Bad knees or low mood? Blame the way you walk

Few of us give much thought to how we put one foot in front of the other, but scientists are investigating whether changing the way we walk can protect our physical and mental health.

One promising focus is on how altering our gait can reduce our risk of knee arthritis. The most common type is osteoarthritis, which typically begins in middle age and gradually leads to the destruction of cartilage.

Cathy Holt, a professor of biomechanics and orthopaedic engineering at Cardiff University, is studying how the way people walk can trigger this.

She believes that teaching people to change their gait in middle age may save them decades of pain — and avoid the need for later knee replacement surgery.

‘The damage can come about through poor walking habits,’ says Professor Holt.

Put simply, walking with your knees too far apart, or too close together, can put excess strain on the inside of the knee.

‘Some people may be naturally a bit bow-legged or knock-kneed,’ says Professor Holt, who is also a spokesperson for the charity Versus Arthritis.

‘However, the way people walk may be affected by a small injury such as a cartilage tear or deformation. As a result, their knees are pushed out from their proper alignment when they take a step.’

Such overloading of one side can trigger a cascade of cellular damage.

In healthy knees, the cartilage and joint bone beneath it stay in constant communication, with the cartilage instructing the bone to release new cells that rejuvenate tissues to compensate for wear and tear. ‘If your tissues are being loaded as they are expecting to be loaded, the system works well,’ says Professor Holt. ‘But when you overload it, this changes the signals between the tissues and they respond badly.’

The system then over-produces osteoclasts — cells that break down tissue as part of the normal process of our bones continually renewing themselves.

This overproduction degrades the bone joints and cartilage.

‘At the same time, the system also overproduces cytokines — immune cells that cause inflammation and the classic burning arthritis pain,’ says Professor Holt. She and her team are researching gait- correcting retraining therapies for people in their 40s and 50s.

Other studies have focused on changing the gait to alleviate arthritis pain. For example, in 2013, Pete Shull, a professor of mechanical engineering at Shanghai Jiao Tong University, asked ten people with knee arthritis to walk on a treadmill while wearing monitoring equipment that gave them feedback on how well they were walking.

Participants learned how to shift the walking load to the optimum parts of the knee joints. After the retraining, the patients reported that their pain had reduced by nearly a third — and their ability to walk had improved by a similar amount. Professor Shull and colleagues at Stanford University in California are now developing wearable equipment.

MEANWHILE, Professor Holt is trialling ways to teach individuals to change their gait. ‘we ask them to walk with different styles — such with a wider gait — to see if that can make a beneficial difference,’ she says.

Other studies suggest that changing your walking style could also help prevent depression.

The latest evidence emerged in February, in a study reported in the Journal of the American Geriatrics Society that, for four years, monitored more than 4,000 healthy people in Ireland over 50. It found a strong link between poor gait and depressive illness later.

‘lower walking speed and shorter steps predict a significantly increased risk of depression,’ says Dr Robert Briggs, a specialist in geriatric medicine research and fellow at The Irish longitudinal Study On Ageing in Dublin.

He says people with poor gaits are likely to get less exercise, probably because they find walking onerous, and it’s known that walking energetically may protect against depression.

But other studies have revealed an intriguing additional factor: research has shown that if we walk ‘happy’, we can boost our mood.

In 2014, Dr nikolaus Troje, a motion biologist at Queen’s University in Ontario, Canada, trained 39 volunteers on treadmills to develop happy or sad gaits, with an upright or slumped posture.

After several hours, they had to memorise positive and negative words. Those in the ‘depressed walk’ group remembered many more negative words.

‘The difference in recall suggests the depressed walking style actually created a more depressed mood,’ he says.