Episode 45: Durability and Fatigue Resistance with Coaching Legend Joe Friel

Joe Friel — author of the Triathlete's Training Bible, co-founder of TrainingPeaks, and one of the most influential coaches in endurance sport — joins Chris Bagg for a conversation centered on durability: what it is, how it is built, and why it matters more than most athletes realize. Joe explains how he developed the concepts of heart rate decoupling and efficiency factor in the early 2000s — more than fifteen years before sports scientists gave durability a name — and walks through the three-phase training structure he uses to build durable athletes from the ground up. The conversation covers zone one and zone two training, the discipline of race-specific pacing, AI's role in coaching, and Joe's revised edition of Fast After 50, due out in June. If you work with long-course athletes, or if you are one, this episode covers the ground that determines who holds on late in a race and who doesn't. Links mentioned in this episode:Joe Friel's website: joefrieltraining.comTrainingPeaks (decoupling and efficiency factor tools): trainingpeaks.comFast After 50, revised edition — coming June 2026 (available wherever books are sold)Kolie Moore / Empirical Cycling: empiricalcycling.comSerious Training for Endurance Athletes by Rob Sleamaker and Ray BrowningCampfire Endurance coaching: campfireendurance.com