December 22, 2009 – Regular, intensive jogging – more than 90 minutes a day – could increase the risk of suffering from osteoarthritis of the knee, according to an American study. But below this threshold, physical exercise would rather have a beneficial effect on the knees.
The study, which has not yet been published, was presented recently at a congress of radiology specialists1.
The clinical trial is based on magnetic resonance imaging (MRI) tests of the knees of 236 people aged 45 to 55, who are physically active to varying degrees.
As a result, the risk of injury that can lead to osteoarthritis of the knee is greater among athletes who engage in high-impact physical activities for the knees – jogging or sports requiring jumping – at a rate of 90 minutes. per day over a long period.
Although the participants had no pain before the study, MRI tests found menisci lesions in 47% of them, as well as lesions of different magnitudes in the cartilage in 74% of the subjects.
This leads researchers to believe that these athletes are more at risk of developing osteoarthritis of the knee.
However, hobbyists doing the same activities less frequently were not at higher risk. And those who swam or biked intensively (90 minutes or more per day) even saw this risk decrease, according to the study.
The majority of athletes are not at risk
“Even if the results of this study were eventually to be confirmed by other studies, that would not mean that the majority of people who train intensively would have osteoarthritis of the knee,” says medical specialist Dr. Ian Shrier. sport at the Jewish General Hospital of Montreal.
According to him, it is recognized that the risk of osteoarthritis of the knee is greatly associated with previous joint injuries that an athlete may have suffered – ligament or meniscal injury, for example.
“But in general, the onset of osteoarthritis of the knee results from a multitude of factors and not just physical activity,” he argues.
Moreover, in a review of studies he conducted in 2004 on the risks of osteoarthritis attributable to physical activity2, the Dr Shrier concluded that low- or medium-intensity physical activity is not associated with the development of osteoarthritis. It even turns out to be beneficial for the knees, for all amateur athletes.
“The evidence also tends to show that moderate physical activity does not worsen symptoms in people already suffering from osteoarthritis of the knee,” he said in his study.
Martin LaSalle – PasseportSanté.net
1. Stehling C, Subjects with Higher Physical Activity Levels Have More Severe Focal Knee Lesions Diagnosed with 3T MRI: Analysis of the Non Symptomatic Incidence Cohort of the Osteoarthritis Initiative. Unpublished study. On this subject, see also the press release issued in December 2009: www.rsna.org
2. Shrier I, Muscle dysfunction versus wear and tear as a cause of exercise related osteoarthritis: an epidemiological update, British Journal of Sports Medicine, October 2004, vol. 38, no.5, 526-35.
