Even avid runners often worry that the repetitive motion of running causes excessive wear and tear on their joints, and particularly their knees. This seems like common sense, but the numbers tell us something every different: runners are significantly less likely to develop knee problems than people of the same age who do not run.
A new study gives insight into why this might be.
Why Runners Have Fewer Knee Problems
One hypothesis advanced to explain why running seems to protect knees, not harm them, is that runners tend to have lower body mass than non-runners. Carrying less weight reduces joint strain, and consequently, your risk of developing problems like knee arthritis. According to a study recently conducted at Brigham Young University (B.Y.U.) in Provo, Utah, however, running may actively benefit the health of your knees.
Scientists at B.Y.U. devised an experiment to study the effects of running on otherwise healthy joints. Participants — male and female runners under the age of 30 with no history of knee injury or arthritis – visited a clinic where the scientists drew samples of their blood and synovial fluid, a liquid that reduces joint friction. Increased quantities of synovial fluid tend to indicate underlying joint issues.
Participants then spent 30 minutes either sitting quietly or running on a treadmill in the biomechanics lab at their preferred pace. After the 30 minutes was up, the researchers took new samples of their blood and synovial fluid. Each participant came in twice, completing the sitting session during one visit and the running session during the other.
Does Running Reduce Inflammation?
The researchers examined the blood and synovial fluid to detect the presence of molecules that play a role in joint inflammation. Even inflammation so mild that you’re not aware of it has been linked to the development of arthritis. The researchers looked for molecules that increase inflammation as well as those known to quell it.
Although the study was done with a limited number of participants, the data generated was remarkably consistent. The researchers found substantially lower levels of two types of cells known to cause inflammation in the samples taken 30 minutes of running than in the baseline samples or in the samples taken after 30 minutes of sitting.
They also found changes in the levels of a substance called cartilage oligomeric matrix protein (COMP) which builds up in the knees of individuals with arthritis or other joint problems. Scientists use COMP levels to help track a person’s risk of developing arthritis and to monitor the progress of the disease. The B.Y.U. team found the synovial samples taken after running contained lower levels of COMP while the blood samples contained more. It appeared that running released COMP molecules back into the bloodstream, thereby preventing them from accumulating around the joint.
One More Reason You Should Go For a Run Today
The study’s findings, though limited, suggest that running can reduce inflammation and lower your risk of developing arthritis, stated Dr. Robert Hyldahl, professor of exercise science at B.Y.U. and lead author of the study. He noted that the study was quite small and short-term, and that he and his colleagues would like to conduct a follow-up study with much larger numbers.
In the future, Hyldahl and his team hope to investigate how factors such as running distance and pace affect changes within the knee, and to assess how running affect the knees of older individuals as well as individuals with pre-existing joint issues.
For now, if you’ve been avoiding running out of concern for your knees, Hyldahl says running seems “not likely to harm healthy knees” and to “probably offer protection.” Sounds like we now have one more reason to go for a run today!