I have a polar sports watch . . . .
Could I connect ( direct ) from flow.polar.com to citystrides ?
( not through strava ? )
Thanks,
Wouter Wethmar
Hi Wouter 
welcome!
CityStrides currently only supports what’s listed in the main sign in/up pages. I’ve had two longstanding projects of adding Suunto and Polar support that I haven’t completed yet. 
Thanks for adding this post - it’ll help me gauge interest based on the number of votes it gets. It’ll also help me work with anyone who would be interested in helping out by being the first/beta-test users of the Polar connection (maybe you?).
If I can help by testing let me know . . . . . . !