You can train our mind, body, and craft. In recent episodes on training your body, we skimmed the surface of training endurance and economy. If you run a lot of miles, often on race-like terrain and run all out for short bursts a few times per week, you're doing the majority of the work that will improve your body's capacities. To further extend stamina, you may want to run comfortably hard intervals, the topic of today's episode.