Yeah, mine is shot. I don't know what to blame and it might have happened anyway, though I haven't been truly comfortable on a horse or pushbike since my first chemo in 2006. I'll never ride a motorbike again.
Some of the things that help are yoga type activities which get your body and brain connecting. Strengthening the muscles in your ankles by doing simple thing like standing on one leg (and then the other) whenever you think of it is useful. Close your eyes (though hang onto something) if you are game. Brain-body connection