To knee or not to knee?

[Set for Ross]

Look at Rich "Ace" Franklin when he fights. When he knees someone in the head he just grabs the person's head and brings the guy's head down while he brings up his knee. I doubt he cares about what part of his knee hits the guys in the head.

 

[Woob]

I have always been told to knee with the front on the knee not the top and not to knee up but knee through them. This protects your knee and delivers more power. Is you knee up, it can damage the knee ligaments and tendons, if you knnee through, its much more structured.