I've stopped not only ballet but even going for walks, so my physical activiy decreased.

I feel like my body has no strength.

...The biggest problem is when Onee-chan is dressing me.

Ah...

Onee-chan, what's wrong?

No, it's nothing

It's nothing. I'll put your top on, Mio.

The skirt's constriction and Onee-chan's reaction.