Objective: Flat foot is common deformity in children that medial longitudinal arch is decreased, which if not treated in childhood may lead to pain and other problems in adulthood. Insoles and orthopedic shoes usually prescribed for treatment of flat foot in children, but the biomechanical impact of these devices is not yet clear. The purpose of this study is comparison of two conventional orthoses intervention in Iran, including medical shoe and functional foot orthosis on static balance by measurement of displacement of center of pressure and cop sway velocity in children with flexible flat foot .

Materials & Methods: This Quasi experimental study were accomplished on 30 children with flat foot and 10 healthy children for achievement of normal data in healthy children. Children stood unilaterally on force plate of Neurocom and in order to measurement of balance, displacement of center of pressure and COP (Center of Pressure) sway velocity were recorded.

Results: The results related to displacement of the center of pressure in a flat foot showed with insoles and conventional shoe the amount of displacement of center of pressure significantly were reduced (P<0.05). There was no significant difference between orthopedic shoe and functional foot orthosis, (P=0.12). Results of COP sway velocity showed in barefoot condition COP sway the most and in comparison with orthopedic shoe COP sway velocity were decreased with functional foot orthosis and regular shoe (significant level was 0.05).

Conclusion: According to result of this study about static balance in flat foot children, there was no significant different among orthopedic shoe and functional foot orthosis. Due to the reduced displacement of center of pressure with functional foot orthosis and rejection of orthopedic shoe by children it seems that prescription of functional foot orthosis with regular shoe can be properly administered in flat foot children.