Do not take it personally.

 

People behave in a certain way is because who they are, not because who you are.

Focus on and respond to his words (instructions,) don't get distracted by the tone.

It's an opportunity to train her sense of the self and boundaries, i.e., do not let his tone cross that boundary, which guards her sense of self-worth.

 

(The athlets' inadequacy triggers the coach's own feeling of inadequacy. He needs the tone and volume to compensate for the perceived lackings of the athlets, as well as his own. The triggering can go in the opposite direction too.)