Is running bad for your knees? The truth from the research

The "running ruins your knees" statement is probably the most common myth about sports and exercise out there. However, what does the scientific evidence on this topic really say? In fact, regular runners experience significantly fewer cases of knee arthritis compared to inactive individuals. So, how was this myth originated? What is the role of correct running technique, shoes, surface, gradual increase in mileage, and conditioning in avoiding joint problems associated with running? Where does the line between beneficial and excessive run volume lie? Discuss your own experience, if any.