FTP (Functional Threshold Power)

FTP is the maximum power output a cyclist can sustain for ~60 minutes. The cycling-specific operational definition of lactate threshold.

Mechanism — Roughly corresponds to LT2 — the inflection above which lactate accumulates faster than clearance. Power-based training zones are anchored to it: Z2 is 55-75% of FTP, threshold work is 95-105%, etc.

Use case — Calibrating cycling training. Tested via 20-minute all-out × 0.95, or a true 60-min effort. Re-test every 6-12 weeks.

Caveats — Bike-specific (cycling FTP doesn't translate to running). 20-min protocol overestimates true FTP for untrained or under-fueled cyclists. Power meter dependent.