Kris Stallenberg 45-min Z2 (Endurance) Easy #06 This workout features an 'Endurance Pyramid,' where you'll progressively climb to the top of your Z2 zone and then descend back down. This structure builds aerobic capacity and mental toughness as the duration at higher Z2 power increases. It's an excellent session for simulating a long, sustained climb within the parameters of the Coggan Power Zones for endurance training. bike