Hand check

[rwest]

I've not called any hand checks this year (10 games). I've not seen many called by my partners, either. So here's my question. What do you look for when calling a hand check? Do you call any contact with the hand? Do you wait until the defenders arm is locked? Would you call hand check if the defender placed his/her hand on the offensive player and then immediately removed it? Or does it have to be on the offensive player for some period of time? Do you warn the player ahead of time before making the call? I've had some refs tell me that they say something like "21, get your hands off!". They do that once or twice then they start calling it.

Bottom line, at what point does it become an advantage gained by the defender?

Thanks!