The Truth about Running and Your Knees

Prior to a decade ago, the widely held belief among running researchers and armchair quarterbacks of the sport was that long-term and long-distance running harm the knees. Specifically, the entrenched conviction was that running accelerated the natural wear and tear on the knee joints, leading to arthritis.

It makes sense logically, of course: Running is a high-impact activity that puts continuous stress on the body’s joints — particularly, the knee joints.

Yet the evidence in the past several years has largely overturned the association between running and arthritis, including a 2013 study of close to 75,000 runners that found “no evidence that running increases the risk of osteoarthritis, including participation in marathons.” (The runners in the study actually had a lower risk of developing arthritis than people who weren’t as active.)

Running isn’t a risk, but a protective activity for the knees

Osteoarthritis is the most common form of arthritis. It’s an inflammation of the joints, which are the parts of the body where bones come together. Osteoarthritis occurs when cartilage — the protective tissue covering the ends of bones — thins and breaks down. While it used to be considered a “wear and tear” disorder, osteoarthritis is now viewed as a disease of the joint, with possible causes including age, genetics, weakness or instability elsewhere in the body, past knee injuries, and obesity.

Carrying extra weight increases the strain on the joints, which can, in turn, damage the knees. It also causes harmful inflammation throughout the body, including the knee joints. Because runners tend to have a lower body mass index, or BMI, than the average person, they’re at a lower risk for osteoarthritis.

An increasing body of evidence has also found that knee injuries are caused by a weakness somewhere else in the body, most often the hips, which is why strength and cross-training are so important — the stronger the muscles, the less impact absorbed by the joints.

More recently, studies have found that running actually protects the knees from osteoarthritis. For example, research has found that running doesn’t cause joints to break down as previously thought but actually stimulates the body to repair minor cartilage damage and condition the existing cartilage to become more resilient.

Knee pain and injuries often from overuse

None of this is to say that runners can’t get osteoarthritis, or knee pain or injuries, of course. Knee injuries like iliotibial band syndrome (ITBS) — commonly known as IT band syndrome — and patellofemoral pain syndrome (PFPS) — often referred to as “runner’s knee” — are actually among the most common injuries reported by runners. It’s just that they’re often overuse injuries, or injuries that occur when you put more stress on a part of your body than it’s currently equipped to handle, and not attributed to running alone.

If you’ve already had a knee injury, however, especially one that required surgery, running can increase your risk of osteoarthritis.

The bottom line? As always, listen to your body. And don’t skip rest days, which give the body (knees included) time to recover and build strength for the next workout.

Now get out there and run your life.