I have looked on here re this issue but only find reference to very fit people regaining fitness by extreme exercise. I am 71, I had PKR to my right knee in January and am due to have the left one done in September. My general decline in health and fitness is terrifying, muscle wastage (where did my calf muscles go?), and general weakness. I try to walk 10000 steps a day and use my exercise bike to try to build strength but my bad knee is holding me back and both legs are constantly stiff, sore and the left very painful. I am fearful that with a further period of enforced inactivity after the second operation is just going to hasten my decline further. I was previously relatively fit and healthy for my age and all I can see now is continuing to go downhill....... am I alone in this?