Effects of rigid and soft foot orthoses on dynamic balance in females with flatfoot

Background: Various types of foot orthoses are prescribed for people with flatfoot. It has been reported that orthoses not only improve the biomechanics of the lower limb, but also have good effects on some balance parameters in these subjects. It is hypothesized that the latter effect is dependent on the rigidity of the orthoses. The aim of this study was to evaluate and compare the effects of rigid and soft foot orthoses on dynamic balance in females with flatfoot. The Biodex Balance System was used in a clinical trial study. Methods: 20 healthy students with bilateral flatfoot were randomly assigned to two equal groups. Each participant was tested on two days with 2-week interval. On each day, dynamic stability test was performed while standing in single-leg stance on an unstable platform of the balance system in 3 conditions (barefoot, with shoe, shoe with orthosis). SPSS11.5 was used for statistical analysis. Results: A significant group-by-day-by-condition interaction was found. Both groups on day 2 testing had a decreased overall stability index while wearing orthoses. Overall stability index was significantly lower on day 2 testing. Conclusion: Foot orthoses, depending on the amount of rigidity, were associated with some improvements in dynamic balance in subjects with flatfoot.