Ankle Joint Dynamic Stiffness in Long-Distance Runners: Effect of Foot Strike and Shoes Features

Foot strike mode and footwear features are known to a ect ankle joint kinematics and loading patterns, but how those factors are related to the ankle dynamic properties is less clear. In our study, two distinct samples of experienced long-distance runners: habitual rearfoot strikers (n=10) and habitual forefoot strikers (n=10), were analysed while running at constant speed on an instrumented treadmill in three footwear conditions. The joint dynamic sti ness was analysed for three subphases of the moment–angle plot: early rising, late rising and descending. Habitual rearfoot strikers displayed a statistically (p<0.05) higher ankle dynamic sti ness in all combinations of shoes and subphases, except in early stance in supportive shoes. In minimal-supportive shoes, both groups had the lowest dynamic sti ness values for early and late rising (initial contact through mid-stance), whilst the highest sti ness values were at late rising in minimal shoes for both rearfoot and forefoot strikers (0.21 0.04, 0.24 0.06 (Nm/kg/ 100), respectively). In conclusion, habitual forefoot strikers may have access to a wider physiological range of the muscle torque and joint angle. This increased potential may allow forefoot strikers to adapt to di erent footwear by regulating ankle dynamic sti ness depending upon the motor task. Keywords:running; biomechanics; footwear; joint work; loading 1. Introduction There is an ongoing debate on whether the foot strike pattern of long-distance runners plays a role in de ning performance and injury risk in this population [1–3]. Experienced long-distance runners are able to change their foot strike pattern during a competition [4] or if they are asked to [5]. Their ability

The study investigates the impact of foot strike and footwear on ankle stiffness in long-distance runners.