How to Complete a Power Test
If you are training with a power meter, there are a few steps you will need to take to be able to use your data. Most importantly, a power test. This will give you your Functional Threshold Power (FTP). FTP is the power that you can maintain for one hour. You will use this number to calculate training zones for structured training.
There are different methods to determine your FTP. Since FTP is the power you can hold for one hour, one way is to ride as hard as you can for one hour. However, that is physically, mentally, and logistically challenging for most people. Luckily, there are other methods to estimate your FTP. Many software platforms will estimate your FTP based on power data from rides, but if you are new to power training, you still need to do a test to have an accurate starting point. Two of the most popular tests are the 20-minute or 8 minute test.
Ideally, you should stick to the same format each time you do a power test. You also should try to keep conditions as similar as possible across your tests, for example using the same bike and stretch of road, or perform your test on a trainer.
The 20-Minute Cycling Power Test
One 20-minute effort performed at the max power you can sustain over 20 minutes. FTP is 95% of your average power for the interval.
Pros:
Is easier to perform than a one hour test.
Cons:
Can be difficult to pace if you have never done a power test before, and as a result, it can underestimate FTP if not paced well.
Can be difficult to find a place to perform outside depending on where you live.
How to Perform the 20-Minute Power Test
Find a stretch of road where you can ride uninterrupted by traffic or terrain for 20 minutes, or complete the test on a trainer.
Calibrate your power meter
Warm-up including some hard efforts
Ride as hard as you can maintain for 20 minutes. For the most accurate results, you want to hold a steady effort and avoid big surges at any point. It can help to break the test into smaller 5-minutes chunks to help with pacing.
Your FTP is 95% of your average power for the 20-minute interval.
8-Minute Cycling Power Test
Two 8-minute efforts with complete recovery in between—performed at the max power you can sustain over 8 minutes. FTP is 90% of your average power for both intervals.
Pros:
Easier to pace for less experienced riders.
Easier to find a place to perform outside.
Cons:
Can over estimate FTP for some riders.
How to Perform the 8-Minute Power Test
Find a stretch of road where you can ride uninterrupted by traffic or terrain for 8 minutes, or complete the test on a trainer.
Calibrate your power meter.
Warm-up including some hard efforts.
Ride as hard as you can maintain for 8 minutes. Ride easy for 10 minutes and then do second 8-minute effort.
Your FTP is 90% of your average power for the average of the two 8-minute intervals.