Kris Stallenberg 90-min Z2 (Endurance) Pushing #04 This session, named 'Endurance Terraces', builds your staying power with progressively longer blocks at the upper end of Z2 (Endurance). The structure is designed to challenge you mentally and physically as the duration at a challenging aerobic intensity increases. This workout is rooted in the Coggan Power Zones framework to methodically increase time-in-zone, a proven way to boost aerobic capacity and muscular endurance for sustained efforts. bike