Functional Threshold Power (FTP) is a key metric in cycling that represents the highest power output a rider can sustain for approximately one hour without fatiguing. Measured in watts, FTP is widely used to determine training intensity, measure fitness progress, and optimize race strategies. By understanding FTP, cyclists can train more efficiently and enhance their endurance and overall performance.
How is FTP Measured?
Various testing protocols typically measure FTP, each offering a practical approach to estimating a cyclist’s threshold power:
- 20-Minute FTP Test: The most commonly used method, where a cyclist rides at their maximum sustainable effort for 20 minutes. FTP is then calculated as 95% of the average power output during this test.
- Ramp Test: A progressive test where power increases every minute until the rider can no longer maintain the effort. FTP is estimated as a percentage of the rider’s peak one-minute power.
- 8-Minute Test: Involves two all-out 8-minute efforts, with a short recovery between them. The FTP is determined as 90% of the average power from these efforts.
- AI-Based FTP Detection: Some modern training platforms use AI to estimate FTP based on recent ride data, eliminating the need for a dedicated test.
Zwift has several FTP test options, including the Ramp Test.
Why is FTP Important?
FTP is a crucial tool for cyclists for several reasons:
- Training Zones: FTP helps define personalized training zones, ensuring that workouts target the right intensity for endurance, tempo, or interval sessions.
- Pacing Strategy: Knowing FTP allows cyclists to pace themselves effectively in races and long rides, preventing early burnout.
- Fitness Benchmarking: Tracking changes in FTP over time helps measure improvements in aerobic capacity and cycling efficiency.
You can work out your zones using your FTP and either the power training zone calculator or heart rate training zone calculator.
FTP and Energy Systems
It represents the balance between a cyclist’s aerobic and anaerobic energy systems:
- Aerobic System: Uses oxygen to produce energy efficiently over long durations, supporting endurance efforts.
- Anaerobic System: Generates energy quickly without oxygen but leads to lactate accumulation and muscle fatigue.
- Lactate Threshold: FTP closely aligns with the point at which lactate production surpasses the body’s ability to clear it, making sustained effort difficult.
Training to Improve FTP
Increasing FTP requires structured training with a mix of endurance and high-intensity efforts:
- Sweet Spot Training: Riding at 84-97% of FTP to maximize efficiency without excessive fatigue.
- Threshold Intervals: Workouts at 102-108% of FTP, typically 4×8-minute or 5×6-minute intervals with short recoveries.
- Over/Under Workouts: Alternating between efforts slightly above and below FTP to improve lactate clearance.
- Long Endurance Rides: Extended sessions at lower intensities to build aerobic capacity.
- Strength Training & Nutrition: Complementary strength exercises and proper fueling support muscle endurance and power output.
Common FTP Mistakes
Many cyclists make errors in FTP estimation and training, including:
- Overestimating FTP: Setting FTP too high can lead to overly intense training, increasing fatigue and injury risk.
- Ignoring Power-to-Weight Ratio: FTP alone does not determine performance—power output relative to body weight (W/kg) is crucial, especially for climbing.
- Inconsistent Testing Conditions: Changes in environment, fatigue levels, and pacing strategies can skew FTP results.
FTP Limitations and Alternatives
While FTP is a useful metric, it has its limitations:
- Not Ideal for Sprinters: FTP does not reflect short-duration power bursts crucial for sprinting and criterium racing.
- Lack of Durability Insights: FTP does not account for power degradation over long rides.
- Alternatives: Metrics like Critical Power (CP), VO2 Max, and Lactate Threshold provide additional insights into a cyclist’s endurance and overall fitness.
So what is FTP in cycling? is an essential tool for cyclists to guide training, measure progress, and optimize race performance. However, it should be used in conjunction with other metrics for a well-rounded training approach. Regular testing, structured training, and a holistic view of fitness will help cyclists maximize their performance and achieve their cycling goals.
FTP Training Plan
Looking to improve your FTP and fitness? Take a look at the FTP builder training plan designed to do just this.
