Probably the 2nd one with a tiny bit of fun/whimsy and approachable in terms of visual impression....especially if you want to broaden your market base.

I assume the core message/skill is still your physical therapy expertise and experience..it needs to be since it is a skill, unlike coaching just can't be picked up without rigorous schooling plus exams and legislated certification (at least I'm aware in Canada, physiotherapists undergo lots of rigorous academic studies. But I maybe influenced having worked in a teaching/research hospital).

Wahine: I've never used a bike fitter before. Maybe it's because I spend less per bike purchase than others...under $1,000.