Kris Stallenberg 90-min Z2 (Endurance) Medium #02 This workout challenges your aerobic system with three ascending blocks of endurance work. By gradually increasing the intensity within Zone 2, you'll train your body to sustain effort as fatigue begins to set in. This mimics the feeling of a long ride where the pace subtly increases. Referencing the Coggan Power Zones, this session builds strength at the upper end of your endurance capabilities. bike