While a thick skull and a strong, solid neck lend themselves to the phenomenon of having a good chin, they aren't the only factors. Much of it is psychological. For example, Brock Lesnar, by any reasonable physical analysis, ought to have an amazing chin. His head is the size of nine bowling balls and his neck looks like he stole it off of a bull. He was also a high-level wrestler, something also to consider. Now we've seen Brock take a mean punch, but few would describe him in the same terms that we might of Roy Nelson. Big Country can take a gorilla swinging a sledgehammer to the head. Why is that? Nelson also has a large head and thick neck. Those are certainly contributing factors. I think, however, that there is an aspect of mental toughness that contributes to what we observe in the cage as having a good chin. Brock Lesnar has said that he didn't like getting hit. That is something that Big Country or Hendo or Fedor or The Axe Murderer would simply never say. They have a certain toughness that is simply part of their nature as a person. This also accounts nicely for why there appears to be a correlation between former wrestlers and tough fighters. Wrestling is grueling in and of itself. The way these guys practice and the physical contact and roughness these guys get used to throughout the course of an amateur wrestling career is not to be underestimated. Anyone that has grappled for any amount of time knows that it is certainly a contact sport even though you aren't striking. But if wrestling, especially high level NCAA wrestling, is supposed to toughen you up, why did Brock fail to inherit these traits? I would suspect that Lesnar was able to use both his physical gifts and the intimidation factor those create to his advantage. I don't mean to say that Brock Lesnar was a great big wuss, but just to point out that if he had the toughness of Shogun, he might have been one of the all time greats. I think years of WWE work also softened him a bit. Sure, that is a rough line of work, but it's not another highly trained man of your size coming to beat you down. It's another highly trained man of your size coming to perform with you. That's a huge difference. It's the difference between sparring and a fight. You try things out and take breaks in sparring. A fight is a fight until it's over. At least that's the way the top tier heavyweights fight. The point of this tangent: we often celebrate but typically take for granted that professional mixed martial arts fighters are tough. Like offshore drilling or bull riding, it's not for the faint of heart. Having a good chin is an extension of that prerequisite for fighters.
