Effects of changes in waist of last on the high-heeled in-shoe plantar pressure distribution

In order to clear which kind of arch design of the last is optimal for high heeled shoes with 20mm, 50mm and 80mm heel height, ten healthy female subjects participated in this study. Their 3D model of the right foot in the normal weight bearing and in standing on the elevated heel was scanned and averaged foot arch was calculated. Three last designs with different arch shape were provided: control last in which the averaged foot arch was applied; the higher and lower last were constructed with 2.5mm higher or lower in the position of cuboids than the control last. The insole region was divided into hind, mid and fore foot and peak pressure (PP), contact area (CA) and pressure-time integrals (PTI) were selected for evaluation. Paired-t test with the significant level a=0.05 was selected for difference comparison between the control and lower last, control and higher last. The result shows that for the low heel-height shoes such as 20mm, the higher last received a lowest PP and PTI under the forefoot; however for the mid and high heel-height shoes for instance 50 or 80mm, the control last was shown to be the optimal one with lower value on both PP and PTI variables for the forefoot area. The optimal last design would be applied on the current high heel-heighted shoes manufacture