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Studies of age at menarche in Poland have a long history and consistently show an urban-rural gradient. The objectives of the study were to to estimate the age at menarche among school girls resident in ten rural communities of the Greater Poland province in 2016 and to compare ages at menarche by weight status and by population growth. The sample included 1146 girls, 7–16 years of age, resident in ten rural communities. Menarcheal status was obtained via interview. Heights and weights were measured; the BMI was calculated. Based on the latter, the girls were classified as thin, normal weight and overweight (including the obese) relative to IOTF criteria. Population growth between 1986 and 2016 in each community was estimated from local records. Ages at menarche were estimated with the probit regression protocol (SPSS) using the logistic model with log 10 transformation for the total sample and for the subsamples by weight status and population growth. The median age at menarche for the total sample of rural girls was 13.25±0.20 years. Menarche was earlier among Overweight (13.06±0.32 years) compared to Normal Weight (13.25±0.37 years) and Thin (13.81±0.41 years), and among girls resident in communities with Major population growth (12.58±0.44 years) compared to Little/No growth (13.65±0.14 years). Results of the present survey were generally consistent with recent surveys of age at menarche among rural girls in Poland and among girls classified by weight status. Corresponding comparative data relating menarche to population growth are lacking.

Anthropometric, functional and physical activity characteristics of contemporary adult descendants of Upper Silesian immigrants to Texas in the mid-19th century and current residents in Upper Silesia were compared. The sample included 45 residents in Central Texas, 25 women and 20 men, and 36 residents in rural Upper Silesia, 24 women and 12 men, 54-76 years of age. Variables included selected demographic characteristics, anthropometry, estimated body composition, several physiological indicators, strength and functional fitness, and physical activity. Sex-specific MANCOVA and Chi square were used for comparisons. Descendants of Silesian immigrants to Texas were taller, on average, while differences in other anthropometric variables were variable. All residents in Silesia and the majority of descendants of Silesian migrants to Texas were overweight or obese. Differences in hemodynamic and respiratory functions and responses to a 6-minute walk were inconsistent, while none of the fitness variables differed significantly between the samples. Although residents in Upper Silesia were significantly more physically active descendants of Silesians in Texas, >80% of the men and women in both samples scored below the criterion-reference standard for the maintenance of physical independence in the 6-minute walk.

Under marginal nutritional conditions, growth in utero is related to subsequent growth and adult height. The aim of this research is to compare the young adult body size of women grouped by estimated duration of pregnancy relative to World War II. Subjects were 620 university students 18-25 years, for whom archival data for date of birth, age, height and weight were available; the BMI was calculated. Based on estimated time of pregnancy and birth relative to WWII, the women were grouped as follows: (1) pregnancy and birth before the war (n=203); (2) pregnancy before the war, birth during the war (n=54); (3) pregnancy and birth during the war (n=173); (4) pregnancy during the war, birth after the war (n=16); and (5) pregnancy and birth after the war (n=174). Heights of women born before and after WWII were significantly taller than heights of women born during the war. Though not significant, the height of women who were conceived before but born during the war was intermediate between those of women born before and during the war. The height of women conceived during the war but born after the war was similar to that of women conceived and born during the war. In contrast, BMIs and the distributions of women by weight status did not differ among the five pregnancy groups. The results suggested that heights of young adult women exposed in utero to the conditions of WWII (marginal nutritional status, maternal stress, among other factors) were shorter than women who were not exposed in utero to wartime conditions.

Estimated ages at take-off (TO) and at peak height velocity (PHV) based on two models and maturity status based upon age at PHV and skeletal age (SA) were compared in a longitudinal sample of male soccer players. In addition, estimated ages at PHV in 13 longitudinal samples of soccer players were compared. The longitudinal height records of 58 players of European ancestry, measured annually on four or five occasions between 11 and 16 years, were modeled with Superimposition by Translation and Rotation (SITAR) and Functional Principal Component Analysis (FPCA) to estimate ages at TO and PHV. SAs were assessed with the Fels method. Ages at PHV in 13 longitudinal samples of soccer players (Europe 7, Japan 6) were evaluated with meta-analysis. Estimated ages at TO, 11.2 ± 0.8 (SITAR) and 11.0 ± 0.8 (FCPA) years, and at PHV, 13.6 ± 0.9 (SITAR) and 13.7 ± 0.0 (FCPA) years, were similar. An earlier age at PHV was associated with advanced skeletal maturity status (rho = -0.77 at ~14 years). Ages at PHV among European players indicated a north (later) -- south (earlier) gradient, and were later than ages at PHV among Japanese players. In summary, ages at TO and PHV were similar with SITAR and FPCA, and ages at PHV were most strongly correlated with SA at ~14 years. Mean ages at PHV showed a north-south gradient among European samples, and were later compared to Japanese samples. [ABSTRACT FROM AUTHOR]

The pubertal transition can present an interesting paradox for the young dancer, with growth and maturation leading to improvements in some areas such as strength and power and detriment to others, such as flexibility and co-ordination. These challenges highlight the need to consider the interactions among biological, psychological and sociocultural factors during the pubertal transition in the context of the ballet environment. Awareness of these potential interactions will likely provide insights as to why some dancers successfully adapt to the challenges of puberty while others have greater difficulty. This review explores how we might extend existing biocultural models to the context of ballet in order to garner a greater understanding of the pubertal transition. Future research should explore the interactions among social, psychological and biological factors during puberty in adolescent ballet dancers in order to document important determinants of adaptive responses at puberty and to inform future endeavours aimed at promoting healthy pubertal transitions among young dancers.

Objectives: To evaluate secular change in body size and weight status of adult Indian males born in 1891–1957 and surveyed in the 1970s. Methods: Data are from Anthropological Surveys. Only men were included in the surveys due to high female illiteracy and lack of female researchers. Indian society was also strongly conservative at the time, especially in rural areas, and the measurement of women by men was not permitted. Heights and weights of 43 950 males 18–84 years (born 1891–1957) were measured. The BMI was calculated; weight status of individuals was classified relative to WHO criteria and suggested criteria for the Asia‐Pacific region. Heights of men 35+ years were also adjusted for age‐related stature loss. Trends in measured and adjusted heights, body weight and the BMI, and in weight status were evaluated by age groups. Linear regression of measured height and adjusted height on year of birth was used to estimate secular effects. Results: Mean heights declined slightly with age to 50 years and declined sharply through 60+ years, while mean weights increased into the 40s and then declined. Mean BMIs were relatively stable from 30 to 60 years. The prevalence of thinness and normal weight was high, while that of overweight and obesity was low. Regression analyses indicated limited secular change across the total range of birth years but suggested a decline in adjusted heights among men born in 1891 through the 1930s, and little change among men born subsequently. Conclusions: Age‐related trends and results of the regression analyses by year of birth indicated negligible secular change in heights of Indian men 18–84 years born between 1891 and 1957. BMIs indicated a high prevalence of thinness and normal weight and low prevalence of overweight and obesity. [ABSTRACT FROM AUTHOR]

Background: Research on relationships between lifestyle behaviors and adiposity in school youth is potentially important for identifying subgroups at risk. This study evaluates the associations between waist circumference (WC) and objective measures of sedentary behavior (SB) in a sample of rural school adolescents. Methods: The sample included 254 students (114 boys, 140 girls), 13-16 years of age, from rural regions of the Portuguese midlands. Height, weight, and WC were measured. Cardiorespiratory fitness (CRF) was assessed with the 20-m shuttle-run test. An uniaxial GT1M accelerometer was used to obtain 5 consecutive days of physically activity (PA) and SB. Multiple linear regression was used to test associations between WC and SB, adjusted for several potential confounders (age, sex, PA, CRF, parental education). Results: SB was not significantly associated with the WC, neither in the unadjusted model nor after adjustment for all potential confounders. In the final model, the unique significant predictor of the WC was cardiorespiratory fitness (ß = -0.82; 95% confidence interval [CI], -1.02 to -0.62). Conclusion: WC was not independently associated with SB time in rural school adolescents. Future research is claimed among rural adolescents in different geographic contexts to try to clarify recent findings of less studied communities.

Background: The objective of the study was to evaluate secular changes in the physical fitness of rural school youth, 7–15 years, in west-central Poland between 1986 and 2016. Methods: The fitness of cross-sectional samples of school youth resident in the same 10 communities was evaluated in 4 decennial surveys: 1986—1417 boys/1326 girls; 1996—979 boys/947 girls; 2006—871 boys/843 girls; and 2016—1189 boys/1105 girls. Five tests evaluated speed (5-m run), agility (figure 8 run), explosive power (vertical jump), flexibility (stand and reach), and cardiovascular fitness (modified Harvard step test). Age- and sex-specific descriptive statistics were calculated by survey, while differences among surveys were compared in 3 broad age groups (7–9, 10–12, and 13–15 y) using analysis of variance with age and age squared as covariates. Results: Speed and flexibility declined, while the jump and step test index changed variably across surveys. Although agility improved across surveys, the major improvement occurred between 1986 and 1996. Conclusions: Performances of rural school youth on 5 tests of physical fitness changed significantly, but, variably, between 1986 and 2016. The results were generally consistent with other studies of Polish school youth that spanned a similar interval. [ABSTRACT FROM AUTHOR]

Growth and maturation are central concerns in the organization of training and competitions in youth sports. This study examined maturity-associated variation in body size and adiposity among adolescent girls participating in competitive age group youth soccer. The sample included 441 players 10.08-16.73 years of age. Stature and body mass were measured and body composition was predicted. The Fels method was used to estimate skeletal age. Skeletally maturity status (late, average or early maturing) was based on the difference between chronological and skeletal age for each player. Mean stature approximated the 50th percentiles of the general population in all competitive age groups, while mean weight fluctuated between 50th and 75th percentiles. Age- and maturity-specific means for estimated fat mass ranged between 18.0% and 28.2%. The number of players classified as skeletally mature increased with competitive age groups (under-13: 0%; under-15: 8%; under-17: 49%). In general, early maturing girls tended to be heavier than their age group peers and especially when compared to late maturing players. [ABSTRACT FROM AUTHOR]

Short term secular change in body size and physical fitness of Polish youth 7-15 years of age resident in an industrial region of Lower Silesia in southwestern Poland was considered across two surveys, 2001-2002 and 2010-2011. Subjects were students in the same schools in both surveys 1892 boys and 1992 girls in the first and 1237 boys and 1236 girls in the second. In addition to height and weight, performances in six fitness tests were measured in each survey. Height, weight and BMI increased significantly across surveys. Statistically controlling for secular gains in height and weight, only static strength (hand grip) and running speed - agility (shuttle run) improved significantly between surveys in three age groups (7-9, 10-12, 13-15 years), while explosive power (standing long jump) showed negligible changes except in girls 13-15 years among whom performances declined significantly. Speed of upper limb movement (plate tapping), flexibility (sit and reach) and trunk strength (sit-ups) declined between surveys, except for trunk strength in boys 13-15 years which did not change. In conclusion, after statistically controlling for secular gains in body size, physical fitness items changed variably over the decade.

Growth, maturation, and development dominate the daily lives of children and adolescents for approximately the first 2 decades of life. Growth and maturation are biological processes, while development is largely a behavioral process. The 3 processes occur simultaneously and interact. They can be influenced by physical activity and also can influence activity, performance, and fitness. Allowing for these potential interactions, 10 questions on growth and maturation that have relevance to physical activity, performance, and fitness are presented. The questions are not mutually exclusive and address several broadly defined topical areas: exercise and growth, body weight status (body mass index, adiposity rebound, "unhealthy weight gain"), movement proficiency (hypothesized barrier, role in obesity), individual differences, tracking, maturity-associated variation in performance, and corresponding variation in physical activity. Central to the discussion of each is the need for a biocultural approach recognizing the interactions of biology and behavior as potential influences on the variables of interest.