Investigation of the effect of insoles of different types on electromyographic muscle activation in individuals with pes planus

The aim of this study is to examine the effect of insoles made of different materials on lower extremity muscle activity in individuals with pes planus and to investigate whether it changes towards the pattern seen in people with normal foot arch. Six individuals with flexible pes planus voluntarily participated in the study. The mean age of the individuals was 33.8±11.1 years, height 1.64±0.06 m, mean weight 62.3±7.3 kg, mean BMI 23.1±2.7 kg/m^2. Pes planus severity of individuals was measured with Clark angle and Foot Posture Index (FPI) using podoscope device and footprint method. Activation of the muscles was measured with a surface electromyography (sEMG) device for maximum isometric contraction (MIC) and during walking with non-insoles, soft (silicone), semi-rigid (polyform) and rigid (steel) insoles at one-day intervals. Functional conditions affecting the foot were evaluated with the Foot Function Index (FFI). No relationship was found between the Foot Function Index (FFI) and the severity of pes planus. No difference in %MIC values was observed between the insoles, soft (silicone) semi-rigid (polyform) and rigid (steel) insoles in the same phase of gait. A significant difference was found between the heel strike (0-10%) phase of gait and the swing (60-100%) phases of gait in terms of %MIC value in the emg measurement taken from the tibialis anterior with a rigid (steel) insole. In the emg measurement taken from the peroneus longus muscle with a semirigid (polyform) insole, a significant difference was found between the mid-stance (10%-40%) phase of the gait and the swing (60-100%) phases in terms of %MIC value. While rigid (steel) insoles reduce tibialis anterior muscle activation in heel strike phase compared to swing phase, semirigid (polyform) insoles increase peroneus longus muscle activation in mid-stance phase of gait compared to swing phase.