(RxWiki News) It's a balance to keep knees strong. The key is neither too much exercise nor too little.
Exercising on both extremes can damage knee cartilage among middle-aged adults, a new study presented at a conference has found.
"Knee problems? Do low impact exercises."
Activities like running, which has a high impact on the knees, was linked with greater wear on the cartilage, researchers found. This higher risk also increased the odds of developing osteoarthritis.
Researchers, led by Wilson Lin, a research fellow and medical student at the University of California in San Francisco looked at how cartilage in the knees changed over a four-year period in 205 patients between 45 and 60 years old. The patients were recruited through the Osteoarthritis Initiative study that focuses on preventing and treating osteoarthritis across the country.
Using magnetic resonance imaging, researchers took photographs of patients' knees at the start of the study and after two and four years. They specifically looked at cartilage in the kneecap and the major bones of the lower right leg. The participants tracked how often they exercised and were physically active.
Researchers focused on T2 values in the knee, which better shows cartilage breakdown in detail.
"Standard MRI shows cartilage defects that are irreversible," said Thomas Link, MD, professor of radiology and chief of musculoskeletal imaging at UCSF.
"The exciting thing about the new cartilage T2 measurements is that they give us information on a biochemical level, thus potentially detecting changes at an earlier stage when they may still be reversible."
"When we compared the scores among groups, we found an accelerated progression of T2 relaxation times in those who were the most physically active. Those who had very low levels of activity also had accelerated progression of T2 values," Dr. Link said. "This suggests that there may be an optimal level of physical activity to preserve the cartilage."
By avoiding risky activities that put too much stress on the body and maintaining a healthy weight, people can take care of the cartilage in their knees, according to Dr. Link.
"Lower impact sports, such as walking or swimming, are likely more beneficial than higher impact sports, such as running or tennis, in individuals at risk for osteoarthritis," he said.
The study was presented at the Radiological Society of North America meeting November 25. One of the researchers is a consultant for General Electric, which supported the study. Research presented at academic conferences should be considered preliminary until published in a peer-reviewed journal.