Effects of lower extremity muscle strengthening exercise and foot orthoseson medial longitudinal arch height in individuals with flexible flatfoot

Abstract

Background: Foot orthoses and lower extremity exercises have been widely recommended to improve medial longitudinal arch (MLA) height in adults with flexible flatfoot. However, there is little evidence to guide the choice between foot orthoses or lower extremity exercises.

Objectives: This study comprised two separate studies. Study 1 aimed to establish the more effective exercise protocol by comparing the MLA height in groups performing foot exercises with and without gluteus medius (GMed) muscle strengthening exercise. Study 2 compared the established exercise protocol in Study 1 with foot orthoses to determine the actual effectiveness of each intervention.

Main outcome measures: Navicular drop (ND), arch height index (AHI), plantar pressure, static balance, dynamic balance, and lower extremity muscle strength were measured at baseline, 4 weeks, and 8 weeks.

Results: Study 1 included 52 participants with bilateral flatfoot who were randomly assigned to either the foot exercise group (n = 26) or the foot plus GMed exercise group (n = 26). After 4 and 8 weeks, the foot plus GMed exercise group showed significant improvements in all outcome measures, except dynamic balance, compared to the foot exercise group. Study 2 included 38 bilateral flatfoot participants who were randomly assigned to either the foot plus GMed exercise group (n = 19) and the foot orthoses group (n = 19). The foot plus GMed exercise group showed significant improvements in all outcome measures, except plantar pressure, static and dynamic balance in certain directions, compared to the foot orthoses group.

Conclusion: Adding GMed muscle strengthening exercise to foot exercise proved to be more effective in supporting the MLA compared to performing foot exercise alone. In healthy adults with flexible flatfoot, lower extremity exercise was found to be more effective than foot orthoses in improving MLA height and related parameters.