Gonzo's right.
I, like "Assault", have been (tho long ago) for YEARS involved in martial arts. (full disclosure I am not going to give my "pedigree", brag, or claim "all knowing" status)
I've been in MANY a "street fight". Won most, but lost enough to not want to admit it.
If you KNOCK SOMEONE OUT it's a MAJOR injury that is NOTHING like what Hollywood exemplifies. I have knocked a few people out, but almost always it was through a choke-hold or lyrynx (?sp) or sternum snap (loss of ability to breath at a time when they are worked up). I have NEVER "punched/kicked" a guy to unconscienceness. I have beaten their will to fight out of them, but that's not the discussion point.
If your head (and this depends on physiology) recieves enough kinetic energy to SNAP you from conscienceness then often, but not always(rare as truth from a feminazi), you are spitting up a lot of blood, lost some teeth, break a jaw bone and/or are also going to have received some neck/soft-tissue damage.
It's a SERIOUS trauma. The human body is amazing in it's ability to deal/absorb damage.
But PHYSICS cannot be ignored.
Again, without bragging, I've been in a LOT of fights (lo those many years ago - thank God!) and I honestly won many many more than I lost. Even when I won you are HURTING. (gave more damage than I received and still hurt like the DICKENS the next day - ouch - I am a little arthritic from my training days!)
Clear "total victory" Mortal Kombat shit is for kids and TV.
Steven