rivergrl, I think that our joints were meant to be used, and the harm comes from using them too hard, you know? The way I understand cycling is that it's not weight bearing, so doesn't really stress our knee joints like running does -- pounding on them, you know?

We can probably do some damage when we "hammer," but if I'm guessing correctly, that's more to the connecting tissues surrounding the joint itself than to the "padding" that's in there keeping friction from happening.

I wouldn't be surprised to learn that using our joints, which are self-lubricating, is what stimulates our bodies to produce more of the lubricants that keeps them moving smoothly! (then again, there's my fingers, and you'd think...)

Karen in Boise