Kris Stallenberg 75-min Z2 (Endurance) Pushing #04 Welcome to Z2 Over/Unders. This workout keeps you entirely within your endurance zone but alternates between the top and bottom of it. This continuous variation in effort prevents complacency and improves your ability to make subtle power adjustments, a key skill for group riding and varied terrain. Based on Coggan Power Zones, this session is a mentally demanding way to accumulate quality time in Zone 2, enhancing metabolic efficiency without generating high levels of fatigue. bike