Purpose: The purpose of this study was to investigate the effect of a 6-month period of intensive running followed by the participation at a marathon run on cartilage volume and thickness in knees of marathon beginners.
Methods: Ten asymptomatic marathon beginners underwent a supervised 6-month training program, which was finalized by the participation at a marathon run. Three-dimensional quantitative magnetic resonance imaging was performed before the training program (baseline measurements) and 1 day after the marathon (follow-up measurements). Cartilage volume and thickness of the medial and lateral femur, medial and lateral tibia, and patella were measured using semiautomated cartilage segmentation and three dimensional data postprocessing.
Results: Significant differences between baseline and follow-up measurements were observed at the lateral femur, where cartilage volume and thickness decreased by a mean of 3.2 ± 3.0% (p = 0.012) and 1.7 ± 1.6% (p = 0.010), respectively. No significant changes in cartilage volume and thickness were observed at the medial and lateral tibia, the medial femur, and the patella.
Conclusion: Significant cartilage loss was observed at the lateral femur; however, the measured values are comparable to previously reported precision errors for quantitative cartilage measurement and thus most likely not of clinical relevance. High-impact forces during long-distance running are well tolerated even in marathon beginners and do not lead to clinical relevant cartilage loss.
Level of evidence: IV.