muscle weakness

I had peripheral neuropathy but that's usually pretty evident - pins and needles, tingling, sometimes burning and considerable pain, mainly in the extremities. But general weakness, no. I can walk well, all day if required, but find standing still for any length of time still turns my feet to jelly and as the feelings in my feet have significant blank patches, I sometimes have problems on uneven surfaces, so I keep running to a minimum as I too am sometimes not entirely sure where my sense deprived feet are!  My knees aren't wonderful (getting up and down off the floor is mildly comic) but they were getting a bit like that before I started chemo and that was nearly 5 years ago, So probably not chemo caused.