Kris Stallenberg 30-min Z2 (Endurance) Easy #10 This workout builds your aerobic base with a primary focus on Z2 (Endurance) while incorporating very brief, high-cadence 'spin-ups'. These short bursts into the VO2 Max zone, as defined by the Coggan Power Zones, are too short to cause anaerobic fatigue but are excellent for activating fast-twitch muscle fibers and improving pedaling mechanics. The main goal remains steady endurance development. bike