The purpose of this study is to investigate the effects of intrinsic strengthening and dynamic balance exercises in patients with flexible pes planus. Forty-five participants aged 18 to 35 years were enrolled in the study, and the first group underwent intrinsic foot muscle strengthening training with short foot exercises (SFE) and used insoles. The second group trained using the dynamic balance board, which promotes dynamic balance and used insoles. The third group used only insoles. The total duration of treatment was 8 weeks/3 days. The degree of foot deformity was assessed with the, medial longitudinal arch (MLA) angle, measurements of subtalar angle and navicular drop test. Foot position assessed using Foot Posture Index (FPI) Static balance was assessed with the Flamingo Balance Test and dynamic balance with the " BOBO Health Platform with Gaming®" device.

Pes planus (flatfoot) is generally defined as valgus of the hindfoot, disappearance of the medial longitudinal arch (MLA) in the midfoot, and supination of the forefoot relative to the hindfoot when the foot is loaded. MLA height is the most important measurement for determining the degree of pes planus. The decrease in MLA disrupts this balance and causes the muscles and bones that are supposed to balance the effect of external forces to be subjected to greater stress. As a result, the balance is affected. Conservative treatment options that can be used as the first step in treating pes planus include activity modifications, exercises, manipulations, serial cast applications, weight loss, shoes changes, shoes modifications, use of foot orthotics. Several methods are used to strengthen foot intrinsic muscles, including toe towel curls, picking up objects, shin curls, unilateral balance activities, and the short foot exercise. The common exercises are strengthening exercises defined for intrinsic muscles, "short foot exercises" (SF). It is known that arch support insoles improve foot malalignment, correct dynamic posture, effectively support leg alignment and pain relief, and normalize gait. The use of silicone insoles is a product whose range of application has increased in recent years. The extremely soft and flexible material ensures that the shape of the foot is adopted. The researchers believed that the presence of a pes planus foot deformity, common in young people, negatively affects the balance of the individual, revealing small disturbances and different balance strategies. In this situation, the training of intrinsic muscles is of great importance. The investigators aim in this study is to investigate the effects of intrinsic muscle strengthening and dynamic balance exercises performed with silicone soles in individuals with flexible pes planus.

Inclusion Criteria:

• Patients were included in the study if they were 152° above the MLA, participants with flexible pes planus at the 1st, 2nd, and 3rd level according to Jack's test, between 18 and 35 years of age, and had not received previous treatment for pes planus.

Exclusion Criteria:

• Individuals who had previously used orthotics, who had an orthopedic injury to the ankle, and who did not wish to participate in the study were excluded from the study.