Comprehensive assessment of physical development in children and adolescents is a critically important component of the pediatric population health status estimation. This makes it possible to identify the effects of the lifestyle factors, environment, and learning process on the growing child’s body [1, 2]. A considerable amount of scientific research on assessing physical development in children during various age periods is carried out in order to monitor the pediatric population health status. The children’s harmonius development, well-being, and social adaptation determine the future of our country [3, 4].

The physical development level is determined by the values of key anthropometric parameters (body height and weight), and the ratio of these parameters determines whether the child’s development is harmonious. Furthermore, physiological parameters that reflect the activity of body’s structural components also play an important role in assessment of physical development [5, 6].

The results of large-scale studies confirm unfavorable trends in children and adolescent health. There is a decrease in the number of healthy children, along with the increase in the number of children with chronic disorders or disability [7]. The child’s body continuously grows and develops; any deviations from normal can indicate health problems. Physical maturation follows biological patterns and reflects the general patterns of body’s growth and development [8]. However, the long-term urbanization, transformation of the environment, changes in the population ethnic makeup, effects of the climatic and georgaphic conditions, lifestyle, as well as different quality of care provision also influence the processes of children’s physical development.

The regional indicators of physical development used to assess the development of traits are based on the anthropometric assessment of homogenous groups of children. These indicators need to be continuously updated and adapted for each region of Russia. The regional standards of physical development for children and adolescents living in the Samara Region, which were updated in 2013, need to be revised.

In this regard, it is relevant to assess dynamic changes in the main physical development indicators in this region considering the regional and temporal features.

The study was aimed to assess the dynamic changes of physical development indicators in the high school-age children in the Samara Region over a decade.

METHODS

The surveyed group included 476 children aged 14–16 years (256 boys, 220 girls), who attended secondary educational institutions in Samara and had no clinical manifestations of disorders; at the time of measurement they belonged to the health status groups 1 and 2. The surveyed children had been permanent residents of Samara for more than 5 years. The children belonging to the health status group 3 or higher, who did not attend general educational institutions or lived in Samara for less than 5 years, were excluded from the study. Body height and weight were measured using standard equipment: body height using a stadiometer (Tves; Russia) with an accuracy of up to 0.5 cm, body weight using the VEM-150- Massa-К scales (Massa-К; Russia) with an accuracy of up to 60 g. The anthropometric characteristics (body height and weight) were estimated using the regional regression scales for the Samara Region in the Anthro-prof software package "Program for Assessing Physical Development in Schoolchildren” [9, 10].

The data obtained were compared with similar physical development indicators obtained in the study conducted in 2013. The study involved 496 adolescents aged 14–16 years (263 boys and 231 girls), who attended secondary educational institutions in Samara [11].

Statistical processing of the results was performed using the StatTech 4.0 (StatTech; Russia) software package and MyOffice (New Cloud Technologies; Russia). Significance of differences between the values compared was determined using the chi-squared test (χ²); Yates's correction was applied when necessary. The critical significance level was considered to be 0.05, when testing the statistical hypotheses. Student’s t-test was used to estimate significance of differences between the mean values. The differences were considered significant at р ≤ 0.05.

RESULTS

Estimation of children’s physical development throughout two assessment periods revealed no children with disharmonious physical development due to abnormal body height.

Estimation of physical development in senior school-age boys revealed significant differences in boys aged 14 and 15 years relative to their peers examined in 2013. Thus, the share of 14-year-old children with harmonious physical development was 69.5% in 2013, while in 2023 it was 50% (p = 0.024). However, the share of children with disharmonious physical development due to excess body weight increased: it was 14.7% in 2013 and 31.5% in 2023 (р ≤ 0.05). Furthermore, the percentage of children with disharmonious physical development due to underweight increased in 2013.

The share of 15-year-old boys with harmonious physical development was 72.5% in 2013 and 68.2% in 2023. The share of children with disharmonious physical development due to excess body weight was 8.7% in 2013, while in 2023 it was 16.6%. The differences between peers assessed in two different decades were significant (р ≤ 0.05). Comparison of physical development in the 16-year-old boys assessed in 2013 and 2023 revealed no significant differences (p > 0.05).

In 2013, the share of boys with harmonious physical development was 61%, while in 2023 it was as low as 38.2%. Furthermore, the percentage of adolescents with disharmonious physical development due to underweight increased increased in this age group: in 2013 it was 22.0%, and in 2023 it was 47.1%. Amidst this the percentage of overweight boys decreased: it was 17% in 2013 and dropped to 14.7% in 2023 (tab. 1).

Such trend was also observed in girls. By the age of 16, the share of today’s children with harmonious physical development becomes the same as the share of their peers examined in 2013. Assessment of 14-year-old girls revealed significant differences in the physical development estimation results (р ≤ 0.05). The share of girls with harmonious physical development dropped to 37.5% in 2023, while in 2013 it constituted more than a half of the surveyed adolescents of the same age group (56.3%). In contrast, in 2023 the share of girls with disharmonious physical development due to excess body weight increased to 34.5%. In 2013 the value of this group was 23.1%. Despite the growing number of overweight girls, the prevalence of underweight among girls also increased relative to 2013 (to 28 and 20.6%, respectively). Physical development of the 15- and 16-year-old girls surveyed in 2023 did not differ from that reported in 2013. Harmonious physical development was reported in 51.2% of 16-year-old girls surveyed in 2013 and 61.8% of girls surveyed in 2023. No differences were also revealed in the OW and UW groups of both 15- and 16-year-old girls (tab_2;).

Comparison of the mean values of major anthropometric traits of children surveyed in different decades revealed significant differences. According to the assessment results obtained in 2023, a significant increase in body height was revealed in the groups of 14- and 15-year-old-boys relative to their peers surveyed in 2013. Thus, body height of 14-year-old boys was 157.3 ± 0.64 cm in 2013 and 168.2 ± 1.8 cm in 2023 (p < 0.01). In 15-year-old boys, body height was 163.6 ± 0.77 cm in 2013 and 170.3 ± 1.1 cm in 2023 (p < 0.01.) There were no significant differences between the values of 16-year-old boys: 176.53 ± 0.93 cm in 2013, 176 ± 1.1 cm in 2023 (p = 0.37).

When comparing body height in girls surveyed in 2023, a significant increase in body height at the age of 14 and 15 years relative to the peers surveyed in 2013 was reported. Thus, body height of the 14-year-old girls was 147.3 ± 0.64 cm in 2013, and in 2023 it was 153.9 ± 1.1 cm (p < 0.01). Body height of the 15-year-old girls was 160.8 ± 1.1 in 2013 and 165.8 ± 0.77 cm in 2023 (p < 0.01). The values of 16-year-old girls were as follows: 2013 — 176.53 ± 0.93 cm, 2023 — 176.0 ± 1.1 cm (p = 0.66) (fig. 1).

Physical development of the boys surveyed in 2023 was significantly different from that of girls (р = 0.003): the percentage of underweight children among boys (15%) was significantly lower than among girls (30%) surveyed in 2023. However, boys with harmonious physical development showed no significant differences from their female peers (р = 0.605).

When comparing boys and girls surveyed in 2013, it was found that the share of boys with harmonious physical development (68%) was significantly higher (р = 0.019), than the share of girls (50%). Underweight and overweight boys were statistically the same as girls (р = 0.103).

Comparison of body weight in the high school-age boys showed that the 14-year-old schoolboys surveyed in 2013 significantly (р = 0.044) lagged behind their peers surveyed in 2023. Body weight values became the same by the age of 15 years. This could be due to the larger number of overweight children (Table 2). Thus, body weight of 14-year-old boys was 46 ± 4.08 kg in 2013, 50.3 ± 0.86 kg in 2023 (р < 0.01). The values of 15-year-old boys were as follows: 64.2 ± 0.4 kg in 2013, 62.2 ± 0.7 kg in 2023 (р = 0.05). Body weight of 16-year-old boys was 66.73 ± 0.3 kg in 2013 and 67.6 ± 1.2 kg in 2023 (р = 0.05) (fig. 2).

A similar trend was observed when comparing body weight in girls. Thus, the 14-year-old girls surveyed in 2013 had significantly lower body weight (р < 0.01), than their peers surveyed in 2023. However, the body weight values obtained in 2013 and 2023 became the same by the age of 15 years.

Body weight of 14-year-old girls was 49.6 ± 1.8 kg in 2013 and 53.5 ± 0.7 kg in 2023 (р = 0.045). The values of 15-year-old girls were as follows: 54.27 ± 0.6 kg in 2013, 54.4 ± 1.1 kg in 2023 (р = 0.91). Body weight of 16-year-old schoolgirls was 54.6 ± 0.8 kg in 2013, 55.7 ± 1.3 kg in 2023 (р = 0.47) (fig. 2).

DISCUSSION

Comparative analysis of the physical development assessment results has shown that children with harmonious physical development are significantly less common among today’s schoolchildren of the Samara Region, than among their peers surveyed in 2013.

The study of the features of the indicator dynamics has revealed significant differences in the major anthropometric traits in each gender-age group. The lag in development of one anthropometric trait is not always associated with the corresponding trends of other developmental indicators in the same gender-age group. Significant differences in the number of underweight boys were revealed when comparing boys and girls. The observed decrease in the number of children with harmonious physical development resulting from the increase in the number of overweight boys and girls that was confirmed by significant differences in the average body height and weight can suggest specific features of sexual development in the discussed age groups [12, 13]. The change in the age of growth spurt was revealed when comparing the average anthropometric parameter values. In our opinion, which is in line with the other authors’ opinions [14, 15], the change can result from the features of the course of puberty and the impact of the altered diet, urbanization, and increased information load.

According to a number of researchers, the current trend is a significant increase in the number of children of this age group compliant with the basic principles of healthy lifestyle and actively involved in sports, which also has an effect on the anthropometric parameters. Thus, the authors note than body weight of the children engaged in swimming is significantly higher than body weight of their peers [16], while children engaged in tennis have body height that is significantly higher, than in children, who do not practice intense physical exercise [17].

A significant increase in the schoolchildren’s body weight relative to the values reported in 2013 can be associated with the quarantine measures due to coronavirus infection (COVID-19): large amount of time spent at home, sedentary lifestyle, decreased physical activity [18].

CONCLUSIONS

The identified differences in the anthropometric indicators of 14–16-year-old children acquired in different decades in Samara demonstrate the need for thorough investigation of the current features of physical development in the majority of childrens’ age groups aimed to decide on the need to revise the regional standards of the physical development anthropometric traits. The features of the growth shift identified provide the context for the more thorough study of biological development in today’s schoolchildren. Multiple studies suggest possible effects of the living conditions and lifestyle, including the amount of children’s physical activity. In this regard, it seems necessary to assess the possibility to use the data of the children actively involved in sports and allocate the groups of children with various levels of physical activity for more thorough and reliable estimation of their physical development, when studying anthropometric indicators.