Growth charts of Brazilian youngs: 20-years data of 95,000 children and adolescents from "Projeto Esporte Brasil".

This article aims to present growth curves for height, weight, and BMI of 95,000 Brazilian youths aged 6 to 17 years, including the five regions of the country, the Amazon region, and indigenous populations, and compare them with the World Health Organization (WHO) growth references. The final sample consisted of 52,729 boys and 42,731 girls from the "Projeto Esporte Brasil" database. Body mass and height information were used to derive the curves. The generalized additive model for location, scale, and shape was employed. In this study, we present smoothed weight-for-age, height-for-age, and BMI-for-age curves for boys and girls. Differences were observed between the results of the Brazilian curves and the WHO growth references. The developed curves will be valuable for professionals in medicine, public health, nutrition, physical education, and other related fields, regarding the assessment of physical growth in Brazilian children and adolescents and monitoring the nutritional status of this population. Additionally, these curves will facilitate the identification of individuals or subgroups at risk of diseases and delayed growth, with a greater focus on specific country-related factors.

Associations of sleep time, quality of life, and obesity indicators on physical literacy components: a structural equation model.

AIM: To verify the association between ideal sleep time and physical literacy components while also considering multiple mediators, such as quality of life and obesity, using a sample of adolescents. METHODS: This cross-sectional study consisted of 470 adolescents aged 11-17 years from southern Brazil. Sleep time, health-related quality of life, and physical literacy components (i.e., physical education enjoyment, sports participation, sedentary behavior, moderate to vigorous physical activity, sex, and age) were evaluated through self-reported questionnaires. In addition, body mass index (BMI), and waist circumference were determined. The theoretical/statistical support of the structural equation model was evaluated according to fit parameters and strength of association. RESULTS: A direct association was observed between more sleep time and lower levels of obesity. The obesity indicators also had a negative association with HqOL, and HqOL had a positive association with physical literacy. The indirect associations indicated that the ideal sleep time was positively associated with HqOL and physical literacy components, considering the negative mediation effect of obesity. The model explains physical literacy in 31% of the variance (R = 0.31). CONCLUSION: There was an indirect association between ideal sleep duration and quality of life and between both variables with physical literacy. These relationships occur even considering the negative influence of obesity. Therefore, a child who sleeps adequately has a higher likelihood of being physically active, regardless of obesity, potentially enhancing overall quality of life across various domains.

Effects of a physical education intervention on children's physical activity and fitness: the PROFIT pilot study.

BACKGROUND: Physical education classes are widely accepted as one of the most effective settings for promoting physical activity and health and have often been used to implement physical activity interventions. The aim of this pilot study was to test a physical education intervention program on physical activity levels and physical fitness in a sample of school-age children. METHODS: Participants were a convenience sample of 50 children (34 experimental group and 16 in the comparative group) aged between 6 and 11 years old (Mean = 8.28 years). A 21-week intervention was implemented, consisting of high-intensity and physical fitness-focused exercises, in addition to a once-a-month extra class nutritional education. The following variables were evaluated before and post-intervention: physical fitness, sedentary behavior (SB), light physical activity (LPA), moderate physical activity (MVA), and vigorous physical activity (VPA). Propensity score analyses calculated the average treatment effect on the treated (ATET) within a quasi-experimental framework. RESULTS: Physical fitness variables showed improvements after the intervention, specifically for agility (ATET = -0.67 s; p < 0.001), cardiorespiratory fitness (ATET = 89.27 m; p = 0.045), lower limbs power (ATET = 4.47 centimeters; p = 0.025), and speed (ATET = -1.06 s; p < 0.001). For physical activity and SB levels, there were no improvements after intervention implementation. CONCLUSION: The intervention program showed preliminary effectiveness to improve physical fitness of children, but not SB nor physical activity.

Replacing screen time, with physical activity and sleep time: influence on cardiovascular indicators and inflammatory markers in Brazilian children.

OBJECTIVE: To examine if the substitution of different screen time intervals with light physical activity (LPA), moderate to vigorous physical activity (MVPA) and sleep is associated with cardiovascular indicators and inflammatory markers in children. METHODS: This is a cross-sectional study developed with 186 children aged between six and 11 years old from public schools in southern Brazil. CRF was measured with the 6-minute running and walking test, following the Brazil Sports Project procedures. The percentage of fat was evaluated through DXA. LPA and MVPA were measured using accelerometers. Sleep and screen time were assessed by questionnaires answered by parents. Leptin and C-reactive protein were measured by fasting blood collection. Systolic and diastolic blood pressure were determined through a digital sphygmomanometer. Isotemporal substitution models were used for statistical analysis. RESULTS: Replacing 1 h of screen time with MVPA was associated with lower BMI, systolic and diastolic blood pressure, fat percentage, leptin, and C-reactive protein. When screen time was substituted for sleep time, lower waist circumference was observed. Regarding the substitution of 1 h of screen time with LPA, significant values were found only for leptin. CONCLUSION: The replacement of screen time with physical activities of different intensities and sleep time was associated with benefits in cardiovascular indicators and inflammatory markers in childhood.

A network analysis involving mental difficulties, cognition, physical fitness, 24-hour movement components, fatness, and sociodemographic factors in children.

Background: Evidence supports the beneficial linear influence of diverse lifestyle behaviors on brain health since childhood; however, multiple behaviors -and not only one-simultaneously affect such outcomes. Therefore, the aim was to explore the multivariate relationship through a network analysis among mental difficulty and cognitive function with physical fitness (PF), 24-h movement components, fatness, and sociodemographic factors in children. Methods: Cross-sectional study involved 226 children (52.2 % boys) aged between six and 11 years. Mental difficulties were evaluated through the Strengths and Difficulties Questionnaire and cognitive function by the Raven's Colored Progressive Matrices Test. The body mass index and PF were assessed according to the procedures suggested by the Proesp-Br, while moderate-to vigorous-intensity physical activity (MVPA) using accelerometry. The socioeconomic level, sleep, and screen time were evaluated by questionnaires. A network analysis was carried out to evaluate the associations among variables and establish centrality measures. Results: Age and PF moderated the negative relationship between cognitive function and MVPA. Furthermore, the direct and inverse relationship between cognitive function and mental difficulties appears to be affected by the 24-h movement components. Finally, age, PF, and screen time are the nodes with higher values of expected influence, indicating more sensitivity to interventions for decreasing mental difficulty and improving cognitive function. Conclusion: Mental health and cognitive function were moderated by the multivariate interaction among age, PF, and the three 24-h movement components. Nonetheless, centrality measures from the network analysis suggest that PF, MVPA, and screen time are crucial nodes in order to implement future interventions.

Secular trends in the physical fitness of Brazilian youth: Evidence that fitness is declining for the majority but not for a fit minority.

BACKGROUND: There has been a decline in children's physical fitness in recent decades. Such concerns are largely based on evidence from North America, Europe, and Asia. The current study describes the secular trend and variation (spread) in the physical fitness scores of young Brazilians from 2005 to 2022. METHODS: This study is a repeated, cross-sectional surveillance study (1999-2022). Children and adolescents (n = 65 139; boys = 36 539) participated between 2005 and 2022. In each cohort six physical fitness tests were conducted: (1) 20-m sprint speed (m s-1 ), (2) cardio-respiratory 6-min run test (m min-1 ), (3) abdominal strength test (sit-ups per min), (4) horizontal jump test (cm), (5) the agility test (m s-1 ), and (6) the medicine ball throw test (cm). Means and distributional characteristics of the population were assessed using ANOVA, ANCOVA adopting BMI as the body-size covariate, Levene's test of equality-of-error variances, and Box and whisker plots. RESULTS: ANOVAs and ANCOVA's identified significant declines in physical fitness over time/year in 5 of the 6 physical fitness variables (e.g., 20-m sprint speed slope B = -0.018 (m s-1 y-1 ); 95% CI -0.019 to -0.017; p < 0.001), the only exception being the medicine ball throw test (cm). The Levene's test of equality-of-error variances also identified a systematic increase in the variances/standard deviations over time/years. CONCLUSIONS: Results provide powerful evidence that children and adolescents' physical fitness is declining, a trend that is also diverging asymmetrically, becoming more extreme in more recent years. The "fit" appear to be getting fitter, but the fitness of the "less-fit" appears to be declining further. These results have important implications for sports medicine and government policy makers.

Electronic device and social network use and sleep outcomes among adolescents: the EHDLA study.

BACKGROUND: Considering the evident risk in the literature between the use of screen devices and sleep, there are still few studies on the relationship between each electronic screen device, media programs and sleep duration and sleep-related problems among adolescents and which variables interfere in these relationships. Therefore, this study has the following objectives: (1) to determine which are the most common electronic display devices related to sleep time and outcomes and (2) to determine which are the most common social network applications, such as Instagram and WhatsApp, associated with sleep outcomes. METHODS: This was a cross-sectional study with 1101 Spanish adolescents between 12 and 17 years old. Age, sex, sleep, psychosocial health, adherence to the Mediterranean diet (MD), sport practice, and time spent on screen devices were assessed by an ad hoc questionnaire. Linear regression analyses were applied, adjusting for several covariables. Poisson regression was applied between the sexes. A p value < 0.05 was considered statistically significant. RESULTS: Cell phone use was more associated with sleep time (13%). In boys, time spent on cell phones (prevalence ratio [PR] = 1.09; p < 0.001) and videogames (PR = 1.08; p = 0.005) had a higher prevalence ratio. When psychosocial health was included in the models, we found the greatest association (Model 2: PR = 1.15; p = 0.007). For girls, time spent on the cell phone was significantly associated with sleep-related problems (PR = 1.12; p < 0.001), and adherence to the MD became the second most important in the model (PR = 1.35; p < 0.001), followed by psychosocial health and cell phone use (PR = 1.24; p = 0.007). Time spent on WhatsApp was associated with sleep-related problems only among girls (PR = 1.31; p = 0.001) and was the most important variable in the model along with MD (PR = 1.26; p = 0.005) and psychosocial health (PR = 1.41; p < 0.001). CONCLUSIONS: Our results suggest a relationship between cell phones, video games, and social networks with sleep-related problems and time.

Speed, agility, and musculoskeletal fitness are independently associated with areal bone mineral density in children.

Background: There is still little understanding of the associations between physical fitness variables and bone health in children taking into account key confounders. Aim: The aim of this study was to analyze the associations between performance in tests of speed, agility, and musculoskeletal fitness (power of the upper and lower limbs) with bone mass of different regions in children, considering the adjustment to maturity-offset, lean percentage, and sex. Methods: Cross-sectional study design: the sample consisted of 160 children aged 6-11 years. The physical fitness variables tested were 1) speed, assessed with the running test at a maximum speed of 20 m; 2) agility, assessed through the 4×4-m square test; 3) lower limb power, assessed using the standing long jump test, and 4) upper limb power, assessed using the 2-kg medicine ball throw test. Areal bone mineral density (aBMD) was obtained from the analysis of body composition by dual-energy X-ray absorptiometry (DXA). Simple and multiple linear regression models were performed using the SPSS software. Results: In the crude regression analyses, the results indicated a linear relationship between all the physical fitness variables and aBMD in all body segments, but maturity-offset, sex, and lean mass percentage seemed to have an effect on these relationships. Except for the upper limb power, the other physical capacities (speed, agility, and lower limb power) were associated with aBMD in at least three body regions in the adjusted analyses. These associations occurred in the spine, hip, and leg regions, and the aBMD of the legs presented the best association magnitude (R 2). Conclusion: There is a significant association between speed, agility, and musculoskeletal fitness, specifically the lower limb power and aBMD. That is, the aBMD is a good indicator of the relationship between fitness and bone mass in children, but it is essential to consider specific fitness variables and skeletal regions.

Related-factors of social support for students' physical activity in a network perspective / Fatores relacionados ao suporte social para atividade física de estudantes em uma perspectiva de rede

This study investigates the relationship between social support and moderate to vigorous physical activity, as well as the possible relationships between social support and socioeconomic status, gender and body mass index. Cross-sectional study with a non-randomized sample of 71 students (boys and girls) aged 7 to 12 and their parents or legal guardians. Social support and socioeconomic status were assessed using validated questionnaires. Height and body mass measurements were used for the body mass index equation. Moderate to vigorous physical activity was measured by accelerometers. The associations between all variables were tested by a network analysis. Moderate to vigorous physical activity is negatively correlated with socioeconomic status, body mass index and a question from the social support questionnaire: "How many times in the last week have you watched your child be physically active?". We observed a positive correlation between moderate to vigorous physical activity with gender and a question from the social support questionnaire: "How many times in the last week did you provide transport for your child's physical activity?". Thus, moderate to vigorous physical ac-tivity has a negative correlation with socioeconomic status, body mass index and the variable "parents sometimes observe their child to be physically active", and parents who provide transportation for the child to practice physical activity. In future, it is import to consider the network analysis in the intervention studies to promote adolescents' physical activity

Este estudo investiga a relação entre suporte social e atividade física moderada-vigorosa, bem como as possíveis relações entre suporte social e nível socioeconômico, gênero e índice de massa corporal. Estudo transversal com amostra não randomizada de 71 escolares (meninos e meninas) de 7 a 12 anos e seus pais ou responsáveis. Apoio social e nível socioeconômico foram avaliados por meio de questionários validados. Medidas de altura e massa corporal foram usadas para a equação do índice de massa corporal. Atividade física moderada-vigorosa foi medida por acelerômetros. As associações entre todas as variáveis foram testadas por uma análise de rede. A atividade física moderada a vigorosa está negativamente correlacionada com o nível socioeconômico, índice de massa corporal e uma questão do questionário de apoio social: "Quantas vezes na última semana você observou seu filho ser fisicamente ativo?". Observou-se correlação positiva entre atividade física moderada-vigorosa com o gênero e uma questão do questionário de apoio social: "Quantas vezes na última semana você forneceu transporte para a atividade física de seu filho?". Assim, a atividade física moderada-vigorosa tem correlação negativa com o nível socioeconômico, índice de massa corporal e a variável "os pais às vezes observam que seu filho é fisicamente ativo, e pais que fornecem transporte para a criança praticar atividade física. No futuro, é importante considerar a análise de rede nos estudos de intervenção para promover a atividade física em adolescentes

Sedentary time play a moderator role in the relationship between physical fitness and brain-derived neurotrophic factor in children. A pilot study.

Aim: Despite some advances, there are many controversies concerning brain-derived neurotrophic factor (BDNF) and its relationships with variables related to physical fitness and sedentary time, especially in children. The aim of the study was to explore the moderating role of sedentary time on the association between physical fitness and BDNF. Therefore, this study will add to the perspective of understanding how much time children may spend being sedentary with no deleterious influence on the positive association between physical fitness and BDNF. Methods: This cross-sectional study included 44 children aged between 6 and 11 years (9.02 ± 1.43) from a public school in Porto Alegre, Brazil. Cardiorespiratory fitness (CRF) was determined by the 6-min walk/run test, and muscular strength was determined through the lower limb strength test (LLS). Sedentary time was assessed through accelerometers, and blood samples were collected to determine serum BDNF levels (z score). Moderation analysis was performed using the PROCESS macro adjusted for sex, age, somatic maturation, waist circumference, and socioeconomic level. Results: Sedentary time moderates the relationship between CRF and BDNF, such that children should spend less than 511 minutes per day sedentary to achieve the benefits of CRF in BDNF concentrations. Conclusion: Sedentary time plays a significant moderating role in the relationship between CRF and BDNF. Therefore, to promote brain health in children, both increasing physical fitness and reducing sedentary time might be encouraged.

Sprint and upper limbs power field tests for the screening of low bone mineral density in children.

Background: The possibility of carrying out screening, with acceptable accuracy, of a child's bone mass status based on a physical fitness test can advance the concept of health-related physical fitness. In addition, the relevance of the applicability of this type of screening in educational environments is mainly due to the difficulty of direct assessments of bone health indicators. This study aimed to propose cut-off points for physical fitness tests based on children's bone health indicators. Methods: This is a two-phase cross-sectional study. Phase-1: 160 children (6-11 years-old) performed the 20-m sprint test (20-mST) and the 2 kg medicine ball throw test (2 kgMBTT). Areal bone mineral density (aBMD) and content was assessed by DXA. The area under the ROC curve greater than 70% was considered valid. Phase-2: It was carried out a secondary analysis in a sample with 8,750 Brazilians (6-11 years-old). The percentile values (identified in phase-1) were used to identify the values of the cut-off points in the unit of measurement of the tests. The validation of the cut-off points found was by odds ratio values and p ≤ 0.05. Results: Phase 1: The areas under the ROC curve were 0.710, 0.712 (boys and girls-20-mST), 0.703, and 0.806 (boys and girls-2 kgMBTT) with total spine and pelvis aBMD as the outcome. Phase 2: From percentile values, we find valid cut-off points in the Brazilian sample (OR > 3.00; p < 0.001) for boys and girls. Values ranged between 5.22 s-4.00 s to 20-mST and between 125.0 cm-160.0 cm to 2 kgMBTT. Conclusion. The 20-mST and the 2 kgMBTT presented sufficient accuracy for the screening of children aged between 6 and 11 years with greater chances of having low aBMD in the total spine and pelvis, with valid cut-off points.

Relaciones entre actividad física y calidad de vida relacionada con la salud en niños y adolescentes durante la distancia social COVID-19 / Relações entre a atividade física e a qualidade de vida relacionada à saúde em crianças e adolescentes durante o distanciamento social COVID-19 / Relationship between physical activity and health-related quality of life in children and adolescents during COVID-19 social distancing

Este estudio tuvo como objetivo verificar la relación entre la actividad física (AF) y los dominios de la calidad de vida relacionada con la salud (QVRS) en niños y jóvenes durante la distancia social COVID-19. Se aplicó un estudio transversal y analítico con enfoque cuantitativo en una muestra de 119 niñas y 121 niños. Se aplicaron cuestionarios y métodos estadísticos. La correlación entre AF y HQOL fue más fuerte en los niños (46,9%) que en las niñas (14,5%), lo que puede explicarse porque existe una relación considerable y más fuerte entre la edad y el grado escolar con HQOL en las niñas. En conclusión, la actividad física se asoció con la QVRS de los niños y adolescentes durante la distancia social COVID-19. Estos hallazgos muestran la importancia de que esta población se mantenga físicamente activa para que los parámetros de salud no se vean afectados durante este período. (AU)

This study aimed to verify the relationship between physical activity with health-related quality (HQOL) of life domains in children and adolescents during COVID-19 social distancing. A Cross-sectional and analytical study with a quantitative approach in a sample of 119 girls and 121 boys aged between 6 to 14 years old. The moderate to vigorous physical activity (MVPA) practice was measured by days a week and HQOL was obtained with Kidscreen-27. We applied descriptive statistics, z-scores conversions, linear correlations, regression graphs, and generalized linear models for each sex with adjustment by age and school grade. The linear correlation between MVPA and HQOL was stronger in boys (46,9%) than girls (14,5%), which may be explained because there is a considerable and stronger relationship between age, and the school grade with HQOL in girls. In another way, in boys only MVPA was associated with total HQOL, one day of MVPA represented an association with 2.36 points of HQOL, without the significant impact of age and school grade, being the double of power relationship than girls (1.16). In conclusion, physical activity was associated with the quality of life of children and adolescents during social distance due to the COVID-19. These findings show the importance of this population to remain physically active so that health parameters are not affected during this period. (AU)

Este estudo teve como objetivo verificar a relação da atividade física (AF) com domínios da qualidade de vida relacionada à saúde (QVRS) em crianças e jovens durante o distanciamento social COVID-19. Foi aplicado um estudo transversal e analítico com abordagem quantitativa em uma amostra de 119 meninas e 121 meninos. Questionários e métodos estatísticos foram aplicados. A correlação entre AF e QVRS foi mais forte nos meninos (46,9%) do que nas meninas (14,5%). Isso foi explicado porque há uma relação considerável e mais forte entre idade e ano escolar com QVRS em meninas. Em conclusão, a atividade física se associou à qualidade de vida de crianças e adolescentes durante o distanciamento social COVID-19. Esses achados mostram a importância dessa população se manter fisicamente ativa para que os parâmetros de saúde não sejam afetados nesse período. (AU)

Team sports, running, walking: activity-specific associations with perceived environmental factors in adolescents.

This study aimed to analyze the association between the practice of different types of physical activity (PA) with perceived environmental factors in boys and girls adolescents. Were evaluated 1,130 adolescents from Porto Alegre, Brazil. To evaluate different PA, students answered whether or not they practiced walking, running, team sports, and others general PA. Perceived environmental factors were assessed through Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Analyses were performed using logistic regression. Adolescents who reported perceiving a distance up to 20 minutes to walking/running track, had their chances of practicing all types of PA increased in the total sample and for girls. For walking, it was also found an association with access in adolescents. For girls, it was found an association between shortest distance to indoor recreation or exercise facility and other playing fields/court with running and team sports. Aesthetics and road safety were associated with team sports in adolescents. Other general PA were associated with park, bike/hiking/walking trails in the total sample and for girls. Therefore, for each type of PA, specific associations of perceived environmental factors were found.

Team sports, running, walking: activity-specific associations with perceived environmental factors in adolescents / Esportes coletivos, corrida, caminhada: associações específicas de atividades com fatores ambientais percebidos em adolescentes

Abstract This study aimed to analyze the association between the practice of different types of physical activity (PA) with perceived environmental factors in boys and girls adolescents. Were evaluated 1,130 adolescents from Porto Alegre, Brazil. To evaluate different PA, students answered whether or not they practiced walking, running, team sports, and others general PA. Perceived environmental factors were assessed through Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Analyses were performed using logistic regression. Adolescents who reported perceiving a distance up to 20 minutes to walking/running track, had their chances of practicing all types of PA increased in the total sample and for girls. For walking, it was also found an association with access in adolescents. For girls, it was found an association between shortest distance to indoor recreation or exercise facility and other playing fields/court with running and team sports. Aesthetics and road safety were associated with team sports in adolescents. Other general PA were associated with park, bike/hiking/walking trails in the total sample and for girls. Therefore, for each type of PA, specific associations of perceived environmental factors were found.

Resumo Este estudo teve como objetivo analisar a associação entre a prática de diferentes tipos de atividade física (AF) com fatores ambientais percebidos em meninos e meninas adolescentes. Foram avaliados 1.130 adolescentes de Porto Alegre, Brasil. Para avaliar diferentes AF, os alunos responderam se praticavam ou não caminhada, corrida, esportes coletivos e outras AF em geral. Fatores ambientais percebidos foram avaliados pelo Neighborhood Environment Walkability Scale for Youth. As análises foram realizadas por meio de regressão logística. Adolescentes que relataram perceber uma distância de até 20 minutos para pista de caminhada/corrida tiveram suas chances de praticar todos os tipos de AF aumentadas na amostra total e para as meninas. Para caminhada, também foi encontrada associação com o acesso em adolescentes. Para as meninas, foi encontrada uma associação entre a menor distância para instalações de exercícios e outros campos de jogos/quadra com corrida e esportes coletivos. A estética e a segurança de ruas foram associadas com esportes coletivos em adolescentes. Outras AF gerais foram associadas com parque e trilhas de bicicleta/caminhada na amostra total e para meninas. Portanto, para cada tipo de AF, foram encontradas associações específicas de fatores ambientais percebidos.

Changes in children's self-perceived physical fitness: results from a Physical Education internet-based intervention in COVID-19 school lockdown.

Background: Children have a higher chance of decreasing health-related physical fitness during periods of school lockdown due to pandemic situations such as with COVID-19 disease. Aims: To establish the changes in children's self-perceived physical fitness (SPPF) during pandemic COVID-19 social distancing in a school lockdown and to describe the individual prevalence of changes in SPPF according to sex. Methods: It is an intervention study with a convenient sample, 67 children (6-13 years old; 50.7% girls). An intervention occurred according to the Brazilian Base Nacional Comum Curricular (BNCC) and the State Education Secretary orientations for remote Physical Education classes. SPPF was evaluated through a questionnaire (QAPA). Generalized estimative equations (GEE) and the prevalence of changes in individual score delta (Δ) from baseline to follow-up determined the effects. Results: Positive individual changes in SPPF were observed for 21.2% of girls and 26.4% of boys. Older children presented fewer SPPF total points. There was no interaction between the evaluation period, sex, and age. However, higher baseline SPPF values presented a negative association with the individual SPPF variation (ß = - 2.52%; CI 95% - 3.97 to - 1.07; p = 0.001). Conclusion: A remote Physical Education intervention effectively maintained or even increased individual results of children's SPPF. Thereby, this study suggests that this kind of initiative should be retained for the duration of social distancing and pandemic conditions to help children maintain an active lifestyle and, consequently, achieve health benefits. Improving intervention effectiveness by focusing on girls seems to be a challenge in this matter. Supplementary Information: The online version contains supplementary material available at 10.1007/s11332-022-00897-1.

Exercise in school Physical Education increase bone mineral content and density: Systematic review and meta-analysis.

ABSTRACTThis systematic review and meta-analysis aimed to evaluate the effectiveness of interventions through Physical Education (PE) exercises on bone mineral content (BMC) and density (BMD) of children and adolescents. The research was conducted using the online electronic databases PubMed, Science Direct, Web of Science and Scopus (March 2021). The analysis was restricted to school-based studies that examined the effect of PE interventions on BMC and BMD in schoolchildren (<18 years old). Standardised mean differences (SMD) with 95% confidence interval (CI) and random-effects models were calculated. The heterogeneity and inconsistency of the studies were estimated using Cochran's Q-statistic and I2, respectively. Twenty-two studies with 2,556 participants were selected. PE interventions were associated with a significant increase in BMC (SMD = 1.348; 95% CI, 1.053-1.643) and BMD (SMD = 0.640; 95% CI, 0.417-0.862). Femoral neck subgroup analysis indicate an increase in BMC for boys (SMD = 1.527; 95% CI, 0.990-2.065) and girls (SMD = 1.27; 95% CI, 0.782-1.767), and in BMD for boys (SMD = 0.518; 95% CI, 0.064-0.972) and girls (SMD = 0.817; 95% CI, 0.349-1.284). Finally, increases are reported in the lumbar spine BMC for boys (SMD = 1.860; 95% CI, 1.018-2.700) and girls (SMD = 1.275; 95% CI, 0.782-1.767). This meta-analysis provides insights into the effectiveness of interventions aimed at including physical exercise in PE on bone mass, suggesting that increasing the proportion of curriculum time allocated to PE may improve students' BMD and BMC, especially in the femoral neck and lumbar spine.

Association between physical fitness components and fluid intelligence according to body mass index in schoolchildren.

Physical fitness is considered a protective factor for children's general health and has been related to enhanced cognitive functioning. However, it appears that cognition could be affected in children with overweight or obesity. The present study aimed to determine the relationship between physical fitness components and fluid intelligence in normal-weight and overweight/obese children. In this cross-sectional study, a total of 317 schoolchildren participated (165 boys, 52.05%), aged between six and 11 years old (1st to 5th grade), belonging to a public school in the south of Brazil. Psychologists evaluated fluid intelligence through the Raven's Colored Progressive Matrix Test. The physical fitness evaluation followed the procedures of the "Brazil Sports Project". Weight and height were measured to determine body mass index and generalized linear regression analyses were used with a 95% confidence interval. Our results showed that agility was inversely associated with fluid intelligence only in the overweight/obese group (ß = -1.506; p = 0.01). Cardiorespiratory and muscular fitness were not associated with fluid intelligence. In conclusion, agility was the only physical fitness component related to fluid intelligence, and this relationship was found exclusively in overweight/obese schoolchildren.

Efeitos de dois programas de educação física na aptidão física relacionada à saúde de crianças de acordo com sexo / Effects of two physical education programs on children's health-related physical fitness according to sex

RESUMO Este estudo quase-experimental avaliou os efeitos de dois programas de exercício físico, ofertado no contexto das aulas de Educação Física escolar, sobre indicadores de aptidão física. A amostra por conveniência foi composta por 91 alunos com idades entre 9-12 anos que formaram os grupos Formação Corporal (PFC; 45 alunos) e Educação Física (PEF; 45 alunos). Foi mensurado o índice de massa corporal (IMC), aptidão cardiorrespiratória (ApC), flexibilidade e força muscular localizada (FML). Recorreu-se ao "Teste t pareado" e ANOVA de medidas repetidas. O tamanho do efeito foi estimado pelo "eta ao quadrado parcial", estratificado por sexo, sendo aceito a probabilidade de 5% de erro. Os resultados mostraram nos meninos efeito muito elevado no grupo PFC na ApC, flexibilidade e FML e efeito elevado no grupo PEF na flexibilidade e FML. Nas meninas efeito muito elevado no grupo PFC na ApC, flexibilidade e FML e no grupo PEF efeito muito elevado na flexibilidade e FML e de efeito elevado na ApC. Não houve efeito no IMC em ambos os grupos. Ressaltamos que este único encontro semanal (15 minutos de PFC) foi capaz de apresentar efeito muito elevado e elevado na aptidão física a favor do PFC em ambos os sexos.

ABSTRACT This quasi-experimental study evaluated the effects of two physical exercise programs offered in the context of physical education classes on physical fitness indicators. The convenience sample consisted of 91 students aged 9-12 years who formed the group's Body Training (GBT; 45 students) and Physical Education (PE; 45 students). Body mass index (BMI), cardiorespiratory fitness (CRF), flexibility, and abdominal muscle strength (LMS) were measured. The "Paired t-test" and repeated measures ANOVA were used. The size of the effect was estimated by the "partial squared eta", stratified by sex, with a 5% probability of an error being accepted. The results showed in boys a very high effect in the PFC group on CRF, flexibility, and FML and a high effect in the PEF group on flexibility and FML. In girls, a very high effect in the GBT group on CRF, flexibility, and FML, and the PE group greatly affected flexibility and FML and had a high effect on CRF. There was no effect on BMI in either group. We emphasize that this single weekly meeting (15 minutes of GBT) was able to have a very high and high effect on fitness in favor of the GBT in both genders.

Prevalence of responders of a school intervention at physical fitness and mental health of children: a quasi-experimental study

Abstract Aim: to verify the effect of a physical education program at school on physical fitness and mental health in children and to determine the individual prevalence of responders. Methods: This is a quasi-experimental study, developed with 67 children aged between 6 and 11 years old. (8.09 ± 1.81). A 21-week intervention was performed, that intervention condition (IC) consisted of sports and circuit training, and nutritional education. For the control condition (CC) classes followed to the Common Curricular National Base. The following variables were evaluated at baseline and post-intervention: physical fitness and mental health through the strength and difficulties questionnaire. Mixed analysis of variance and the prevalence of responders were used for statistical analysis. Results: The main results indicate that there were improvements in the IC in the components of physical fitness (cardiorespiratory fitness, speed, and agility) and mental health indicators (total difficulties, emotional symptoms, problems with peers, and prosocial behavior) after a school physical education program in comparison with the CC. Concerning the prevalence of responders between groups, it was found differences in cardiorespiratory fitness (CC: 33.33%; IC: 65.38%), agility (CC: 36.66%; IC: 73.07%), speed (CC: 43.33%; IC: 79.16%), emotional symptoms (CC: 28.57%; IC: 50.00%), and prosocial behavior (CC: 17.14%; IC: 46.87%). Conclusion: It is reinforced that well-planned physical education classes and simple intervention programs can be adopted at the school level and are capable of promoting children's physical and mental health.

Pressão Arterial de Crianças: Associação a Indicadores Antropométricos, Composição Corporal, Aptidão Cardiorrespiratória e Atividade Física / Blood Pressure in Children: Association with Anthropometric Indicators, Body Composition, Cardiorespiratory Fitness and Physical Activity

Resumo Fundamento: Evidências apontam variáveis antropométricas e de condicionamento físico como fatores associados à pressão arterial infantil. Analisá-los em apenas um contexto é um meio relevante de identificar o peso que cada um deles pode apresentar no desenvolvimento da hipertensão arterial. Objetivo: Identificar as possíveis associações de medidas antropométricas, da composição corporal, da atividade física moderada-vigorosa (AFMV) e da aptidão cardiorrespiratória (ApC) com a pressão arterial em crianças. Métodos: Estudo correlacional com abordagem quantitativa. Duzentos e quinze (215) estudantes com idades de 6 a 12 anos de uma escola pública de Porto Alegre, selecionados por critério de conveniência. A pressão arterial foi aferida através de um esfigmomanômetro digital. Para o tratamento dos dados, os valores de pressão arterial sistólica e diastólica foram padronizados (escore Z) e somados. As variáveis testadas como preditoras foram: AFMV; Percentual de gordura (%G); Índice de massa corporal (IMC); Razão cintura/estatura (RCE); Maturação somática; ApC. Após a verificação dos parâmetros de normalidade, as associações brutas e ajustadas (para sexo, idade e maturação somática) foram testadas através de equações de regressão linear. Para as análises, foi considerado p < 0,05. Resultados: Três diferentes modelos indicaram os melhores conjuntos de fatores associados à pressão arterial padronizada: O Modelo 1 (R2 = 0,21) se constituiu das variáveis RCE (β = 9,702) e AFMV (β = - 0,021); O Modelo 2 (R2 = 0,19) foi composto pelas variáveis IMC (β = 0,156) e AFMV (β = - 0,021); O Modelo 3 (R2 = 0,18) incluiu as variáveis %G (β = 0,063) e ApC (β = - 0,004). Conclusões: A pressão arterial de crianças é predita pelas variáveis corporais %G, IMC e RCE. Além disso, está associada negativamente à AFMV e a ApC.

Abstract Background: Evidence points to anthropometric and fitness variables as associated factors with children's blood pressure. Analysing these factors in a single context is a relevant possibility of identifying the weight that each factor can present for the development of arterial hypertension. Objective: Identify the possible associations between anthropometric measurements, body composition, moderate-vigorous physical activity (MVPA) and cardiorespiratory fitness (CRF) with blood pressure in children. Methods: Correlational study with a quantitative approach. Sample: 215 schoolchildren aged 6-12 years selected by convenience criteria of a public school in Porto Alegre, Brazil. Blood pressure was measured with a digital sphygmomanometer. For data treatment, the values of systolic and diastolic blood pressure were standardized (Z score) and added. The variables tested as predictors were: MVPA; body fat percentage (BF%); Body Mass Index (BMI); waist-height ratio (WHTR); maturity-offset and CRF. After checking the normality parameters, the crude and adjusted associations (for sex, age and maturity-offset) were tested with linear regression equations. For the analyses, p <0.05 was considered. Results: Three different models indicated the best sets of factors associated with standardized blood pressure. Model 1 (R2 = 0.21) consisted of the variables WHTR (β = 9.702) and MVPA (β = −0.021). Model 2 (R2 = 0.19) was composed of the variables BMI (β = 0.156) and MVPA (β = −0.021). Model 3 (R2 = 0.18) included the variables BF% (β = 0.063) and CRF (β = −0.004). Conclusion: Blood pressure in children is predicted by the body variables BF%, BMI and WHTR, in addition, it is negatively associated with MVPA and CRF.