I spend a lot of time in these pages talking about base and volume and the critical adaptations we get from both. Recently, I went to the other end of the spectrum and covered some ideas on power endurance and lactate tolerance. Admittedly, the amount of time you spend both training and racing on the former is large and, on the latter, small. In the middle, lies a critical zone of intensity which is probably where the real selection in races is made. We don't spend a ton of time here when competing but it often represents the most decisive zone in which we operate in a race. In a word, it's called THRESHOLD. This is what you exceed when you blow trying to hang with the leaders on a climb. In a ski mountaineering race, your threshold either keeps you in the hunt on the climbs or you watch the top placings move away from you up the skin track. In a cycling time trial, threshold is where you try to spend 99% of the race. God, do we ever hear a lot about this these days.