The videos may look painful, but the sport is becoming wildly popular, and many parents are having their children train in mixed martial arts to battle bullying.
In Central Florida, children as young as 5 years old are learning mixed martial arts, known as MMA. The kids get in a cage and learn how to punch, kick and choke each other out.
"The trend I've seen with children and mixed martial arts is an explosion," says Jonathan Burke, the owner of The VI Levels, a mixed martial arts gym in Ocoee.
He's not surprised by the latest numbers, which show that more than 3 million kids under the age of 13 are taking MMA classes around the country. In fact, YouTube has numerous videos showing boys and girls competing in MMA.
But unlike the violent fights you see in those YouTube videos, Burke says his goal is not to train boys and girls to fight in a cage like the pros.
"We use it to teach these kids self-defense, and how to deal with mental issues," says Burke. "It's not about fighting, it's about getting in great physical shape, improving your mental focus and discipline."
Parents tell us that they got their kids involved to deal with one of the most troubling issues out there.
"We thought he might have had a bullying problem because he's small for his size," says Keith Ori, a local father who's talking about his 8-year-old son, Ayrton.
"It happened to me as a kid, and it happens to them as well," says Prince Fielder, the All-Star first baseman for the Detroit Tigers.
Even a pro athlete like Fielder knows the painful realities of bullying. He and his two sons train at The VI Levels. And Fielder says that MMA is already turning his kids into men.
"I just never want them to feel, have their feelings hurt or lose confidence, just because of what someone says," says Fielder.
Even though the lessons at The VI Levels are pretty PG, you can't deny the violence and aggression in those YouTube videos, where kids are fighting in a cage.
So it had us wondering -- could MMA, over time, turn these children into bullies themselves?
"I think there's always a chance," says Dr. Andrew Pittington, a child psychologist in Lake Mary.
He says parents need to find an MMA school that teaches good values first, like self-control and discipline. Otherwise, kids may get the wrong idea.
"It's self-defense, and it's not to be used in an aggressive manor, or to attack other people, or to intimidate or bully other people," says Pittington.
We asked Burke at The VI Levels: How can you guarantee that these kids won't take these fighting skills, and become bullies themselves?
"I can't guarantee they won't be a bully, but I can guarantee that the way we present the information, we're going to make bullying look so bad, they're going to be ashamed to be associated with that word," says Burke.
And, of course, there's always the risk of injuries, especially concussions.
That's why doctors recommend that children wear headgear when they train.
For more information about The VI Levels in Ocoee, click here.