We open this week with a roundup of the Millrose Games, top milers, and our training week. Then, at minute 22, we begin our conversation about the seemingly confusing topic of threshold training. This discussion was so exhaustive that we had to break it into two episodes. In part one we define blood lactate, lactate threshold, tempo running, and other key terms, share the most recent research on these topics, connect these efforts with race paces and other indicators, and clarify some common misconceptions about threshold training. In part two we'll move from the what to the how and why.