Can distance running be good for your knees?
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Published September 2019 in BMJ Open Sports and Exercise Medicine
Our first study was based on the 2018 London Marathon. 115 runners participated — all first-time marathon runners in their 40s, with no known running injuries. Our findings provide evidence to suggest that training for and running a marathon rebuilds the health of middle-age knees, although it can also erode one vulnerable part of the knee if you’re not careful.
Long-distance running has become a worldwide phenomenon, with more than 30 million people running marathons each year. Running exerts repetitive stress on the lower extremities, especially the knee joint, and therefore, in excess, can lead to injuries and the development of osteoarthritis. Preparation for a marathon run has been linked to an incidence of musculoskeletal problems as high as 90%, especially at the knee joint, including patellofemoral pain. Many participants are first-time runners, and the number of older marathoners is significantly on the rise. As a result there are growing concerns about the negative health impacts.
There’s been a lack of robust evidence as to whether long-distance running, often on hard surfaces such as roads, is bad for the knees. Evidence has relied on small numbers of subjects (<22 participants) and a study designs with a range of drawbacks, for example, low MR field strength, varying follow-ups, different knee structures being assessed, unclear clinical significance, and differences in the scoring systems used for each knee structure.
Few studies have investigated the effects of marathon running specifically on the internal knee structures. MRI provided us with the perfect tool to assess whether running a marathon changes the ‘normal’ structure of the knee. With this study we wanted to better understand the effect of marathon running on the knee joint by performing high resolution 3T MRI scans of both knees of first-time marathon runners before and after running a marathon.
In short…
The study
Our objective was to evaluate the short-term impact of long-distance running on knee joints using MRI
82 healthy adults participating in their first marathon underwent MRI of both knees 6 months before and half a month after the marathon:
71 completed both the 4 month-long standardised training programme and the marathon; and 11 dropped-out during training and did not run the marathon.
Two senior musculoskeletal radiologists graded the internal knee structures using validated scoring systems.
Participants completed Knee Injury and Osteoarthritis Outcome Score questionnaires at each visit for self-reporting knee function.
What we found
The main weight-bearing compartments presenting subchondral bone marrow oedema before the marathon, in asymptomatic middle-aged adults, showed reversibility following the training for and completion of running a marathon.
The patellofemoral compartment was the region most injured by marathon running.
Marathon running did not result in progression of meniscal tears and their presence did not affect performance.
What it means
Study findings could help inform marathon running-related decision making.
During training for a marathon, injury prevention exercises that target those areas of the knee which are more susceptible to damage, especially the patellofemoral joint, should be considered.
Runners, clinicians and the general public can use this data for a better understanding of the effect of high-intensity exercise on the knee.
