Functional Threshold Power (FTP): How to Perform a 20-Minute Test, Calculate Results, and Set Training Zones

How to do a 20 minute FTP test?

To perform a 20-minute Functional Threshold Power (FTP) test, you will execute a structured warm-up, followed by two short, maximal efforts, and then a sustained, maximal 20-minute effort, from which 95% of your average power will be calculated as your estimated FTP.

What is Functional Threshold Power (FTP)?

Functional Threshold Power (FTP) is defined as the highest average power output you can maintain for approximately one hour. It is a critical metric in cycling and endurance training, serving as a robust indicator of an athlete's aerobic fitness and a cornerstone for setting individualized training zones. While a true 60-minute maximal effort is impractical for regular testing, the 20-minute FTP test provides a highly reliable and widely adopted proxy. The principle is that a maximal 20-minute effort can accurately predict your 60-minute threshold power by applying a correction factor.

Why Test Your FTP?

Regularly testing your FTP offers several significant benefits for any serious cyclist or endurance athlete:

• Track Progress: It provides an objective benchmark to monitor improvements in your aerobic capacity and power output over time.
• Personalize Training Zones: FTP is the foundation for establishing highly individualized power training zones (e.g., Active Recovery, Endurance, Tempo, Threshold, VO2 Max, Anaerobic Capacity). These zones ensure your workouts are performed at the correct intensity to elicit specific physiological adaptations.
• Prescribe Effective Workouts: With accurate training zones, coaches and athletes can design targeted training plans that optimize performance gains and prevent overtraining or undertraining.
• Pacing Strategy: Knowing your FTP helps you understand your sustainable effort levels for various durations, aiding in race pacing and strategic effort management.

Essential Equipment

To conduct an accurate and repeatable FTP test, specific equipment is non-negotiable:

• Power Meter: This is the most crucial piece of equipment. It measures your power output in watts and is essential for the test. Ensure it is calibrated correctly before each test session. Power meters can be found in cranksets, pedals, hubs, or as part of a smart trainer.
• Cycling Computer/Head Unit or Smart Trainer Software: A device capable of displaying and recording your power data (average and instantaneous) and lap times. This is vital for following the protocol and analyzing results.
• Indoor Trainer (Recommended): A smart trainer or a high-quality fluid/magnetic trainer provides a controlled environment free from external variables like traffic, wind, and terrain changes, ensuring maximal repeatability.
• Heart Rate Monitor (Optional but Recommended): While power is paramount, heart rate data can offer additional insights into your physiological response to the effort.
• Fan: Essential for cooling, especially during maximal indoor efforts, to prevent overheating and maintain performance.
• Water Bottles: Adequate hydration is critical before, during, and after the test.
• Towel: For managing sweat.

Pre-Test Preparation

Thorough preparation is key to a successful and accurate FTP test.

• Physical Readiness:
  • Rest: Ensure you are well-rested. Avoid intense training for at least 24-48 hours prior to the test. A light spin or complete rest day is ideal.
  • Health: Do not attempt an FTP test if you are feeling unwell, overly fatigued, or experiencing any pain.
• Nutrition and Hydration:
  • Carbohydrates: Fuel your body with adequate carbohydrates in the 24-48 hours leading up to the test.
  • Hydration: Be well-hydrated. Drink plenty of fluids throughout the day before the test. Avoid excessive caffeine or alcohol.
  • Pre-Test Meal: Consume a light, easily digestible meal 2-3 hours before the test. Avoid heavy or fatty foods that can cause digestive distress.
• Mental Preparation:
  • Focus: An FTP test is mentally demanding. Prepare yourself for a sustained, uncomfortable effort.
  • Pacing Strategy: While the goal is maximal, avoid starting too hard and fading dramatically. Aim for a strong, sustainable effort that you can maintain, ideally with a slight increase in effort towards the end.
• Environment Setup:
  • Calibration: Calibrate your power meter and/or smart trainer according to the manufacturer's instructions immediately before the test. This is crucial for accuracy.
  • Ventilation: Ensure good airflow with a fan. Open windows if possible.
  • Distraction-Free: Choose a quiet environment where you won't be interrupted.

The 20-Minute FTP Test Protocol

This protocol is designed to elicit your maximal sustainable power for 20 minutes. Stick to it precisely for consistent results.

• Warm-up Phase (20-25 minutes):
  • 5-10 minutes: Easy spinning, Zone 1-2. Focus on getting the legs moving and heart rate up gradually.
  • 5 minutes: Build intensity gradually to Zone 3 (Tempo).
  • 5 minutes: Easy spinning, Zone 1-2.
  • 3 x 1-minute high cadence efforts: Spin at 100+ RPM with moderate resistance (Zone 3), separated by 1 minute of easy spinning. This helps activate fast-twitch muscle fibers.
• Pre-Test Efforts (5 minutes):
  • 1 minute: All-out effort, maximal power, emptying the tank. This "opens up the legs" and helps clear residual fatigue from the warm-up, preparing your body for the sustained effort.
  • 4 minutes: Easy spinning, Zone 1-2, to recover.
  • 1 minute: All-out effort, maximal power, again clearing the system.
  • 4 minutes: Easy spinning, Zone 1-2, to recover fully before the main effort.
• The 20-Minute Test Segment (20 minutes):
  • Start Strong, but Sustainable: Begin the 20-minute segment with a power output that feels hard but sustainable. Avoid going out too hard in the first 5 minutes, as this can lead to a significant drop-off later.
  • Pacing: Your goal is to maintain the highest average power possible for the entire 20 minutes. It should feel like a very hard time trial effort. Focus on maintaining a consistent cadence and effort.
  • Mental Fortitude: This segment will be uncomfortable. Break it down mentally: think in 5-minute blocks, or focus on maintaining your power number. Push through the discomfort.
  • Final Push: In the last 2-3 minutes, try to increase your effort and empty your reserves. Finish strong.
• Cool-down Phase (10-15 minutes):
  • Easy Spinning: Immediately after the 20-minute effort, spin easily in Zone 1-2. This helps flush metabolic byproducts and aids recovery.

Calculating Your Functional Threshold Power (FTP)

Once the test is complete, you'll need to calculate your FTP.

1. Identify Average Power: Review your recorded data and find your average power output for the 20-minute test segment.

2. Apply Correction Factor: Multiply that average 20-minute power by 0.95 (or 95%).

   • Formula: FTP = (Average Power over 20 minutes) x 0.95

   • Example: If your average power for the 20-minute segment was 250 watts, your estimated FTP would be 250 watts * 0.95 = 237.5 watts.

Interpreting Your FTP and Setting Training Zones

Your FTP number is more than just a figure; it's a powerful tool for structuring your training.

• Understanding Your Number: Your FTP represents your current aerobic ceiling. A higher FTP generally indicates better endurance performance potential. Compare it to previous tests to see if you've improved.

• Establishing Training Zones: Once you have your FTP, you can set personalized power training zones. While specific zone percentages can vary slightly by coach or system (e.g., Andrew Coggan's zones are widely used), here's a common breakdown:

  • Zone 1: Active Recovery (<55% FTP)
  • Zone 2: Endurance (56-75% FTP)
  • Zone 3: Tempo (76-90% FTP)
  • Zone 4: Lactate Threshold (91-105% FTP) - Your FTP sits within this zone.
  • Zone 5: VO2 Max (106-120% FTP)
  • Zone 6: Anaerobic Capacity (>120% FTP)

  Use these zones to guide your workouts, ensuring you hit the intended intensity for each session.

Maximizing Test Accuracy and Repeatability

For your FTP test results to be meaningful for tracking progress, consistency is paramount:

• Identical Protocol: Follow the exact same warm-up, pre-test efforts, and main test segment every time.
• Consistent Conditions: Use the same bike, power meter, trainer, fan setup, and even the same room if possible.
• Time of Day: Try to test at the same time of day, as performance can vary.
• Similar Pre-Test Status: Ensure similar rest, nutrition, and hydration status prior to each test.

When to Re-Test Your FTP

The frequency of re-testing depends on your training phase and goals:

• Focused Training: If you are actively training to increase your FTP, re-testing every 4-6 weeks can be beneficial to track progress and adjust training zones.
• Maintenance: For athletes in a maintenance phase or off-season, re-testing every 8-12 weeks might suffice.
• Significant Changes: Re-test after a prolonged break from training (e.g., illness, injury, vacation) or if you feel your current zones no longer reflect your fitness level.

Safety Considerations and Common Pitfalls

An FTP test is a maximal effort and should be approached with caution.

• Listen to Your Body: If you experience sharp pain, dizziness, or severe nausea, stop the test immediately.
• Consult a Professional: If you have any underlying health conditions or concerns, consult with a healthcare professional before undertaking maximal exercise tests.
• Avoid Overtraining: Do not perform FTP tests too frequently, as they are highly taxing and require adequate recovery.
• Pacing Errors: The most common pitfall is starting too hard and "blowing up" before the 20 minutes are up. This will yield an inaccurately low FTP. Conversely, not pushing hard enough will also underestimate your true FTP.

Conclusion

The 20-minute FTP test is an invaluable tool for any cyclist or triathlete serious about optimizing their training and performance. By meticulously following the protocol, accurately calculating your results, and consistently re-testing, you can gain profound insights into your physiological capabilities, personalize your training, and effectively track your journey towards greater endurance and power. Remember, consistency in execution and a commitment to pushing your limits are the keys to unlocking the full potential of this powerful assessment.