FTP Test Guide: How to Test Your Functional Threshold Power
FTP, or Functional Threshold Power, is the highest average power output you can sustain for approximately one hour. It is the single most important number in structured cycling training — the benchmark from which all power-based training zones are calculated and the most accurate measure of cycling-specific fitness available outside a laboratory. This guide explains what FTP is, how to test it using the two most common protocols, how to set your power zones, and how to use FTP data to structure effective training in Fitiv Pulse.
What Is FTP (Functional Threshold Power)?
FTP is the average power, measured in watts, that a cyclist can maintain for approximately 60 minutes at maximum sustainable effort. It corresponds closely to the second lactate threshold — the exercise intensity above which lactate accumulates progressively and performance cannot be sustained indefinitely.
FTP is measured in watts (absolute power) and often also expressed as watts per kilogram (W/kg) — a body weight–normalized figure that allows meaningful comparison between riders of different sizes.
W/kg benchmarks (for context): | Category | Men (W/kg) | Women (W/kg) | |----------|-----------|-------------| | Recreational | 2.0–3.0 | 1.5–2.5 | | Trained enthusiast | 3.0–3.5 | 2.5–3.0 | | Cat 3–4 racer | 3.5–4.0 | 3.0–3.5 | | Cat 1–2 / elite amateur | 4.0–5.0 | 3.5–4.5 | | Professional | 5.5–7.0 | 4.5–6.0 |
Tour de France contenders typically produce 6.0–6.5 W/kg for the duration of long climbs. A well-trained 75 kg amateur with FTP of 250W is at 3.33 W/kg — solidly trained, competitive in local events.
Why FTP rather than maximum sprint power? Because cycling performance in any event lasting more than a few minutes is primarily determined by sustainable aerobic power, not peak sprint capacity. FTP predicts performance in time trials, hill climbs, triathlons, and road races far better than any other single metric.
The 20-Minute FTP Test Protocol
The most widely used FTP test uses a 20-minute maximum effort, then applies a correction factor of 0.95 to account for the difference between 20-minute power and true 60-minute power.
FTP = 20-minute average power × 0.95
The 0.95 correction is based on the observation that most cyclists can sustain approximately 5% more power for 20 minutes than for 60 minutes. This correction is reasonably accurate for most trained cyclists; well-paced riders with high lactate tolerance may need a correction closer to 0.93–0.92.
Full 20-Minute Test Protocol
Day before the test:
- Rest day or very easy Zone 1 session only
- Normal nutrition — do not reduce carbohydrates
- Avoid alcohol
Test-day morning:
- Full carbohydrate breakfast 2–3 hours before testing
- Hydrate well
- No hard training in the 48 hours prior
Warm-up (30–35 minutes total):
- 10 minutes easy spinning, Zone 1–2, gradually raising heart rate
- 3 × 1-minute efforts at high cadence (100+ rpm), intensity Zone 3–4, with 1 minute easy between each
- 5 minutes easy Zone 2 spinning
- 5-minute "opener": all-out effort at a pace you cannot sustain more than 5 minutes — depletes some glycolytic energy stores and primes the aerobic system
- 5 minutes complete rest (spinning at very low resistance)
The 20-minute effort:
- Set a power target based on your best guess of 20-minute maximal power (if you have no prior data, start conservatively — you can always revise the target mid-effort)
- Aim for even pacing: the most common mistake is starting too hard in the first 3–4 minutes and fading badly in the final 5 minutes
- A well-executed 20-minute test ends with maximum effort in the last 60–90 seconds, not a complete collapse at minute 12
Post-test:
- 10 minutes easy spinning cool-down
- Record average power for the 20-minute effort from your cycling computer or Fitiv
- Calculate FTP: Average power × 0.95
Example: An athlete averages 295W for the 20-minute effort. FTP = 295 × 0.95 = 280W
Common 20-Minute Test Mistakes
Pacing errors: Going out too hard is by far the most common mistake. The first 5 minutes should feel sustainable — you should finish the first 10 minutes feeling like you have pushed hard but could continue. If you are fading badly at 12 minutes, you went out too hard and the test result will underestimate your true FTP.
Skipping the 5-minute opener: The opener depletes phosphocreatine stores and activates anaerobic pathways before the test. Without it, some cyclists effectively have a "free" 2–3 minutes of high-power output at the start of the 20-minute effort — inflating the result beyond what the 0.95 correction accounts for.
Testing after a hard training week: FTP tests require genuine freshness. Testing on accumulated fatigue produces artificially low results and discourages athletes. Take 2–3 easy days before testing.
Indoor vs. outdoor differences: Most athletes produce 5–10% less power indoors on a trainer than outdoors on a real road, primarily due to greater heat stress (indoors) and the efficiency differences between fixed trainer resistance and variable road loads. Keep your testing environment consistent — always test indoors or always test outdoors if you want comparable results over time.
The Ramp Test: An Alternative FTP Protocol
The ramp test has become increasingly popular as an easier-to-execute alternative to the 20-minute test. Developed by Neal Henderson and popularized by TrainerRoad and Wahoo, the ramp test is shorter, less psychologically demanding, and less dependent on perfect pacing.
Ramp Test Protocol:
- Begin at a very low power (around 50% of estimated FTP)
- Increase power by a fixed increment (typically 20W) every minute
- Continue until you can no longer maintain the target power
- The test ends when you drop below the required power for 5 consecutive seconds
FTP Calculation from Ramp Test: FTP ≈ Peak 1-minute power × 0.75
The 0.75 factor converts the neuromuscular peak power of the final completed minute to an estimated FTP. This factor is derived empirically and works well for most trained cyclists, though athletes with a very high anaerobic capacity relative to aerobic fitness (sprinters, track cyclists) may see slightly inflated results.
Example: An athlete's highest completed ramp minute averages 370W. FTP = 370 × 0.75 = 278W
20-Minute Test vs. Ramp Test: Which Should You Use?
| Factor | 20-Minute Test | Ramp Test | |--------|---------------|-----------| | Duration | ~60 min total | ~25 min total | | Pacing dependency | High | Low | | Psychological demand | Very high | Moderate | | Accuracy | Higher for most | Excellent for most | | Best for | Experienced testers | New testers, frequent retesting |
Most coaches recommend learning the 20-minute test first — it builds pacing skill and provides a benchmark you can compare directly to race performance. Once familiar, alternating between the two protocols is common.
Setting Power Zones from FTP
Once FTP is established, Coggan's 7-level power zone system is the most widely used standard:
| Zone | Name | % of FTP | Description | |------|------|----------|-------------| | Zone 1 | Active Recovery | <55% | Very easy, recovery | | Zone 2 | Endurance | 56–75% | Aerobic base, fat-burning | | Zone 3 | Tempo | 76–90% | Aerobic threshold, sustained effort | | Zone 4 | Lactate Threshold | 91–105% | FTP zone — where threshold intervals live | | Zone 5 | VO2 Max | 106–120% | High intensity, 3–8 minute efforts | | Zone 6 | Anaerobic | 121–150% | Short, very hard efforts | | Zone 7 | Neuromuscular | >150% | Sprints, max power |
For a cyclist with FTP of 280W:
- Zone 2 (endurance): 157–210W
- Zone 3 (tempo): 213–252W
- Zone 4 (threshold): 255–294W
- Zone 5 (VO2 max): 297–336W
Enter your FTP in Fitiv and all zones are calculated automatically.
How Often Should You Retest FTP?
Every 6–8 weeks is the recommended retesting frequency for most training programs. FTP improves most rapidly in the first 12–16 weeks of structured training, then more slowly as you approach your genetic potential.
Retest more frequently (every 4 weeks) if:
- You are new to structured training and improving rapidly
- You have returned from illness or injury and are rebuilding
- Your perceived exertion at a given power has dropped dramatically
Retest less frequently (every 8–12 weeks) if:
- You are an experienced athlete with stable fitness
- You are in a long base-building phase where FTP is expected to plateau
- Frequent testing is disrupting training rhythm
Signs your FTP estimate may be outdated:
- Zone 4 intervals feel significantly easier than expected
- You are completing prescribed workouts with perceived exertion lower than intended
- Race power data substantially exceeds your current FTP estimate
How Fitiv Guides You Through FTP Testing
Fitiv Pulse includes guided FTP test workouts for both the 20-minute protocol and the ramp test, with structured warm-up segments, interval timers, and real-time power display.
Fitiv FTP test features:
- Structured workout guide that walks through each warm-up segment with timing and power targets
- Real-time average power display during the 20-minute effort — the number you need to watch
- Automatic FTP calculation applied at test completion (20-min average × 0.95, or ramp peak × 0.75)
- Prompt to update all power zones with the new FTP value
- Historical FTP chart showing trend over all completed tests
During the 20-minute effort, Fitiv displays:
- Current power (instantaneous)
- 3-second average power (smoothed for readability)
- Average power for the elapsed interval (the most important number)
- Heart rate and time remaining
After each FTP test, Fitiv automatically recalculates all cycling power zones and updates the training load benchmarks used in your workout history. Sessions completed before and after the update are normalized to the FTP current at the time of the session, allowing accurate comparison of training stress over time.
FTP integration with training load: Fitiv uses your current FTP as the denominator in TSS calculations. An accurately calibrated FTP ensures that your TSS scores reflect genuine physiological stress — an outdated (too low) FTP will inflate TSS scores, making training appear harder than it was and overstating fatigue in the CTL/ATL model.
Frequently Asked Questions
Q: My FTP test result seems low — did I do something wrong? A: Pacing errors are the most common cause of an unexpectedly low FTP test result. If you started too hard and faded significantly in the final 5–8 minutes, your average power underestimates your true FTP. A well-paced effort feels nearly constant throughout — not collapsing at the end. Retest after 2–3 easy days with a more conservative starting pace.
Q: Can I test FTP outdoors? A: Yes, on a flat or very gradually climbing road without traffic stops. A gradual climb is often preferred because it forces consistent effort and reduces the temptation to surge and recover. Outdoor FTP tests on rolling terrain with variable wind produce less consistent results than flat-road or indoor tests. If you train primarily indoors, test indoors; if primarily outdoors, test outdoors.
Q: Is FTP the same as lactate threshold power? A: They are closely related but not identical. Lactate threshold power (LTP) is precisely defined as the power at which blood lactate concentration is approximately 4 mmol/L (the Onset of Blood Lactate Accumulation, or OBLA). FTP is a field-test estimate that tends to correlate with LTP within 5–10% for most athletes. In practice, FTP and LTP are used interchangeably in structured training; a laboratory LTP test is more precise but requires a sports science facility.
Q: Do I need an expensive power meter to use FTP-based training? A: A power meter or smart trainer with power measurement is required. Entry-level smart trainers (Wahoo Kickr Core, Saris H3) range from $600–900 and provide power measurement accurate enough for FTP testing and structured training. Garmin Rally, Favero Assioma, and Stages pedal power meters start around $400–600. These are significant investments, but they transform the precision of cycling training. If a power meter is not available, Fitiv supports HR-based training using TRIMP and heart rate zones.
Q: What happens to FTP if I stop cycling for a few weeks? A: FTP begins declining within 2 weeks of complete inactivity. Research shows approximately 5–10% reduction in FTP within 4 weeks of detraining, accelerating to 20–30% reduction over 8–12 weeks. Maintaining 1–2 moderate-intensity cycling sessions per week can preserve most of the FTP gain. When returning after a break, retest FTP after 2–3 weeks of resumed training to recalibrate your zones.
Q: How is running FTP different from cycling FTP? A: Cycling FTP is measured in watts; running performance is more commonly expressed as pace at threshold (critical velocity or pace at lactate threshold). Some running power meters (Stryd, Garmin running power) now allow FTP-equivalent testing for running, where running FTP is the power you can sustain for approximately 60 minutes. Fitiv supports running power data from Stryd and compatible devices, enabling TSS-based load calculation for runs as well as rides.