high school kick off into end zone rule

[RickW]

You must certainly be talking about the Federation rule, which apparently doesn't allow the receiving team to advance the ball out of the end zone. I can't speak to the reasoning behind that rule, other than it does prevent some tricky goal line scenarios and prevents the possiblity of a safety on a free kick, which could actually be the reason for it (why have the possiblity of a safety when the receiving team is supposed to be getting the ball back). Again, don't know for sure.

As far as injuries, I've been calling football for quite a while and I can't really say that I've seen more injuries occurr on kick plays than on any other type of play. Maybe it's true overall, but not in my personal experience.