The problem with kids that young is if they are acting out and being a bit angry they can sometimes go down the bully track. my friend who is a child psych usually recommends more team based activities at this age such as soccer. Boxing is great for self discipline but can leave you a little isolated as much of it as you know is just getting down to it yourself.

Difficult one mate but respect for you for trying to get him involved in something, most people these days resort to the television or computer games for kids.

Good for you mate, we can break the cycle if we want to .