The Influence of Position and Area of Shock Absorbing Material of Shoes on Ground Reaction Force during Walking

The purpose of this study was to identify the influence of position and area of shock absorbing material on ground reaction force. Seven subjects volunteered to participate in this study. These subjects were instructed to walk along a 8m long walkway at 1.0m/s (slow), 1.5m/s (medium), 2.0m/s (fast). These trials were repeated until three successful assignments. When subjects walked, they wore four kinds of shoes (Type1, Type2, Type3 and Type4). The differences of these shoes were position and area of shock absorbing material. Type1 did not contain the shock absorbing material at all. The other shoes were inserted the shock absorbing material in the heel region (Type2 and Type3), or between inside bottom and midsole (Type4). The area of the shock absorbing material of Type2 was smaller than that of Type3. The ground reaction forces from 6m to 7.8m of the walkway were recorded by the force plates. Walking velocity was measured by a laser apparatus. For each shoe condition, maximum values of vertical ground reaction force of the three trials were averaged, and the mean value was shown as GRF

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. GRF

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of all trials was normalized to that of Type1. For slow trial, GRF

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of all conditions was almost the same. On the other hand the walking at medium and fast, GRF

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of Type3 was only smaller than that of the others. Our results indicated that the increase of area of the shock-absorbing material is effective in the decrease of GRF

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. However, a significant difference was not found in each shoe.