Xel’s post is a good one and something that often goes overlooked. I’ve seen a handful of people follow the method to a T but say it’s still not working for them. These are often people that are drastically increasing their training load, going from significantly less training right into the standard 3 x 60 min easy, 3 x 30 mins of sub-T, 90 minute long run. If you aren’t already running pretty decent volume, increasing to 7.5 hours a week with three workouts, even if they’re sub-T workouts, is asking for trouble.