Although running can cause knee damage, recreational running does not cause osteoarthritis at any age and may even be protective, according to new research. People who don’t have osteoarthritis of the knee don’t need to stop running for fear that it will cause knee damage, said Dr. Houston Baylor College of Medicine, who also emphasized that the study’s results don’t apply to people who already have osteoarthritis of the knee. Previous studies have been limited to professional male runners, looking at the association between running and osteoarthritis of the knee. There is always a concern that running is enough to cause osteoarthritis. All of the included individuals underwent knee x-rays and symptom assessment. They also completed a modified version of the Lifetime Physical Activity Questionnaire, which categorized participants into age groups 12 to 18 years, 19 to 34 years, 35 to 50 years, and 50 years and older. Osteoarthritis was assessed by x-ray 4 years after participation in the Osteoarthritis Pilot Study. Participants with a use rating greater than or equal to 2 were considered to have signs of osteoarthritis, and pain was also used as an indicator for evaluation. Osteoarthritis was defined as having imaging signs of osteoarthritis and frequent pain in at least one knee, and participants who had total knee replacement were considered to have frequent knee pain and imaging signs and symptoms of osteoarthritis. In all age groups, the incidence of knee pain was significantly lower in runners than in nonrunners, as was the incidence of imaging signs and clinical symptoms of knee arthritis. Results of the study were similar with little change after correction for age, sex, and body mass index. Running can prevent the development of osteoarthritis, however, Dr. also said there may be selection bias in this study because runners are mostly trying to lose weight and will generally have healthier diets than non-runners. Runners will generally be more physically fit. There is concern that running may cause knee impingement and cause osteoarthritis of the knee, but there is little data to support this view. This study is the first to address this issue in a large sample, and the results help us to recognize that high-impact activities like running do not increase the incidence of osteoarthritis of the knee.