Think your FTP is the power you can hold for 60 minutes? Think again! We dig into a classic Billat paper on time to exhaustion (TTE) and training threshold by adding time in zone. Then we discuss into the metabolic implications of these results, how they align with real world experience, and how this affects training and assessment of its effectiveness. Finally, we answer your questions as asked in Kolie's Instagram stories @empiricalcycling.