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Does walking ‘wear out’ your knees? Here’s what the science says and how to protect them over time

The team of doctors and fact-checkers from the National Order of Doctors addresses the main health concerns

9 September 2026

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5' min read

Translated by AI

Versione italiana

Key points

What exactly is knee cartilage, and what is its function?
Does walking really ‘wear away’ cartilage?
But do running or more intense sports actually increase the risk of osteoarthritis?
What role does body weight play in knee health?
Is it true that the way the knee is ‘structured’ can also make a person more prone to osteoarthritis?
What practical steps can I take to protect my knees over time?

5' min read

Translated by AI

Versione italiana

If, after an activity that is perhaps more strenuous than usual, you experience some discomfort in your joints, it is not uncommon for many people to stop walking or doing sport for fear of ‘wearing out’ their knees. The available scientific evidence, however, does not support this belief: movement does not damage cartilage; on the contrary, it is necessary to keep it healthy. Any problems, when they do arise, are more often due to other factors, such as body weight, previous knee injuries and, at times, unfavourable knee biomechanics or excessive and sudden loads.

What exactly is knee cartilage, and what is its function?

The knee is the joint formed by three bones: the femur, the tibia and the patella. Their ends are covered by a layer of articular cartilage, a smooth, resilient tissue that acts as a cushion: it reduces friction between the bones as they move over one another and distributes weight and impact with every step, enabling smooth movement. It consists mainly of water, which accounts for around 80 per cent of its weight, as well as collagen and proteoglycans – substances that retain water and give the tissue its ability to withstand compression – and contains a small number of cells, called chondrocytes, which maintain this structure over time. An important characteristic is that cartilage has neither blood vessels nor nerve endings: it derives its nourishment mainly from the synovial fluid, the fluid that lubricates the joint, and for this very reason, it is not, in itself, the direct source of pain when something in the knee is not working properly.

Does walking really ‘wear away’ cartilage?

No, regular and appropriately moderated physical activity does not ‘wear away’ cartilage; on the contrary, it helps to keep the joint healthy. An international study that followed over 5,000 people for a period of between 5 and 12 years found no association between energy expenditure linked to walking, cycling and recreational sports, and the onset of radiographic osteoarthritis, painful osteoarthritis or new-onset joint pain. On the contrary, moderate mechanical load regulates the activity of cartilage cells and helps to maintain them over time; it is a load that exceeds the tissue’s tolerance threshold—not the movement itself—that can lead to damage.

Occasional discomfort following unusual exertion is, for this reason, common and does not necessarily indicate damage to the cartilage, which – as we have seen – has no nerve endings and is therefore not the direct source of pain. The situation is different in the case of persistent pain, swelling, joint instability or a locked joint: in these situations, it is advisable to consult your GP.

But do running or more intense sports actually increase the risk of osteoarthritis?

For recreational running, the evidence is reassuring: in a study conducted as part of the Osteoarthritis Initiative involving over 2,600 people, those with a history of recreational running did not have a higher risk of symptomatic osteoarthritis of the knee than those who did not run. The picture changes, however, when it comes to very intense physical activity sustained over many years: a systematic review found that a very high cumulative training load is associated with a greater likelihood of early-onset osteoarthritis of the knee and hip, whilst moderate and recreational sporting activity has a minimal degenerative effect and is not linked to osteoarthritis severe enough to require joint replacement surgery. The literature is not entirely consistent on this issue: a more recent review observed a link between very high levels of physical activity and an increased risk of knee osteoarthritis compared with moderate levels, whilst noting that further studies are needed to establish precisely which type, intensity and duration of exercise are safest. Overall, the factor that seems to matter most is not the movement itself, but repeated excessive loading over time.

What role does body weight play in knee health?

Body weight is one of the best-documented risk factors for knee osteoarthritis and acts in two ways. The first is mechanical: greater body weight means a greater load on the joint with every step. The second is metabolic and less intuitive: adipose tissue produces substances, known as adipokines, which can promote inflammation in the joints, independently of the mechanical load alone. In a randomised study of overweight or obese adults with knee osteoarthritis, weight loss achieved through diet and exercise reduced the compressive load on the knee and improved pain, function and walking ability, with greater benefits seen in those who had lost more weight.

Is it true that the way the knee is ‘structured’ can also predispose a person to osteoarthritis?

Yes. As well as body weight, the biomechanics of the joint – that is, the way in which the load is distributed during movement – also play a role. A systematic review with a meta-analysis of nearly 60 studies found that people with knee osteoarthritis are more likely than those without the condition to have joint misalignment (knock-knees, i.e. ‘bow-legged’, or valgus, i.e. ‘X-shaped’ knees), reduced muscle strength around the knee, a deficit in proprioception – that is, the ability to perceive the joint’s position in space – and altered ligamentous laxity A large cohort study conducted in the United States also showed that knee varus increases the risk of developing new-onset tibiofemoral osteoarthritis, and that in knees where osteoarthritis is already present, both varus and valgus deformities accelerate deterioration in the part of the joint most stressed by the misalignment. This explains, in part, why two people with the same physical activity habits may have a different risk of developing osteoarthritis: it is not just a question of how much one moves, but also of how the load is distributed across the joint. A physiatrist, an orthopaedic surgeon or a physiotherapist

They can assess these aspects and, where appropriate, recommend targeted muscle-strengthening exercises. Another factor to consider, particularly in women, is the menopause: the hormonal changes during this phase are associated with a higher incidence of musculoskeletal pain and may also contribute to the development of osteoarthritis, although the causal role is not yet fully understood (we discussed this in the factsheet ‘Can the menopause cause joint pain?’).

What practical steps can I take to protect my knees in the long term?

The strongest evidence comes from a Cochrane review which analysed 139 randomised trials involving a total of over 12,000 participants: therapeutic exercise reduces pain and improves physical function in people with knee osteoarthritis, with a moderate benefit in the short term. Some practical tips that are useful both for prevention and for managing existing osteoarthritis: walking, cycling or water-based activities are generally well tolerated and should be introduced gradually; strengthening the muscles around the knee, particularly the quadriceps, helps to stabilise the joint, especially where misalignment is present; if new pain develops or discomfort increases during exercise, it is advisable to temporarily reduce the load and adapt the exercise; if the pain is severe or persistent, or if swelling, buckling or joint locking occurs, a medical assessment is recommended; maintaining a healthy body weight, where necessary, helps to reduce both the mechanical load and the metabolic component of inflammation; if you experience persistent pain, swelling, buckling or stiffness that does not improve over time, you should consult your GP.

Finally, it is worth noting that osteoarthritis – when it does occur – is not simply a problem of ‘worn-out’ cartilage: it is a condition that affects the entire joint, including the underlying bone, the synovial membrane and the ligaments, and it is not an inevitable consequence of ageing. Worldwide, it affects around 528 million people, representing a 113 per cent increase since 1990. In Italia, according to data from the Istituto Superiore di Sanità, osteoarthritis and arthritis together affect a significant proportion of the population, particularly older women.

Read the full article on the dottoremaeveroche website, run by Fnomceo

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