The influence of heel fit on rearfoot motion in running shoes

Prior research into eversional control in running has reported the occurren ce of calcaneal slipping, defined as the difference between calcaneal and h eel counter eversion within the shoe. Inadequate heel fit has been proposed to explain the observed slippage. Therefore, the purpose of the current st udy was to investigate whether eliminating excess space around the calcaneu s by narrowing the heel counter or by introducing heel inserts could minimi ze eversional slipping of the calcaneus within the shoe and, in so doing, i mprove eversion control of the calcaneus. Three-dimensional rearfoot kinema tics of 20 subjects running on a treadmill at 3.8 m (.) s(-1) were recorded using a three-camera Vicon movement analysis system. ANOVA analyses of the angular displacement data revealed a significant (p < .05) reduction in ma ximal eversion of the calcaneus in shoes with a narrower heel fit though th e heel counter of the same shoes displayed more eversion than their wider c ounterparts. Calcaneal eversion in the shoes with a wider heel counter, how ever, could be reduced significantly (p < .05) using heel inserts. Maximal relative eversion (referenced to the value at heel strike) and eversional v elocity were only affected by the heel inserts, the latter however, not sig nificantly All these results show that heel fit affects the eversional beha vior of the calcaneus during ground contact and that running shoes equipped with a rigid heel counter will improve rearfoot control, thus only reducin g the risk for overload injuries If a snug heel fit used.