Kris Stallenberg 75-min Z2 (Endurance) Pushing #09 This session maximizes time at the upper end of your endurance zone by using very short active recovery periods. The 4-minute blocks in upper Zone 2 are challenging, and the 1-minute Zone 1 recoveries are just enough to take the edge off before you go again. This structure, based on Coggan Power Zones, is a highly effective way to build a robust aerobic base and improve your ability to recover while still working. It mimics the ebb and flow of a fast-paced group ride. bike