A little history on my 65 year old husband, diabetic, arthritic and has had 2 total knee replacements 10 years ago. Also 2 neck surgeries in the 1990 s. Went to bed fine last night but in middle of night noticed he couldn t move his legs. They felt heavy and sore ( not painful). I found a walker for him to use and he is using it, but is weak all over, but mainly legs. He is getting to and from bathroom. Seems to have improved since I gave him naproxen at 5pm. What could this be?