(Ivanhoe Newswire) -- Don't blame your knee pain on exercise. Physical activity neither hurts nor helps when it comes to knee osteoarthritis (OA), according to researchers. The finding holds true even for people who are overweight.

Previous studies have suggested exercise can protect against the development of knee pain, while others have concluded it may lead to the condition, especially in people who are obese or overweight.

Researchers from the Boston University School of Medicine followed nearly 1,300 people over about 10 years, and found no relationship between physical activity, like walking or jogging, and the development of knee osteoarthritis.

Another study published along with the Boston investigation supports the finding. Researchers from the Netherlands reviewed previous medical studies on exercise and knee pain and report there is little evidence to suggest physical activity contributes to the condition.

If exercise isn't the culprit in knee osteoarthritis, what is? Writing in an accompanying editorial, University of Missouri-Columbia researcher Marian A. Minor, Ph.D., suggests the time has come for studies that delve deeper into possible causes.

"Future research, whether designed to evaluate the effectiveness of interventions or to identify risk factors for development or progression, should characterize subjects in terms of variables relevant to knee osteoarthritis," wrote Dr. Minor. "These variables will likely include individual characteristics as well as social and environmental factors."

SOURCE: Arthritis Care & Research, published online Jan. 31, 2007