But it seems these negative opinions may be undeserved. New findings suggest that running actually changes the biochemical environment within the knee to prevent inflammation and benefit the overall joint.
Researchers from Brigham Young University conducted a study on 15 male and 15 female runners with no prior history of knee injury or arthritis. Each participant submitted a blood sample from the arm and a small amount of synovial fluid from the right knee at the beginning of the study. The participants were then transported by wheelchair to the university’s biomechanics lab where they were asked to either sit for 30 minutes or run on a treadmill for 30 minutes. Afterwards, the patients were transported back to a clinic for an additional sample of blood and synovial fluid. Each participant completed one sitting session and one running session on different days.
In examining the samples of blood and synovial fluid, researchers specifically looked for GM-CSF and IL-15, which are molecules associated with inflammation, and a substance known as cartilage oligomeric matric protein (COMP). COMP is a marker of disease activity and is about five times more prevalent in the synovial fluid of arthritis patients compared with healthy individuals.
Due to difficulties with safely extracting full samples of synovial fluid, researchers were only able to complete numbers on six participants. However, their findings were consistent among all testable samples. In nearly every case, researchers noted substantially lower levels of GM-CSF and IL-15 compared to baseline readings. Interestingly, COMP levels increased in the blood and decreased in the synovial fluid, suggesting that running may push these molecules out of the knee joint and into the blood.
Sitting appeared to have the opposite effect. Individuals who sat for 30 minutes showed increased COMP levels in the knee and had high concentrations of one of the inflammatory molecules.
While these findings are encouraging, the researchers acknowledge that the study is quite small. Further research involving more participants and larger samples of synovial fluid is needed to produce more conclusive results. In the meantime, lead study author Robert Hyldahl concludes that moderate running is “not likely to harm healthy knees” and likely offers protection against joint damage (Source: The New York Times).