Coach touching runner

Question
My player hit a ball out over the center fielder's head. As she was running to first and heading toward second base my first base coach touched her shoulder as she was saying go to second, go to second. When my player reached second base the umpire called her out because my first base coach touched her. I could not find anything in the rule book about this, but my understanding was that you had to physically assist the runner in some way, i.e., pick her up if she fell, pull her back on the base to avoid getting thrown out, or physically assisting her to the next base. Could you please clarify this.
Response
A base coach touching a runner in the act of coaching is considered assisting physically.
Any touch to tell the runner to stop at the base; go on to the next base or start on a tag play would fall in this category and the runner should be called out.
From your description of the play, the umpire enforced the rule correctly.

RULE 8. BASE RUNNING
Sec 18. Any runner is out when:
AA. When anyone other than another Runner physically assists him while the ball is in play.