Transcript for Cage-Fighting Kids
Parents would be upset to hear their child had been part of a playground scuffle. But most parents aren't like at -- and -- who it seems will stop at nothing to make sure his ten year old daughter. Is a champion in cage fighting one of the world's toughest sports. And is ABC's David Wright founder mr. -- and -- is not alone. Falcons hope is -- just bowled his ten year old. Not get very Santos is preparing to defend her title -- -- -- striking. Capacity of the Venice they call her the beast answered dad at the side of her treadmill how bad you want that sentence about. Really bad. It's tough as any drill sergeant of in the military and I suppose people could -- me. As a people just quit on me because -- bulletins are visible and in the -- he is nemesis is shot and Bowman so that's her over there. Also ten years old billed as the bulldozer. Bulldozer and what you do it. -- -- -- Two tiny gladiators have vowed to fight it out not -- ring with a -- -- they fought each other three times before. -- -- -- Once and I want it and she's beaten months. Twice but today she Diane is hoping to take the title. Diane and Nadia -- even the youngest fighters here at this competition in San Diego. Your kids as young as five cage fighting has their parents cheer the more. What did you think when you so. I'm shocked. -- Foster is executive officer of the California State Athletic Commission he oversees all fighting sports in the Golden State. After watching video from a similar -- Which a kid accidentally took a blow to the head. He stopped that -- he says kids have no business. -- -- And you come at this from a position of knowledge you're familiar with the sport that's correct -- professional mixed -- Lawrence -- -- -- the lockdown. Well versed enough in more floor and I don't believe -- went off all what is that you worry about. We're about the safety of the -- -- about six million American boys and girls practice one form or another. Learning valuable lessons of self discipline and physical fitness. -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Full contact blues two games. Most telling yeah. The inspiration these days isn't the Karate Kid it's contests like. Fighting championship -- video games hugely popular with kids. So it's probably only natural kids would wanna get into the ring -- you can have soccer is a nice safe sport so Little League. I did she is this we've tried that. -- girls not only played each other. Did a fairly common thing for girls to do these days. Anyway. And the -- -- the boys go about beckoning them but that but I girls. Some of these kids fighting is almost a secret identity. Ten year old Krista -- -- says her classmates have little idea what she can do not. School friend change that religion. People more. She gets a lot of damage and it. -- -- -- -- -- She spends three to four hours a day there. -- to take somewhat better. We showed Andy Foster a video of -- to fight him he was impressed and also -- -- -- -- ten years. She's tough little kid I highly skilled on her -- points for goodness easily establish the darkest point. I'm walked home from where this -- -- -- -- vs ago. At some point we will -- -- serious injury. Fight moms like Lindsay being kids are devoting their blood sweat and tears to -- work. Wrong communities haven't figured that variances are we had a beautiful event here just a few weeks ago. No children injured they all left the smile on their -- that medals around their necks and they had a great time so -- Some -- Foster daughter gyms and event organizers need to get the message to cease and desist. These kinds of tournaments. Physicians say he's right. We talked to sports medicine doctors at the Scripps clinic pediatrician Paul stricker says he sees lots of MMA injuries. When -- asked these kids a -- had a concussion or been knocked out. The -- is almost always know if I asked him have you ever been -- days -- following year have a headache after you've competed. The answers almost always yes but they -- concussion with -- they may have had some -- trauma -- -- it's. I wouldn't. So how is it that these tournaments continue to take place in California. Even after the athletic commission has stopped similar events to be honest I don't know about it. The promoter insists he wasn't aware of the commission's ruling until it was too late to cancel this what. You never received a cease and desist order and he insists that this is -- contact him in May not full contact. -- to the head are off limits he says they do happen accidentally. As several did well -- cameras were rolling. The -- are on the fight get stopped. One quarter. An illegal strike the faith that he. -- contacted me ask qualities and taking him at five year old girl's -- they trained -- easily. You're gonna take away that because your own -- us. Indeed these parents fully support it. Another -- -- just case her dad encouraged her to be more aggressive if you could take it down take it down. You know I -- again the -- -- Time ten minutes those kids -- It's -- probably the simplest. -- Their herds but these ten year old girls also drive themselves. The -- was always like. I don't want -- future I want him. Go join MMA so was his or her again she push it. She and her it's just more like art records -- the passionate she likes and she enjoys. As if there weren't enough pressure. Nadia has to lose five pounds to qualify for the weight class to fight with China she. -- -- -- -- Ninety assumptions -- The coaches keep them in check and make -- in UK pounds UK -- pounds now. Backstage on fight day success -- made the weight class she got down to eighty pounds losing nearly five pounds in two days. Time for the title fight between the beast the -- those -- And it's not looking good for not here. 33 seconds into the first round -- all over and for Nadia that tears start to. The -- Cheyenne Bowman takes the -- Have. Nadia this crushed like almost every other kid that wants today she weeks in the locker room. Tough lesson to absorb -- age ten that she's a tough girl she'll be back. I'm David Wright for Nightline in Chula Vista, California.
This transcript has been automatically generated and may not be 100% accurate.