I used to hear this same **** about Chavez back when he was feasting on bombs. We know what happens when he got punched in the mouth.
That's partly what those exercises are for though. Most people think they make your chin more resistant but in reality they're there to keep your head from being knocked out of position and giving your opponent openings to the chin. Doesn't work with fighters who don't keep their chin tucked though.
I'm pretty sure neck exercises help your chin because stronger neck muscles mean more bracing for your head. Punches will move your head less which means that your brain doesn't get battered like jelly in the skull.
Are you talking about Chavez Sr? Because not a lot happened. He got KD'd by Randall I guess? Then stopped when he was past it? Don't see your point.
Good shitt in this thread. Actually learn something. Which isn't something I can see on this foru mfor years