I think the majority of us have been in this position. It's hard not to fall into despair and hard not take revenge. Tolerating that kind of stuff could have a good and bad outcome. You can't just ignore them because they'll increase their advances and be even crueller so you must take action. And yes, it may come to punches or kicks but don't do anything that really isn't necessary. Don't be like me and pull their arms out their sockets, resolved the issue, got me in a little trouble though. But if you don't have to fight, don't fight. Establish yourself and hold your ground; something to declare that they are beneath you. And sometimes a good comeback will suffice, I can think of several that would make their weak little hearts break. But still, its way better to defend yourself by putting them beneath you and not backing down when it comes to anything.