Kris Stallenberg 90-min Z2 (Endurance) Pushing #09 Build your aerobic engine with a punch. This workout consists of solid Z2 (Endurance) blocks, each concluding with a short, high-power anaerobic micro-burst. This teaches your body to produce power when already under aerobic stress and then quickly clear lactate to return to an endurance pace. It's a demanding session that uses principles from the Coggan Power Zones to simulate attacking over the top of a climb and immediately settling back into a group. bike