The Association Between Rearfoot Motion While Barefoot and Shod in Different Types of Running Shoes in Recreational Runners

Abstract

The rearfoot angle (RFA) is a biomechanical variable widely used to determine the rearfoot motion (RM). Shoe manufacturers began to develop running shoes with RM control that would supposedly alter foot-ground interaction mechanics and neutralize excessive pronation or supination; moreover, some studies have not shown differences in rearfoot motion in shod condition compared to barefoot. This study intended to answer three questions: Do the shoes runners wear correspond to their respective barefoot RM? Does the eversion angle change during shod running, regardless the shoes worn? Can footwear designed for a specific RM (supination, pronation, neutral) correct or neutralize the eversion angle of runners? One hundred and eleven runners (38.6 ± 9.7years; 74.9 ± 12.0kg; 1.74 ± 0.08 m), who ran an average of 32 ± 17km/week, were included in this cross-sectional study. They had their RFA measured by a motion capture system when running barefoot and wearing their habitual running shoes (shod condition). Chi-squared test was used to assess associations between barefoot and shod condition and RFA was compared between conditions using Wilcoxon tests (p = 0.05). There was no association between the type of running shoe and barefoot RM (p > 0.05). There was an association between RFA when barefoot and when shod (p < 0.05). Among all participants classified as neutral, 61% continued to exhibit a normal/neutral RFA when wearing their habitual shoes. Among the overpronators, 100% showed a change in the RM to either normal or supinator. Among the participants classified as supinators, 62% exhibited normal pronation when shod even without using the appropriate footwear, claimed by the manufacturer. Only 44.1% of the sample chose the correct running shoe for their barefoot RM. The majority of runners did not choose their shoes designed for their natural type of RM. The rearfoot eversion angle changed an average 4 degrees when running shod and the RM barefoot altered quite a lot when using a running shoe. The running shoes did not correct the pronation detected barefoot, as claimed by the manufacturers.

Keywords: Running; biomechanics; footwear; kinematics; rearfoot motion.