ehh i dont know about this.. for my first surgery all that I did was the bike and swimming, and ended up with about 30-45 degrees less motion in my right knee, and still to this day i barely have any flexibility in it. On my second surgery I ran once it stopped hurting to run during the healing process, and I got full range of motion and it seemed to heal much faster. Definately dont run on a treadmill, but after a couple of months if its feelin better then go to a local track at a high school (look for a rubber track, its easier on the knees) and do some long distance running, keeping your feet low off the ground like a mile runner.. Believe me i lost .2 seconds off my 40 for my first one and none after my second and the only difference was running... Sorry for the book