Researched injuries in martial arts this afternoon. Surprisingly there is very little accurate data out there. I found data relating to head injuries but nothing significant on Traumatic Brain Injuries (TBI). I am sure they can and have occurred but am encouraged to believe it is a very minimal amount.
  The most thorough study I found was a nine year retrospective Canadian study. It analyzed 9 years of 58 individual competitions including 904 injuries.The most common locations for injury were the head, foot, and thigh. Injuries were most common among color belts and and the most common injury is bruises or contusions. This is possibly due to more aggressive tactics and lack of control. Younger athletes were more likely to be injured then older ones. Presumably for the same reason.
  Not a lot of surprises in the results of the study. I believe an active caring teacher/coach working with athletes who are properly trained and wearing all the correct safety gear is the best way to keep young martial artists safe.