So, I've always heard and strongly agree that biking is really good exercise for your knees. It's low impact usually and your knees are in constant motion, working hard (which is also called exercise, commonly accepted as a good thing).
I've seen some posts on this forum mentioning how things like hills or applying backward pressure on a fixie is bad for your knees.
I think this is total B.S. I think that 90% of biking is really good for your knees. My guess is that fixie skid-stops and technical mountain biking without suspension aren't too good for your knees. But the majority of riding is great for them.
What does everyone think? Is biking bad for your knees?