Effect of a Heel-arch Pad on the Acceleration of the Knee Joint and Anterior Pelvis in Walking

[Purpose] The purpose of this study was to clarify the effects of a heel-arch pad on anterior pelvis and knee joint acceleration and timing of the "foot flat" (FF) phase during walking. [Subjects] The subjects were 43 legs of 28 healthy adults, 22 male legs and 21 female legs. [Method] Subjects were allocated to the Early group or Delayed group according to the timing of the incidence of FF, early or delayed. Using an accelerometer, we investigated the differences in acceleration rates between the two groups and the changes in acceleration rates after fixation of the heel-arch pad. [Results] In the Early group, anterior acceleration of the knee joint increased just before FF, and just after FF anterior acceleration of the knee joint decreased. In the Delayed group, anterior acceleration of the knee and pelvis just before FF were significantly decreased by fixation of the heel-arch pad, and just after FF, anterior acceleration of the pelvis was significantly decreased by fixation of the heel-arch pad, revealing the mutual interaction of pad height and the timing of FF. [Conclusion] The results suggest the timing of FF and heel-arch pad influence anterior acceleration of the pelvis and knee.