Kris Stallenberg 30-min Z2 (Endurance) Easy #01 This workout is a foundational endurance session designed to build your aerobic base. The main set is a continuous 20-minute effort in what the Coggan Power Zones model refers to as Zone 2 (Endurance). The goal is to maintain a steady, conversational pace, improving your body's ability to efficiently use fat for fuel. Focus on smooth, consistent pedaling. bike