The relationship between the height of the medial longitudinal arch (MLA) and the ankle and knee injuries in professional runners.

BACKGROUND Usually the rate of lower extremity's injuries in sports such as running is known to be correlated with the height of foot arches. Foot pressure measurement studies have shown controversial results in this issue, mainly due to the complexity of the foot structure. This study aimed to investigate if any relationship exists between the MLA height and the ankle/knee injuries in professional runners. It was also aimed to find out any association between the foot pressure patterns and the clinical navicular drop test in the subjects. MATERIALS AND METHODS Forty-seven professional runners were participated in this study and using the clinical navicular drop test, they were categorized into normal, low and high arch foot subjects. Using an Emed pedography platform (Novel, Germany), the maximum force, peak pressure and the contact area of their feet were studied in both static (single limb support) and dynamic conditions. RESULTS The results of this study showed no strong correlation between the height of MLA and the rate of the ankle/knee injuries (P=0.58). The correlation between the clinical navicular drop test and the modified arch index (MAI) was between 0.32 in static and 0.57 in dynamic tests. CONCLUSION The results of this study conveyed that having a lower or higher than a normal MLA is not a definite risk factor for sports-related injuries. This might be due to the complexity of the foot structure and its ability to accommodate with new situations routinely occurs in sport. Furthermore, although a high correlation was not found between the clinical navicular drop test and the foot pressure indices, due to the clinical entity of this test, the obtained association is relatively good. A significant correlation was found between the foot pressure distribution in single limb support (static) and the dynamic conditions, which provides an extrapolation of the results of this type static condition tests to the dynamic conditions.