Interval training sessions with repeats of 30:30s, 40:20s, and 30:15s have become very popular. How does the endurance-trained body respond to this type of high-intensity interval prescription? Here, I will answer that question and set the stage for two more videos that show practical examples (Part II) and discuss how the body adapts to this type of training when performed regularly (Part III).
Reposted on Fast Talk Laboratories with permission of Dr. Stephen Seiler.