Effects of foot exercises and customized arch support insoles on foot posture, plantar force distribution, and balance in people with flexible flatfoot: A randomized controlled trial

Background: Exercises strengthening foot muscles and customized arch support insoles are recommended for improving foot posture in flexible flatfoot. However, it is not known what the effects of exercises and insoles on plantar force distribution obtained during walking at different speeds. Also, randomized controlled trials comparing the effects of exercises and insoles are limited. Research question: What are the effects of foot exercises, customized arch support insoles, and exercises plus insoles on foot posture, plantar force distribution, and balance in people with flexible flatfoot? Do exercises, insoles, and exercises plus insoles affect outcome measures differently? Methods: Forty-five people with flexible flatfoot were randomly divided into three groups and 40 of those completed the study. The exercise group performed tibialis posterior strengthening and short foot exercises three days a week for six weeks. The insole group used their customized arch support insoles for six weeks. The exercise plus insole group received both interventions for six weeks. The assessments were performed three times: before the interventions and at the 6th and 12th weeks. Outcome measures were (1) foot posture, (2) plantar force distribution in the following conditions: static standing, barefoot walking at different speeds, and walking immediately after the heel -rise test, and (3) balance. Results: Foot posture improved in all groups, but insole was less effective than exercise and exercise plus insole (p <0.05). Plantar force variables obtained during standing and walking changed in all groups (p <0.05). The superiority of the interventions differed according to the plantar regions and walking speed conditions (p <0.05). Static balance improved in all groups, but limits of stability improved in the exercise plus insole and exercise groups (p <0.05). Significance: The superiority of the interventions differed according to the assessed parameter. The management of flexible flatfoot should be tailored based on the assessment results of each individual.