If you've spent any time in cycling forums or training apps, you've probably encountered the term FTP. It's one of the most important metrics in power-based training, and understanding it is essential for effective structured workouts.
What FTP Actually Means
FTP stands for Functional Threshold Power. It represents the highest power output you can sustain for approximately one hour. More precisely, it's the point at which lactate production and clearance are in balance - train above this point for too long, and you'll accumulate fatigue rapidly.
FTP is measured in watts and typically ranges from 150-200w for recreational cyclists up to 400w+ for elite professionals. However, absolute watts aren't the full picture - your watts per kilogram (w/kg) is equally important, especially for climbing.
Why FTP Matters
FTP serves as the foundation for all power-based training zones. When a workout prescribes "sweet spot intervals at 90% FTP," the system needs to know your FTP to calculate the target power.
With an accurate FTP:
- Your training zones are correctly calibrated
- Workouts provide the intended stimulus
- You can track fitness changes over time
- Training Load calculations are meaningful
An inaccurate FTP leads to workouts that are either too easy (limited adaptation) or too hard (excessive fatigue and potential overtraining).
How to Test Your FTP
The 20-Minute Test
The most common FTP test protocol:
- Warmup (20 min): Easy spinning with a few short accelerations
- Blowout (5 min): Hard effort to clear fast-twitch fibers
- Recovery (5 min): Easy spinning
- Main effort (20 min): As hard as you can sustain for exactly 20 minutes
- Cool down (10 min): Easy spinning
Your FTP is calculated as 95% of your 20-minute average power. For example, if you average 263w for 20 minutes, your FTP is approximately 250w.
The Ramp Test
A newer, less painful alternative:
- Start at low power (typically 100w)
- Increase by 20w every minute
- Continue until you cannot maintain the target power
- FTP is estimated at 75% of your best 1-minute power
The ramp test is shorter and less psychologically demanding, but may be less accurate for athletes with very good or poor anaerobic capacity.
The 60-Minute Test
The gold standard, but rarely used due to its demanding nature. Simply ride as hard as you can sustain for one hour. Your average power equals your FTP.
Tips for Accurate Testing
Be rested: Test after a recovery day or easy day. Fatigue will suppress your results.
Standardize conditions: Test on the same equipment (trainer or road), at the same time of day, with similar nutrition and hydration.
Pace correctly: Start conservatively. It's better to have energy left at the end than to blow up at minute 15.
Use the same protocol: Switching between 20-minute and ramp tests makes comparison difficult.
Mental preparation: FTP tests are hard. Accept that the last 5 minutes will be uncomfortable and commit to holding your power.
When to Retest
Retest your FTP every 4-8 weeks during structured training, or when:
- Workouts consistently feel too easy or too hard
- You've completed a training block
- You're returning from time off or illness
- You've achieved a new 20-minute+ power PR
WattPlan can also detect when your FTP may have changed based on workout performance and will suggest retesting when appropriate.
Beyond FTP
While FTP is crucial, it's not the only metric that matters. Power at different durations (5-second, 1-minute, 5-minute) reveals your strengths and weaknesses. A complete power profile helps you understand whether you're a sprinter, time trialist, or climber - and how to train accordingly.
FTP is your foundation. Get it right, and everything else in your training becomes more effective.