Kris Stallenberg 90-min Z2 (Endurance) Pushing #06 This is a test of mental fortitude and aerobic consistency. The workout features a single, very long, and slowly progressing ramp entirely within your Z2 (Endurance) range. Starting at the bottom of the zone and finishing at the top, this session maximizes time-in-zone to build a formidable aerobic base. It's a pure endurance ride based on Coggan Power Zones, designed to enhance fat metabolism and teach your body to be incredibly efficient over long durations. bike