FTP test on the trainer: 20-minute or ramp test?
All target watts in indoor training are percentages of your FTP. If the FTP is wrong, every session is either too easy or too hard. With a test of 20 to 30 minutes you find it out, on a smart trainer even very accurately.
- FTP is the power in watts you can hold for about an hour.
- 20-minute test: 20 minutes evenly as hard as possible, FTP ≈ 95 % of the average.
- Ramp test: the power rises every minute until you can no longer continue. FTP ≈ 75 % of the best minute.
- Repeat: every four to eight weeks if you train regularly.
What is FTP?
FTP stands for Functional Threshold Power. It describes the highest power you could hold for about an hour. Most people cannot do that in a test, so you measure shorter and convert.
The training zones are derived from FTP. An interval at “90 % FTP” is something quite different at an FTP of 200 watts than at 300 watts. That is why you need a current value as soon as you train by watts.
Which test is the right one?
20-minute test
You ride 20 minutes as evenly hard as possible. Needs experience in pacing, but usually gives the most reliable value.
Ramp test
The power rises automatically, you do not have to pace anything. Takes about 25 minutes and suits getting started.
As a beginner the ramp test is the better choice: you cannot misjudge, because the trainer sets the pace. The 20-minute test is worth it when you already have a feeling for your limit.
The 20-minute test step by step
- Warm-up (about 20 minutes): start easy, then three times one minute fast and one minute easy. Then 5 minutes light.
- The test (20 minutes): ride the 20 minutes as evenly as possible and as hard as you can keep up to the end. Rather start a little too easy: anyone who is too fast in the first minutes collapses at the end.
- Cool-down (5 to 10 minutes): spin easily.
- Calculate: FTP ≈ 95 % of the average power of the 20 minutes. With an average of 240 watts the FTP is about 228 watts.
You find the 20-minute test in Zombike as FTP Test 20: warm-up, test and cool-down are set, you only have to pedal.
The ramp test step by step
- Warm up easily: 5 to 10 minutes.
- The steps: the target power rises in small steps, usually every minute. You ride until you can no longer hold the step.
- Calculate: FTP ≈ 75 % of the power of the best full minute.
In Zombike there is the Ramp Test with a matching structure. The result is somewhat higher or lower than with the 20-minute test for some people. So stay with one method if you want to compare progress.
Preparation: how to get a usable value
- Arrive rested: an easy or free day before. If you test tired, you get an FTP that is too low and then train too easy.
- Fan on: indoors it gets hot quickly. Heat costs power and distorts the result.
- Drink and eat: have a bottle ready and eat something light beforehand.
- Calibrate the trainer: many smart trainers measure more accurately after warming up. The manufacturer’s instructions usually mention a calibration run (“spin-down”).
- Same conditions: the same time of day, the same trainer, the same gear, so you can compare tests with each other.
Typical mistakes
- Starting too fast: the first minute feels easy, the last becomes torture. Pace your power.
- Testing while tired: see above, the most common reason for a too low value.
- Never updating the value: after a few weeks of training the FTP is often higher. If you never measure it again, you stay below your potential.
- A test with another device: two measuring devices can give different values. Stick to the device you train with.
What you do with the result
Enter the FTP in your training app. All target watts recalculate. After that the sessions fit again: easy riding stays easy, the intervals challenge you without running you over.
In Zombike you set the FTP on the dashboard or in every workout. The training plans often end with a test so you see how far you have come.
Frequently asked questions
How often should I test my FTP?
Every four to eight weeks if you train regularly. After a break or an illness a new test is worth it earlier, because your power may have dropped.
Is the 20-minute or the ramp test more accurate?
That depends on you. The 20-minute test is often closer to the real threshold if you can pace yourself well. The ramp test is simpler and well repeatable. What matters is that you stay with the same method for comparisons.
What if I have no power meter?
Then you need a smart trainer with power measurement or pedals with power measurement. Without watt values there is no FTP. Which trainers are suitable is in the article Buying a smart trainer.
I am not a racer. Do I need a test?
Yes, as soon as you train by watts. Even for hobby riders a fitting FTP makes training more pleasant and more effective. If necessary, estimate it at the start and correct it after the first test.
Note: This article is general advice and does not replace medical or sports-science guidance. If you have pre-existing conditions or complaints, talk to a doctor before hard tests.
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