but i'm running so very hard with everything that i've got
Fiora would never have thought herself likely to be a horse girl.
For one thing, the closest thing they'd had to horses on the Bionis were Ponios, and Ponios' backs are way too scaly to ride comfortably, let alone safely. Much more than just a circular, connected structure of horns - Bionis life was gnarly!
But besides that...she'd never thought herself down-to-earth (earth?) enough for it. She'd never exactly been one for bare feet.
It's a nice little excuse, then, that she's the one running alongside as Ilia rides, almost wishing she'd her old Machina speed frame to keep up.