It's called post-polio syndrome. There's a good book "Polio Paradox" by Dr. Richard Bruno about it.
Interestingly, he theorizes that some cases of CFS may, in fact, be post-polio, i.e., the patient had the non-paralytic version which was written off as "flu". As for those of us who had the vaccine as tots, "nature abhors a vacuum" -- when the polio virus was eradicated, another enterovirus took its place, causing similar problems. (Dr. Ryll observes that in the 30s, they were already aware that polio and ME/CFS travelled in side-by-side epidemics and that ME/CFS patients were later found to be immune to polio; they believed the ME/CFS virus was simply a less-potent version of polio.)
All of which makes sense to me, because the things that were recommended to Sheila for her post-polio also help me.