Kris Stallenberg 45-min Z2 (Endurance) Easy #02 This session introduces gradual progression within your endurance zone. By stepping up the intensity through three distinct blocks within Z2, you'll challenge your aerobic system without accumulating significant fatigue. This method, based on Coggan Power Zones, helps improve stamina and teaches the body to handle sustained efforts. The final 10-minute block will be at the higher end of your endurance range. bike