Those who have studied this K1 KO montage clip will have noticed the high porportions of boxing used and the KOs done with a punch
http://whitetigermartialarts.blogspot.com/2010/12/kickboxing-kos.html
When a KO kick happens it is usually with a Thai round kick, either the classic dte or "rainbow" version, with the "knuckle" of the shin.
There are a couple of occasions where the foot is used for a KO.
We also see Thai leg kicks and the occasional knee.
Something to think about.
