^^ Since arthritis is a cumulative wear-and-tear condition that is evident in EVERYONE beyond a certain age, your point is lost on me. Muscles don't mitigate the load on your knees. There is no such thing as a muscle that supports weight. The best conditioned athletes in the world don't competitively get beyond their 30s -- sometimes 20s -- because "the first thing that goes is the legs." And what usually "goes" is the joints due to wear and tear.