lbeyerl,
Wright would be the best at describing what a "good" EMG process would look like, and what the specialist is looking for (You might want to do a forum search for an earlier response to the EMG question, as I know it has been discussed in detail before). The equipment of both my local neuro and the academic medical center had a monitor to watch the waveforms, but, like BethU, I had a fellow being trained during my exam. Listening seemed to be a critical component, and both doctors used a handful of tricks to get me to relax my muscles to get a valid reading before having me contract. They also retested a couple of areas.
The fact that your GP was concerned at the chart notes, and that the EMG took such a brief time seem to indicate the test wasn't thorough. Has your GP decided on "next steps?" One phrase I have found helpful is, "What would you do if you were in my shoes," or, "Which specialist would you see?"
Best of luck,
Robert