06/06/2026
🏃♀️ “Running is bad for your knees.”
It’s one of the most common myths I hear as a physiotherapist.
With Comrades Marathon just around the corner, I thought I would talk a little about running and your knees- so let’s look at what the research actually says.
In a fascinating study by Horga and colleagues, healthy first-time marathon runners underwent MRI scans of their knees before training and again after completing a marathon.
Before training, many runners already showed MRI findings that would often worry people:
✔️ Meniscal tears
✔️ Cartilage changes
✔️ Bone marrow oedema
✔️ Tendon abnormalities
✔️ Joint effusions
The surprising part?
After months of marathon training and completing the race:
-Meniscal tears had not progressed.
-Several bone marrow oedema changes had actually improved.
-Most runners remained completely symptom-free.
This doesn’t mean running magically “fixes” knees, but it does challenge the belief that running inevitably causes knee damage.
Even more interesting, large studies have shown that recreational runners are less likely to develop knee osteoarthritis than people who don’t run at all.
We also know that a higher BMI is associated with osteoarthritis in joints such as the hands — joints that don’t experience the repetitive loading of running. This suggests that osteoarthritis is about much more than simple “wear and tear” and that factors such as systemic inflammation and metabolic health may play an important role.
The takeaway?
💡 MRI findings do not always equal pain.
💡 Movement is not the enemy.
💡 Healthy joints are designed to be loaded.
💡 For most people, running is not ruining their knees.
As thousands of runners prepare for Comrades, perhaps it’s time we retire the myth that running is inherently bad for your knees.
The human body is remarkably adaptable. In many cases, it’s not movement that damages our joints—it’s the absence of it. 🏃🏃🏃
References:
Horga LM, Henckel J, Fotiadou A, et al. Can marathon running improve knee damage of middle-aged adults? A prospective cohort study. BMJ Open Sport & Exercise Medicine. 2019;5:e000586.
Alentorn-Geli E, Samuelsson K, Musahl V, et al. The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis. Journal of Orthopaedic & Sports Physical Therapy. 2017;47(6):3