In the US, it's almost entirely rich, white people that upload data to strava. You can easily see racial/economic divisions in any major united states city. Baltimore is a great example[1]; white people live in the center but not on the east or west sides (Canton excepted).
I'm not sure it is that simple. May be college/university education is a better predictor for Strava usage. But given that education in the US correlates with both race and income it is hard to say without controlling other variables.
[1]: https://i.imgur.com/RXSfgz1.jpg