Effects of Modified Insole on Lower Extremities Biomechanics in College Male Basketball Players

The purpose of this study was to investigate the effect of fore-medial-side thin insole on lower extremities kinematics and kinetics in college male basketball players. Seven male college basketball players voluntarily participated in the study (heights= 173.1 ± 3.1 cm; weights= 68.6 ± 5.7 kg; age= 21.1 ± 2.0 yrs.). They wore the same basketball shoes with 2 types of insoles: one type was original insole (OI); another one was fore-medial-side gradually thin insole (TI). Participants were asked to perform L-cut, V-cut, Backdoor-cut, walk, shuttle run of basketball movement in a 5-meter running way with their maximum speed. They were instructed to step with their right leg when they changed direction. The kinematic and kinetic data were collected during support phase. Non-parametric Wilcoxon signed rank test and the effect size were used to determine the difference of the variables of interest between the original and fore-medial-side thin insoles. The fore-medial-side thin insole showed less foot inversion angle at contact, peak ankle lateral shear force and ankle dorsiflexion moment than the original insole in L-cut (p<.05). In V-cut, the fore-medial-side thin insole showed less hip internal rotation at contact than the original insole (p<.05). In the shuttle run, the fore-medial-side thin insole showed less hip abduction at contact than the original insole (p<.05). In case of foot pressure, it showed no statistically significant but had large effect size on left foot’s pressure time integral (PTI), in L-cut (≥0.8), large effect size on left foot’s PCP, PTI, right foot’s PTI in V-cut (≥0.8), large effect size on left foot’s peak contact pressure of 1st metatarsal (PCP), PTI, peak pressure gradient (PPG), right foot’s PTI in BD-cut (≥0.8), large effect size on left foot’s PTI, medium effect size on left foot’s PPG (≥0.5), and medium effect size on left foot’s the distance from the point of peak contact pressure to the medial edge of 1st metatarsal (PCPd) (≥0.5). In conclusion, the fore-medial-side thin insole can help to push our body to the medial side and decrease the risk of injuries of the lower extremity during cutting movements.