Definition
Functional Threshold Power (FTP) is the highest average power you can sustain for roughly an hour, expressed in watts. In practice riders use FTP as a proxy for aerobic capacity and a baseline for power zones, pacing, and structured training.
Why It Matters
FTP turns raw wattage into actionable training. It defines your power zones, guides interval intensity, helps estimate race pacing, and provides a single number to track fitness over months. For group-ride efforts and time trials, knowing your FTP keeps you from blowing up or leaving watts on the road.
Quick links to kit that helps you test and use FTP.
Powermeters — the gold standard for accurate, repeatable FTP measurements
Bike Trainers — controlled environment for consistent FTP tests and intervals
Power meters & computers — pair power data with structured plans and zone calculations
Heart-rate monitors — useful to cross-check effort and fatigue during tests
How It Works
FTP is a practical metric, not a perfect physiological constant. It approximates your lactate/ventilatory threshold and represents sustainable aerobic power. Coaches and apps typically derive FTP with one of three models:
Direct 60-minute test: ride maximal effort for 60 minutes. This is the most literal measure of FTP but taxing and time-consuming.
20-minute test: ride the best 20-minute effort and multiply the normalized power (NP) by 0.95 to estimate a 60-minute FTP. Widely used because it balances accuracy and practicality.
Ramp or algorithmic tests: short progressive stages (e.g., 1-minute increases) until failure; software estimates FTP from peak power. Fast and repeatable, but can over- or under-estimate FTP for some riders.
Conceptual diagram: imagine a power-duration curve where FTP is the inflection point separating sustainable aerobic efforts from rapidly decaying anaerobic efforts. You can produce a family of curves (fresh vs. fatigued), and testing maps your current curve so you can choose training intensities.
Practical notes: run tests on similar gear (same cassette, tires, rolling resistance), at the same time of day, well-fueled, and rested. For on-road 20- or 60-minute tests, pick a flat, traffic-free loop. Indoors, use a calibrated direct-drive trainer and a good cadence strategy (90–100 rpm for many road riders).
> Pro tip: use a warm-up with two short hard efforts to prime FTP. Consistency trumps any single "perfect" test.
Key Specs/Thresholds
FTP units: watts (W) and watts per kilogram (W/kg). Elite men: 5.8–6.5+ W/kg; elite women: 4.5–5.5+ W/kg (race-specific and role-dependent).
60-minute test: direct FTP if you average maximal power for the full hour.
20-minute test: FTP ≈ 0.95 × normalized 20-min power (commonly used multiplier).
Ramp test: protocol-dependent; common ramps increase workload 20–40 W per minute.
Repeat cadence: test cadence 85–100 rpm for road-type FTP estimates; lower cadence shifts neuromuscular contribution.
Measurement accuracy: power meter error typically ±1–3%; trainer algorithms can add variance—calibrate devices (spindown or firmware) before testing.
Common Misconceptions
FTP is not a fixed trait. It changes with fatigue, nutrition, heat, and training status.
A single test gives a baseline, not your peak potential. Use repeated, standardized tests to track progress.
Ramp tests are faster but not always more accurate than a 20-minute test for interval prescription.
Heart rate and perceived exertion still matter; power is objective but doesn’t capture hydration, glycogen, or illness.
When to Choose/Use
If you want accurate training zones for a season: use a 20-minute on-road or indoor test with good recovery and repeat every 4–8 weeks.
If you need frequent checks (weekly/biweekly) and minimal disruption: use a ramp test on a calibrated trainer.
If you need a definitive baseline and can commit the time: the 60-minute maximal test is the truest measure.
If you race short events (crit, TT under 40 minutes): use event-specific testing and consider peak power and power-duration curve rather than FTP alone.
Sources
TrainingPeaks (2020) — FTP definition and practical testing guidance.
TrainerRoad (2019) — ramp and 20-minute protocol explanations and algorithmic approaches.
Research article (2008) — study on FTP, peak power and predictive relationships.
Key Takeaways
FTP is your best practical estimate of sustainable one-hour power and the foundation for training zones.
20-minute tests (×0.95) balance accuracy and practicality; ramp tests give repeatable checkpoints.
Test consistently: same equipment, fueling, time of day, and warm-up to track real changes.
Use power together with heart rate and RPE—FTP is a guide, not the whole picture.
FAQs
Which FTP test should I use?
For most riders the 20-minute test (multiply NP by 0.95) is the best mix of accuracy and practicality. Use ramp tests for frequent checks and a 60-minute test if you want the most literal FTP and can commit to a maximal hour.
How do I make FTP tests consistent?
Standardize equipment (same power meter or calibrated trainer), time of day, nutrition, warm-up, and course or trainer settings. Calibrate devices before testing and rest well the day prior to reduce variability.