Some things to keep in mind. First, "Knockout Power" generally refers to the ability to turn someone's lights out. This is not necessarily a direct measurement of force, though that obviously has a lot to do with it. High force is needed, and that comes from the classic answers: hips, generating power through your base, rotation, etc. This is where you use F=MA and more importantly momentum (regular and angular) to generate impact. There are other factors, though. Speed helps, both because the opponent has no time to defend (tighten his jaw, turn away, etc.) if he doesn't see it coming, and because it will increase the power of impact (power depends on the amount of time it takes to deliver a force, which is why pushing slowly but hard on someone with all of your body weight hurts way less than a punch.) Angles matter a lot too, which is why I think Anderson is so good at it. Snapping the neck and jaw around with angled shots, using the chin, head and neck as levers to generate rotation, is way more damaging than straight impacts. It also puts the force on the spine, jaw, and nearby nerve endings instead of the stronger neck muscles. This is why a right hook "on the button" is so brutal, while the right cross that lands clean on the mouth often seems to do very little. Side-to-side motion before the strike, and the right angle of attack can make a medium-strength shot become brutal. Finally, timing allows all of the above to be better, and can generally screw with the opponent. Again, not seeing and reacting to a shot makes it do way more damage, because your body naturally does a lot of little things when it knows an impact is coming. Also, catch someone breathing in through their mouth, and they are probably going to sleep for a few different reasons. Catch someone with their feet together (Lyoto v Rashad), and if its not a KO, it could very well set one up in the near future while the guy is off balance and hurt, as it did to Rashad. Catch someone stepping in to the strike, and you get a highlight with 1500000 hits on youtube