Runtastic might be a bit more popular than SyncMyTracks. We know about 1 link to it since March 2021 and only 1 link to SyncMyTracks. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
If you are on android I have succesfully used SyncMyTracks: https://syncmytracks.com/ to import my historical activity form google fit / suunto into Garmin Connect. It does include Samsung Health as an account it will sync. Allows syncing both ways, and you can have it automated (can't remember which features require purchase - but its not expensive and the automation works very well - never have to remember to... Source: over 2 years ago
Workaround is to use SHealth only, export gpx file, then import it through runtastic.com (Profile (Arrow Next to profile picture) ->Settings->Activity Import). The imported workout count for the challenges. Source: almost 2 years ago
Health Sync - Health Sync is a mobile application that synchronizes your health data from multiple fitness applications, including Strava, InBody, Samsung health, Fitbit, Polar, Suunto, Oura, and many more.
Strava - The #1 app for runners and cyclists
tapiriik - Automatically synchronize your fitness activities between Garmin Connect, Runkeeper, Strava and more.
RunKeeper - Join the community of over 45 million runners who make every run amazing with Runkeeper. Track your workouts and reach your fitness goals!
RunGap - Free Workout Data Manager for iOS.
MyFitnessPal - Track the number of calories that you consume each day with MyFitnessPal. The app also lets you create a diet and track the exercise that you complete each day whether it's walking, running or some other type of program.