Awesome! Wish it was legal.
On the prelims, if you didn't see it. Goodman vs Bilstein
I don't see how a soccer kick is any more forceful than a nice headkick, and it certainly pales in comparison to a spinning back kick.
A knee to the dome as someone pulls you into it? Way worse.
Learn what leverage is, and you'll understand.
In 4 gif 
The only way to test is fight science lab no BS sport science lab.
Shotokanman - I don't see how a soccer kick is any more forceful than a nice headkick, and it certainly pales in comparison to a spinning back kick.
A knee to the dome as someone pulls you into it? Way worse.
Physics how do they work?
You can't kick a soccerball as hard in the air as you can winding up behind it on the ground
Chaos ur wrong. 
Got MMAlk - Chaos ur wrong. <img src="/images/phone/droid.png" alt="Phone Post" border="0" style="vertical-align:middle;"/>
try it then, throw a soccer ball head high and kick it ten times
and then kick a soccer ball winding up behind it ten times.
See which one goes further