Richard Diaz has been coaching and advising athletes of all sports and levels longer than most of us have been alive. Diaz is known for his ability to analyze and improve running form, posture, cadence, efficiency, and economy, as well as for working with some of the best athletes in the sport of OCR. Today he walks us through his revolutionary approach to Endurance Training, details his journey as a coach and researcher, and whets our appetite for his new book, Training the Dark Side.