My nephew who is 14 now was on the receiving end of a bit of bullying in his early school years, but his dad (my brother) had him taking karate lessons early at a young age and basically told him, "Don't start anything with any kid, but if they do with you, defend yourself and make it count." And my nephew did several times. He knocked the crap out of a couple kids in separate incidents and no one has messed with him since and he is a happy 14-year old who has a good circle of friends now. You hate to have to do that, but bullies will keep at it unless you hit back and make them back off, and I have no doubt that if he had just sat back and taken it, he'd still be on the receiving end of it to this day.