Change in the Area of the Plantar Surface of the Foot as an Indicator of Its Functional State in Children

The widespread occurrence of disorders and diseases of the musculoskeletal system in children determines the need to study the functional state of the foot in the process of preventive and health-improving measures and in the hygienic assessment of factors of foot formation, including the influence of wearing children’s shoes of different designs and weights. The aim of the study was to evaluate the functional state of the musculoskeletal system of the foot in children using standard functional physical activity. The study was conducted with the participation of 59 children aged 7–10 years. The load consisted of maximally raising and lowering the heels of both feet simultaneously 25 times at a pace of 1 cycle (stand on your toes and lower yourself) in 2 seconds. The area of the plantar surface of the foot was determined using the podobarography method, the condition of the arch of the foot, using the plantography method. It was found that under the influence of the load, the area of the right foot did not significantly change—82.33 ± 1.58 and 81.70 ± 1.74 cm2 (p = 0.642), the area of the left foot decreased from 86.72 ± 1.50 to 81.93 ± 1.44 cm2 (p = 0.000). For the right leading foot, this load turned out to be insignificant, which can be characterized as a manifestation of the “functional rigidity” of the foot in response to the load. For the left foot, the load caused a reaction of mobilization of the musculoskeletal system. The change in the area of the right foot before and after the load, depending on the condition of the arch of the foot, also turned out to be insignificant. For the left foot, in the normal state of the arch of both feet, the area after loading decreased from 80.31 ± 2.27 to 76.14 ± 2.55 cm2 (p = 0.022), with flattening—from 92.78 ± 3.88 to 88.50 ± 3.55 cm2 (p = 0.028), with flat feet – from 90.17 ± 5.35 to 84.25 ± 5.49 cm2 (p = 0.050). The change in the area of the plantar surface of the foot in response to physical exertion can be used to study the functional state of the musculoskeletal system of the foot during preventive medical examinations, evaluation of the effectiveness of preventive and corrective technologies, as well as in the hygienic evaluation of the design of children’s shoes.