A TCX (Training Center XML) file is a data exchange format used to share data between fitness devices. It was introduced in 2008 with Garmin’s Training Center product. Workout data such as heart rate, running cadence, bicycle cadence, calories, and lap time is stored in XML format inside the TCX file. In addition, summary data about the workout track is also included in the TCX file. TCX files are similar to FIT files that are created with Garmin sports wearable devices.
TCX File Format - More information
TCX files are saved to disc as XML files with each record saved as an activity. An activity comprises all the data of a workout such as time, lap time, Id, heart-rate, intensity, cadence and track information that contains the pairs of position along with the timestamp for that lat-long position similar to the GPX files.
TCX File Format Versions
There are two versions of this format with their own XML schemas hosted by Garmin. Following are few of them: