The relationship between the position of the spine in the sagittal plane and longitudinal arching of the feet in school-age girls and boys - cross-sectional study.

Introduction: Discoveries concerning the role of connective tissue and myofascial chains require a change in thinking about the functioning of the human body and verification of the approach to correcting posture defects. The aim of the study was to evaluate the relationship between the shape of the spine in the sagittal plane and longitudinal arching of the feet. Material and methods: 271 girls and 241 boys aged 10-12 years were examined. Height and body weight were measured. The BMI was calculated and the status of body weight was estimated. The depth of thoracic kyphosis and lumbar lordosis as well as the sagittal trunk inclination were assessed using the Zebris Pointer ultrasound system. Arching of the feet was determined on the basis of the Arch Index on BTS P-walk platform. Statistica v13 software was used to analyse the data. Results: Both sexes showed a tendency to have deeper thoracic kyphosis and lumbar lordosis. About 15% of the participants had flatfeet. Hollow and correct arching of the feet was observed with a similar frequency (38-43%). Hollow feet arching was accompanied by shallower lumbar lordosis and a shift of the body's general centre of gravity backwards. The participants with flat foot arching tend to have deeper lumbar lordosis. A greater depth of physiological curvatures of the spine and lower longitudinal arching of the feet were observed in boys. BMI was positively correlated with decreased arching of the feet and deepened lumbar lordosis. Conclusions: Longitudinal arching of the feet significantly correlates with the depth of lumbar lordosis and trunk balance.