Do you have osteoarthritis of the knee and fear walking will cause pain? It actually strengthens the joints and lowers the risk of pain, study finds

I didn’t think about serious walking until my doctor squinted at my bone density scans. “You’re going to have to do something about this,” he said as he tapped the images on his light box. “But I swim!” I protested indignantly. “That won’t make any difference to your skeleton strength,” he said. I would need to bear weight on dry land, by walking – further, faster, and more frequently. I wondered how my knees would react to this. I had noticed the occasional twinge and they sometimes clicked as I lowered myself down the ladder into the pool. Still, I paid attention to the doctor: I bought a pair of decent trainers which I hoped would cushion my footfall and decided to ignore my complaining joints. Perhaps walking will strengthen those too, I thought. Grace Lo, an assistant professor of medicine at Baylor College of Medicine in Houston, Texas, in the United States, recently co-authored a study that looked at this issue. It was published in the journal Arthritis and Rheumatology in June. On World Osteoporosis Day, how to spot the disease – and head it off People with X-rays or other scans that showed evidence of osteoarthritis and who didn’t have regular knee pain and walked often were less likely to develop permanent – or worsening – symptoms of the condition, it found. “If fewer people develop regular symptoms, presumably this would translate into delay or avoidance of knee operations,” Lo said. Osteoarthritis is the deterioration of cartilage inside a joint – what your doctor might refer to as “wear and tear”. Think of your knees as shock absorbers: with every step you take, your knees absorb the impact of around one and a half times your body weight. (It should be no surprise that keeping an eye on body weight is important for knee health, too.) Over time, that impact adds up and erodes the cushioning cartilage within the joint. When that goes, pain, swelling and compromised mobility start to be a problem. Why would walking improve knees? Well, for a start, improved blood flow helps, as does the inevitable strengthening of the support systems around it: the muscle and ligaments. Prevention is better than cure, Lo says: if you can catch people before they begin to suffer regular symptoms and persuade them to walk, this might be very helpful in warding off the development of permanent knee pain. “The opportunity might already be lost once knee pain has developed,” she warns. “When we looked at those who did not have regular knee pain at the beginning of the study, those who walked for exercise were less likely to develop regular knee pain and stiffness compared to those who did not walk. “They also had less structural damage in their knees.” We need to shift the mindset that exercise will cause knee pain. It is actually our behaviour, rather than the exercise, that can increase the risk of injury Edward Robinson, physiotherapist at Joint Dynamics The study Lo co-authored found that those who walked for exercise had a 40 per cent lower chance of developing new frequent knee pain compared to non-walkers. Edward Robinson, a physiotherapist and clinical manager at Joint Dynamics in Hong Kong, is not surprised by the study results. “The evidence around knee pain suggests you’re more likely to get issues if you are inactive compared to if you’re active,” Robinson says. “We need to shift the mindset that exercise will cause knee pain. It is actually our behaviour, rather than the exercise, that can increase the risk of injury.” If there is knee pain, he says, and “if it’s associated with swelling, clicking, locking or giving way, or you’re unable to bear weight” he would recommend seeing a physiotherapist for assessment first. What if it’s just the odd twinge? “If it’s solely pain, then I’d advise people to reduce their frequency, intensity or load to a level that is tolerable,” he stresses. “It is important to keep moving. If people stop moving over a matter of weeks, the muscles get weaker, joints get stiffer, fitness decreases, confidence drops and weight gain can happen. “We also notice [that] if people avoid all exercise, the pain is likely to lessen but when you go back to exercising the pain comes back. So it is important to maintain a level of exercise that is tolerable. Modify exercise but keep it tolerable and non-aggravating,” Robinson says. The squashy artificial joint that could stave off hip replacements Although the incidence of knee pain increases with age, it is not inevitable; there are ways to protect your knees and prevent pain and – especially – surgery. If we are consistent with exercise, says Robinson, our body can adapt very well to the forces placed upon it. We just need to be mindful of going slowly and carefully, and to give the body time to adapt to the new demands placed on it when we increase the frequency and intensity of exercise and thus the load placed on our joints. Remember the imperatives of warm-ups and cool-downs, Robinson adds. Think of them as lubricating the joints before you run. Several months later, I am suddenly aware of something: my knees have stopped complaining. Despite the extra distance – I walk up to 10km a day now – there’s no pain. Time to up the step count. Like what you read? Follow SCMP Lifestyle on Facebook, Twitter and Instagram. You can also sign up for our eNewsletter here.