I first came across muscle testing upon discovering
The Emotion Code, but I've let it come to pass without me actually knowing how to do it.
Maybe more than 4 years later, I saw it again in action as the main diagnostic tool by the holistic doctor in the documentary,
The Way of Miracles. I was so inspired by it that I decided to pick up a book dedicated to muscle testing.
And voila! I've finally nailed muscle testing using my snap fingers.
I wrote a full-length article about it (with a video demo by the author)
here>>
Hope it helps. :)