A few days ago, Strava upset its users over some restrictive API changes . It might seem odd for one app’s users to fume over an API, but at the heart of the matter is the inherent messiness of fitness data. Here’s a typical scenario. Say you’re all in on Garmin’s platform. You use their watches for running and strength training. Then, you pick up a Peloton bike for indoor cycling. Well, Garmin devices aren’t compatible with Peloton bikes because the two companies haven’t struck a direct deal