Introduction and objective:
Correct arching of the feet plays an important role in the development of the musculoskeletal system in children. Early school age is a critical period for the formation of the longitudinal arch of the foot and is simultaneously associated with a high prevalence of its abnormalities. The aim of this study is to assess the prevalence of foot deformities in 7-year-old children and to analyze the relationship between foot arch structure, anthropometric parameters, and the level of extracurricular physical activity.

Material and methods:
This cross-sectional study included 110 children aged 7 years. Measurements of body weight, height, and BMI were performed, and the level of extracurricular physical activity was assessed. Foot arch morphology was evaluated using a podoscopic examination with calculation of the Clarke’s angle. Based on the obtained values, feet were classified as normal, with lowered arch, flatfoot, or cavus foot. Statistical analysis was conducted using the Mann–Whitney U test.

Results:
Foot deformities were identified in 53.6% of the examined children, with lowered longitudinal arch being the most common abnormality. Physically active children demonstrated significantly higher Clarke’s angle values for both feet, compared to physically inactive children (p < 0.000). The mean Clarke’s angle was higher by 12.93° in the physically active group. No significant differences were found between the groups in terms of body weight, height, or BMI

Conclusions:
Foot deformities are a common problem among early school-age children. Extracurricular physical activity is associated with more favourable foot arch morphology, and may constitute an important element in the prevention of foot structure disorders in children.