The lack of uniform regulations, especially for amateurs, is a sharp contrast to boxing. All amateur boxing bouts in the country are regulated by a national organization, USA Boxing, with rules ranging from ringside physicians to pre-and-post bout physical exams.

In states like Nebraska, where amateur mixed-martial arts fights are regulated, the regulations are often on par or exceed boxing regulations. In Nebraska, for example, mixed-martial arts amateurs must have physical exams, blood tests for viruses like AIDS, health and life insurance, and both doctors and ambulances onsite at fights that are overseen by licensed referees.

But in states that don't regulate mixed-martial arts, it can be hard to tell the difference between a mixed-martial arts bout and a bar brawl.

Tim Bazer, the owner of Omaha Fight Club, takes some precautions when putting on an event in Iowa even though there are no laws that require it.

Fighters at his events must take blood tests to make sure they don't have viruses like HIV, for example. His referee is an emergency medical technician.

But absent are things such as onsite ambulances, which are required in states that regulate amateurs.

"They're going to have a major injury and their face is going to be plastered everywhere because they didn't regulate appropriately," Tim Lueckenhoff, president of the Association of Boxing Commissioners and administrator of the Missouri Office of Athletics.

In Missouri, the state regulates only professional fights, but groups that must be licensed by the state regulate amateurs.

At another recent amateur event in Iowa, Iowa Athletic Commissioner Dave Neil said a mentally challenged 21-year-old with the reading skills of a fifth grader was drawn out of a bar crowd and into a mixed-martial arts ring.

He got knocked out shortly after getting in the ring.

"He was taken advantage of," Neil said.