Running Myth: recreational running causes knee osteoarthritis
Exercise is an important part of our lives, apart from the enjoyment it can bring, it also comes with a huge amount of health benefits ranging from mental health, to heart and lung health, as well as bone density to name a few (Warburton, 2006).
Unfortunately, it’s becoming more and more common for people to avoid exercise due to the fear of developing knee osteoarthritis or the fear of accelerating existing osteoarthritis.
Osteoarthritis is a condition that affects the whole joint (joint lining, bone and soft tissues) and it occurs when the cartilage that cushions the ends of bones in your joints undergoes normal age-related changes. Normally, damaged cartilage is constantly being repaired as old cartilage is degraded. When the balance between degradation and repair is thrown off, cartilage thinning occurs. As a result of cartilage thinning, the joint has more friction causing a joint to become irritated.
Thankfully, science has come to find that exercise is not a risk factor to osteoarthritis, nor will it accelerate ongoing osteoarthritis. In fact, studies have found that knee osteoarthritis is almost three times less common in recreational runners than it is in sedentary people (Alentorn-Geli et al., 2017).
Why is this the case? First we need to understand that joints have minimal nerve or blood supply and that they are nourished from synovial fluid via dynamic load. This means that an activity like running will actually help to nourish a joint. On top of this, the muscles surrounding the joint will get stronger with exercise and provide dynamic stability to the joint which can help offload some of the pressure going through the joint itself. Extensive research into the topic has proven that movement not only improves symptoms and physical function, but also reduces intake of painkillers and sick leave (Skou & Roos, 2017).
Unfortunately however, just like everything in life, you can have too much of a good thing. Heckelman et al. (2020) found that ex-elite or professional international runners were 3% more likely to have osteoarthritis when compared to sedentary individuals.
So what is the magic formula? While we can be confident that recreational running will not lead to the development of osteoarthritis and that running will not accelerate existing osteoarthritis, unfortunately there is no one size fits all formula for how much running and how frequently. Like any kind of training, runners with osteoarthritis would benefit from strength training as well as spacing out training or cross training to allow for sufficient cartilage recovery between running bouts (Alexander, Willy, Culvenor & Barton, 2021).
Alentorn-Geli, E., Samuelsson, K., Musahl, V., Green, C., Bhandari, M., & Karlsson, J. (2017). The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis. Journal Of Orthopaedic & Sports Physical Therapy, 47(6), 373-390. doi: 10.2519/jospt.2017.7137
Alexander, J., Willy, R., Culvenor, A., & Barton, C. (2021). Infographic. Running Myth: recreational running causes knee osteoarthritis. British Journal Of Sports Medicine, 56(6), 357-358. doi: 10.1136/bjsports-2021-104342
Skou, S., & Roos, E. (2017). Good Life with osteoArthritis in Denmark (GLA:D™): evidence-based education and supervised neuromuscular exercise delivered by certified physiotherapists nationwide. BMC Musculoskeletal Disorders, 18(1). doi: 10.1186/s12891-017-1439-y
Warburton, D. (2006). Health benefits of physical activity: the evidence. Canadian Medical Association Journal, 174(6), 801-809. doi: 10.1503/cmaj.051351