Functional Threshold Power (FTP) represents the highest power output a cyclist can sustain in a quasi-steady state for roughly an hour. Because riding at 100% effort for 60 full minutes is mentally and physically draining, coaches and software platforms use shorter field tests to estimate threshold power.
Which FTP test protocol should you choose?
Select a test based on your pacing ability, rider phenotype, and available equipment. Steady endurance riders and sprinters extract different results from the same protocol.
| Protocol | Calculation Formula | Best Suited For | Primary Bias / Drawback |
|---|---|---|---|
| 20-Minute Test | 20-min Avg Power × 0.95 | Experienced pacers, balanced phenotypes | Requires self-pacing; overestimates anaerobic riders |
| Ramp Test | Peak 1-min Power × 0.75 | Beginners, quick indoor checks (ERG mode) | Overestimates sprinters (high W') by 15–50W |
| 3-Min All-Out (CP) | Final 30s Avg = CP; Work > CP = W' | Track/crit racers, data-driven interval work | Extremely painful; overestimates CP by ~35W in elite riders |
| Outdoor Field Test | 20-min or 40km TT Power | Road racers, hill climbers | Subject to wind, gradient, traffic, and temperature |
| Passive eFTP (AI) | Power-duration curve modeling | Frequent group riders and racers | Requires regular maximal effort data points |
How do you execute the 20-Minute FTP test?
The 20-minute test (developed by Dr. Andrew Coggan and Hunter Allen) estimates 60-minute threshold power by applying a 0.95 multiplier to a 20-minute maximal time trial effort.
Protocol Structure:
- Warm-Up:20 minutes easy pedaling (65% FTP) with 3×1-minute high-cadence spin-ups (>100 rpm).
- Blowout Effort:5 minutes all-out maximal effort. This step is critical—it depletes your anaerobic capacity (W') so that the subsequent 20-minute test measures pure aerobic power.
- Recovery: 10 minutes light spinning.
- Main Test: 20 minutes steady, maximal time trial effort in slope or resistance mode (not ERG mode).
Phenotype Multipliers: Research by Sitko et al. (2023) across 120 cyclists revealed that the 0.95 multiplier is not universal. Depending on aerobic development:
- Professional Cyclists: 0.96 multiplier
- Well-Trained Cyclists: 0.95 multiplier
- Moderately Trained Cyclists: 0.92 multiplier
- Recreational Cyclists: 0.88 multiplier
Recreational riders rely more heavily on anaerobic energy during 20 minutes, causing standard 0.95 calculations to overestimate their true 60-minute power.
What are the pros and cons of the Ramp Test?
Popularized by platforms like TrainerRoad and Zwift, the Ramp Test starts easy and increases target power by 20 watts every 60 seconds (or a fixed percentage step) until absolute cardiovascular or muscular failure.
How it Works:FTP is calculated by taking 75% (a 0.75 multiplier) of the highest 1-minute power achieved. This multiplier is derived from Ric Stern's research showing FTP typically equals 72–77% of Maximal Aerobic Power (MAP).
Phenotype Bias:Because the final steps of a ramp test push deep into anaerobic territory, riders with a large anaerobic reserve (W')—such as sprinters and criterium racers—can survive higher steps than their aerobic engine supports. A punchy rider with a true 250W FTP might hit a 400W peak minute, yielding an inflated 300W FTP estimate. Conversely, steady diesel riders (like triathletes) may fail early, yielding a deflated estimate.
Execution Rule: Remain seated throughout the entire ramp test. Standing up recruits different muscle groups and spikes anaerobic power, distorting your aerobic FTP estimate.
Is Critical Power (CP) different from FTP?
Critical Power is mathematically distinct from FTP. Critical Power represents the theoretical upper asymptote of sustainable aerobic power, while W' (pronounced W-prime) represents the finite reserve of work (measured in Joules) available above CP before exhaustion.
In a comparative study by Karsten et al. (2021), Critical Power averaged 256 ± 50 W compared to 249 ± 44 W for 20-minute FTP. While strongly correlated, CP is slightly higher than FTP and isolates your anaerobic battery capacity.
The 3-Minute All-Out Test (3MAOT): Developed by Vanhatalo et al. (2007), this protocol requires riding at absolute 100% maximal effort for 3 minutes without pacing. W' is fully depleted within the first 120 seconds; average power during the final 30 seconds equals Critical Power.
Once you have determined your FTP, plug your result into our FTP Power Zone Calculator to map your training zones, or see how testing fits into a full schedule in our Cycling Training Plan Guide and Zone 2 Base Training Guide.
