Functional Threshold Power (FTP)
The Foundation of Power-Based Training
Key Takeaways
- What: FTP is the highest average power you can sustain for approximately 1 hour without fatiguing
- How to Test: Most common is the 20-minute test protocol: 95% of your best 20-minute average power
- Why It Matters: FTP enables personalized power zones, accurate TSS calculation, and objective fitness tracking
- Typical Values: Recreational: 2.0-3.0 W/kg | Competitive: 3.5-4.5 W/kg | Elite: 5.5-6.5 W/kg
- Testing Frequency: Retest every 6-8 weeks during training blocks to update zones as fitness improves
What is FTP?
Functional Threshold Power (FTP) is the highest average power output you can sustain for approximately one hour without accumulating fatigue. It represents your aerobic threshold—the boundary between sustainable and unsustainable efforts. FTP serves as the foundation for all power-based training, enabling personalized training zones and accurate training load quantification.
Functional Threshold Power revolutionized cycling training in the early 2000s by providing a single, practical metric that defines your physiological threshold. Unlike lab-based lactate testing, FTP can be measured with just a power meter and an open road.
🎯 Physiological Significance
FTP closely corresponds to:
- Lactate Threshold 2 (LT2) - Second ventilatory threshold
- Maximal Lactate Steady State (MLSS) - Approximately 88.5% of true FTP
- Critical Power (CP) - Typically within ±5W of FTP
- ~4 mmol/L blood lactate - Traditional OBLA marker
Why FTP Matters
Functional Threshold Power is the foundational metric that unlocks all advanced power-based training:
- Power Training Zones: Personalizes intensity zones based on your individual physiology
- TSS Calculation: Enables accurate Training Stress Score quantification
- CTL/ATL/TSB: Required for Performance Management Chart metrics
- Progress Tracking: Objective measure of threshold power improvement over time
- Race Pacing: Determines sustainable power outputs for time trials and road races
📱 Bike Analytics Automates All FTP-Based Training
While this guide explains the science behind FTP, Bike Analytics automatically detects and tracks your Functional Threshold Power from your ride data—no manual testing or calculations required.
The app handles:
- Automatic FTP estimation from training data
- Personalized power zone updates as your FTP improves
- Real-time TSS, Intensity Factor, and Normalized Power tracking
- Historical FTP progression charts and fitness trends
- Separate FTP tracking for road vs MTB disciplines
FTP vs Other Power Metrics
Understanding how FTP compares to other cycling performance indicators helps you choose the right metric for your training goals.
| Metric | What It Measures | Test Method | Sustainable Duration | Best Use Case |
|---|---|---|---|---|
| Functional Threshold Power (FTP) | Maximum 1-hour power (aerobic threshold) | 20-min test (95%) or 60-min test | ~60 minutes | Training zones, TSS calculation, race pacing |
| Critical Power (CP) | Aerobic-anaerobic boundary | Multiple maximal efforts (3, 5, 12, 20 min) | 30-40 minutes | More accurate modeling, W' balance tracking |
| Normalized Power (NP) | Physiological cost of variable efforts | Calculated from ride data | N/A (derived metric) | Variable intensity rides, real-world TSS |
| 5-Minute Power (VO₂max) | Maximum aerobic capacity | 5-min all-out test | 5-8 minutes | VO₂max intervals, short climbs |
| 20-Second Power (Anaerobic) | Neuromuscular power | 20-sec max sprint | 20-30 seconds | Sprint training, final kicks |
Why Choose FTP?
FTP strikes the perfect balance between accuracy and practicality. Unlike Critical Power (which requires multiple tests) or laboratory lactate testing (expensive and inconvenient), FTP can be measured in a single 20-minute effort. This makes it ideal for regular retesting every 6-8 weeks to track fitness progression and update training zones.
How to Test Your FTP
Three proven protocols to determine your Functional Threshold Power
🏆 20-Minute FTP Test
Most Common Method
-
Warm-up (20 minutes)
Easy spinning, gradually increasing intensity. Include 2-3 short bursts at race pace.
-
5-Minute All-Out
Maximum sustainable effort to deplete anaerobic reserves. Don't hold back.
-
Recovery (10 minutes)
Easy spinning to clear lactate. Let heart rate drop below 120 bpm.
-
20-Minute Test
All-out sustainable effort. Hold steady power—don't blow up early. Record average power.
-
Calculate FTP
FTP = 95% of 20-minute average power
Example: 250W for 20 min → FTP = 238W
⚡ Ramp Test
Shorter Alternative (20-30 minutes total)
-
Warm-up (10 minutes)
Easy spinning at endurance pace to prepare legs.
-
Ramp Protocol
Start at easy power (100-150W). Increase by 20W every minute until exhaustion.
-
Ride to Failure
Continue until you can no longer hold the target power. Record maximum 1-minute average power.
-
Calculate FTP
FTP = 75% of max 1-minute power
Example: 340W max 1-min → FTP = 255W
🥇 60-Minute Test
Gold Standard (Most Accurate)
-
Warm-up (20 minutes)
Progressive warm-up with several race-pace efforts to prepare for sustained threshold work.
-
60-Minute Maximal Effort
All-out sustainable effort for one full hour. Pacing is everything—start conservatively.
-
Record Average Power
Your average power for the full 60 minutes IS your true FTP. No calculation needed.
🔄 Testing Conditions Matter
For consistent, comparable results:
- Indoor vs Outdoor: Indoor tests are more controlled (no wind, traffic, terrain) but may be 5-10W lower due to heat buildup
- Time of Day: Test at the same time you typically train for comparable results
- Hydration & Nutrition: Well-fueled and hydrated, but not immediately after eating
- Fatigue Status: Test when relatively fresh, not after hard training blocks
- Power Meter: Use the same power meter for all tests to avoid calibration differences
🔄 When to Retest FTP
Update your FTP every 6-8 weeks during active training blocks, or when:
- You can consistently complete workouts above prescribed zones
- Your heart rate is lower at the same power outputs
- After a training phase change (base building → build → peak)
- Following significant fitness changes (injury, illness, off-season)
- Before starting a new training plan or race season
FTP vs Critical Power: What's the Difference?
Both FTP and Critical Power (CP) describe your threshold, but they use different approaches.
Functional Threshold Power (FTP)
- Single number: One power value defines your threshold
- Simple to test: One 20-minute or 60-minute effort
- Widely adopted: Industry standard since early 2000s
- Easy to understand: "Maximum 1-hour power"
- Practical: Quick to retest regularly
- Limitation: Doesn't account for anaerobic capacity (W')
Critical Power (CP)
- Two-component model: CP (sustainable power) + W' (anaerobic capacity)
- More complex: Requires 3-4 maximal efforts at different durations
- More accurate: Models power-duration relationship precisely
- Enables W' balance: Tracks "anaerobic battery" depletion/recovery
- Better for variable efforts: Road racing, criteriums, MTB
- Trade-off: More testing time, more complex analysis
Which Should You Use?
- Use FTP if: You want simple, practical training zones for steady-state efforts (time trials, triathlons, climbing)
- Use CP if: You want precise modeling of variable-intensity efforts (criteriums, road racing, MTB) and need W' balance tracking
- Good news: FTP and CP are typically within ±5W of each other. Many cyclists use FTP for simplicity, knowing CP would give similar zones
Using FTP for Training Zones
FTP unlocks the 7-zone Coggan power training system, enabling precise intensity prescription for every workout.
The Coggan 7-Zone Model
Dr. Andrew Coggan developed this system based on physiological thresholds. Each zone targets specific adaptations:
| Zone | Name | % of FTP | Example (250W FTP) | RPE | Purpose |
|---|---|---|---|---|---|
| 1 | Active Recovery | <55% | <138W | 1-2/10 | Recovery rides, warm-up, cool-down |
| 2 | Endurance | 56-75% | 140-188W | 3-4/10 | Aerobic base, fat oxidation, mitochondrial density |
| 3 | Tempo | 76-90% | 190-225W | 5-6/10 | Muscular endurance, carbohydrate metabolism |
| 4 | Lactate Threshold | 91-105% | 228-263W | 7-8/10 | Raise FTP, lactate clearance, race pace |
| 5 | VO₂max | 106-120% | 265-300W | 9/10 | Maximum aerobic capacity, 3-8 minute efforts |
| 6 | Anaerobic Capacity | 121-150% | 303-375W | 10/10 | Anaerobic power, 30 seconds-3 minutes |
| 7 | Neuromuscular | >150% | >375W | MAX | Sprint power, very short bursts (<30 seconds) |
🎯 Training Distribution
For optimal endurance development, most cyclists follow a pyramidal or polarized training distribution:
- Zone 1-2 (Easy): 70-80% of training time—builds aerobic base
- Zone 3-4 (Threshold): 10-15% of training time—raises FTP
- Zone 5-7 (High Intensity): 5-10% of training time—develops top-end power
FTP and Training Stress Score (TSS)
FTP is the denominator that makes Training Stress Score (TSS) calculation possible, enabling objective training load quantification.
How TSS Uses FTP
Training Stress Score quantifies the training load of any ride by combining intensity and duration:
TSS Formula
Where:
- NP = Normalized Power (weighted average accounting for variability)
- IF = Intensity Factor (NP / FTP)
- FTP = Your Functional Threshold Power
Simplified:
One hour at FTP = TSS of 100
Example TSS Calculation
Ride Data:
- Duration: 2 hours (7,200 seconds)
- Normalized Power: 210W
- Your FTP: 250W
Step 1: Calculate Intensity Factor
IF = 210W / 250W
IF = 0.84
Step 2: Calculate TSS
TSS = 0.706 × 2 × 100
TSS = 141 TSS
Interpretation: This 2-hour endurance ride at 84% of FTP created a training load equivalent to 1.41 hours at threshold. It's a solid aerobic workout that will contribute to fitness without excessive fatigue.
Why Accurate FTP Matters for TSS
If your FTP is set too low, TSS will be artificially inflated, making you think you're training harder than you actually are. If FTP is too high, TSS will be deflated, potentially leading to overtraining because you underestimate fatigue. Accurate FTP = accurate training load monitoring.
Road vs MTB FTP: Important Differences
Road and mountain bike FTP values differ significantly due to biomechanics, cadence patterns, and power delivery differences.
🚴 Road Cycling FTP
- Higher absolute power: Sustained steady-state efforts
- Optimal cadence: 85-95 RPM at threshold
- Smooth power delivery: VI (Variability Index) of 1.02-1.05
- Aerodynamic position: Lower, more aggressive posture
- Longer sustained efforts: 20-60 minute threshold blocks
🚵 MTB FTP
- 5-10% lower power: Due to technical demands and position
- Variable cadence: 70-85 RPM average, frequent changes
- Bursty power: VI of 1.10-1.20+ with constant surges
- Upright position: Compromises power for bike handling
- Intermittent efforts: Constant micro-recoveries on technical sections
⚠️ Why MTB FTP is Lower
MTB riders experience:
- Body position: Upright position for technical control reduces power transfer efficiency
- Cadence variability: Frequent accelerations and technical sections disrupt rhythm
- Suspension losses: Full suspension bikes absorb 14-30% of power on rough terrain
- Muscle recruitment: Upper body engagement for bike control diverts energy from legs
- Terrain variability: Rocks, roots, and technical features require constant power modulation
✅ Track Separate FTP Values
Bike Analytics automatically tracks separate FTP values for road and MTB disciplines. Testing protocols:
- Road FTP: Test on flat road or indoor trainer with sustained steady power
- MTB FTP: Test on moderate climbing trail or indoor trainer in MTB position
- Expected difference: MTB FTP typically 5-10% lower than road FTP
Typical FTP Values by Level
🥇 World Tour Professionals
Grand Tour contenders and professional cyclists. Years of elite training with full-time coaching, nutrition, and recovery protocols.
🏆 Elite Amateurs / Cat 1-2
High-level competitive cyclists, national-level racers. Structured training 12-18 hours per week with dedicated coaching.
🚴 Competitive / Cat 3-4
Regular racers and serious enthusiasts. Consistent training 8-12 hours per week with structured plans.
🚵 Recreational / Fitness
Regular riders training 5-8 hours per week. Building fitness with group rides and occasional events.
🌟 Beginners
New to structured training or returning after time off. Less than 1 year of consistent power-based training.
W/kg vs Absolute Watts
Power-to-weight ratio (W/kg) is more meaningful than absolute watts for climbing and comparing riders of different sizes:
- Climbing: W/kg directly predicts climbing speed (gravity-limited)
- Flat terrain: Absolute watts matter more (aerodynamics-limited)
- Time trials: Absolute power + aerodynamics trump W/kg
Calculate your W/kg: FTP (watts) / body weight (kg)
Scientific Validation of FTP
Allen & Coggan (2019) - Training and Racing with a Power Meter
Dr. Andrew Coggan and Hunter Allen established FTP as the foundational metric for power-based training in their seminal work, now in its 3rd edition:
- Practical threshold definition: Maximum 1-hour power without fatigue accumulation
- 20-minute test protocol: 95% of 20-minute power correlates strongly with 60-minute power
- Enables Training Stress Score: Objective quantification of training load
- Personalized training zones: 7-zone system based on physiological thresholds
- Industry standard: Adopted by TrainingPeaks, Zwift, TrainerRoad, and all major platforms
MacInnis, Thomas & Phillips (2019) - FTP Test Reliability
Validation study demonstrating high reliability and reproducibility of FTP testing in trained athletes:
- High reliability: ICC = 0.98, r² = 0.96 between test-retest
- Excellent repeatability: ±2W bias, typical error 2.3%
- Identifies 1-hour power: Accurately predicts sustainable threshold in 89% of athletes
- Practical alternative: Valid substitute for expensive laboratory lactate testing
Source: MacInnis, M.J., Thomas, A.C.Q., & Phillips, S.M. (2019). "Is the FTP Test a Reliable, Reproducible and Functional Assessment Tool in Highly-Trained Athletes?" International Journal of Exercise Science, PMC6886609.
Karsten et al. (2019) - FTP Validity for Performance Prediction
Research demonstrating FTP's superiority over VO₂max for predicting cycling performance:
- Strong performance correlation: W/kg at FTP correlates with race performance (r = -0.74, p < 0.01)
- Better than VO₂max: VO₂max showed no significant correlation (r = -0.37)
- Practical relevance: FTP directly translates to race pace and training prescription
Source: Karsten, B., et al. (2019). "The Validity of Functional Threshold Power and Maximal Oxygen Uptake for Cycling Performance in Moderately Trained Cyclists" PMC6835290.
🔬 Why FTP Works
Functional Threshold Power represents the boundary between the heavy and severe exercise domains. Below FTP, lactate production and clearance remain balanced—you can sustain effort indefinitely (theoretically). Above FTP, lactate accumulates progressively until exhaustion within 20-60 minutes.
This makes FTP the perfect intensity for:
- Setting sustainable time trial and climbing paces
- Prescribing lactate threshold interval training
- Monitoring aerobic fitness improvements over time
- Calculating training load, fatigue, and recovery needs
Frequently Asked Questions About FTP
What is FTP in cycling?
FTP (Functional Threshold Power) is the highest average power output you can sustain for approximately one hour without accumulating excessive fatigue. It represents your aerobic threshold—the intensity where lactate production equals lactate clearance. FTP serves as the foundation for personalized power-based training zones and accurate training load calculation.
How do I test my FTP?
The most common FTP test protocol: (1) Warm up for 20 minutes, (2) Ride all-out for 5 minutes, (3) Recover for 10 minutes, (4) Ride maximum sustained effort for 20 minutes and record average power, (5) Calculate FTP = 95% of 20-minute average power. Alternative methods include the ramp test (75% of max 1-minute power) or true 60-minute test (most accurate but very demanding).
How often should I retest my FTP?
Retest your FTP every 6-8 weeks during active training blocks to update training zones as your fitness improves. Test more frequently (every 4 weeks) during intensive build phases, or when you can consistently exceed prescribed power zones. Also retest after significant fitness changes (illness, injury, off-season), before starting new training plans, or when heart rate at threshold power drops noticeably.
What's a good FTP for a beginner cyclist?
For beginners with less than 1 year of structured training, a typical FTP is 2.0-2.5 W/kg (140-175W for a 70kg rider). Recreational cyclists training 5-8 hours/week typically achieve 2.5-3.5 W/kg. Don't compare yourself to professionals (5.5-6.5 W/kg)—focus on improving your own FTP by 10-20% over a training season. Any FTP is a valid starting point for power-based training.
Is FTP the same as Critical Power?
FTP and Critical Power (CP) are closely related but different. FTP is a single number representing your 1-hour power, while CP is part of a two-component model (CP + W' anaerobic capacity). They typically differ by only ±5W, with CP usually 5-7W higher than FTP. FTP is simpler and more practical for most cyclists, while CP provides more accurate modeling of variable-intensity efforts and enables W' balance tracking for race situations.
Why is my indoor FTP lower than outdoor?
Indoor FTP is often 5-10W lower than outdoor due to heat buildup, lack of cooling airflow, and psychological factors. Indoors, your body temperature rises faster without natural wind cooling, forcing you to reduce power output to prevent overheating. The static position on a trainer also reduces muscle recruitment efficiency. For accurate training, use separate FTP values for indoor and outdoor riding, or test in the environment where you'll do most training.
What's the difference between road and MTB FTP?
MTB FTP is typically 5-10% lower than road FTP due to: (1) upright riding position reducing power transfer efficiency, (2) suspension absorbing 14-30% of power on rough terrain, (3) variable cadence from technical sections, (4) upper body engagement for bike handling. Track separate FTP values for each discipline. Learn more about road vs MTB differences →
Can I estimate FTP without testing?
While you can estimate FTP from recent race data or hard group rides, direct testing is far more accurate for TSS calculation and training zone prescription. Estimates from race power: use 95-100% of a strong 40-60 minute climb or time trial effort. However, the 20-minute test takes only 50 minutes total (including warm-up) and provides the precision needed for effective power-based training. Bike Analytics can also estimate FTP from your training data automatically.
Apply Your FTP Knowledge
Now that you understand Functional Threshold Power, take the next steps to optimize your training:
- Explore the 7 power training zones and learn how to structure workouts for specific adaptations
- Calculate Training Stress Score (TSS) based on your FTP to quantify workout intensity
- Compare FTP with Critical Power to understand which model suits your riding style
- Learn about Normalized Power and how it improves TSS accuracy for variable rides
- Download Bike Analytics to automatically track FTP, power zones, and performance trends