Effect of foot pronation during distance running on the lower limb impact acceleration and dynamic stability

Foot pronation is not an isolated factor influencing lower limb functions. Exploring gait variability and impact loading associated with the foot posture are crucial for understanding foot pronation-related injury mechanisms. This study aimed to evaluate how foot posture affects impact loading and running variability during running. Methods: Twenty-five male participants were recruited into this study. Pressure under the foot arch, acceleration and marker trajectory were recorded in the right limb for each runner after 1, 4, 7 and 10 km running, respectively. Linear mixed effects models were used to analyze the statistical difference of the data. Results: FPI-6 has significantly increased after the 10 km running ( p < 0.01). For the tibial acceleration, peak resultant acceleration after 10 km running was significantly increased than after 4 km running ( p = 0.02). At the dorsum of the foot, the short-time largest Lyapunov exponent (LyE) after 10 km running decreased 0.28 bit/s compared with LyE after 7 km running ( p = 0.03). In the tibia, LyE after 4 km and 10 km running was decreased significantly ( p < 0.01 and p = 0.01). Conclusions: The foot was significantly pronated at the middle and at the end of running. Foot pronation during distance running increased the distal tibia peak impact acceleration but did not increase running instability.