You absolutely DO NOT have to be an expert in the method to use it.
You do have to have some experience training, you can't just start a novice with it. The goal is to do Igloi workouts so that day in and day out you feel like you did doing whatever training you did before.
I went from a 58 to a 54 min 10 mile doing Igloi. Unfortunately, I suffered a freak accident, that had nothing to do with training, before I could obliterate my 1600, 3200 and 5000 times. My second fastest continuous 5k ever was run during that Igloi trained 54 min 10 mile.