Hi Joe, I'm 63, started participating in road races 5years ago. I've been doing workouts using a power meter since 3 years ago, which has made me faster so far. These days I've been a bit concerned about my taking many rest days while my younger bike friends do workouts more often. After having read this book, the scales have fallen from my eyes and I've become more confident in myself. Thanks for your solid and insightful work.