I wish you strenght, heartily. Mom also has it; maybe I could understand some of it.
Situation apart, I find interesting the description you provide about how it is having it, that is, since the "interior" or personal point of view of having it; that meaning I could only see it by "the outside" or not having it, and certainly the lack of muscle where it is supposed to be muscle could be a dary phenomena to describe, at least not being studied medicine.
Treatment appart, I try to think for my mom to not be too rigid about it, in the sense of making a worse cure to lease it by using worryness. True is that to worry is a way to measure it; but then it passes onto more of a personal choice. Those of us that are outside couldn't help but tu be helpful whenever appropiate, as if making room for the very disease to also be a house dweller. I could understand that last as making habit of a treatment...
Also glad to hear biking helps! I would Imagine it'd be better muscle wise to go light and practice scalating