ask a neurologist about the effect of repeated trauma on developing children.
Regarding the event it looks like k-4/k-5 rules. Same as the shin-karate organization that runs very popular amateur glove karate tournaments (glove karate = more or less kyokushin but with boxing gloves and punches to the head allowed) in Japan. Shinkarate had a deal with FEG/old K-1 and was licensed to use the names k-2, k-3, K-4 and k-5. K-2 being basically same as k-1, (at least visually, in actuality scoring is closer to kyokushin) and k3-5 rules adding more protective equipment and restrictions. Shin-karate fed a lot of successful fighters to k-1, Masaaki Noiri being possibly the most well known today (him being a youth k-2 champion before entering K-1 Koshien and eventually earning a spot in the real k-1).
K-2 2015 GP highlight
https://www.youtube.com/watch?v=k4y9CTQZG54