The effect of foot hyperpronation on spine alignment in standing position

Background: According to clinical observations, foot hyperpronation is very prevalent and may cause malalignment of the lower extremity, leading to structural and functional deficits in standing and walking. This study aimed at investigating the effect of foot hyperpronation on spine alignment in the standing position.   Methods: Thirty-five healthy males with an age range of 18-30 years participated in this cross-sectional study. Evaluation was performed with two examiners in four standing positions (on the floor, and on the wedges angled at 10, 15, and 20 degrees) using a motion analysis system (Zebris). Moreover, each of the measurement methods was repeated for three short times.  Paired t- test and repeated measures ANOVA test were used for statistical analysis.   Results: Significant differences were observed between all modes in the sacral angle, pelvic inclination, lumbar lordosis, and thoracic kyphosis variables (except between the first and second mode). Finally, a positive correlation was obtained for the examiners and all the variables with an increasing slope of the angle of wedge.   Conclusion: The results of the present study revealed sacral angle, pelvic inclination, lumbar lordosis, and thoracic kyphosis were increased with an increase in bilateral foot pronation. In fact, each one of them is a compensatory phenomenon.