This study examined the effects of a 5-week short foot exercise (SFE) program with visual feedback on the balance and knee joint function in flexible flatfeet and compared the measures between a flexible flatfoot and normal foot.

A total of 30 subjects participated in this study (15 subjects with a flexible flatfoot, 15 subjects with a normal foot). The subjects were divided through the Navicular Drop Test (NDT). The flexible flatfoot group included subjects with an NDT greater than 10mm. The normal foot group included subjects with an NDT of 5–9mm. The subject group performed SFE with visual feedback. SFE programs were completed 20minutes a day, five times a week for 5 weeks.

A significant difference in the static balance area was observed between the flatfoot group and normal foot group on the pre-test (P<0.05), and there was a significant difference in the Ant. direction and PM direction between the flatfoot group and the normal foot group on the pre-test (P<0.05). The knee joint motions accuracy on the closed chain was significantly different between group on the pre-test (P<0.05). A comparison of the pre- and post-intervention revealed a significant difference in the static balance area and all directions of dynamic balance in the flatfoot group, but only the dynamic balance was significantly different in the normal group (P<0.05). The closed chain motions accuracy of the knee joint after the intervention was similar in the flat foot group and normal foot group.

The balance and knee joint motions accuracy was different in the flat foot group and normal foot group. The SFT program with visual feedback was effective in improving the balance and knee joint motions accuracy.