Cardio fitness data (for running, swimming, biking etc.) shows up in a variety of digital formats based on device and vintage. From Strava, there are at least three formats that can come across

  • GPX: XML based
  • TCX: XML based
  • FIT: binary, recent Apple Watches produce this format

GPX

TCX

Go (lang) library for tcx

FIT

Flexible and Interoperable Data Transfer (FIT) format.

Go (lang) library for FIT