http://s33.yousendit.com/d.aspx?id=1NJP77R...JY0459CJJQWAWSE
Watch it and see for yourself.
The common argument from TKD and Tradiational Martial Arts guys is that you can't grapple in the street, because the concrete will scratch you up, blah blah blah.
After seeing this, you'll understand why grapplers want to fight on concrete.
It's funny, during the whole thing, I could hear Rorion and Rener Gracie's voice in my head saying, "That the Headlock is the most common thing you'll encounter when fighting with an untrained grappler".
There were other ways of winning, but this was the best way to make a point.