I just finished my FIRST 1/2 marathon. That is using their program. I've run three 1/2 marathons this year alone. Yesterday's was my fastest time of the year and 9 minutes faster than May. The only difference was based on FIRST training. More cross training and I hit it hard, more weights and core strengthening and I did that 5 times per week. The best part of yesterday was I ran negative splits and my last 2 miles were my fastest 2 miles of the course. I had fun passing people all the way in. I went to their running retreat in June and really got motivated. Let me know if questions or just buy their book and "Just do it"