Kris Stallenberg 45-min Z2 (Endurance) Easy #08 This workout splits the main endurance effort into two strong, sustained blocks separated by a short period of active recovery. This structure helps improve focus and allows you to maintain a high quality of effort throughout both work periods. The second block is slightly harder, teaching you to push on when already under some load. This is a classic method for building aerobic fitness based on Coggan Power Zones. bike