Originally Posted by Ianian58
It's a ridicolous motion that if a fighter gets hurt in a fight his chin 'weakens' or 'deteriorates'.
There is a finite amount of damage a person can take to the head and it directly correlates with brain damage. When you get a concussion, your coordination and balance are negatively affected. If you're a "fresh" fighter, meaning you haven't accumulated too much damage, then you can recover either between rounds or between fights. However, it comes to a point that fighters can no longer recover and they stay affected from the accumulated damage; that's what we call punchy.