How to merge a Garmin fit file with a Zwift/RGT Cycling etc. file into a fit file that contains GPS data, Elevation, Speed, Cadence, Power AND Training Effect/Training Load: 

Merging a Garmin and Zwift RGT Cycling File using OptiSync
FFRT OptiSync Doku.pdf
PDF-Dokument [3.6 MB]



The clever Toolbox for all your FIT / TCX / HRM / HRM+GPX files !

  • Repair corrupted files with sophisticated error detection and correction
  • Edit your files with a modern Graphical User Interface
  • Convert between different file formats (FIT <-> TCX <-> HRM <-> GPX)
  • NEW: Batch Upload function for Strava etc: upload your complete history with one mouse click easily!  
  • Analyse your files with Map and Chart features
  • Display your activity in Google Maps
  • Combine HRM and GPX files into one activity
  • Edit Swim Data Files
  • Import and Export R-R (HRV) values 
  • Upload your files to Garmin Connect, Strava TrainingPeaks etc. with ONE click
  • Merge multiple files (helpful, if you recorded an activity with two training devices and would like to combine the recorded data into one file)
  • Convert courses (FIT) into activities (FIT, TCX, HRM) and activities into courses



This homepage is created for those who are in need of a tool to repair their FIT files. As a matter of fact activity files are sometimes corrupt and cannot be uploaded/imported into training diary software. 


The fit file repair tool which I have developed helps you to repair corrupted FIT files and rescue your valuable data.


The main features are:

  • import of (corrupted) FIT, TCX and HRM files
  • export as FIT, TCX or HRM file
  • automatic detection and treatment of data corruption during the import
  • modern user interface
  • can be used as comfortable file converter for FIT / TCX / HRM file formats

The tool requires a PC with Windows. If someone is interested in developing a Mac or web version of my tool (s)he is invited to contact me and get all the support I can offer.


Feature (I=Import, E=Export) FIT files TCX files HRM files GPX files   
GPS position data I+E I+E I (*.gpx)  I+E  
Heartrate data I+E I+E I+E    
Cadence data I+E I+E I+E    
Speed data I+E I+E I+E  (I)  
Distance data I+E I+E I+E  I  
Power data I+E I+E I+E    
Temperature data I+E        
R-R (HRV) data I+E -- I+E (*2.hrm)    
Pool Swim Data I+E        
Open Water Data I+E I+E      
Weather Conditions I+E        
Batchmode for File Conversion Yes Yes Yes  Yes  
Automatic Data Repair during File Import Yes Yes Yes  Yes