Effects of stack height on running biomechanics during level, uphill and downhill running at different speeds

This study aimed to investigate the effects of shoe stack height on comfort assessment, step frequency and lower limb joint range of motions (ROMs) during level, downhill and uphill running with different running speeds since stack height is one of the highly discussed key features of running shoes and was not intensively investigated for sloped running conditions. Seventeen male experienced runners completed the running protocol by wearing three running shoes with different stack heights. The kinematics were collected with a 3D motion capturing system. A comfort questionnaire was asked for each shoe. The lowest stack height resulted in the highest perceived stability and the lowest cushioning. Decrease in stack height resulted in increased step frequency and sagittal ROM in lower body joints (up to 10% change due to different stack heights) particularly in sloped running conditions. The results of this study can help to understand the effects of footwear technologies on running biomechanics and ultimately to improve running shoes to maximize their benefits in terms of running performance as well as injury risk.