QT2 Physiological States — Zone Curve v6

Physiological States — Zone Curve

Fiber recruitment & glycolytic demand across the intensity spectrum
Very Low Aerobic Sustainability Relative to Capacity Low Aerobic Sustainability Relative to Capacity Moderate Aerobic Sustainability Relative to Capacity High Aerobic Sustainability Relative to Capacity
Type I Type IIA Type IIX ZR Z1 Aerobic base Z2 OGC crossover Z3 Threshold W' Anaerobic reserve IIA oxidative IIA O→G crossover IIA glycolytic Intensity → Low High Energy system / Fiber recruitment
All four profiles shown Curve color encodes energy system; line style encodes the profile. The gradual rise through Z1 is physiologically accurate — no sudden jumps. The exponential character only truly kicks in above OGC. Above CP the curve goes near-vertical as W' becomes the only limiting factor.
QT2 Systems — Threshold Analyzer CP:pVO2max ratio comparison