If a client threw up in a session, would you feel good about yourself or bad?
I’ve never worked so hard that I vomited (despite the fact it was praise worthy in high school track and field) nor have any of my clients.
If you are well-acquainted with who you’re training, you won’t push them to that point since there is no benefit. So, to answer your question: I would feel horrible if I got somebody to that point; that said, the client has to bear some responsibility in letting you know how he/she is feeling…
The clients that come to me want to enhance their life, and how they travel through it, through movement that is energizing, challenging, dynamic, and thoughtful. Vomiting has no place in that scenario.