I added a user story to the site to reflect this idea! I can't promise we'll ship it, but I can promise we'll think about it.
I use Strava, and overall I am happy with it but for the lack of one feature that really bugs me - it has no option to set it up to do a one button start. Currently to record a ride or other activity I have to press record, then press Start - which doesnt always start recording.
Having the ability to set your app to do one touch activity recording would be a feature Strave does not have and therefore an advantage
There may be no direct 1:1 solution at this time, but you can do a lot with IFTTT and Webhooks. So long as your fitness tracker's host service (Apple, Fitbit, etc.) supports IFTTT, you could -- for example -- send a post to Mastodon with whatever information you desired. I do something similar with Untappd since there's no direct integration with Masto at this time.
Fittrackee is working towards it. https://github.com/SamR1/FitTrackee/issues/16