MMA is an abrieviation commonly used for Mixed Martial Arts. And at Mixed Martial Arts events, athletes are free to use whatever martial arts style or combination of styles they have learned. Three very popular MMA organizations are UFC (which is mainly held in Las Vegas Nevada), Pride which is held in Japan, and K1 which is also mainly held in Japan. There are many many more organized events put out in various countries. For example here in hawaii we have SuperBrawl, and Rumble on the Rock. Usually every organization has a set of rules which differs from the others. ex: In Pride elbow strikes are illegal but kicking a downed opponet is legal, While in UFC its vice versa. The UFC which started in the early 90's began with absolutely no rules at all, but to further it as a sport rather than just a spectacle the had to start incorporating rules and weight classes. The UFC was doing well but then went through some problems and survived off of PPV and the Internet for almost 10 years. MMA is getting alot more reconition now days beacause of Spike TV and Fox having the balls to show MMA on public TV. MMA has been around at least since acient greece were it was called Pankration, which uses a combination of boxing and wrestling. I hope this gives you a brief idea about Mixed Martial Arts. Fell free to PM me or anything if you have any questions. and thanks for reading.