
New Year, New Zones: Build an 80/20 Plan With Your VO₂ and Threshold Data
You can make big endurance gains this year by pairing laboratory-measured zones with a simple weekly split: 80 percent easy and 20 percent hard. With VO₂ and threshold testing, your ventilatory thresholds (VT1 and VT2) give you precise anchors for easy, moderate, and hard training so you stop guessing and start adapting. This guide shows you how to translate your








