Aerobic capacity : Base endurance
LoadThe body's ability to sustainably produce energy using oxygen : the foundation of every long-distance plan.
Aerobic capacity covers two dimensions: peak aerobic power (VO2max, a genetic ceiling that is trainable) and aerobic economy (how much oxygen you consume at a given pace). In long-distance racing, this aerobic base determines what fraction of VO2max you can sustain over 42 km. Z2 training during base and build phases is the most effective way to raise it.
In TriPaced:
In TriPaced, the Z2 volume in your plan (long rides and runs, base endurance) is calibrated to build aerobic capacity first. It's the foundation on which high-intensity sessions (intervals, threshold) then stack.