Does Running Cause Wear & Tear of Your Joints?
Something I hear way to frequently from my patients is that they are experiencing pain as a result of “wear and tear” in their joints. Almost everyday, I hear patients say this when talking about knee pain, hip pain, shoulder pain or back pain. But is this really the way it works? Do we experience more pain as we age because there has been more wear and tear over the years?
Let’s take a look at running as an example. If our joints wear out due to increased use, we would expect people who run to have more osteoarthritis than those who don’t run. However, this isn’t what the research is telling us. In fact, the opposite may be true; exercise and physical activity can provide a protective effect for our joints. I would like to mention a study published in 2017, in the Journal of Orthopaedic & Sports Physical Therapy to help highlight this point. These researchers found that only 3.5% of recreational runners had hip or knee osteoarthritis, compared to 10.2% in non-runners, indicating that running may have a protective effect for hip and knee joints. The researchers concluded that running at a recreational level for many years may be safely recommended as a general health exercise, and benefits hip and knee joint health. The findings indicate that remaining sedentary and foregoing exercise increases your rate of knee and hip arthritis, compared to regular recreation running. However, high-volume (> 92km/week) and high-intensity training also may also increase your risk for arthritis. In this study, elite, ex-elite or professional runners had a hip or knee arthritis at a rate of 13.3%.
So here we see an "Inverse U Relationship" Being inactive or doing an extreme amount of physical activity are associated with the highest rates of hip and knee osteoarthritis. However, the "sweet spot" in the middle (recreational physical activity) is associated with decreased rates of hip and knee osteoarthritis.
Let’s take a deeper look into why physical activity is good for joint health. In general, hyaline cartilage (the cartilage within joints) has poor blood supply. But that cartilage still needs to get fresh nutrients and get rid of metabolic waste. This occurs through a process called imbibition. To help you understand the process of imbibition imagine the cartilage within our joint as a sponge within soapy dish water. Every time you load the cartilage (e.g. move the joint or land on that leg) it is like squeezing the sponge. The sponge (or cartilage) will push out the fluid it was holding. Each time the cartilage is unloaded (e.g. swing phase of running) the sponge (or cartilage) will absorb fluid from the surrounding soapy water (or synovial fluid). When this process occurs repetitively, as it does when we run, it helps to keep the cartilage well hydrated and full of fresh nutrients.
I love research like the article published in the Journal of Orthopaedic & Sport Physical Therapy because it is helping to break down old misconceptions and aids in building a new framework that promotes physical activity as a healthy option, instead of one that damages your body. If you are looking to start running for the first time or are thinking of re-starting your running career, please reach out to me so we can discuss the best options for you.