Punch resistance is affected by many things. For example your neck acts as a shock absorber to blows landed on your chin. Strengthening your neck and shoulder muscles would help a great deal in improving your chin/ punch resistance.
Also, there is a layer of fluid that surrounds your brain to protect your brain from rattling against your skull when you take a big shot. As your body becomes dehydrated this fluid layer depletes itself. That's why sometimes when guys move up in weight their punch resistance increases.
Last edited by RlCKY; 11-15-2012 at 08:13 AM.