@bluespirit - I don't know what "abnormal" looks like and I am assuming there are different variations of abnormal.
But what I do know is it is neat! They test detects the electrical activity of muscle. So apparently there is some level of electrical activity that is within the normal range.
I wonder if it is like blood pressure it can vary based on how you are feeling, like if you are feeling anxious will that show up in your muscle's electrical activity level?
Also I have read that many disorders are looked based on the electromyogram test some that I have heard of are: amyotrophic lateral sclerosis (ALS), pinched nerves, and muscular dystrophy.