao Margarito Provodnikov