Kris Stallenberg 120-min Z2 (Endurance) Pushing #03 This workout, known as Z2 Over/Unders, builds aerobic strength by alternating between the top and bottom of your endurance zone. By pushing at 75% FTP and then recovering at 58%, you improve your body's ability to clear lactate and recover while still working. This is a key skill for long, undulating rides. The session adheres to the principles of Z2 training within the Coggan Power Zones framework to maximize aerobic adaptation. bike