My knees went South after 8.5 years of biking. Went to 2 doctors, both which said I didn't need surgery, one who recommended physical therapy. Got off the bike for a number of years when I went to live overseas, but was still doing the same repetitious movements using g the subway. The aching got real bad and I went to an alternative practitioner who fixed them. They have never returned to the point they were at. Three years ago I did more online research and started taking Cod liver oil pills. They became my little magic pill. I highly recommend them. I've switched recently to fish oil pills and feel no difference (they're cheaper).