Discrepancies between Stryd and Strava can occur because of the difference in data processing between the two programs.
Stryd uses 3-dimensional motion capture and changes in barometric pressure to determine pace, distance, and changes in elevation.
Strava "takes the distance data recorded in the file and parses it into a data stream to calculate total distance, average speed, and max speed." Here is the link to the Strava web page where they talk about the Pro's and Con's of their data presentation method: https://support.strava.com/hc/en-us/articles/216919487-How-Distance-is-Calculated
Strava runs a calculation on the GPS coordinates as recorded by the GPS watch to get the distance. This means that Strava may determine that the distance is different than what is shown by the watch (and in the Stryd ecosystem).
Strava does not always measure hills accurately. Strava uses GPS points and a flat path is assumed. Here is what Strava has on their website, "A flat surface is assumed, and vertical speed from topography is not accounted for. Similar to the above, straight lines connect the GPS points."
Stryd has better accuracy on hills and mountain trails than Strava because Stryd can measure the line called "c". Strava can only measure the line called "b".
This is an image of a right triangle and the road is represented by the line called “c”. The elevation would be measured by the line called “a”.
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