I agree with the pont of View of the Fitness Trainers qouted in the linked article. The main objective for a great workout is to show my clients how to do the exercises correctly and how to follow a regime. If they are interested in the muscles that are being targeted I will tell them but in most cases they trust that I know which exercises will work best to meet their work out needs. The trust is based upon results and isn't that the true barometer of whether or not you have a good trainer?
http://www.reuters.com/article/2011/11/07/us-fitness-jargon-idUSTRE7A63B420111107