Pro-inflammatory molecules actually go down in the knee joint after running, according to a team of researchers at Brigham Young University.
According to Hyldahl et al, running may slow the process that leads to osteoarthritis. Image credit: Skeeze.
“It flies in the face of intuition. This idea that long-distance running is bad for your knees might be a myth,” said Dr. Matt Seeley, a researcher in the Department of Exercise Sciences at Brigham Young University and senior author of a paper published in the European Journal of Applied Physiology.
In the study, Dr. Seeley and co-authors measured inflammation markers in the knee joint fluid of several healthy men and women aged 18-35, both before and after running.
“A total of 15 healthy, recreational runners (11 men and 4 women) were recruited to participate in this study,” they explained.
“Each participant was (i) between the ages of 18 and 40, (ii) had no history of lower-extremity surgery in their lifetime, (iii) no history of knee articular cartilage injury, (iv) no knee pain in the 3 months prior to data collection, and (v) able to run at 3.0, 3.5, or 4.0 m/s for 30 continuous minutes.”
“Participants completed a running (30 min) and control (unloaded for 30 min) session in a counterbalanced order,” the authors said.
“Synovial fluid (SF) and serum samples were taken before and after each session. Cytokine concentration was measured in SF and serum using a multiplexed cytokine magnetic bead array. Ground reaction forces were measured during the run.”
“Due to the difficulty of collecting SF from healthy joints, we were only able to collect sufficient SF at both time points, under both conditions (control and run), in 6 of the 15 subjects,” they added.
The researchers found that the specific markers they were looking for in the extracted SF — two cytokines named GM-CSF and IL-15 — decreased in concentration in the subjects after 30 minutes of running.
When the same fluids were extracted before and after a non-running condition, the inflammation markers stayed at similar levels.
“What we now know is that for young, healthy individuals, exercise creates an anti-inflammatory environment that may be beneficial in terms of long-term joint health,” said lead author Dr. Robert Hyldahl, also from the Department of Exercise Sciences at Brigham Young University.
“The study results indicate running is chondroprotective, which means exercise may help delay the onset of joint degenerative diseases such as osteoarthritis.”
This is potentially great news, since osteoarthritis — the painful disease where cartilage at the end of bones wears down and gradually worsens over time — affects approximately 27 million people in the United States.
“This study does not indicate that distance runners are any more likely to get osteoarthritis than any other person,” Dr. Seeley added.
“Instead, this study suggests exercise can be a type of medicine.”
The scientists now plan to turn their attention to study subjects with previous knee injuries.
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Robert D. Hyldahl et al. 2016. Running decreases knee intra-articular cytokine and cartilage oligomeric matrix concentrations: a pilot study. European Journal of Applied Physiology 116 (11): 2305-2314; doi: 10.1007/s00421-016-3474-z
