RT Journal Article SR Electronic T1 Can marathon running improve knee damage of middle-aged adults? A prospective cohort study JF BMJ Open Sport & Exercise Medicine JO BMJ OPEN SP EX MED FD BMJ Publishing Group Ltd SP e000586 DO 10.1136/bmjsem-2019-000586 VO 5 IS 1 A1 Laura Maria Horga A1 Johann Henckel A1 Anastasia Fotiadou A1 Anna Hirschmann A1 Camilla Torlasco A1 Anna Di Laura A1 Andrew D'Silva A1 Sanjay Sharma A1 James Moon A1 Alister Hart YR 2019 UL http://bmjopensem.bmj.com/content/5/1/e000586.abstract AB Objectives To evaluate the short-term impact of long-distance running on knee joints using MRI.Methods 82 healthy adults participating in their first marathon underwent 3T (Tesla) 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.Results Premarathon and pretraining MRI showed signs of damage, without symptoms, to several knee structures in the majority of the 82 middle-aged volunteers. However, after the marathon, MRI showed a reduction in the radiological score of damage in: subchondral bone marrow oedema in the condyles of the tibia (p=0.011) and femur (p=0.082). MRI did also show an increase in radiological scores to the following structures: cartilage of the lateral patella (p=0.0005); semimembranosus tendon (p=0.016); iliotibial band (p<0.0001) and the prepatellar bursa (p=0.016).Conclusion Improvement to damaged subchondral bone of the tibial and femoral condyles was found following the marathon in novice runners, as well as worsening of the patella cartilage although asymptomatic. This is the most robust evidence to link marathon running with knee joint health and provides important information for those seeking to understand the link between long distance running and osteoarthritis of the main weight-bearing areas of the knee.