Abstract
Background
Over 30 million people run marathons annually. The impact of marathon running on hips is unclear with existing literature being extremely limited (only one study of 8 runners).
Aim and Objectives
We aimed to better understand the effect of marathon running on the pelvis and hip joints by designing the largest MRI study of asymptomatic volunteers. The objectives were to evaluate the pelvis and both hip joints before and after a marathon.
Materials and Methods
This was a prospective cohort study, Fig.1. We recruited 44 asymptomatic volunteers who were registered for the Richmond Marathon. They were divided into novice and experienced marathoners, Fig.2.
All volunteers underwent 3T MRI of pelvis and hips with Dixon sequences 4 months before, and within 2 months after the marathon. Outcome measures were: 1. change in radiological score of each hip joint structure and muscle from the pre- to the post-marathon MRI; 2. change in the self-reported hip function questionnaire score (HOOS) between the two timepoints.
Results Pre-marathon, Asymptomatic novice marathoners' hips showed few joint abnormalities (cartilage, bone marrow, labrum), while minimal fatty muscle atrophy of the abductors and CAM-type hip impingement were common (68%; 34%, respectively).
Experienced marathoners had no cartilage lesions and slightly lower prevalences of abnormalities than novice runners.
Post-marathon, Hip joint cartilage, bone edema and labrum did not worsen in neither novice nor experienced marathoners. Abductor muscles were unaffected post-marathon.
Self-reported hip outcomes were not significantly different after the run for both groups.
Conclusion
This is the largest MRI study of long-distance runners. We showed that marathon running has no negative impact on the pelvis and hip joints.
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