I recently went through an application process with the police department in Henrico County, Virginia.  The process included a polygraph for pre-employment screening.   

I had the unfortunate experience of meeting both of their examiners, one male and one female.  I got that privelege because the first test was terminated, and I had to return for a second go round.   

Both examiners claimed I was using countermeasures and specifically asked what websites about polygraph I had viewed.  The "countermeasure" was that I was supposedly breathing too slowly.  One of them even asked if I was counting my breaths.

There were multiple reasons why their suspicion was absurd.  First, why would I manipulate the test by doing something they could recognize?  In particular, why would I continue to do it and continue to think it could trick them, once they had already told me they were "on to me"?  Second, when presented with the accusation from the examiners, I told them that I had no faith in the polygraph whatsoever and then asked them why I would try to manipulate a test that I didn't believe had the ability to measure anything in the first place.  This apparently didn't impress them.   

Both knew that I had taken polygraph exams before, but the second one still tried all the standard tricks...like leaving the room after the test to "read the charts" and then coming back to tell me that the test "showed a reaction" on 2 questions...as if I would then break down and make admissions.   

Aside from my personal disdain for the polygraph exam, these 2 examiners both struck me as particularly unintelligent and inarticulate.  I am certain that both had lower levels of education than I have, yet they were the "experts" who were supposed to judge my fitness for law enforcement employment!  Please don't think this is purely a sour-grapes statement...I actually rather liked the 2 previous polygraph examiners from other departments where I had tested...but these 2 from Henrico County were just amateur from the word "go".  Ironically, I had been offered law enforcement employment after my first polygraph last year, but I was not offered employment by Henrico.  My "poor performance" on the polygraph may have contributed to my failure to get the job.

I am certain that police departments lose good candidates and also miss bad candidates when they screen potential cops with the polygraph.   

In truth, the accusation that I was using some trick or technique to beat the polygraph is an insult to my intelligence.  The only countermeasure you need to "beat" the polygraph is to KNOW IN ADVANCE that the whole process is a BLUFF TECHNIQUE, designed to get you to believe you will be caught if you lie...just so that you'll make their job easier by making admissions.