FTP Test and Power Zones: Testing and Calculating Yours

What is FTP?

FTP is the highest power you could sustain in a quasi-steady state for about an hour — the practical stand-in for the physiological threshold above which fatigue accelerates. It is not a physiological measurement in itself; it is a performance estimate that happens to sit close to LT2 for most riders. That distinction matters, because it explains why two riders with the same FTP can need different training zones.

Which FTP test should you ride?

All of the common protocols work; they differ in how much they hurt and how much they depend on pacing skill.

• 20-minute test: warm up thoroughly, ride 20 minutes as hard as you can hold evenly, multiply the average power by 0.95. Most accurate of the field tests, and the most dependent on even pacing.
• Ramp test: power rises steadily until you cannot continue; FTP is estimated at roughly 75% of your best one-minute power. Short and hard to pace badly, slightly less precise.
• 8-minute test (2 × 8 min): two maximal 8-minute efforts, average multiplied by about 0.90. Easier to complete than a 20-minute effort, more sensitive to how you split the two.
• Modelled estimate: no test at all — FTP is derived from your recorded rides. No test-day dependency, but it needs a body of data to settle.

How do you calculate power zones from FTP?

The widely used seven-zone model expresses each zone as a percentage of FTP. Treat the boundaries as guidance rather than physiology — they are a convention that works well for most riders:

• Zone 1 — active recovery: under 55% of FTP.
• Zone 2 — endurance: 56–75%. The bulk of most training weeks.
• Zone 3 — tempo: 76–90%.
• Zone 4 — threshold: 91–105%. Sweet spot sits at the lower end, around 88–94%.
• Zone 5 — VO2max: 106–120%.
• Zone 6 — anaerobic capacity: 121–150%.
• Zone 7 — neuromuscular: above 150%, too short to pace by power.

How often should you retest?

Every six to eight weeks is the usual advice, and it exists because zones drift out of date as fitness changes. In practice, retesting is disruptive: a test day replaces a training day, and a bad test sets your zones wrong for the next block. A continuously modelled estimate sidesteps that problem — which is why it is worth having even if you also like the reference point of a hard test twice a year.

Why do zones from FTP alone have limits?

FTP is one number, so every zone boundary is a fixed percentage of it. Real physiology has two anchors, LT1 and LT2, and the distance between them varies between riders. A rider with a wide gap has a genuinely large aerobic range; a rider with a narrow one does not, even at identical FTP. If your zone 2 always feels too hard or your threshold work suspiciously easy, that gap is usually the reason.

How does ENDURE handle FTP and zones?

ENDURE models your FTP and VO2max continuously from recorded power and heart-rate data across indoor and Strava- or intervals.icu-synced outdoor rides, so you see a trend rather than a test result with an expiry date. ERG mode holds test steps precisely if you do want to ride a protocol, and the time-in-zones breakdown after each ride shows how the session was actually distributed. If you also log lactate readings, ENDURE estimates LT1 and LT2 so you can check your percentage-based zones against measured thresholds. Available on iOS and Android.