One of the most enduring running myths is that it's harmful for your joints. In reality, the research contradicts this, showing that running is at the very least neutral and most likely positive for joint health.
So, where does this myth come from?
Osteoarthritis (OA) is a condition that involves the degeneration of joint structures such as cartilage and even the underlying bone. Classically, OA is thought of as a disease of 'wear and tear', and
while mechanical loading does play some role, modern research demonstrates that there are metabolic & systemic factors that contribute to the disease, rather than simply being load-related. In fact, it seems appropriate loading can be of benefit.
While it's logical to think that repetitive impact on joints from running could cause such degeneration, research shows
that runners do not have a higher risk of OA compared to non-runners. Running can appear to 'harm' cartilage directly after exercise when studied, but it also stimulates the synthesis of the components of cartilage, such as proteoglycans and collagen, enhancing its structure and function. Therefore, much like muscle (but to a lesser extent), cartilage adapts to stress and becomes more resilient with repeated exposures.
Moreover, running aids in limiting or reducing bodyweight, which is also an important factor for joint health. Again this is not just down to weight impacting the joints, but also the consequences of obesity that propagate low level inflammation and metabolic dysfunction (the extent of the causal relationship here remains to be elucidated).
Finally, it should be noted that running can have a strengthening effect too, albeit for those who are currently inactive. If you are already lifting
weights, running probably isn't going to strengthen your muscles or cause growth, but this can occur in sedentary individuals.
Therefore, rather than wearing down the joints or other components of the musculoskeletal system, regular running helps to maintain and even improve their health. Even in those with established OA, running should not be discouraged. As with any form of exercise, inappropriate programming, load management, and sustaining injuries (especially joint trauma) may indeed harm joint health, especially at the extremes of training dose, but this is not unique to running.
Overall, I view running as a positive
activity for musculoskeletal health.
