Hi, Mike. I'm not sure I got mine figured out. I did have one lucky break at the time of my knee op and that was to be invited to be part of a federal study to try to find out why our quads quicker and to a greater degree than other leg muscles get weak in the wake of knee replacement surgery, For a month before and a month following the surgery I went to a hospital lab where I was made to exercise my both legs so that my quad strength could be recorded. I credit that fed study with keeping my legs, including the one with the replacement, in at least half-good shape. Today, my legs, and in particular my knees, still feel pretty good –– except for arthritis! That seems to get a little worse every year. I figure that the time-release diclofenac that my doctor gave me is at least helping to keep arthritis from getting too painful. These days I miss the pleasure of walking more than anything. Walking isn't much fun anymore. –Ray