Is Running Really Bad for Your Knees?

Is Running Really Bad for Your Knees?

(intro) If you like to run, someone has probably warned you that you’re wrecking your knees. The idea is that when you run, the flexible, tough tissue that cushions your knee joints, called cartilage, takes a pounding. And over time, that cartilage supposedly wears down, which makes your bones rub together, and leads to the pain, stiffness and swelling of Osteoarthritis. But is this actually true? Past studies that compared runners to non-runners, sometimes collecting data over a couple decades, have found mixed results. A few found that there’s more risk of Knee Osteoarthritis in specific groups of runners, like in men younger than 50 who run more than 32 kilometers per week. But lots of papers comparing long-term runners to swimmers, non-runners, or sedentary people 𝐝𝐢𝐝𝐧’𝐭 turn up evidence that running will doom you to arthritic misery. In some cases, runners even seemed to be 𝐥𝐞𝐬𝐬 likely to get arthritis. So could running actually protect your joints somehow? To find out, a study published in 2016 looked at what’s happening inside your knees when you run. Scientists gathered a group of male and female runners younger than 30, with no history with knee problems, and brought them in for two experiment sessions over two days. They started each session collecting a blood sample, and a bit of synovial fluid, the natural lubricant inside the knee joint. Then they had the participants spend 30 minutes running on a treadmill one day, and thirty minutes sitting another day. Afterwards, they took more samples. Getting a useful amount of fluid from healthy knees turned out to be tricky. And the researchers only ended up with complete data from 6 people. But the results are still interesting. The scientists were looking for molecules related to inflammation, because extra inflammation has been linked to the development of arthritis. They were also a compound called Cartilage Oligomeric Matrix Protein, or COMP, which can be a marker of arthritis if there’s a bunch of it in your synovial fluid. After running, the subjects had less of these molecules in their knees, and more in their blood’s, spread out in their body. Sitting, on the other hand, slightly increased concentrations of COMP, and some other inflammatory molecules in their knees. It’s hard to tell exactly what this means, but it seems like running might squeeze inflammatory compounds out of your knees, which could reduce cartilage damage and arthritis. But this study 𝐝𝐢𝐝 have a pretty tiny sample size, so… Jury’s still out. But if you like running and it makes you feel healthy, the next time someone says, “But you’ll ruin your knees!” Take it with a grain of salt. Thanks for asking and thanks especially to our patrons who keep these answers coming. For more running related science, check out this other SciShow video where Hank explains why you get that sharp pain in your sides sometimes. (outro)

100 thoughts on “Is Running Really Bad for Your Knees?

  1. Scishow, I am disappoint.ed in you, a sample size of six is never credible. It is unreasonable and unscientific to extrapolate from any sample that small.

  2. My uncle and a friend of his ran for a cross-country team at the same High School I went to, and he said to me that his knees were shot as a result. So I stuck by with walking and some bicycling, though I do run from time to time.

  3. Why is the sound on the vignette so much louder than the voice of the talk? (The talk is too silent.)

  4. it's not running specifically but what you run on that can do damage . running on concrete or asphalt is much worse than running on grass and dirt trails

  5. Knee pain/injury is mostly attributed to running/walking form, some people kick their feet forward while running/walking others bring their foot closer to the ground when moving that food forward, a non kicking form.

  6. I'm surprised no one mentions around here the huge bias factor which is the surface on which people run. Tarmac is usually the one incriminated for being "bad for the knees".

  7. I have a brilliant idea: just take a break when things start to hurt. It's pretty safe to trust your body to tell you when you're harming it. That's what we generally do in our lives. Why would running be an exception?

  8. anecdotally, running did screw up my knees. However, I'm tall, weigh a lot, and didn't necessarily wear the right running shoes or employ all the right techniques, so maybe I did it to myself.

  9. i dont like running. it doesnt make me feel healthy. but i have a class called PE which makes me have to run a lot. we run about a mile a day. i hate school for this. btw im pretty damn healthy.

  10. "I don't run because it's bad for my knees"
    "Isn't that tub of butter bad for your heart?"
    "Yeah, but….delicious!"

  11. I've had problems with knee inflammation, pain, and crunching since middle school; it seems hereditary, since my Dad and grandmothers on both sides have had significant knee problems. However, I'm a fairly serious runner, doing long distance runs every weekend and several speed training drills through the week, Running generally causes more swelling in my knees afterward, but I have found that running and building up the muscles around the knee have actually helped with a lot of the knee problems I've had most of my life. It still is a problem now, and I'm pretty much betting that I will need to get knee replacement sometime when I'm older. But maybe by that point I can have super awesome robotic knees or something cool. 🙂 Thanks as always for the info!

  12. This doesn't take into account those of us who are rather heavy and large people so probably running a lot isn't great.

  13. did sci show seriously attempt to draw a conclusion based on data from 6 people? i get the small sample size was brought up but still that is ridiculous.

  14. There are just so many factors, age, general health, genes, weight, height, how long, how fast you run, shoes, insoles, arch support, no arch support, minimalist shoes, even how someone lands with their foot with every step.

    I look at it like all exercise. There can be too much or too little of it. And a just the right amount. But you have to run to find that balance

  15. I was told by my doctor not to run but walk; he said a brisk walk was much better for your knees and back than running. I am now 72 and I have OA and I have always been very active. I was a runner in my youth but today I walk, but not without pain. The trick is to never give up. I don't take the elevator I climb the stairs, I drive to work some 8 miles but park in a towered parking garage and walk the rest of the way to my part time. job.

  16. I never got arthritis, but running caused me a lot of knee pain. After I stopped running, my knees eventually healed, but it took many years.

  17. however relevant if you like to be in bed it helps to work your abbs moving your legs up in down while you Lay down

  18. They have another video where they say the human body is built for long distance running. … I run but my preference of endurance sport is cycling.

  19. as someone being in the army I can say there were dozens of people including myself who had short or long term knee problems from running on roads and terrain all the time. I still have a problem with the muscle above my right knee and many people got runners knee, stress fractures, spurs, or worse.

  20. Interesting video. Though, I've heard people claim that what you're running on matters too. Like let's say comparing soft soil in a forrest to hard concrete and asfalt in the city. They claimed that the harder surface of concrete and asfalt resulted in less cushioning and thus was worse on your knees. Though, I have no idea if this is true or not, it sounds true though.

  21. I think it depends on the type of ground you run. Running in concrete might damage your knee cartilage more while running in sand, grass, or rubber track can cause less damage.

  22. No, we're not talking about arthritis when people say to be careful about running wrecking your knees. They're talking about cartilige and ligaments (I always forget which are in your knees…).

    Which, if you are overweight or obese, are obviously under more stress because of the increased impact of more weight bearing down on it. That's why many people reccomend that running not be those people's excersize of choice- even jogging would be better- and doctors and friends alike are more likely so suggest other, just as positive forms of being active like walking, swimming, biking, etc.

    I like reccomending walking in particular because it is incredibly easy and can fit right into your day, if you choose to walk somewhere instead of driving. And it's very easy to reinforce this behavior positively by setting a destination. A friend of mine and I have found a lot of success walking three miles, uphill, to get a muffin and coffee at a Mcdonalds at the top of a steep hill. We've even done this in freezing winter. Knowing what you're earning with it can make it feel effortless, and push you past fatigue. We've even taken up walking places for fun and to go shopping, and we're healthier.

    I'd say it's fine for you to run if you don't run too much if you are a normal weight and keep in mind you are risking hurting yourself. If you have pain, take a rest.

    Oh, and there is apparently a physiologically correct way to run: see the other comments.

  23. It's hard to believe since apparently running played a major role in human evolution which means humans have been running since before we were humans. I'm sure Mother Nature equipped us appropriately

  24. So science doesn't know yet.. and no one will believe elderly ex-marathon runners when they say they regret it, because they don't know if they would still be in agony if they had cycled or swam instead. Oh well. At least run toe to heal like they teach you in the army

  25. Quality of science in these videos is going steeply downhill. Please don't ruin this channel it's too important to society

  26. I ran for four years in high school both cross country and track and had a coach that didn't care about hurting knees and I am a 22 year old guy that can barely go up two flights of stairs without his knees killing him.

  27. i often go jogging as part of my healthy routine and i have been told by an elderly lady that im setting myself up for knee problems when i get older so i asked her where are you going she said shopping why and i said well then why dont you bag it you old bag LMFAO actually true story

  28. => Never had knee problems
    => Gone to the army
    => Can no longer run more than 4miles before excruciating pain takes over right knee
    => Can walk in super rough terrain for 20+ miles with 2-3miles of altitude change + heavy bag with no problem at all.

    => Explain this please XD

  29. What if you had a fractured knee 1 year ago surely running is what is good for it to heal healthy and strong, as sedentary wastes away the bone and cartilage causing it to go weak?

  30. While in the Marines I never saw so many people with knee problems. We ran at least 12 miles a week. Marines with more than 15 years serving almost always had knee, ankle, and lower back problems but kept running making it worse. Maybe weight and technique factor into running, not just the distance and how frequent someone runs.

  31. I wish you guys would change the intro sound.. lol I try and sleep listening to these videos then I hear the loud as intro and it snaps me awake .. amazing video though guys love it !

  32. this idiot only focuses on age and not weight. If you are extremely overweight then you need walking exercises before taking up running. The extra body weight might be too much for your back bones and knee joints.

  33. My brother used to be a marathon runner. In his early 30's, he started having pretty bad issues with his knees and feet and stopped. I've always been more of a lifter, and I'm approaching 30, and my knees and joints are fine. I've recently taken up running, but I plan to keep it under 3 miles a day, and no more than a few days a week to avoid potential issues.

  34. Hard to say.. the cartilage and Meniscus are pretty A-vascular, they don't get much blood flow at all.. so would constant banging/usage wear it out faster than it can repair?

    Or would the body compensate by thickening the joint or increasing repair rates? I mean our bones do this, the more you damage/compress a bone the stronger it gets. The more you damage/strain a muscle the bigger it gets. Repetitive use of tasks forces the brain to change and remember.. its seems whatever we do the body compensates by improving on itself.

    So going for light jogs, one would assume the joints would maintain their strength or improve themselves. But the difference here is that all the previous examples are blood rich organs.. capable of quick adaptation, The joints not so much..

    I don't know. Using logic alone i'd say that they're pretty damn well lubricated and they have evolved to take the brunt of what they do take.. so jogging wouldn't shorten the life. But sitting down or being inactive just has a negative impact overall on your body, so I can see that actually being worse for your joints/rest of your body.

    May as well jog, keep that blood pressure healthy, that fat % low, and that cardio-system top notch.

  35. A guy goes to a doctor appointment, only to be told he is overweight. "It's not my fault," he says, "obesity runs in my family!" "No," says the doctor, "the problem is that nobody runs in your family!"

  36. Eh if you run with proper form, mix your pace throughout the week and cross train you can run like a loon well into your 80's injury free. Anything is dangerous and injury inducing if you're not smart about it.

  37. Its funny, I'm not a runner yet I have arthrosis (something similar). My left knee is the one that hurts the most but always started running/walking with the right leg.

  38. It was this one:

  39. Okay, you're seriously going to make an accusation with that data? Lazy!!! I bet form is a huge factor. #crackpotscience

  40. When the knees hurt, you definitely don't wanna put any force like running to it. But when they only crack, then running is the deal. I have a friend who shared with me about her cracking knees and the moment she started running on the treadmill (meaning flat surface) and cut off a few pounds of weight, her knees cracking sounds disappeared. So impressive.

  41. your exercise depends on your age, weight and type of lifestyle…. or health history…. i never recommend running for weight loss…. regular running 100% leads to joint injury in some time…

  42. 1:55 "its hard to tell what this means" you should have stopped there. its actually ridiculous to try and explain data from 6 samples. Its not worth mentioning actually and that explanation requires more nerve that what it took to publish data with a sample size unrepresentative of the studied population.

  43. I sympathize with their problems collecting fluid, but a study with a sample size of 6 is too small to be scientifically useful.

  44. I'm a runner at school…..



  45. The research group was below 30 years old! And only 6 people! It makes a difference if you are 30 or 60, if you are overweight or not, etc. Bad video.

  46. Tread mill running is a different surface than running on the streets which changes it's impact. Does scientific observations always need to be made in the lab?

  47. Well now I'm really confused…. Love running, I always have but I don't want hip and knee replacements either..inlaw of mine just had his hip replaced
    … osteoarthritis and I understand was linked to decades of long distance running. There must be a genetic component to this…

  48. Old, but one thing I noticed wasn't touch on was how running on concrete can cause damage. Speaking from experience, running miles on a concrete walkway wrecked my knees but as soon as I went to a rubber track… the pain started to go away.

    Going with our ancestors' line, they likely ran more on dirt etc. which is still far softer than concrete and doesn't send all the shock back up through your leg.

  49. Yes it is think of your body like a car The more miles you put on it and the ruffer you are on it the faster it will ware out, and it depends on your genetics. If your genetics are like a Ford Fiesta you need to take it easy on your body. If your genetics or like a Toyota then you can be harder on your body And run all you want. We are all not meant to last like a Toyota. So if you are a Ford fiesta take it easy on your self your not a toyota. So dont try to Compete with one you will just be hurting yourself.

  50. yeah get some good running shoes just in case. Some people do dirt trails for softer impact, but be carefull not to bend or twist ankles on uneven ground. Some say cannibus reduces inflamation as well.

  51. Well, these were people who didn't have knee problems, it happens that I have knee problems since my early twenties already so I'll stick to resistance training, walking and light cycling.

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