Getting Your FTP Estimate
The device uses your user profile information from the initial setup to estimate your functional threshold power (FTP). For a more accurate FTP value, you can conduct an FTP test using a paired power meter and heart rate monitor (Conducting an FTP Test).
Your FTP estimate appears as a value measured in watts per kilogram, your power output in watts, and a position on the color gauge.
For more information, see the appendix ( FTP Ratings).