if a muay thai fighter gets his hands around your neck draws you down and then kicks with his knee into the are are of your lower ribbs... they gonna break... it will lead to serious internal rupture maybe pierced lungs... maybe other critical areas will be damaged there is enough there right beneath your ribcage...
this is an impact of the thai fihters knee into your body ... therefore I used impact ... I was not relating to impact damage in game terms at this point...
(btw I know what "impact" is and also a bit of physics about it like kinetic energy,momentum/impulse and stuff...)
they measured the kinetic energy which was generated with a high tech dummy originally designed to be used in car crashes and the tech staff was trained for car crashes and they made the relation to car crashes and said this is... in numbers...about as deadly as a frontal car crash with 50 km/h
no thai fighter can deliver this deadly blow in a muay thai match because the opponent is blocking and guarding and that means the attacker cannot direct the blow in an ideal way ...
furthermore these are trained martial artists... especially kung fu and muay thai fighters and the lot repeatedly punch/kick/hit hard stuff with their bones (shin/knee for example of thai fighters) which hardens the bones... which again means the would take less damage then the average person (me for example and probably you)
although much of this knowledge is indeed taken from a movie(documentary) it is not taken from hollywood or whatnot movies if you're intrested maybe watch it yourself
http://www.imdb.com/title/tt0775470/
I think the relevant scene is about nearly halfway through the documentary
and one of my best friends does thai fighting... my brother did... (and I had several other friends doing different kinds of martial arts altough I never did myself) so this is no nonsense and was not about game terms
personally I do not know what kind of forces and and how much of them are taking place during a carcrash and where it hits you and with what effect so this is just something I "heard from a documentary" and "hung onto it" granted