The FTP test lasts 20 minutes. Complete the test while trying to maintain the highest level of power throughout. Reach the power level that you think you can maintain for the duration of the test. If it is too high for you and you cannot maintain it, change down a gear to make it easier or, in other words, move fewer watts.
People usually start off with too much power and have to gradually lower it to find a comfortable level. If it is too hard to begin with, you will find that the final value from the test is below your potential. If it is not overly difficult to begin with, you will obtain a value that is close to ideal. If you are overly cautious to begin with, raise the number of watts mobilised until you find the level that is right for you, otherwise the final value will be slightly below the ideal.
Your first test
It is important to know the number of watts at which you begin your first test so you can use it as a reference for the next test. Your first test will usually not be perfect but you will become more and more precise on future tests. We recommend that you do not start out too strong.
Repeating the test
The FTP test is not an invasive test and the load is relative low when compared with other maximal effort tests. This means that you can repeat the test every 24 hours in order to obtain a more and more specific FTP value.