There are few scientists who get Coach Connor more excited than our guest in this episode. Dr. Stephen Seiler has revolutionized our understanding of endurance training. (In fact, Coach Connor refers to him as the Jay-Z of physiology!) In this episode, we'll take a deep dive into the many theories he has brought to sport science and physiology.

His three-zone model of training is built around two physiological breakpoints. He feels these breakpoints define three physiological zones. Zone 1 is below the aerobic threshold, and what we call easy base training. Zone 2 is between the breakpoints and has many names including no-man's land or sweet spot. The third zone is our high intensity training zone.

Next we'll talk about how, by studying elite athletes, Seiler found a remarkable consistency: Most endurance athletes train about 80 percent of the time in Zone 1, around 15 to 20 percent in Zone 3, and very little in Zone 2. This has become known as polarized training.

We'll also take a deep dive with Dr. Seiler into both Zone 1 and Zone 3 training and how to approach both. A theme will start to emerge, and you'll hear one of the top physiologists in the world repeat it again and again: Keep it simple. That might seem surprising, but the research is clear: Complex intervals and overly detailed training plans may hurt more than they help. Ultimately it may be as simple as accumulating time in the various zones in the right ratios.

Finally, we'll discuss how these principles apply specifically to training. Seiler's research includes Nordic skiers, rowers, runners, and cyclists. So be warned, at times you'll hear some concepts that may be unfamiliar to you. For example, cycling is one of the few places where endurance athletes do five-hour workouts. In other endurance sports, they add volume by doing two-a-days.