Foot Arch Posture Development in Children and Adolescents aged 6 to 19 Years: A Cross-sectional Descriptive Study

Abstract Background: The arch height index (AHI) is a commonly used method for measuring foot arch posture. However, there are little studies have investigated the natural growth and normative values of the foot arch using the AHI. The objective of this study was to establish normative and cut-off values for foot arch posture and to identify factors influencing foot arch posture across childhood and adolescence. Methods: In this cross-sectional study, a sample of 3532 healthy children and adolescents (1804 boys, 1728 girls; aged 6 to 19 years) was recruited for the navicular height (NH) and AHI measurements and anthropometry assessment (weight, height, BMI and foot length). Data were explored descriptively and graphically, comparisons between groups used t-tests or ANOVA model as appropriate and a multiple regressions was conducted. The 95% and 68% prediction intervals were used as cut-off values. Results : approximately 69% had a normal AHI range, 12% low arched foot, 3% severely low arched, 14% high arched and 1.8% severely high arched foot. The mean (SD) AHI was 15.16 (2.61). Very little gender bias was found for AHI values, being higher in males 15.32 (2.54) than in females 15.0 (2.68) ( p = .019). Regression showed approximately 3%, 0.3% and 2% of the AHI change was explained by age, BMI and foot length, respectively. The mean NH significantly increased from the age of 6 (2.62 cm) to 19 (4.20 cm). Conclusions: This study confirms that the ‘flexible flatfoot’ or low arched foot decreases with age. Simultaneously, increase of high arched foot type and shift in foot posture towards more normal foot type are also confirmed. BMI does not seem to be an important determinant of children foot arch posture. Keywords: Foot posture, Navicular height, Arch height index, Normative values, Medial longitudinal arch, Foot arch development, Children, Adolescents