Walking, running, and recreational sports for knee osteoarthritis: an overview of the evidence

Key points

1. 01Across 20 reviews and 12 original studies, walking, recreational running, and many recreational sports were not linked to faster structural progression of knee osteoarthritis.
2. 02People who meet WHO physical activity guidelines were not at increased risk of developing radiographic or symptomatic knee osteoarthritis.
3. 03Recreational runners had lower odds of osteoarthritis and knee surgery than non-runners, not higher.
4. 04Higher-risk groups include people with obesity, previous knee injury, or structural abnormalities, where activity should be more supervised and gradual.
5. 05Sport-specific risk exists for some activities (such as elite soccer, weightlifting, and wrestling), but this is often confounded by injury.

How it was conducted

Design

Overview (narrative review) of narrative reviews, systematic reviews, and meta-analyses, plus selected original studies

Search

PubMed using MeSH terms exercise AND knee osteoarthritis, reviews 2005 to 2020; 114 abstracts screened, 74 excluded

Included evidence

20 reviews and 12 original studies summarized

Exposure

Physical activity including walking, running, and recreational sports

Outcomes

Structural progression of knee osteoarthritis (radiographic OA, cartilage, bone marrow lesions, joint replacement)

What they found

• Meeting WHO physical activity guidelines was not associated with increased risk of incident radiographic or symptomatic knee OA (HR 1.2, 95% CI 0.9 to 1.8).
• Felson et al found walking 9 or more miles per week was not associated with joint space loss or incident knee OA over 9 years.
• Alentorn-Geli et al meta-analysis found recreational runners had lower odds of OA than controls (OR 0.83).
• Timmins et al meta-analysis found runners had 54% lower odds of knee surgery for OA (pooled OR 0.46) versus non-runners.
• Bricca et al reported 10 of 14 comparisons showed no effect of weight-bearing aerobic activity on cartilage, 3 of 14 positive, and 1 of 14 negative.
• Martin et al found obese women with the highest unstructured physical activity had higher incident OA (OR 1.8), suggesting obesity is the driving factor.
• Two original outcome studies showed improvement, for example Waterman et al VAS pain fell from 7.3 to 1.7 and Harris score rose from 54.8 to 84.2.

Limitations

• As an overview of reviews rather than a pooled meta-analysis, it does not produce a single combined effect estimate.
• Most underlying studies relied on self-reported or questionnaire-based physical activity rather than objective measurement.
• Sport-specific risk findings are confounded by prior joint injury, making it hard to separate the activity from the injury.
• Direct evidence that meeting physical activity guidelines preserves knee structure over time is still lacking.

Why it matters

For patients

If you have knee osteoarthritis, walking and moderate recreational running are generally safe and unlikely to wear your knee out faster, though you should get tailored advice if you are obese or have had a knee injury.

For clinicians

Clinicians can confidently recommend WHO physical activity guidelines for most patients with knee OA while individualizing advice for those with obesity, prior injury, or structural abnormalities.

For readers

The long-held wear-and-tear idea that activity accelerates knee osteoarthritis is not supported by the current weight of evidence.