I've seen a similar show,but was only about boxing...
The thing is that the brain needs touch the inside of the skull...that can be done with brute force,
but also with the right technique...for example if the chin is hit at the right angle you improve the
chances of a knockout bigtime,cause the head moves the right(or wrong,depends on your point of view)
way for the brain to touch the inside of the skull...because of that it is so important for a boxer to
have a strong neck...you don't wanne have your head moved in awkward angles...

They also said on this show that an average boxer hits two times as hard as a nonboxer of the same
size and weight...