What is my Default FTP? How does this get set and change over time?
Your Default FTP (Functional Threshold Power) is the number you initially entered as your Default FTP number. After you ride your first FTP Check, PowerBrain uses the adjusted test results (best 20 minute power minus 5%) in place of your Default FTP.
The first ride of the season marked as an FTP Check will be used to calculate the starting FTP value for the entire season. This is because the formula for predicting FTP over time needs a stable beginning point. All rides marked as FTP Checks throughout the season contribute to improving the accuracy of your predicted FTP. However, they do not alter the Default FTP like the first FTP Check of the season does. Conversely, PowerBrain calculates training loads using the most recent FTP Check. The Training Progress graph is based on having at least 5 FTP Checks (and at least 20 rides) in the past 200 days.