Here at The Melbourne Sports Medicine Centre we are often asked by our patients about the link between various forms of physical activity and knee pain. In particular there is a general perception held by many people that running is a major cause of knee osteoarthritis (OA) and pain.
Similarly a group of researchers in the US set out to prove that “a history of leisure running may increase the risk for knee symptoms and ROA, even at lower levels.” (ROA refers to radiographic evidence of arthritis.) To their surprise after reviewing the x-rays of both the running and non-running groups they concluded that “A history of leisure running is not associated with increased odds of prevalent knee pain, ROA, or SOA [symptoms of arthritis]. In fact, for knee pain, there was a dose-dependent inverse association with runners. This means that the people who ran the most had the least knee pain”.
When looking for an explanation for this relationship between weight bearing physical activities and knee osteoarthritis we can refer to a major literature review on “What Is the Effect of Physical Activity on the Knee Joint?” undertaken by Monash University and the Alfred Hospital. The researchers concluded –“that knee structures are affected differently by physical activity. Although physical activity is associated with an increase in radiographic osteophytes (bony spurs), there was no related increase in joint space narrowing (a sign or arthritis), rather emerging evidence of an associated increase in cartilage volume and decrease in cartilage defects…..
Given that optimizing cartilage health is important in preventing osteoarthritis, these findings indicate that physical activity is beneficial, rather than detrimental, to joint health.”
For those who already have knee osteoarthritis it is important to note that the peak body Arthritis Australia states that regular exercise is one of the most effective treatments for arthritis. It can help to:
Mobility and flexibility of joints
Posture and balance
Muscle tension and stress
Generally you will need to do a mix of:
· flexibility: to maintain or improve the mobility of your joints and muscles
· muscle strengthening: strong muscles help to support and take pressure off sore joints, strengthen bones and improve balance.
· fitness: to improve the health of your heart and lungs.
Arthritis Australia’s advice regarding which type and how much to exercise is along the lines of: “The most important thing to do is to listen to your body. A general guide is the ‘two hour pain rule’ – if you have extra or unusual pain for more than two hours after exercising, you’ve done too much. Next time you exercise, slow down or do less. If you have arthritis and you have not exercised for a while, you may need to start with shorter sessions then build slowly. Talk to your physiotherapist or exercise physiologist about getting started to help you avoid an injury or over-doing it or if you continue to experience pain after exercising.
So the take home message is that weight bearing physical activity including running is not generally shown to be the cause of knee osteoarthritis and pain, but in fact the knee can benefit from these activities. For individual cases of the osteoarthritic knee it is worthwhile to remember that exercise is one of the most effective treatments and to seek professional health care advice in order to help select the appropriate type and amount of exercise that should be undertaken. Achieving the right balance of joint loading, flexibility, fitness and in particular strengthening is valuable in order to prevent knee osteoarthritis and to optimally manage it when it has occurred.