Holy Christ on a communion cracker!
Actual living and breathing and presumably somewhat sentient parents enrolled their kids in Mixed Martial Arts (MMA) training classes and allow their precious progeny to enter combat in the freakin' octagon. As if pee wee football not dangerous enough by causing concussions with effects accumulating over a lifetime to cause chronic traumatic encephalopathy (CTE).
Your long suffering commentator shouldn't even have to break this down for the pencil neck geeks pushing/allowing their kids into MMA fights. The bones, joints, ligaments, and tendons have to fully mature, allowing the possibility of greater injury more possible.
Extreme Youth Sports: Have they lost their minds? Kids this age have little self control, especially in a situation bringing out aggression. The "insane" arm bar the winner used could splinter one in a split second, and a kid using it is literally insane.
Years ago, I interviewed perhaps the greatest wrestler who ever lived: Lou Thesz. Mr.Thesz wrestled freestyle and Greco Roman in high school and turned pro at age 16 in an age when even though outcomes came scripted, wrestlers had to protect themselves in case their opponent went off script, protect themselves with actual wrestling, not this showboat carnival crap purveyed to audiences today. Damn youse, Vincent K McMahon Jr!
Mr. Thesz trained hard all over the world, becoming a hooker, one who knew wrestling moves called hooks, which could legitimately cripple people. At the age of 83, he demonstrated the double wrist lock on me, and I felt how he could rip my arm out of my shoulder joint.
So yes, let your kids train in karate, wrestling, and the sweet science of boxing.
But let them in a ring for an actual fight? Never in a million years, at least until they go to high school.
Just for grins, look at the beer swilling, overweight, cholesterol challenged white bums in the audience living their lives on gratuitous child on child violence, seen in 1st link above.
People die doing this shit: http://www.bloodyelbow.com/2012/6/4/3062505/mma-dustin-jenson-death-editorial-stephen-koepfer