Glutes are going but still work, but I never had much of an ass. Quads almost gone, calf muscles useless, whatever that muscle is that hurts when you get shin splints still works. I can barely wiggle my toes so those muscles are gone. Hamstrings still work a little but all the hip and pelvic girdle muscles are mostly shot, that's why I can't pick up my feet, like to put on the brakes or step up on a curb. Spinal muscles are unaffected and everything above my hips works fine. I can't stand unsupported for more than a few minutes, but with something to lean against like a kitchen counter or a fence post I can stand for an hour or so in a pinch. Often do while gossiping with neighbors on my walks or cooking.
Y'know when the doctor taps on your knee with that little rubber hammer? How your leg jerks? Mine doesn't. Doctors get the funniest looks on their faces.
Exercise doesn't help because the muscles aren't just atrophied from lack of use, they've turned into something that isn't muscle at all.
On the plus side I can't get leg cramps anymore because those muscles aren't muscles anymore. They can't contract.
A certain amount of overall weakness is caused by my inability to do much of anything without falling down. I'm looking at a manual chair as a sort of portable gym to regain some strength I've lost in my upper body. I'm pretty excited about getting started with it.