The purpose of the study was to work out the main criteria of physical development and to analyze current trends in physical development of 11-year-old schoolboys and schoolgirls according to the indices of body height, body weight and chest circumference. An anthropometric examination of 382 schoolchildren of 11-year-old (177 schoolboys and 205 schoolgirls) in Lviv was conducted during 2018–2020. The main criteria and regression scales for assessing physical development based on the obtained parameters have been developed and updated. Body height, body weight and chest circumference, assessment of physical development by height (average, above and below average, low and high), the degree of its harmonicity (harmonious, disharmonious, sharply disharmonious) was determined by conventional methods. The assessment of physical development was conducted according to the regression scales developed by us and the body mass index. The dynamics of changes in anthropometric indices was analyzed for 26 years, from 1996 to 2020. Mathematical and statistical processing of the obtained parameters was conducted by a least-squares method with determination of the significance of the results by Student’s t-test using Microsoft Excel which is part of the Microsoft Office software and RStudio. Anthropometric indices of the observed schoolchildren correspond to the physiological regularities of development of 11-year-old children and are almost the same in boys and girls with a tendency to higher body height in girls than boys, and reflecting physiological sexual dimorphism at this age. Physical development regression scales are developed (independent index is body height (x), variable indices are y – body weight, z – chest circumference, the regression equations for 11-year-old boys were obtained: y = -69.41 + 0.74x, z = 6.99 + 0.43x with an average height from 140 cm to 153 cm, above average – from 154 cm to 160 cm and below average – from 133 cm to 139 cm, high – from 161 cm to 166 cm and low – from 128 cm to 132 cm; the regression equations for 11-year-old girls were obtained: y = -56.97 + + 0.65x, z = 10.41 + 0.39x with an average height of 141 cm to 154 cm, above average – from 155 cm to 161 cm and below average – from 135 cm to 140 cm, high from – 162 cm to 165 cm and low – from 131 cm to 134 cm). It was established that the majority (74.5%) of the examined 11-year-old children in Lviv are of average height, of which 75.7% are boys and 73.2% are girls. More children with above-average height than below-average height among girls and boys were observed. The same part of girls with high and low body height was revealed, but among boys, low body height exceeded the part of high body height. 56.3% of children (53.7% of boys and 58.8% of girls) had a harmonious development. Disharmonious physical development of schoolchildren is due to excess or deficit of body weight of I and II degrees, increase or decrease of chest circumference of I and II degrees and their combinations. Almost half (47.3%) of examined children have deviations in nutritional status. A significant part of schoolboys and schoolgirls (15.9%) are obese (16.5% of boys and 15.4% of girls), which requires proper nutrition and optimization of diet. The increase in height and body weight of children in Lviv for the period from 1996 to 2020 indicates the acceleration processes of physical development of modern schoolboys and schoolgirls. The updated regression scales can be used to assess the physical development of students at the present stage in conducting a retrospective analysis of the dynamics of physical development over time and simultaneously comparing the levels of physical development of children in different regions and localities.
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