Effects of unknown footwear midsole thickness on running kinematics within the initial six minutes of running

摘要

Research on minimal footwear hasn't utilised runners who habitually wear typical training footwear and therefore what adjustments to running patterns are made and how quickly they occur is unknown. Purpose: The purposes of this study were: 1) to investigate how kinematic patterns are adjusted while running barefoot and in footwear with systematic changes in shock attenuating material; and 2) to determine the time it takes for adjustments to occur when little is known about the footwear condition before running commences. Methods: Ten male heel-toe runners performed treadmill runs of 6 minutes in thin, medium, and thick footwear and barefoot. Participants ran immediately after putting shoes on to limit information about each footwear condition. Standard kinematics and acceleration signals were captured. Repeated measures analysis of variance (ANOVA) was utilised (p < 0.05) to determine differences across footwear conditions and time. Results: The foot was flatter at touchdown (due to a more vertical leg segment and more plantar flexion), the knee had reduced excursion, and stance times, eversion and tibial rotation excursions were greater in the thin footwear or when barefoot. Several variables were adjusted from the initial steps to later in the run. Acceleration standard deviations had more variability during initial steps than immediately following. Discussion: Many kinematic adjustments agreed with previous works though participants did not adopt a midfoot or forefoot strike pattern. Experimental design and participant knowledge and experiences may be contributing to discrepancies in footstrike patterns. Runners sensitive to eversion and tibial internal rotation should use caution when barefoot or in minimal footwear. Finally, the greatest kinematic changes occurred within the first six to eight steps, however more subtle changes continued throughout the six minute run.