Shaky legs, another hospital day

My friend and I did our usual hike this weekend.
Going up was fine, same as always.
Coming down, my legs started shaking about halfway, and by the bottom they just ached in that deep, used-up way.
I used to walk for work every day without giving it any thought.
Now I’m retired, with all this open time, and my legs are somehow worse than they were back then.
Most of my other free hours go to the hospital, sitting with my parent in a waiting room that never changes.
I come home from those afternoons stiff in the neck and shoulders too, from all the sitting and bracing.
It’s strange having this much time to myself for the first time in ages, and still not knowing where to put any of it.