Objective: The purpose of this study is to compare the plantar foot pressure and the center of pressure (COP) pathway of normal and flat feet while crossing an obstacle at different heights.
Methods: Nineteen subjects (10 normal feet, 9 flat feet) participated in this study. The plantar foot surface was divided into the following seven regions for pressure measurement: two toe regions, three forefoot regions, one midfoot region, and one heel region. A one-way ANOVA with repeated measurements was used to compare the plantar foot pressure of normal and flat feet according to the obstacle height.
Results: The trend analysis showed a quadratic trend during level walking for the normal foot group, but a linear trend appeared as the obstacle height increased. In the flat foot group, the trend analysis showed a linear trend regardless of the obstacle height. In the 2nd-3rd metatarsal head region, the plantar pressure of the flat foot group increased more than the normal foot group as the obstacle height increased; however, in the 4th-5th metatarsal head region, the plantar pressure in flat feet was lower than in normal feet. In the heel region, the plantar pressure in both groups generally increased as the obstacle height increased, but the plantar pressure in the flat foot group was lower than in the normal foot group.
Conclusion: We believe that, due to a loss of longitudinal arch, the COP path and plantar pressure of flat feet may be different from normal feet when crossing obstacles of different heights.
Keywords: Plantar pressure; flat foot; obstacle; pathway of COP.