I am a martial artist and I have over 20 years experience. I recently read an article on Yahoo news about a young man that accidently killed his older and bigger cousin with a rear naked choke. This is very sad of course and my thoughts are with this family in their time of loss.
The techniques that you see on TV when you watch an MMA fight are done by professionals against other professionals. These men and woman have trained for years to be in the cage. The techniques that they are using have been drilled thousands and thousands of times. If you have not been trained by a martial arts school you MUST NOT TRY TO DO THESE TECHNIQUES.
Of course it is easy to look on TV and see how one guy wraps his arms around the throat of another guy and chokes him out. What you do not see with your untrained eye is the way that the guy being choked is doing his best to keep his air way open or escape the choke hold. Professional jiujitsu players are used to getting choked. They do not panic and know how to move so they will not be seriously injured. Also the guy who is doing the choking knows how long he can hold that choke without causing serious damage. There is a lot going on and the untrained person can not truely grasp all the fine details of what is happening. Also in a MMA match there are the 2nds and the referee watching to make sure that the fighters are not in any mortal danger. At any time the ref can call the fight. You can see this happen often when one opponent is not intelligently defending himself or is knocked out.
When you start training in MMA or any martial arts your teacher (the black belt) watches every move you are making. When you fight in class they are watching and making sure that no one is seriously injured. If you are untrained and just playing around in your backyard you do not have this level of safety. All these moves that martial artists learn are learned from 2 aspects. One how to do the technique and how to defend against it. If you are not trained you have not been shown how to defend. This is where people get hurt.