Running is often blamed for “wearing out” knees and hips. The best short answer is more reassuring: current research does not show that recreational running automatically causes osteoarthritis. But that is not the same as proving every runner, at every training load and with every injury history, has zero risk.
The distinction matters if a sore knee has made you question your next run. Here is what the widely reported marathon study actually found, where its limits sit, and how it fits with the broader evidence.
What did the marathon study examine?
Researchers surveyed 3,804 people registered for the 2019 or 2021 Chicago Marathon. The runners had a mean age of 43.9 and had completed a median of five marathons. They reported their running history, hip or knee pain, previous injuries and surgery, family history, and whether a clinician had diagnosed arthritis.
In the published marathon survey, 7.3 per cent reported hip or knee arthritis. The researchers did not find a significant association between arthritis and weekly distance, average pace, years of running or number of marathons completed.
Factors associated with reported arthritis were older age, higher body mass index, family history, and a previous hip or knee injury or surgery. That is a more precise result than the headline claim that running “does not increase risk”. It says running history did not predict arthritis within this particular group after the researchers adjusted for other measured factors.
Why the study does not settle the question
The study was useful because it included a large and varied group of marathon entrants. It was still observational and based on a survey, so it could identify associations but not prove cause and effect.
There are several important limits:
- Arthritis was self-reported rather than confirmed through a clinical examination or imaging.
- Only 10 per cent of the runners invited to participate completed the survey, so respondents may not represent all marathon runners.
- The researchers could not fully account for joint alignment, bone shape, earlier trauma, genetics or metabolic conditions.
- People healthy enough to enter a marathon are a selected group. Those who stopped running because of joint problems may be under-represented.
The paper therefore offers evidence against a simple dose-response relationship in active marathon runners. It does not prove that running prevents arthritis or that any training plan is safe for every knee and hip.
What does the wider research say?
A single study should not carry the whole conclusion. A 2023 systematic review combined nine observational studies with 12,273 participants. It found no difference in knee osteoarthritis prevalence between runners and controls, including across the weekly-distance groups it analysed. The authors also rated most included studies as having high or very high risk of bias, which keeps the conclusion cautious.
Another 2023 evidence review found that, over the shorter follow-up periods available, running was not associated with worse symptoms or imaging signs of knee osteoarthritis. A 2017 meta-analysis found lower osteoarthritis prevalence among recreational runners than among competitive runners and sedentary controls, but it could not establish that running caused the difference. Previous injury and other factors may partly explain the pattern.
Taken together, the research does not support the idea that ordinary recreational running inevitably wears joints away. The evidence is less certain for very high-volume competitive running and for people whose injury history, symptoms or diagnosis changes their starting point.
Osteoarthritis is not the same as runner’s knee
Osteoarthritis is a long-term condition affecting the whole joint and surrounding structures. It can cause pain, stiffness and reduced movement. Australian health guidance lists ageing, family history, higher body weight and previous joint injury among its risk factors.
A runner can have knee pain without having osteoarthritis. Patellofemoral pain, often called runner’s knee, is a separate problem involving pain around or behind the kneecap. Other running-related pain can come from tendons, muscles or the iliotibial band. A study about diagnosed arthritis should not be used to dismiss new pain or swelling as harmless.
What if you already have osteoarthritis?
This is a different question from whether running causes osteoarthritis. Exercise is a core part of osteoarthritis management, but the right type and load depend on the person. Healthdirect suggests options including strengthening, flexibility work, brisk walking, swimming and cycling, and recommends talking with a physiotherapist or exercise physiologist about an appropriate program.
Some people with osteoarthritis can run; others find that high-impact activity aggravates pain or swelling. The marathon study cannot decide that choice for an individual because it did not test a running program in people with confirmed osteoarthritis.
An Australian story shows how personal this can be. Percy Voigt began training for a 100-metre sprint at 92 while living with osteoarthritis and emphysema. His first attempt was difficult, but he trained with his son-in-law, a GP, mixed track sessions with hydrotherapy, walking and cycling, and later competed at masters events. His experience is encouraging, but it is one person’s story—not evidence that everyone with osteoarthritis should start sprinting.
How should a recreational runner respond?
If you are otherwise well and pain-free, the evidence does not give you a reason to stop recreational running solely because you fear future arthritis. If you are starting or increasing your running, allow time for your body to adapt instead of making a sudden jump in distance, speed and frequency. Australian running experts recommend building gradually and stepping back when problems emerge.
Past injury deserves particular attention because it was strongly associated with arthritis in the marathon survey and is a recognised risk factor more broadly. A clinician or physiotherapist can help assess pain, previous surgery, current capacity and training load rather than applying one rule to every runner.
See a health professional if joint pain lasts more than a few days, affects daily life, limits walking or movement, or comes with persistent swelling. Sudden severe pain, inability to bear weight or a significant new injury also needs prompt assessment.
The practical takeaway
The Chicago study did not find that more years, kilometres, marathons or speed predicted self-reported hip or knee arthritis among its respondents. Broader reviews are also broadly reassuring about recreational running. The responsible conclusion is “no clear increase shown”, not “running can never contribute to joint trouble”.
If you are looking for company as you build a sensible routine, explore local running groups and ask whether they welcome your current pace and experience. The goal is not to ignore your knees; it is to replace the worn-out-joint myth with evidence, gradual progression and attention to your own symptoms.
This article provides general information and is not a substitute for advice from a doctor, physiotherapist or other qualified health professional who knows your medical history.
