For as long as I have been a runner I have always had people tell me, “Running is bad for your knees; your knees are gonna hurt so bad when you're older; good luck with your knee surgeries in the future.” Many people have this idea in their mind that pounding pavement wears down your knees and leads to problems in the future. This could be because they experience their own knee pain when running (which means their form sucks but we’ll get to that later), or because it simply just makes sense. Running involves impact on the pavement, impact creates force, and force wears things down and breaks them. Fortunately for you, this is not the case.
I started running at the age of 12, hundreds of races, thousands of practices, six years of collegiate XC and Track, and have never experienced knee pain. Throughout the many physicals I have gone through in my career, doctors have told me that my knees are actually very healthy, strong ligaments, strong joints, and no signs of early wear. How can this be? It’s because our knees are not some fragile hinge that crumbles under impact. It is a biological system designed to become stronger when properly loaded, and running provides exactly the right type of load to make this happen.
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| College me at 2022 cross country nationals in Seattle |
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| My first race ever (first win as well) |
Most people are shocked when they find out that running actually strengthens your knees. There is MRI based evidence showing that running stimulates cartilage to become stronger, not break it down. Our cartilage contains proteoglycans and glycosaminoglycans (GAGs), these are molecules that are responsible for making cartilage a resilient shock absorber. Research shows that running regularly increases the GAG content of cartilage, meaning the tissue becomes more robust and better suited to handle load (Mosher et al., 2018). MRI studies show that runners experience slower thinning of cartilage than sedentary adults (Zhang et al., 2024).
Running has also been shown to strengthen the bones around the knee joint. Endurance runners tend to show higher bone mineral density in the tibia and femur compared to non-runners, which provides more structural support for the knee (Krajicigr et al., 2024). In conjunction to this, running strengthens the surrounding muscles. Stronger quads, glutes, hamstrings, and calves absorb force and stabilize the knee. Running naturally trains these muscles, protecting the joint and distributing load more efficiently (Noehren et al., 2011).
Your form Sucks
As stated above, if you're experiencing knee pain when running, it's probably because your form sucks. Which is okay! Hit me up with all your coaching needs! Most knee pain in runners comes from poor mechanics, not from the act of running. When your form is off, the knee ends up absorbing forces it was never meant to handle.
One of the biggest contributors is overstriding. This is when the foot lands too far out in front of the body. This creates a braking force with every step, sending excess impact up through the knee joint. Research shows that overstriding and the typical heel strike (landing on your heel first, then pushing off your toes) that comes with it significantly increase knee joint loading and impact forces (Kulmala et al., 2013; Boyer & Derrick, 2015). Runners who over stride typically heel strike hard and place much more load through the knee compared to runners who land on their forefoot and under their center of mass. Another big contributor is weak hip and glute muscles. When these stabilizers aren’t doing their job, the femur rotates inward, making the knee collapse toward the midline. This increases stress on the patellofemoral joint and is one of the primary drivers of runner’s knee (Noehren et al., 2012). It’s not the miles causing the pain, it’s how your body is moving.
Lastly, a lot of runners get hurt simply because they add mileage or intensity too quickly. The body needs time to adapt. Studies consistently show that rapid increases in weekly training load often lead to a significantly higher risk of injury (Nielsen et al., 2013; Buist et al., 2010). This sounds like me my freshman year of college, which resulted in an upper tibial stress fracture. When our training progresses faster than the body can handle, even strong knees (and bones in my case) can get irritated.
So, the next time someone tells you their knees hurt from running, tell them they suck! Just kidding, but it does mean they could benefit from coaching and should even see an increase in resiliency once corrected. Running doesn’t ruin your knees, it builds stronger cartilage, denser bones, and stronger muscles to protect the joints for years to come.
Keep running, our bodies (specifically our knees) were designed for it.
Boyer, E. R., & Derrick, T. R. (2015). Select injury-related variables are affected by stride length and foot strike style during running. Journal of Sports Sciences, 33(14), 1465–1473. https://doi.org/10.1080/02640414.2014.990488
Buist, I., Bredeweg, S. W., Bessem, B., van Mechelen, W., Lemmink, K. A. P. M., & Diercks, R. L. (2010). Incidence and risk factors of running-related injuries during preparation for a four-mile recreational running event. British Journal of Sports Medicine, 44(8), 598–604. https://doi.org/10.1136/bjsm.2008.051904
Krajcigr, M., Kutáč, P., Elavsky, S., Jandačka, D., & Zimmermann, M. (2024). Comparison of bone mineral density of runners with inactive males: A cross-sectional 4HAIE study. PLoS ONE, 19(8), Article e0306715. https://doi.org/10.1371/journal.pone.0306715 (full text free)
Kulmala, J.-P., Avela, J., Pasanen, K., & Parkkari, J. (2013). Forefoot strikers exhibit lower running-induced knee loading than rearfoot strikers. Medicine & Science in Sports & Exercise, 45(12), 2306–2313. https://doi.org/10.1249/MSS.0b013e31829efcf7
Mosher, T. J., Liu, Y., & Torok, C. M. (2018). Functional cartilage MRI T2 mapping and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) in recreational runners: A 5-year longitudinal study. Journal of Magnetic Resonance Imaging, 47(2), 428–436. https://doi.org/10.1002/jmri.25793
Nielsen, R. O., Buist, I., Sørensen, H., Lind, M., & Rasmussen, S. (2013). Training errors and running-related injuries: Overuse injuries are caused by training errors – a prospective 1-year study. Scandinavian Journal of Medicine & Science in Sports, 23(5), 591–597. https://doi.org/10.1111/j.1600-0838.2011.01423.x
Noehren, B., Pohl, M. B., Sanchez, Z., Cunningham, T., & Lattermann, C. (2012). Proximal and distal kinematics in female runners with patellofemoral pain. Clinical Biomechanics, 27(4), 366–371. https://doi.org/10.1016/j.clinbiomech.2011.10.005
Noehren, B., Scholz, J., & Davis, I. (2011). The effect of real-time gait retraining on hip kinematics in runners with patellofemoral pain. Clinical Biomechanics, 26(2), 140–145. https://doi.org/10.1016/j.clinbiomech.2010.09.009
Zhang, Y., Hunter, D. J., Nevitt, M. C., et al. (2024). Long-term recreational running protects knee cartilage: Results from a 15-year longitudinal MRI study. Osteoarthritis and Cartilage, 32(5), 567–576. https://doi.org/10.1016/j.joca.2024.01.005
Hi Calvin, awesome blog post! I honestly cannot remember the last time I ran for leisure, so the fact that you enjoy the sport and have pursued it as a hobby since you were so young is very impressive. It's amazing how our body can adapt to high levels or physical activity overtime to increase our endurance and strength, if we maintain proper form. I also know running is proven to have positive psychological benefits like enhancing mood and is great for cardiovascular health, however, I do remember learning in a development biology course in undergrad that our bodies were not necessarily "made" for running. I linked the url to an article that briefly goes over this idea, but apparently our ancestors only moved when our environment demanded it, like running from a predator. It's confusing to read about how our bodies were designed to conserve energy and not burn it, especially when today's exercise culture encourages us to push beyond our physical limits. The article mentions walking as a sustainable and more "natural" form of exercise for our anatomical design. But I do think that running has so many positive physiological benefits that it's a great form of exercise when performed correctly. I probably won't be running anytime soon unless I'm late for class, but it was cool to learn about how the body adapts through running and the ways injury can be prevented. (https://economictimes.indiatimes.com/magazines/panache/harvard-professor-says-walking-beats-workouts-for-a-longer-healthier-life-humans-were-never-built-to-run/articleshow/122005687.cms)
ReplyDeleteKiller post… nailed it on form fixing knee woes. That GAG boost is real (Mosher et al., 2018), and long-term MRIs back it (Zhang et al., 2024).
ReplyDeleteI've experimented with alpine trails ever since moving here: Grand Teton, RMNP scrambles, Long’s Peak… knees feel bulletproof, no pain after 3k vert drops on scree and talus. Off-road pounding builds extra toughness.
Check out this 2020 MRI study on ultra-marathoners and cartilage adaption after early stress, no further damage over 4,500km (Schütz et al., 2020). Your knees thank you for the miles!
Reference:
Schütz, U., Ehrhardt, M., Göd, S., Billich, C., Beer, M., & Trattnig, S. (2020). A mobile MRI field study of the biochemical cartilage reaction of the knee joint during a 4,486 km transcontinental multistage ultra-marathon using T2* mapping. Scientific Reports, 10, Article 8157. https://doi.org/10.1038/s41598-020-64994-2