Until the late 1990s, it was still thought that osteoarthritis could be caused by "wear and tear." This could mean daily activities, repetitive motions, or exercise. Scientists are getting closer to understanding the mechanisms behind this kind of arthritis, but the exact processes remain unknown.
It is known that impact from sports activities usually doesn't cause osteoarthritis of the weight-bearing joints (hip and knee). The exception to this may be in high-performance runners, those who train and compete at high intensities and long distances. These athletes are exposed to much more impact over a longer period of time. Slower, noncompetitive runners do not have the same risk.