Coach making contact with runner?
 

I know a coach can not physically assist a runner. However, when and when not can a coach give high fives and things of this nature to a runner? Is there a rule that describes these limitations? If so, where is it?

thanks

The only rules regarding this relate to what you mention - physically assisting a runner. High fives are nothing. Back-pats are nothing (unless accompanied by a push in a direction he want the runner to move). Etc.