Effects of orthotic insoles on adults with flexible flatfoot under different walking conditions

[Purpose] This study was to evaluate the effects of orthotics on adults with flexible flatfoot when wearing orthotic insoles while walking on horizontal ground, walking up and down stairs and to determine if flexible flatfoot needs treatment. [Subjects and Methods] Fifteen college students with flexible flatfoot and fifteen college students with normal feet were recruited. First, load rate and contact area were measured by RSscan force plate when the subjects were walking on horizontal ground, walking up and down 10 cm and 20 cm stairs. Then the subjects with flexible flatfoot were instructed to wear orthotic insoles for 3 months, and plantar pressure was measured again. Finally, the data were subjected to repeated measures ANOVA. [Results] After treatment for 3 months, the plantar pressure of flatfoot was significantly improved. In addition, the data of the subjects with normal feet and flatfoot were significantly influenced by walking down 10 cm or 20 cm stairs. [Conclusion] Orthotic insoles could significantly improve the plantar pressure of flatfoot. Additionally, the arches of subjects with normal feet and flatfoot can be significantly deformed when walking down stairs. Therefore, it is essential for subjects with flexible flatfoot to wear orthotic insoles to avoid needless injury.