When I worked as a therapist in a Child & Family area of a large mental health center, a client and I put together a karate program for kids. He had come in for his kids’ problems and it turned out I knew his sensei and we discussed the benefits of martial arts for people. That led to us starting a program for kids. One of our psychologists had been a champion karate-ka, so he was highly supportive. By the time I left the center to go into teaching, the class had around 30-40 students rather than “patients” in it.
I bring this up because npr recently had a report on the effects of exercise on brain function and one of the benefits to children was a severe drop in aggressive behavior. Apparently, the activation of the prefrontal lobe of the cortex (if I have that right) inhibits the impulses surging up from the emotional part of the brain. One school reported a 60% drop in discipline referrals after instituting an exercise program.