It is 2022, and there are still people out there saying that exercises like running or squatting will “ruin your knees.” And this bullshit needs to stop. That’s not how knees work. That’s not how anything works.
We’ve covered the running angle before: It turns out that runners are less likely to get arthritis in their knees. And the types of knee pain that they do get most commonly, like the syndrome known as “runner’s knee,” are often treatable with more exercise, specifically strength training to address muscular imbalances.
Take squats for another example: No type of squat (not even deep squats, nor squats where your knees go over your toes) is inherently harmful. With any type of exercise, it’s important to make sure you’re doing it properly and your body is prepared for the amount of work you’re asking it to do. That applies to running mileage, to the weight of the barbell when you squat, and the type of squat you do.
Your knees don’t just wear down over time
So if exercise doesn’t ruin your knees, why do so many people say it will? I suspect a big part is just that exercise, like diet advice, is a place where people like to feel smug about their own choices and express this by criticizing others.
But when it comes to knees, specifically, one major reason is likely the way that arthritis has historically been described. Osteoarthritis, which half of all adults will likely experience in their lifetime, has been described as “wear and tear” arthritis, and it tends to occur in older people. For decades, the standard narrative was that you wear your joints down little by little, and if the cartilage wears down enough, you have arthritis and your knees hurt.
If you accept that story—which you shouldn’t—the implications would seem clear: The less you use your knees, the better. The less impact, the better. And once your knees start hurting, you better really stop using them. Give up exercising, sit down, and accept your fate.
But that story doesn’t hold up to scrutiny. Scientists who study osteoarthritis have a bunch of theories about what might actually be happening, and they don’t think cartilage just wears down like old tires. The disease process involves things happening in the bone and the ligaments and joint capsule, as well; it’s complicated. And exercise seems to help.
The American College of Rheumatology and Arthritis Foundation wrote in a 2019 guideline that “exercise is strongly recommended” for people with osteoarthritis of the knee (and of the hip and hand). People who exercise tend to see an improvement in their symptoms. They point out that most studies on exercise have involved walking and other cardio exercise, but strength training and neuromuscular exercises have been shown to be effective, too. They recommend patients choose an exercise they enjoy and that isn’t too painful to begin doing.
How to use exercise to take care of your knees
So does that mean you’ll never hurt your knees when you exercise? Unfortunately, pain and injury are part of life, whether you exercise or not. You might twist your knee by stepping in a gopher hole while you’re running, but then again, you could decide not to exercise and twist your weakened knee by stepping in a gopher hole in your backyard.
One thing that’s well accepted is that a strong body is one that’s less susceptible to injury. Any type of exercise, including cardio like running or swimming, will strengthen your muscles somewhat. Strength training does the job particularly well, as the name implies, and there’s plenty of research linking strong legs to better joint health. Strong muscles can help to stabilize the knee joint, for one thing.
And when it comes to cardio, you may have more options than you realize. It’s common to stick to swimming or cycling if your knees hurt, since these activities are considered to be “lower impact” than running. But one idea about why exercise helps osteoarthritis is that the repeated impact of running actually helps knee cartilage get the nutrients to repair itself. Cartilage doesn’t have blood vessels like most of our tissues do, but repeated footsteps may be squeezing it like a sponge, bringing nutrients and waste products in and out.
Another type of exercise worth trying is neuromuscular training, which strengthens muscles around the knees while also giving your body opportunities to practice moving quickly and adjusting to changes in movement. Squats, lunges, and jumps are often included. One good source for neuromuscular training programs is the website Fittoplay, which has exercise routines for people who play different sports. Another program, Nemex, has beginner-friendly exercises that may be more appropriate for people who are starting from scratch. (They recommend seeking guidance from a physical therapist or other professional to figure out what will best help you personally.)
What to do when your knees hurt from exercise
Even if you’re taking care of your knees, they may hurt sometimes. One funny thing about pain is that it isn’t strictly a sensation of damage to our bodies; pain is a perception, and it’s shaped by a lot of other things, including our expectations. Think about times you hurt yourself during an activity or a stressful event and didn’t realize it until later; or maybe you’ve had the opposite experience, where you were worried about an injury only to notice it hurt less after a doctor looked at it and told you you’d be fine.
For the same reason, if you do experience pain or other negative sensations, don’t freak out and start thinking about all of the things that must be going wrong. That goes double if your knee doesn’t actually hurt, but you just got weirded out by it making noise or something. Knees crackle sometimes, and that’s not a problem in itself.
Instead, treat knee pain or discomfort like any other ache or twinge you might get while exercising. Check that nothing is catastrophically wrong (you won’t train through a broken bone or torn ligament without getting it checked out first), and then figure out if there is any movement you can do without pain. Maybe you just need to ease up for a few days, and then you’re good as new.
It also makes sense to use the knee pain as a wake-up call to see if you should be doing something differently. I don’t mean that you should switch to swimming instead of running, but rather that maybe you’ll realize you’ve increased your running mileage too much lately, or that you haven’t been doing that strength training you promised yourself you’d do more of. We have a whole guide to dealing with injuries as a runner here, which recommends a problem-solving approach. And that’s going to be a lot better for your long-term health than tossing your shoes in the trash and telling all the runners you know that they’re going to ruin their knees just like you did.