Punch resistance and neck.

Just about all of it is actually the neck as opposed to the chin as they say. The chin is where fighters hit precisely because it's the closest point to the neck, therefore, has the most direct action on the neck muscles giving them the greatest chance of applying force directly on those muscles in hopes that in can't handle it, and maybe creating that whiplashing/head rattling motion of the head when the muscles can't handle it. The neck is where the your chin is at, that's why it's worked out by fighters the way it is, and why, many fighters with great chins have very sturdy looking no necks.

 

Impossible to say... so many variables.

 

It's all on the internals of the skull as evidenced by not being able to train a chin. Generally fighters with a good chin have a bigger head relative to their body. Other guys are just massive for their division like margarito.

 

The length of the neck would factor how strong the neck is as well, since guys with short necks when punched the whiplash effect is reduced.

 

It's all about your brain moving around in your skull. There are multiple ways to minimize that.
Tuck your chin so when it's hit the torque from the punch don't wobble the head as much.
Stronger neck muscles also can minimize this as would having a thicker skull (genetics)
The more damage the brain has the easier it is to damage it going forward though.

 

http://www.boxingforum24.com/showthread.php?t=182602

 

skull density, big head = good chin

 

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skip to 10:05 to see what Anthony Joshua has to say about the topic.

 

30kg neck reps is the goal then....

brb

 

:good

Although he's a bit off, Tyson's preferred neck strengthening exercise which he popularized (not sure he "started it") was the neck bridge on the floor.

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You can't train a Chin.

 

Actually up to debate, on both the physiological and psychological end of the equation.

I mean, fundamentally, no, you can't go from being Jason Litzau to Salvador Sánchez - to an extent you're going to be in one neighborhood or another, just innately.

Subtler variance over time is possible, though, evidence would suggest.

 

psychological I might agree with but that is not training. A great example of that would be Danny Williams. Sometimes he was KOed or knocked down by nothing punches other times he took bombs. he was a mental nutcase.

But back to the topic if you have a Glass Jaw no amount of neck exercises, squats, etc is going to help. Look at Khan. We were told Roach was going to strengthen his legs etc. Didn't do one bit of good.