i think the way to think about the head is that it is an enormous hard surface, the momentum
of which comes from body's forward motion and/or minimal quick jerky head movement--together
is better. that said, what knocks out a person is the temple--i've seen it, and significant and
unexpected torque of the head. same as punching but with the added bonus that you've used
one of your body's few brick-hard and heavy surfaces to achieve this. forward motion can be simulated [pulling someone in at a quick rate if you're close in]. if your movements come down and across, you have increased the chances of having a stunning--short term or longer lasting [eg///k/o], affect on the
person in front of you. also, if you have hold of someone's head--which gives the added bonus of said
head no longer possessing options to retreat, considering pulsing your head into his. lessor enslaught
of hard surface all they while driving him back. i've practiced the headbutt in this way as a possibility
of landing it twice, and it inclines a faster [for me] growth curve for coordinating it under pressure. all the repetition inclines one in the practicality of not 'over-butting' and getting the angle exactly right. consider trying out 25 rapid blasts in a row, you find out alot about what you need to do with your body
mechanics--and should the situation afford itself, you are now more familiar with how to crash into your target multiple times under the right conditions.
that said, noses, etc...can be broken, etc...with a hard and heavy forward moving object. the affects are
still quite dramatic. rock the head enough, and you might have a nice default going--Richie has a clip
on the headbutt section of a woman head butting a bouncer out cold, i'm guessing from that whip lash
like affect because it otherwise comes straight in--but perhaps slightly upward to. i'll have to have a re-look.
my sense would be to concern yourself more with it landing right so no dammage is incurred to you.
the rest will invariably have a nice affect--if you can have a sense about the whole thing to make the
movement significant enought to create a whiplash affect, more going for you. in training, i've even
thrown my head into someone's solar plexus to create forward motion against a bigger fella. you'd
be surprised at how alarming that was to the big guy in front of me. i just can't say enough about a
good head butt. hope that's the answer you were looking for.