What's fit file?
Fit file is the original file of each activity, it is named with numbers.
The name can indicate the year-month-date-hour-minutes-seconds. of the specific activity.
Steps to find fit files :
1) Power off the device and connect it to a computer.
2) Short press the left button and the device will be recognized as a new disk.
3) You can find the fit file in the folder named "activities".