The effects of intrinsic foot muscles strengthening exercises on knee kinematic in pronated foot subjects during forward jump landing

Introduction: The foot and ankle are a complex set of multiple joints with multiple degrees of freedom that play an important role in static and dynamic activities. The intrinsic and extrinsic muscles of this complex play a role in controlling the deformity of the arch; thus, the aim of this study was to investigate the effect of the intrinsic foot muscle-strengthening exercises on knee kinematic parameters in pronated foot subjects during forward jump landing. Methods: This interventional study was performed on students aged 20-30-years old with foot pronation in the School of Rehabilitation. In this study, the kinematic changes of the knee in the frontal, sagittal and transverse plane before and after 6 weeks of strengthening exercises of the intrinsic foot muscles during the forward jump-landing task were examined using a motion analyser. All data analysis was performed offline using a special software program in the MATLAB software environment. Results: Knee angle variables have a normal distribution before and after exercise. The ICC coefficient of all variables was calculated as between 0.44 and 0.71; therefore, the reproducibility of the variables under study in this study was considered moderate to good. The knee angle on the frontal plate was 2.54 ± 2.4 before the exercises and 2.49 ± 2.14 after the exercises, and there was no significant difference between them (P = 0.21). Conclusion: Plantar intrinsic foot muscle-strengthening exercises alone have no effect on the kinematic changes of the knee in people with foot pronation, or the duration of strengthening exercises should be increased during the day to see the effect of strengthening the intrinsic muscles among pronated foot subjects.