heh... yeah... Gracies fought and won heavyweights once, but now everyone knows what they are doing on the ground, The family is having a hard time keeping there fighters on the top of any weight class, and they aren't a family of heavyweights
Anyways, as Ybot said. Most of the people that took the Gracie challenge had no knowledge of groundfighting. The Gracie representitve forced a clinch, took them down and toyed with them. Even in the early UFC's Royce was to represent the system by winning without hurting anyone.
And we do take a lot of punishment before our bodies die
Injuries that like to hang around for ever are probably more common, but then again they are in sport as well. One thing full contact fighting teaches you that point fighting or static drills don't, is how to protect yourself when someone is beating on you. How to cover, protect the important things, and press forward and clinch rather then turn away and get hit more.
That's something I have yet to see an effective way other then full contact fighting to teach, how to stay protected when someone is beating on you. Yes, in "real world" the beating will hurt more, but we still got to go to work tomorrow and be able to walk in 10 years
