Kris Stallenberg 90-min Z2 (Endurance) Pushing #10 This workout builds mental toughness and muscular endurance with descending interval lengths at a high Z2 (Endurance) power. Starting with the longest effort forces you to dig deep early, and the progressively shorter intervals provide a psychological boost as you knock them down. This structure maximizes quality time at a challenging aerobic intensity, aligning with Coggan Power Zones principles for developing a robust and fatigue-resistant aerobic system. bike