Kris Stallenberg 45-min Z2 (Endurance) Easy #03 Experience 'Endurance Waves' in this session. Instead of a steady effort, you will gently ramp up and down across the Z2 range. This workout mimics the subtle changes in effort required on rolling terrain, improving your ability to control power output smoothly. Aligned with Coggan Power Zones, these waves build aerobic endurance while keeping the ride engaging. bike