Background: The human foot contains one of the most variable structures of the body, which is the medial longitudinal arch. Decrease in the height of this arch results in a flat foot. Although there is some evidence regarding the influence of flat foot on gait performance of flat-footed individuals, there is no strong evidence to support the theory that being flat-footed has an effect on energy consumption. Therefore, the aim of this study was to find the relationship between flat foot and energy consumption.
Method: Two groups of normal and flat-footed participants were recruited in this research project. They were selected from the staff and students of Isfahan University of Medical Sciences. The foot indexes of both groups were obtained using the footprint method with help of Solid worker software. The physiological cost index (PCI) of the participants was measured by the use of a heart rate monitoring system (Polar Electro, Finland). The differences between the PCIs of both groups of participants was determined using a t test. In addition, the influence of using an insole was evaluated using a paired t test.
Result: The energy consumption of flat-footed individuals differed significantly from that of normal individuals (the PCIs of normal and flat-footed individuals were 0.357 and 0.368 beats/m, respectively). Using a foot insole improved the performance of the flat-footed individuals during walking.
Conclusion: The PCI of flat-footed individuals is more than that of normal participants as a result of misalignment of foot structure. Moreover, using a foot insole improved foot alignment and decreased energy consumption.