Kris Stallenberg 90-min Z2 (Endurance) Pushing #08 This dual-focus session combines two effective endurance training methods into one challenging workout. The first half builds fatigue with a long, steady-state interval in mid-Z2 (Endurance). The second half introduces Z2 'over-unders' on tired legs, forcing your body to adapt to power fluctuations efficiently. This structure, based on Coggan Power Zones, is excellent for building the deep aerobic fitness needed for events with variable pacing. bike