I played offensive line, defensive line, linebacker, and all of the special teams...looking back on not only how much I hit or how hard I hit but just the manner in which I hit I would be surprised if I hadn't had SOME injury, I'm absolutely shocked I never lost consciousness or had a diagnosed concussion.

I remember a drill we were doing in practice one day. 1 on 1 o-lineman pass blocking vs a d-lineman. The offensive players had their helmets off in order to teach the player to pass block correctly (which I knew and could do better than anyone on the team). So my turn comes up, well me being a 17-18 year old and thinking I'm a bad ass and having a flair for psychological warfare I ignore the purpose of the drill and with my first motion after engaging the defensive lineman I repeatedly headbutt him in the helmet (a move best used when I was wearing my helmet, but still, I used this moment to make my teammates fear and respect me) it shocked the other player so much he stopped the drill and of course I had a bloody nose, but that's the attitude I had.

Whenever I hit someone (and this may be a difference between football and rugby you're looking for james) the points of impact were my shoulders and my forehead (always with my neck bowed to keep me from breaking it)...my hands and forearms were mainly used AFTER the initial impact.