Athletic footwear does not alter in-shoe hindfoot kinematics during overground running

Abstract

Background: Heel counters are added to most athletic shoes under the premise that they control excessive hindfoot motion. However, it is oftenquestionedwhether this premisehas any scientific evidence. Although previous studies have described hindfoot kinematics during running, they have often used external shoe markers to infer in-shoe footmotionwhich is not a valid technique. The aim of this study was to compare hindfoot kinematics during running both barefoot and in typical running shoes. We hypothesised that running shoes would not alter hindfoot eversion motion but would reduce the rate at which it occurs (angular velocity). Methodology: Eighteen adults participated in this study (mean age 21.2±2.0 years, height 1.73±0.08m, bodymass 70.8±8.3 kg). Each participant completed five running trials both barefoot and wearing shoes (Asics Gel-Pulse 3). Kinematic data were acquired with a 12 camera VICON MXF-20 motion capture system (Vicon Motion Systems Ltd., Oxford, UK) at 100Hz. Variables of interest were the hindfoot eversion angle at initial contact and peak loading (15% stance), as well as the ROM and peak angular velocity during loading response (0–15% stance). Differences between conditions were compared using paired t-tests. Effect sizes (Cohen’s d) were also computed. Results: During running, footwear did not significantly reduce eversion of the hindfoot at initial contact (−7.59±5.69∞ vs. −6.15±5.59∞, p=>.05, ES =0.26) or peak loading (−13.91±4.63∞ vs. −13.24±6.15∞, p=>.05, ES =0.12), nor did it decrease the amount of eversion during loading response (6.88±2.63∞ vs. 7.21±1.99∞, p=>.05, ES =0.14). No difference in eversion angular velocity was identified between barefoot and shod running (−175.46±100.52∞/s vs. −151.73±70.73∞/s, p=>.05, ES =0.27). Conclusion: In this study, footwear didnot changehindfoot eversion at initial contact or peak loading, nor significantly reduce the amount of eversion or the peak eversion velocity occurring during loading. These results suggest hindfoot kinematicswere not altered by the shoe used in this study. We found no evidence that design features in the heel (i.e. heel counter) providemotion control benefits (i.e. decrease hindfoot eversion) to the foot during stance phase of running. It is possible that the purported feature of running shoe heel counters of ‘motion control’ with reference to the hindfoot require re-evaluation.