Apple watch distance overstated when running.

hi, I've read a few posts but none of the suggested fixes have worked. When i run using my Apple watch series 5, using the workout app, my running distances are over-stated by as much as 10%. I have the latest software on both my iPhone & apple watch and all location services turned on. When running with other devices they seem far more accurate.

I have also run a half marathon with someone else wearing an apple watch series 3 using the workout app and their distance was within a few meters compared to mine that was overstated by almost 2km!

( i don't think i zig-zag that much!)