There are still those who say "exercise destroys the knees", although New York University orthopedic surgeon Dr. Cordelia Carter says, "On the contrary, there is a lot of evidence that exercise has a protective effect on the knees."
In 2017, experts participating in the German Orthopedic Congress explained that "the practice of certain types of exercises remains the best way to strengthen the knee joint and stop osteoporosis."
In the same year, researchers followed 2,000 current and former runners for several years and found that they were "less likely to develop arthritis," and their knee pain turned out to be treatable with more exercise.
In 2019, the American College of Rheumatology and Arthritis confirmed that "exercise is very important for those who suffer from osteoporosis and knee pain, and that symptoms decrease with perseverance."
Studies have also shown that mitochondria (the parts of the cell that extract energy from food to sustain life) can be increased by exercise;
This boosts physical fitness and stamina by 50%, and “reduces osteoporosis, making it more dense.”
Recently, a systematic review of 43 MRI studies was published, and confirmed "there is no evidence that running causes damage to the cartilage of the knee."
The danger of cartilage starvation
Michaela Kahn, a researcher at the University of British Columbia who led a new systematic review of 43 studies on running and cartilage, published earlier this year;
"Cartilage is a living, shock-absorbing tissue" that adapts and thrives with regular use, the New York Times told the US (nytimes), while the inactive mode is doomed to become brittle and eventually fail with age.
So periodic weight-bearing exercises such as walking and running compress the supporting cartilage of the knee like a sponge “to flush out waste, pumping out new supplies of nutrients and oxygen-rich fluids, with each step.”
Exercise is very important for people with osteoarthritis and knee pain (Getty Images)
This explains, for example, what a small 2010 study reported as “a 1.9% improvement in cartilage strength and quality in non-runners who followed a 10-week running program.”
It also helps explain why "restraining quickly at the first sign of knee pain can be counterproductive."
Jackie Whitaker, a physical therapist and arthritis researcher at the University of British Columbia, also warns - warning those who suffer from signs of knee problems, and turn to low-impact exercises thinking that they will protect their joints - that this behavior will only lead to "cartilage starvation".
Exercise nourishes and strengthens cartilage
Prevention, then, begins with "strengthening the cartilage" (as a smooth layer of tissue that supports the bones of the knee and other joints, and its collapse is a major cause of osteoporosis) through movement.
The weakening and erosion of cartilage "is what leads to arthritis."
According to animal studies, it was found that the ones that run have stronger cartilage than the ones that run less.
In a study published in 2020, researchers looked at whether these findings applied to humans as well, and noted that "arthritis develops whenever the ability of cartilage to repair is limited."
So runners are likely to develop knee pain at high rates if they do not consider prevention measures related to distance, speed, intensity of exercise and the choice of appropriate shoes, and "unless they train properly," says Dr. Carter, who recommends yoga "as a natural home remedy to help with Avoid joint injuries.
Don't stop but redistribute the loads
There is a limit to how quickly a joint can adapt to stress. According to UCSD physiologist Dr. Keith Barr, cells in cartilage respond positively to exercise for about 10 minutes.
Then "more stress and tissue damage builds up without further benefit";
If exercising once a week for two hours causes you pain in your knees, you can try reducing the duration to one hour twice a week.
So, Dr. Jean-Francois Escollier, co-lead of research for Dr. Khan tells us, “Knee pain that lasts more than an hour after exercise, or that appears in the morning after exercise, is a sign that the joint has been overstretched.”
Even this does not mean that you need to stop exercising, or change exercises;
You just have to adjust it so it's shorter and more frequent, says Dr. Barr.
Cells in cartilage respond positively to exercise for approximately 10 minutes (Getty Images)
Watch out for the weekend rush
Warning to those who do exercise sometimes on the weekends, Whitaker explains, "No exercise comes out of nowhere, after months of inactivity. What your knees can handle today depends on what you've done with them over the past weeks and months."
She recommends doing some strength training to "prepare and rehabilitate your legs before putting any new pressure on them";
A simple program for beginners can squat and push the knees forward, in 3 sets and 10 to 15 repetitions;
To strengthen the muscles that keep the knee stable, and to stiffen the tendons and ligaments around the joint.
Dr. Ewa Ross, a researcher in arthritis at the University of Southern Denmark, advises, “High-quality movement during daily activities, such as sitting and getting up in a chair, using both feet, not using the hands; making sure that the knee and hip are straight and stable (not being able to align, A sign of the need to strengthen the muscles of the legs and hips), and do the same when climbing stairs and sitting on the toilet.
to the cruciate ligament
According to the Mayo Clinic, proper exercise and training — under the supervision of a sports medicine specialist, physical therapist, or athletic trainer — can help reduce the risk of an ACL injury by training in core muscle-strengthening exercises, including the leg muscles. The hips, pelvis and lower abdomen, keeping the knee not moving inward during the squat.