Mini Review: Physical activity and fitness and its relations to cardiovascular disease risk factors in children

Possible determinants of physical fitness in Japanese school children: A cross-sectional study

BACKGROUND

Physical fitness is one of the most important health indicators in children. Although appropriate body composition or certain lifestyle factors such as frequent physical activity are thought to improve physical fitness, results of previous studies are inconsistent, and most studies were from Western countries.

OBJECTIVES

We investigated associations of body composition and modifiable lifestyle factors such as physical activity, screen time, diet and sleep duration with physical fitness in Japanese primary school children.

METHODS

2308 children (age 10-12 years old) in 12 primary schools were analysed in this cross-sectional study. Physical fitness was evaluated by sports battery tests conducted routinely and annually at schools. The total score of sports battery tests, 20-m shuttle run (laps) and grip strength (kg) were selected as outcomes. Information about lifestyle factors was collected by two questionnaires. Associations between lifestyle factors and physical fitness were assessed by multivariable linear mixed models by sex.

RESULTS

Frequent exercise was related to better overall physical fitness. Regarding the 20-m shuttle run, many unfavourable lifestyle factors such as higher BMI in boys (β -7.37, 95% confidence interval [CI] -8.39, -6.35) and girls (β -3.54, 95% CI -4.50, -2.58), longer screen time (β -4.31, 95% CI -7.29, -1.34) in boys and girls (β -5.65, 95% CI -9.01, -2.30); shortest (reference) versus longest, breakfast skipping in boys (β -5.24, 95% CI -8.71, -1.77) and girls (β -3.57, 95% CI -6.84, -0.30); consumers (reference) versus skippers were associated with worse performance. Better quality of diet was associated with better results in the 20-m shuttle run only in girls (β 2.58, 95% CI 0.24, 4.93); lowest (reference) versus highest.

CONCLUSIONS

Frequent exercise was related to better physical fitness. Higher BMI and unfavourable lifestyle factors such as longer screen time and breakfast skipping were associated with worse results of the 20-m shuttle run.

Effect of Glycated Haemoglobin (HBA1c) on Cardiorespiratory Fitness (CRF) in a Population with Type 2 Diabetes Mellitus (T2DM): A Cross-Sectional Study

Background and Objective: The aim of this study was to evaluate cardiorespiratory fitness (CRF) measures, maximal oxygen consumption (VO2 max), and minute ventilation/carbon dioxide production (VE/VCO2 slope and others) among the T2DM population based on glycated haemoglobin (HBA1c). Material and Methods: The present study comprised a cross-sectional design, with two groups, based on HbA1c values (≤7 and ≥7.1). Laboratory samples were taken to evaluate glycated haemoglobin and fasting blood glucose (FBS). Cardiopulmonary exercise testing was performed to calculate various fitness-related parameters. Data analysis: An independent t-test was used to analyse the outcomes in the two groups. p < 0.05 was considered significant. Linear regression was used to examine the influence of predictor variables on dependent variables. Results: A total of 70 patients agreed to participate in the study, with 19 females and 51 males. The mean (standard deviation) BMI (body mass index) of all participants was 29.7(5.2), the mean (SD) weight was 84.4 (18.9) kg, and the mean height was 167.4 (23) cm. The average age of the individuals was 52 ± 8 years. The independent t-test revealed a significant difference between the two groups in terms of CRF measures. Conclusions: The current research identified the presence of poor glycaemic control and cardiorespiratory fitness measures among the Brazilian population with T2DM. HBA1c, duration of diabetes, age, and BMI can be employed to predict the ventilatory threshold (VT) and VO2 max.

Cardiovascular prevention in childhood: a consensus document of the Italian Society of Cardiology Working Group on Congenital Heart Disease and Cardiovascular Prevention in Paediatric Age

Cardiovascular diseases (CVD) may be manifested from a very early age. Genetic and environmental (epigenetic) factors interact to affect development and give rise to an abnormal phenotypical expression of genetic information, although not eliciting changes in the nucleotide sequence of DNA. It has been scientifically proven that increased oxidative stress (OS) caused by disease (overweight, obesity, diabetes), nutritional imbalances, unhealthy lifestyles (smoking, alcohol, substance abuse) in the mother during pregnancy may induce placental dysfunction, intrauterine growth restriction, prematurity, low birth weight, postnatal adiposity rebound, metabolic alterations and consequent onset of traditional cardiovascular risk factors. OS represents the cornerstone in the onset of atherosclerosis and manifestation of CVD following an extended asymptomatic period. OS activates platelets and monocytes eliciting the release of pro-inflammatory, pro-atherogenic and pro-oxidising substances resulting in endothelial dysfunction, decrease in flow-mediated arterial dilatation and increase in carotid intima-media thickness. The prevention of CVD is defined as primordial (aimed at preventing risk factors development), primary (aimed at early identification and treatment of risk factors), secondary (aimed at reducing risk of future events in patients who have already manifested a cardiovascular event), and tertiary (aimed at limiting the complex outcome of disease). Atherosclerosis prevention should be implemented as early as possible. Appropriate screening should be carried out to identify children at high risk who are apparently healthy and implement measures including dietary and lifestyle changes, addition of nutritional supplements and, lastly, pharmacological treatment if risk profiles fail to normalise. Reinstating endothelial function during the reversible stage of atherosclerosis is crucial.

Investigating the influence of physical activity composition on arterial stiffness in youth

Physical activity is beneficial for arterial health in children but less is known about how all daily movement behaviours influence arterial stiffening. Compositional analysis can account for the co-dependent nature of these behaviours and therefore was employed to explore how the movement composition influences arterial health. Augmentation index (AIx) and pulse wave velocity were measured cross-sectionally in healthy children (n = 129; 12.4 ± 1.6 years). Time spent in sedentary, light physical activity (LPA), moderate-to-vigorous physical activity (MVPA) and asleep were derived from seven-day hip-worn accelerometry. The relative effects of individual behaviours and the overall movement composition on arterial stiffness were explored utilising compositional analysis, with predictive modelling used to predict effects of the substituting time between behaviours. Girls (n = 45, 12.1 ± 1.5yrs, 20.5 ± 3.6kg·m^-2) had a higher AIx (+ 3.94; p < 0.05) and accrued physical activity predominantly in LPA, whereas boys (n = 56, 12.6 ± 1.7yrs, 20.6 ± 4.0kg·m^-2) accrued physical activity predominantly in MVPA. Individual behaviours and the movement composition were not significant predictors of any measure of arterial stiffness (P > 0.05), and the reallocation of 20-minutes between behaviours did not elicit significant change in arterial stiffness, irrespective of sex (P > 0.05). The reallocation of time to MVPA from any other behaviour did not predict an improvement in arterial stiffness. This highlights the high potential dose of MVPA required to improve arterial health and the complex nature of the determinants of arterial stiffness. HighlightsMovement behaviours in isolation nor combination predicted arterial stiffness in youth.The reallocation of behaviours from any other behaviour to MVPA did not affect arterial stiffness in youth.Arterial stiffness is a complex, multidimensional health parameter that does not appear to be primarily determined by physical activity levels or intensity.

Using compositional analysis to explore the relationship between physical activity and cardiovascular health in children and adolescents with and without type 1 diabetes

OBJECTIVE

The aim of this study was to use a compositional analysis approach to account for the inherent co-dependencies between behaviors and to explore how daily movement behaviors influence cardiovascular health in children with and without T1D.

RESEARCH DESIGN AND METHODS

Augmentation index, pulse wave velocity (PWV) and heart rate variability were measured in 20 children with (11.9 ± 1.6 years) and 17 children without T1D (11.6 ± 2.2 years). Subsequently, physical activity and sleep were assessed at 20 Hz for 28 consecutive days using a wrist-worn accelerometer. Compositional analyses were utilized to explore the relative effects of each movement behavior and the overall movement complex on cardiovascular parameters, with predictive modeling used to explore the effects of reallocating 20 min between behaviors.

RESULTS

Arterial stiffness markers were most influenced by the total movement composition, whereas autonomic function was most influenced by sedentary time and sleep relative to all other behaviors. Reallocation of time from moderate-to-vigorous physical activity (MVPA) to any other behavior was predicted to negatively affect all cardiovascular measures, independent of disease status, whereas reallocating time to MVPA was consistently predicted to improve all outcome measures. Additionally, the same intensity of physical activity appeared to be more potent for cardiovascular health in T1D children compared to nondiabetic peers.

CONCLUSIONS

Intensity, rather than volume, of physical activity may be key in reducing risk of premature adverse changes in cardiovascular health, whereas increasing time in MVPA could potentially the slow progression of cardiovascular aging in children with diabetes.

Covid 19 May Limit the Use of Anti-hyperglycemic Agents. Does it Call for the Development of New Anti-hyperglycemic Agents?

Diabetes mellitus has been identified as a major risk factor for developing severe COVID 19 complications. In this review article, the efforts were directed to provide insights and the possible extent to which some diabetic pharmacological interventions may exacerbate COVID 19 or may not be idyllic options for COVID 19 patients. Articles reviewed were identified using the Google scholar database, and search was done using the English language. Anti-hyperglycemic is associated with undesirable effects including episodes of hypoglycemia, diarrhea, lactic acidosis, and increased risks of cardiovascular and hepatic hazards. These undesirable effects associated with the anti-hyperglycemic agents possess a threat of developing severe COVID19 complications Therefore, this calls for more studies to understand the extent of the risks these agents possess in diabetic COVID 19 patients. Almost all the anti-hyperglycemic agents have the potential to worsen COVID 19, despite their class. COVID 19 may limit the options in terms of available anti-hyperglycemic agents which may not heighten the risk of developing severe COVID 19 complications. The research towards the discovery and development of new compounds and also new therapeutic targets for hyperglycemia should be encouraged and welcome.

Effects of community health worker-based interventions on physical activity levels in children: a systematic review

Objective:

To identify the strategies and effects of interventions carried out by community health workers (CHW) on physical activity (PA) levels in children and adolescents.

Data source:

In August 2020, a systematic review, designed according to the PRISMA checklist items, was conducted by searches in seven electronic databases and in reference lists. Original studies were searched without restriction with regard to year of publication; they were written in Spanish, English or Portuguese and examined interventions implemented by CHW, involving theoretical and/or practical contents of PA, with a focus on children and/or adolescents between three and 19 years of age.

Data synthesis:

Of the 2,321 studies initially retrieved, eight were included, targeting samples with more specific characteristics (e.g., clinical, ethnic and/or socioeconomic). In all studies, CHW were trained to lead educational activities. In three non-controlled trials, positive results were observed, involving indicators such as moderate and vigorous PA and physical inactivity reduction. Also, two positive results were found in reducing sedentary behavior.

Conclusions:

Even though most of the interventions included did not have a significant effect on increasing PA levels, the available findings reinforce the role of CHW as an important strategy for dialogue between health services and the most vulnerable communities, and they suggest a greater articulation of these professionals in the actions developed in the school context.

Bidirectional Associations between Physical Activity and Sleep in Early-Elementary-Age Latino Children with Obesity

Low-income Latino children are at high risk for obesity and associated comorbidities. Considering the health benefits of proper sleep habits and physical activity, understanding the patterns, or the relationship between these modifiable factors may help guide intervention strategies to improve overall health in this population. Thus, the purpose was to investigate bidirectional associations between physical activity and sleep among Latino children who are overweight/obese. Twenty-three children (boys, 70%; overweight, 17%; obese, 83%) (age 7.9 ± 1.4 years) wore activity monitors on their wrist for 6 consecutive days (comprising 138 total observations). Hierarchical linear modeling evaluated temporal associations between physical activity (light physical activity, LPA; moderate to vigorous activity, MVPA) and sleep (duration and efficiency). Although there was no association between MVPA and sleep (p > 0.05), daytime LPA was negatively associated with sleep duration that night (estimate ± SE = -10.77 ± 5.26; p = 0.04), and nighttime sleep efficiency was positively associated with LPA the next day (estimate ± SE = 13.29 ± 6.16; p = 0.03). In conclusion, increased LPA may decrease sleep duration that night, but increasing sleep efficiency may increase LPA the following day. Although further investigation is required, these results suggest that improving sleep efficiency may increase the level of physical activity reached among Latino children who are overweight/obese.

Influence of Body Composition on Physical Fitness in Adolescents

Background and objectives: Childhood obesity is one of the main public health issues facing advanced societies. The Spanish population presents 28.6% overweight or obese adolescents, and Extremadura, 22.3%. Physical fitness is considered one of the most important health markers and a common predictor of morbidity and mortality caused by cardiovascular diseases. Thus, fitness tests are needed for health monitoring, especially in overweight and obese adolescents. Therefore, this study aimed to explore the relationship between body composition and physical fitness in adolescents and to analyse if there are differences in physical condition and body composition between the sexes, as well as to compare the different body mass index (BMI) categories to each other. This project also tried to find regression equations to predict the physical fitness test results. Materials and Methods: A total of 225 adolescents were recruited. Weight status was classified according to WHO 2007 standards. Body composition variables (i.e., BMI, fat mass (FM), FM percentage (FM%), and fat-free mass (FFM)) and physical fitness (standing long jump (SLJ), speed–agility (SA), cardiorespiratory fitness (CF), and handgrip strength (HS)) were assessed. Results: Significant differences were found between the sexes in body composition (FM%, FM, and FFM) and physical fitness (SLJ, SA, CF, and HS) (p < 0.001) in favour of males. Significant differences were also found in speed (p = 0.002), CF (p < 0.001), and SLJ (p = 0.004) in favour of normal-weight adolescents compared to overweight and obese adolescents. Contrarily, the outcomes revealed a significantly greater HS (p = 0.014) in favour of overweight and obese participants compared to normal-weight adolescents. Moreover, the results showed that CF and SLJ correlated inversely with BMI, FM%, and total FM. There was also a direct relationship between SA and FM percentage, as well as between HS and FFM. Finally, four fitness test predictive models are proposed based on body composition, age, sex, and BMI. Conclusions: Overweight and obese adolescents have lower levels of physical fitness than their normal-weight peers, regardless of their sex. Normal-ranged body composition values are related to a greater physical fitness in adolescents. Furthermore, this study presents several equations that can help to predict the performance of different fitness tests in adolescents.

Physical fitness and activity, metabolic profile, adipokines and endothelial function in children

OBJECTIVES

The prevalence of obesity is increasing. The aim of this study was to investigate if there is endothelial dysfunction in children with normal or excess weight, and whether the metabolic profile, adipokines, and endothelial dysfunction would be more strongly associated with physical fitness or with physical activity levels.

METHOD

Cross-sectional study involving children aged 5-12 years. The evaluation included venous occlusion plethysmography, serum levels of adiponectin, leptin and insulin, lipid profile, physical activity score (PAQ-C questionnaire), and physical fitness evaluation (Yo-Yo test).

RESULTS

A total of 62 children participated in this study. Based on the body mass index, 27 were eutrophic, 10 overweight and 25 obese. Triglycerides, LDL cholesterol, HOMA-IR, and leptin were higher in the obese and excess-weight groups compared to the eutrophic group (p<0.01). HDL cholesterol and adiponectin levels were higher in the eutrophic group compared to the obese and excess-weight groups (p<0.01). Flow-mediated vasodilation after hyperemia was higher in the eutrophic group in comparison to obese and excess-weight subjects (p<0.05). There was no difference in the physical activity levels among groups measured by PAQ-C. The Yo-Yo test was significantly associated with HDL cholesterol (rho=-0.41; p=0.01), and this association remained after adjusting for body mass index z-score (rho=0.28; p=0.03).

CONCLUSION

This study showed that endothelial dysfunction is already present in obese children, suggesting a predisposition to atherosclerotic disease. Moreover, HDL cholesterol levels were correlated with physical fitness, regardless of body mass index.

Lifestyle and awareness of cholesterol blood levels among 29159 community school children in Italy

BACKGROUND AND AIM

Lifestyle habits including indoor and outdoor activities among community school children, adherence to the Mediterranean diet and awareness about total cholesterol blood levels represent determinant factors in cardiovascular disease (CVD) prevention. The aim of this study was to analyze the relationship between adherence to the Mediterranean diet, total cholesterol blood levels, body composition and hours per day spent in in-house or outdoor among 29,159 Italian 6-14 years-old community school children (50% boys). The KidMed questionnaire, modified to handle missing information on olive oil consumption, was used to assess the adherence to the Mediterranean diet among participants.

METHODS AND RESULTS

Associations between variables were tested according to 3 classes of the Mediterranean diet adherence score using analysis of variance. Participants with high adherence to Mediterranean diet were few (1%). Overall awareness of total cholesterol blood levels was low among children (4.5%), slightly higher among parents (26.2 and 24.1% in mothers and fathers, respectively). Among Mediterranean diet adherent children, BMI was significantly (p < 0.001) smaller than among the non-Mediterranean or intermediate adherent children as were the total hours spent per day watching television or playing with videogames (p < 0.001) whereas the hours/day in sport or outdoor activities were more (p < 0.001). These results were confirmed by multiple linear regression with KidMed scored 0 to 8 as dependent variable.

CONCLUSION

Although awareness of total cholesterol blood levels and adherence to the Mediterranean diet are rare among community school children, only among these a healthier lifestyle was practiced with a tendency to lower CVD risks. These results are important as the first sized experience of this type in Italy.

Effectiveness of a multi-faceted intervention among elementary school children

Childhood obesity has been shown to be closely related to future obesity and comorbidities. As its prevalence and impact has increased significantly worldwide, researchers have focused on prevention and intervention. This study assessed a multifaceted intervention for elementary school children.A retrospective data collection with a cohort analysis was employed. A 16-week school-based intervention with nutritional intervention, physical activity, and behavioral education was designed and conducted by a multidisciplinary team for 1860 children aged 6 to 13 years. Basic information, anthropometrics, and physical fitness (PF) were recorded before and after the intervention. The differences compared with a reference group, and compared between subgroups, were analyzed.Significant favorable changes in body weight and composition were found. Children's height, weight, and muscle weight increased, whereas BMI, BMI z-score (zBMI), waist circumference, hip circumference, waist-hip ratio, waist-height ratio, body fat percentage, and visceral fat area decreased. Sit-ups and 800-m run time significantly improved. Girls exhibited a greater reduction in body weight outcomes; boys improved more in body composition and PF. Students with higher zBMI had a greater reduction in all anthropometrics; students with lower zBMI showed greater PF improvement, except for the 800-m run.The intervention improved weight measures, body composition, and PF. Subgroup differences suggested the need for sex- and weight-specific interventions.

Multi-Teaching Styles Approach and Active Reflection: Effectiveness in Improving Fitness Level, Motor Competence, Enjoyment, Amount of Physical Activity, and Effects on the Perception of Physical Education Lessons in Primary School Children

Physical education (PE) researchers sustain that the teaching styles adopted by PE teachers play a key role in defining children’s positive experiences during lessons and have a relevant impact on their psychophysical health. However, a limited number of studies has examined the effect of teaching styles on these aspects. The aim of this study was to investigate the effectiveness of an integrated approach mainly based on integration of multi-teaching styles and active reflection (MTA) on the fitness level, motor competence, enjoyment, self-perception, amount of physical activity (PA), and children’s perception of PE, in Italian primary school children. Participants were 121 children from three elementary schools. Children were randomly assigned into two groups: (a) an intervention group (IG) that received PE lessons based on MTA provided by specifically trained PE students, and (b) a control group (CG) that received standard PE lessons (S-PE) from primary school classroom teachers. Both groups engaged in two PE lessons per week lasting 1 h each for 12 weeks. The findings revealed an increase in the children’s fitness level, motor competence, enjoyment and amount of PA in the IG compared to those in the CG. Furthermore, the children of the IG spent more time being engaged on a task, reflecting on it, and wasted less time during PE compared to the children of the CG. Finally, the children of the IG reported higher levels of satisfaction with PE lessons and teaching styles compared to children of the CG. Integration of different teaching styles lead by specifically trained educators can be suggested as a valuable strategy to provide learning experiences of children of primary school to have positive effects on their physical literacy development promoting healthy lifestyles.

Profiles of Physical Fitness Risk Behaviours in School Adolescents from the ASSO Project: A Latent Class Analysis

The aim of the present investigation was to describe profiles of adolescents’ fitness level, identify latent classes of fitness-related risk behaviours, and describe their sociodemographic and environmental predictors. In total, 883 adolescents (16.4 ± 1.4 years; 167.3 ± 10.4 cm; 62.8 ± 13.5 kg; 62.2% males) were assessed for personal and lifestyle information and for physical fitness components. Eleven possible fitness determinants and seven predictors were included. Latent class analysis (LCA) was used to determine fitness-related risk behaviours. Logistic regressions predicted class membership and assessed associations with fitness levels and fitness components. Five latent classes were recognised: 1—virtuous, 30.7% of respondents; 2—low physical activity/sport, 18.8%; 3—incorrect alcohol/food habits, 25.8%; 4—health risk/overweight, 15.9%; 5—malaise/diseases, 8.8%. Sex, age, parents’ overweightness/obesity and education, and school type predicted most classes significantly. Compared to class 1, class 2 had higher odds of having all poor fitness components except upper body maximal strength; class 4 had higher risk of low muscular endurance; and class 5 was likely to have lower maximal strength, muscular endurance, and speed/agility. Educating adolescents to reach a sufficient practice of PA/sport could help decreasing the risk of low health-related fitness more than discouraging them from using alcohol, addressing proper food behaviours and habits, and helping them understand their psychophysical malaise symptoms.

Non-pharmacological Treatment Options in the Management of Diabetes Mellitus

The global prevalence of diabetes, especially type 2 diabetes mellitus, has reached epidemic proportions in the last few decades of the 20th century because of the obesity pandemic resulting from adverse lifestyles. Diabetes as a consequence of obesity (diabesity), continues to increase exponentially in the 21st century. Although there are a multitude of drugs for the effective management of diabesity with modest benefits, most patients will require insulin for control of diabetes at some stage that would worsen obesity, and thereby diabesity. Therefore, effective non-pharmacological therapy needs to be expedited in all patients with diabesity. These measures include medical nutrition interventions, change of lifestyles and bariatric surgery. Non-pharmacological interventions are also useful for the effective management of even type 1 diabetes mellitus when used along with insulin therapy especially in those with obesity. This review summarises the current evidence base for the non-pharmacological interventions in the management of diabetes.

Handgrip Strength and Blood Pressure in Children and Adolescents: Evidence From NHANES 2011 to 2014

BACKGROUND

Previous studies have reported that handgrip strength, a measure of muscular fitness, is associated with cardiovascular risk factors. However, the association of handgrip strength with blood pressure (BP) in children has been inconsistent. We tested the association of handgrip strength with systolic and diastolic BP in children and adolescents from the National Health and Nutrition Examination Survey (NHANES) 2011-2014.

METHODS

The study included 3,929 participants aged 8-19 years who underwent a handgrip test. The sum of the maximum handgrip strength from both hands was used. General linear models were used to examine the associations between handgrip strength and the outcome variables.

RESULTS

After adjustment for age, race, sex, body mass index, and physical activities, handgrip strength was significantly and positively associated with systolic (P < 0.0001) and diastolic (P = 0.01) BP. There was an increasing trend in systolic BP as handgrip strength increased from the bottom quartile to the top quartile, with 2.1 mm Hg difference between the top and the bottom quartiles (P for trend <0.0001). Similar results were observed for diastolic BP.

CONCLUSIONS

Muscular fitness is positively associated with BP in children and adolescents. The implications and underlying mechanisms for these results need further examinations.

Physical fitness characteristics of Omani primary school children according to body mass index

BACKGROUND

There is evidence that children with high cardiorespiratory fitness and normal body mass index (BMI) have less risk of non-communicable diseases (NCDs), however limited research was undertaken in Omani children. Therefore the aims of the present study were to describe body composition and physical fitness of a large cohort of Omani school children of both genders, and to investigate the effects of weight status on physical fitness.

METHODS

Three hundred and fourteen Omani school children aged 9 to 10 years old took part in anthropometric assessments, body composition and fitness tests, including handgrip strength, the basketball chest pass, broad jump, 20-m sprint, four 10-m shuttle agility, 30-s sit-up, and multistage fitness test (MSFT).

RESULTS

Obese boys and girls performed worse than normal-weight children in sprint, agility and endurance. In addition, fitness measures in the overweight group and underweight groups were not significantly different from other groups, except a better handgrip strength and poorer MSFT in overweight compared to normal weight girls, and poorer agility performance in underweight girls compared to the three other groups.

CONCLUSIONS

Most fitness measures are lower in obese Omani children, which suggests that they will be more at risk of developing NCDs later in life.

Lower Performance in the Six-Minute Walk Test in Obese Youth With Cardiometabolic Risk Clustering

Background: Physical fitness is an important index of health. Our aim was to assess whether cardiorespiratory and/or musculoskeletal components of physical fitness were associated with cardiometabolic risk clustering in obese youth, using adapted and validated field tests. Methods: We evaluated 252 children and adolescents (132 males, 120 females), mean age 10.9 ± 1.9 years with primary obesity. All subjects performed the six-minute walk test (6MWT) for assessing aerobic fitness, the standing broad jump, and the 30 s-chair stand tests for lower-body muscular strength, and the handgrip test for upper body isometric strength. Cardiometabolic risk (CMR) clustering was defined as having two or more of the following risk factors: high SBP and/or DBP, impaired fasting glucose, high triglycerides (TGs), and low HDL-Cholesterol. Results: CMR clustering was found in 44 (17.5%) obese youth. Youth with CMR clustering had a lower cardiorespiratory fitness, as assessed by 6MWT, compared to those without CMR clustering. On the contrary, no difference was found with respect to musculoskeletal fitness. The six-minute walk (6MW) distance was negatively associated with sedentary time, controlling for age and height. CMR factors clustering was significantly associated with BMI standard deviation score (SDS) and negatively with 6MW distance: for each 10-m increase in the 6MW distance, a reduction of about 9% in the prevalence of CMR clustering was expected. Conclusions: A lower performance in the 6MWT may be considered as an additional trait of CMR clustering in obese youth. The 6MWT may represent a valuable, simple and low cost test to estimate the cardiorespiratory fitness in youth with obesity.

RELAÇÃO ENTRE ATIVIDADE FÍSICA, APTIDÃO FÍSICA E RISCO CARDIOVASCULAR: ESTUDO EM MUZAMBINHO, MINAS GERAIS

RESUMO Introdução: A relação negativa entre atividade física, aptidão física e risco cardiovascular está bem estabelecida em populações com baixos níveis de atividade física. Objetivo: O presente estudo investigou essa relação em adultos de Muzambinho, Minas Gerais, uma população com alta taxa de indivíduos fisicamente ativos. Métodos: Participaram 237 indivíduos (132 mulheres), na maioria jovens (44,3% entre 20 e 39 anos). Foram avaliados indicadores de risco cardiovascular (índice de massa corporal, circunferência da cintura, glicemia de jejum, colesterolemia de jejum e pressão arterial sistólica e diastólica), atividade física (volume semanal de atividade física total) e aptidão física (aptidão aeróbica e força manual relativa). Resultados: Mais de 90% dos indivíduos foram classificados como ativos (praticavam atividade física por mais de 150 min/semana). A regressão linear identificou associação negativa da força manual relativa e da aptidão aeróbica ao índice de massa corporal e a circunferência da cintura, bem como associação positiva da força manual relativa à pressão arterial diastólica. Os indicadores de atividade física e aptidão física não se associaram ao risco cardiovascular global. Conclusão: Nessa população, a relação inversa entre atividade física, aptidão física e risco cardiovascular limitou-se aos indicadores de aptidão física e aos de obesidade, sugerindo que em populações com alta taxa de indivíduos fisicamente ativos, o aumento da aptidão física, mas não da atividade física, pode ajudar a reduzir a obesidade. Nível de Evidência II; ECRC de menor qualidade.

Self-Reported Versus Accelerometer-Assessed Daily Physical Activity in Childhood Obesity Treatment

We investigated the relationship between interview-based subjective ratings of physical activity (PA) engagement and accelerometer-assessed objectively measured PA in children and adolescents with overweight or obesity. A total of 92 children and adolescents (40 males, 52 females) with BMI ≥ 90th percentile for sex and age, aged 5-17 years had valid GT3X + accelerometer-assessed PA and interview-assessed self-reported information on PA engagement at the time of enrollment in a multidisciplinary outpatient tertiary treatment for childhood obesity. Accelerometer-derived mean overall PA and time spent in moderate to vigorous physical intensity were generated, applying cut-offs based on Vector Magnitude settings as defined by Romanzini et al. (2014), and a physical activity score (PAS) based on self-reported data. Overall, a higher self-reported PAS was correlated with higher accelerometer-assessed daily total PA levels ( r = 0.34, p < .01) and children who reported a high PAS were more physically active compared with children who reported a low PAS. There was a fair level of agreement between self-reported PAS and accelerometer-assessed PA (Kappa agreement = 0.23; 95% CI = [0.03, 0.43]; p = .01). PAS, derived from self-report, may be a useful instrument for evaluating PA at a group level among children and adolescents enrolled in multidisciplinary obesity treatment.

Metabolic syndrome in children and adolescents: Old concepts in a young population

Many years after first being described, there is still no clear consensus on diagnostic criteria for metabolic syndrome, particularly in children. However, identification of this cluster of cardiovascular risk factors especially in children with co-morbidities, is important in order to reduce their future risk of chronic disease and morbidity. Sustained multidisciplinary and family-based early intervention is required, aiming primarily at life-style change.

Determinants of organised sports participation patterns during the transition from childhood to adolescence in Germany: results of a nationwide cohort study

BACKGROUND

Organised sports (OS) participation is an important health behaviour but it seems to decline from childhood to adolescence. The aim of this study was to investigate OS participation patterns from childhood to adolescence and potential determinants for those patterns.

METHODS

Data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) cohort study with a 6 year follow-up period were used (KiGGS0: 2003-06, KiGGS1: 2009-12). Participants aged 6-10 years at KiGGS0, who were aged 12-16 at KiGGS1, were included (n = 3790). The outcome variable was 'OS participation' between KiGGS0 and KiGGS1 with the categories 'maintenance' (reference), 'dropout', 'commencement' and 'nonparticipation'. Relative risk ratios (RRRs) were calculated using multinomial logistic regression to identify potential predictors for OS patterns. Socio-demographic, family-related, health-related, behavioural and environmental factors were considered as independent variables.

RESULTS

48.5 % maintained OS, 20.5 % dropped out, 12.3 % commenced OS between KiGGS0 and KiGGS1 and 18.7 % did not participate at both times. The RRRs for dropout rather than maintenance were 0.6 (95 % Cl 0.5-0.7) for boys versus girls, 1.5 (1.3-1.9) for the age group 8-10 versus 6-7 years, 0.7 (0.5-0.9) for high versus intermediate parental education, 1.4 (1.1-1.8) for low versus middle household income, 1.4 (1.0-1.8) for below-average versus average motor fitness. The RRRs for commencement rather than maintenance were 0.6 (0.5-0.8) for boys versus girls, 0.6 (0.5-0.8) for the age group 8-10 versus 6-7 years, 1.5 (1.1-2.1) for low versus intermediate parental education, 1.5 (1.1-2.0) for low versus middle household income, 0.7 (0.5-1.0) for no single-parent versus single parent family, 1.8 (1.3-2.5) for below-average and 0.6 (0.4-0.8) for above-average versus average motor fitness, and 1.4 (1.1-1.9) for high versus middle screen-based media use. The RRRs for abstinence rather than maintenance were 0.6 (0.4-0.7) for boys versus girls, 1.5 (1.1-2.0) for low versus intermediate parental education, 2.2 (1.7-2.8) for low and 0.6 (0.5-0.8) for high versus middle household income, 1.6 (1.2-2.1) for psychopathological problems versus no problems, 1.7 (1.3-2.2) for below-average and 0.4 (0.3-0.6) for above-average versus average motor fitness, and 1.6 (1.0-2.6) for rural versus metropolitan residential area.

CONCLUSIONS

OS participation rates among all children living in Germany need to be improved. More tailored offerings are needed which consider the preferences and interests of adolescents as well as a cooperation between public health actors to reduce barriers to OS.

Body Weight and Not Exercise Capacity Determines Central Systolic Blood Pressure, a Surrogate for Arterial Stiffness, in Children and Adolescents

Cardiopulmonary fitness benefits cardiovascular health. Various studies have shown a strong negative correlation between exercise capacity and arterial stiffness in adults. However, evidence for this connection in children and adolescents is scarce. About 320 healthy children and adolescents (252 male, 14.0±2.1 years) were evaluated with regard to their demographic, anthropometric and hemodynamic parameters, and their peak oxygen uptake. Peripheral and central systolic blood pressures were measured with patients in a supine position using an oscillometric device. Peak oxygen uptake was assessed by cardiopulmonary exercise testing. In multivariate regression, only peripheral systolic blood pressure (β=0.653, P<.001) and body weight (β=0.284, P<.001) emerged as independent determinants for central systolic blood pressure. Body weight therefore determines central systolic blood pressure in children and adolescents rather than measures of cardiorespiratory fitness. The prevention of overweight in childhood is necessary to reduce stiffening of the arteries and delay the onset of cardiovascular disease.

A systematic review and meta-analysis of moderate-to-vigorous physical activity levels in elementary school physical education lessons

OBJECTIVE

To examine elementary school students' moderate-to-vigorous physical activity (MVPA) levels during physical education (PE) lessons.

METHODS

A systematic search of nine electronic databases was conducted (PROSPERO2014:CRD42014009649). Studies were eligible if they were in English; published between 2005-April 2014; assessed MVPA levels in PE lessons of elementary school children (aged four-12years); and used an objective MVPA measure. Two reviewers retrieved articles, assessed risk of bias, and performed data extraction. The findings were synthesised using a meta-analysis.

RESULTS

The search yielded 5132 articles. Thirteen studies from nine countries met the inclusion criteria. Eight studies measured MVPA through observational measures, five used accelerometry and one used heart rate monitoring. The percentage of PE lesson time spent in MVPA ranged between 11.4-88.5%. Meta-analysis of seven studies (4 direct observations; 4 accelerometers) found that children spent a mean (95% CI) 44.8 (28.2-61.4)% of PE lesson time in MVPA. When measured using direct observation and accelerometers, children spent 57.6 (47.3-68.2) and 32.6 (5.9-59.3)% of PE lesson time in MVPA, respectively. The review has limitations; the search strategy was restricted to studies in English; theses, dissertations and conference abstracts were excluded; and six studies that provided insufficient data were excluded from the meta-analysis.

CONCLUSION

MVPA levels during elementary school PE lessons do not meet the United States Centre for Disease Control and Prevention and the United Kingdom's Association of Physical Education recommendation (50% of lesson time), but is higher than estimated in the previous review (34.2%). Interventions to increase MVPA in PE lessons are needed.

Modeling longitudinal changes in hypertensive and waist phenotype: The oporto growth, health, and performance study

OBJECTIVES

This study aimed to: (1) model changes in the hypertensive and waist phenotype (HWP) in youth, and (2) investigate the effects of sex, biological maturation, total physical activity (TPA), and physical fitness (PF) in HWP trajectories.

METHODS

Data were obtained annually for 3 years from the Oporto Growth, Health, and Performance Study, and comprised 5,549 adolescents (2,732 girls) divided into four age cohorts (10, 12, 14, and 16 years). The HWP was computed as the sum of the standardized score of waist circumference and mean arterial pressure. Biological maturation was indirectly assessed by the maturity offset procedure; TPA was estimated with the Baecke questionnaire; PF measures included 1-mile run/walk, 50-yard dash (50YD), standing long jump (SLJ), handgrip strength (HGr), and agility shuttle run. Longitudinal changes in HWP were analyzed using multilevel modelling.

RESULTS

HWP increased across time with a nonlinear trend in girls and boys. However, when adjusted for a set of predictors, the trend was reversed: girls and boys had a significant annual decrease on HWP of -0.202 ± 0.032 and -0.147 ± 0.032, respectively. Maturity offset was positively associated with HWP changes (β = 0.913 ± 0.023); TPA had a negative association (β = -0.027 ± 0.011); and improved PF tests were associated with a significant reduction in HWP across time (β1mile  = -0.081 ± 0.009; βSLJ  = -0.003 ± 0.00; β50YD =0.106 ± 0.020; and βHGr  = -3.335 ± 0.196).

CONCLUSIONS

Boys showed higher HWP values compared to girls from 10 to 18 years of age. Adolescents who were more biologically mature had a more adverse HWP. Longitudinal increases in TPA and PF predicted annual decreases in HWP across the adolescence years.Am. J. Hum. Biol. 28:387-393, 2016. © 2015 Wiley Periodicals, Inc.

Relationship between physical activity, physical fitness and multiple metabolic risk in youths from Muzambinho's study

Negative associations between physical activity (PA), physical fitness and multiple metabolic risk factors (MMRF) in youths from populations with low PA are reported. The persistence of this association in moderately-to highly active populations is not, however, well established. The aim of the present study was to investigate this association in a Brazilian city with high frequency of active youths. We assessed 122 subjects (9.9 ± 1.3 years) from Muzambinho city. Body mass index, waist circumference, glycaemia, cholesterolaemia, systolic and diastolic blood pressures were measured. Maximal handgrip strength and one-mile walk/run test were used. Leisure time PA was assessed by interview. Poisson regression was used in the analysis. The model explained 11% of the total variance. Only relative muscular strength and one-mile walk/run were statistically significant (p < .05). Those who needed more time to cover the one-mile walk/run test had an increased in metabolic risk of 11%, and those with greater strength reduced the risk by about 82%. In conclusion, children and youths from an active population who need less time to cover the one-mile walk/run test or who had greater muscular strength showed a reduced metabolic risk. These results suggest that even in children and youths with high leisure time PA, a greater aerobic fitness and strength might help to further reduce their MMRF.

Assessment of aerobic capacity in overweight young females: A cross-sectional study

Context:

Overweight/obese people are prone to develop cardiovascular, respiratory and other chronic diseases at young age because of abnormal weight. Aerobic capacity (VO₂ max) is an accepted index of cardio respiratory fitness. Decrease in VO₂ max can be an early marker for altered cardiovascular physiology.

Objectives:

The present study was carried out with the objective of evaluating aerobic capacity in overweight young females and comparing it with that of normal weight females.

Materials and Methods:

Twenty-three female subjects aged 18–20 years were enrolled in each group. Group 1 comprised overweight subjects and group 2 comprised normal weight subjects. Analysis to assess the difference in VO₂ max between the groups was done by unpaired t-test.

Results:

Mean age of group 1 and 2 was 18.91 ± 0.67 years and 18.83 ± 0.78 years, respectively. Mean BMI in group 1 and 2 was 26.18 ± 1.06 kg/m² and 20.65 ± 1.5 kg/m² respectively. VO₂ max in groups 1 and 2 was 34.52 ± 3.26 ml/min/kg and 37.51 ± 2.88 ml/min/kg respectively. The difference in VO₂ max found in overweight girls was statistically significant with P value of 0.002.

Conclusion:

Overweight girls had significantly reduced, cardio-respiratory fitness when compared to normal weight young females.

Physical activity, body mass index, and cardiorespiratory fitness among school children in Taiwan: a cross-sectional study

There is evidence that cardiorespiratory fitness and physical activity significantly reduce cardiovascular risks in adults. A better understanding of the association between cardiorespiratory fitness, physical activity, and childhood obesity is vital in assessing the benefits of interventions to prevent obesity. This study was to examine the relationship between physical activity, body mass index, and cardiorespiratory fitness levels in Taiwanese children. A cross-sectional study was designed. Study participants consisted of 2419 school children (1230 males and 1189 females) aged 12 years old living in a southern Taiwan county with one the highest countrywide rates of childhood obesity. The weight status of the participants was defined as underweight, normal, overweight, or obese according to specific criteria. Cardiorespiratory fitness was then assessed by an 800-m run. Participants were queried on their physical activity habits via a questionnaire survey. The overall prevalence of overweight/obesity was 29.6%. Normal, underweight and overweight boys and girls had an increased odds ratio of being categorized with higher cardiorespiratory fitness than obese one for both gender. A significantly higher level of cardiorespiratory fitness was found in children who engaged in regular physical activity than in children who engaged only in irregular physical activity. Obese children are more likely to lack cardiorespiratory fitness. Physically active children have significantly better cardiorespiratory fitness levels than inactive children. This study supports the conclusion that BMI and physical activity are significantly correlated with cardiorespiratory fitness levels. Findings may provide educational professionals with information to assist their developing effective health promotion programs to healthy weight and improving cardiorespiratory fitness for children.

Fatores associados ao comportamento sedentário em escolares de 9-12 anos de idade

São recentes os estudos que investigaram impactos do comportamento sedentário (CS) sobre a saúde, principalmente em crianças. O objetivo foi investigar fatores associados ao CS em escolares do município de Uberaba, MG. Trata-se de estudo epidemiológico, transversal, com amostra probabilística (n = 649). Foram coletadas e consideradas variáveis independentes: medidas antropométricas, pressão arterial, exames bioquímicos, tempo gasto em atividade física (AF). CS foi considerado variável dependente, caracterizado pelo tempo de tela (TT), e verificado fatores associados pela regressão de Poisson. Meninas apresentaram valores maiores de dobras cutâneas, triglicerídeos e HDL-c e meninos, maior concentração de glicose sanguínea, atenderam mais à recomendação de 60 min de AF/dia e maior CS. O TT > 2 h/dia foi prevalente em 76,9 % da amostra. CS não foi associado a variáveis sociodemográficas, de saúde e comportamentais em crianças de 9-12 anos de idade. Mais pesquisas são necessárias para elucidar as inter-relações complexas entre TT e fatores associados.

Direct and indirect associations between the family physical activity environment and sports participation among 10-12 year-old European children: testing the EnRG framework in the ENERGY project

Background

Sport participation makes an important contribution to children’s overall physical activity. Understanding influences on sports participation is important and the family environment is considered key, however few studies have explored the mechanisms by which the family environment influences children’s sport participation. The purpose of this study was to examine whether attitude, perceived behavioural control, health belief and enjoyment mediate associations between the family environment and 10–12 year-old children’s sports participation.

Methods

Children aged 10–12 years ( = 7234) and one of their parents (n = 6002) were recruited from 175 schools in seven European countries in 2010. Children self-reported their weekly duration of sports participation, physical activity equipment items at home and the four potential mediator variables. Parents responded to items on financial, logistic and emotional support, reinforcement, modelling and co-participation in physical activity. Cross-sectional single and multiple mediation analyses were performed for 4952 children with complete data using multi-level regression analyses.

Results

Availability of equipment (OR = 1.16), financial (OR = 1.53), logistic (OR = 1.47) and emotional (OR = 1.51) support, and parental modelling (OR = 1.07) were positively associated with participation in ≥ 30mins/wk of sport. Attitude, beliefs, perceived behavioural control and enjoyment mediated and explained between 21-34% of these associations. Perceived behavioural control contributed the most to the mediated effect for each aspect of the family environment.

Conclusions

Both direct (unmediated) and indirect (mediated) associations were found between most family environment variables and children’s sports participation. Thus, family-based physical activity interventions that focus on enhancing the family environment to support children’s sport participation are warranted.

Physical fitness in children infected with the human immunodeficiency virus: associations with highly active antiretroviral therapy

Obesity, sedentary lifestyles, and antiretroviral therapies may predispose HIV-infected children to poor physical fitness. Estimated peak oxygen consumption (VO(2) peak), maximal strength and endurance, and flexibility were measured in HIV-infected and uninfected children. Among HIV-infected children, anthropometric and HIV disease-specific factors were evaluated to determine their association with VO(2) peak. Forty-five HIV-infected children (mean age 16.1 years) and 36 uninfected children (mean age 13.5 years) participated in the study. In HIV-infected subjects, median viral load was 980 copies/ml (IQR 200-11,000 copies/ml), CD4% was 28% (IQR 15-35%), and 82% were on highly active antiretroviral therapy (HAART). Compared to uninfected children, after adjusting for age, sex, race, body fat, and siblingship, HIV-infected children had lower VO(2) peak (25.92 vs. 30.90 ml/kg/min, p<0.0001), flexibility (23.71% vs. 46.09%, p=0.0003), and lower-extremity strength-to-weight ratio (0.79 vs. 1.10 kg lifted/kg of body weight, p=0.002). Among the HIV-infected children, a multivariable analysis adjusting for age, sex, race, percent body fat, and viral load showed VO(2) peak was 0.30 ml/kg/min lower per unit increase in percent body fat (p<0.0001) and VO(2) peak (SE) decreased 29.45 (± 1 .62), 28.70 (± 1.87), and 24.09 (± 0.75) ml/kg/min across HAART exposure categories of no exposure, <60, and ≥ 60 months, respectively (p<0.0001). HIV-infected children had, in general, lower measures of fitness compared to uninfected children. Factors negatively associated with VO(2) peak in HIV-infected children include higher body fat and duration of HAART ≥ 60 months. Future studies that elucidate the understanding of these differences and mechanisms of decreased physical fitness should be pursued.

Evaluation of metabolic risk in prepubertal girls versus boys in relation to fitness and physical activity

BACKGROUND

Low levels of cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a risk of the development of metabolic syndrome. Contradictory findings are reported in the literature regarding the influence of sex and CRF and PA on metabolic changes.

OBJECTIVE

The aim of this study was to analyze the effects of CRF and PA on lipid and carbohydrate metabolism biomarkers in boys and girls.

METHODS

A total of 82 prepubertal boys and 55 girls (7-12 years of age) were classified according to sex, low or high CRF, and performance or nonperformance of PA. Anthropometric and blood pressure (BP) measurements, plasma lipid profile values, glucose and insulin levels, and homeostasis model assessment for insulin resistance were analyzed.

RESULTS

The percentage of boys with high CRF and performance of PA was higher than that of girls (P < 0.05). When children of the same sex were compared, higher values for body mass index and waist circumference z-scores were found for boys with low CRF compared with boys with high CRF (P < 0.001) without differences between girls, and in all groups classified by PA. Systolic and diastolic BPs were higher in boys than in girls, in both CRF and PA groups (P < 0.05). In the low CRF and no PA groups, girls had higher plasma glucose, total cholesterol, and low-density lipoprotein cholesterol levels than boys, with higher high-density lipoprotein cholesterol and apolipoprotein A levels (P < 0.05).

CONCLUSIONS

Sex in relation to CRF and PA could affect the plasma lipid profile. These changes in girls are associated with low CRF and low levels of PA. Considering these results, we suggest the need to improve CRF and promote PA, especially in girls, to reduce metabolic risk.

Physical activity is related to insulin sensitivity in children and adolescents, independent of adiposity: a review of the literature

In adults, there is evidence that physical activity effectively improves insulin sensitivity regardless of adiposity. Whether this is also the case in children and adolescents is less clear. Clarifying this matter may help to identify the best outcomes to target in exercise programs for these age groups, where changes in adiposity may not always be desirable or realistic. A review of the literature was conducted on studies that examined the relationships of physical activity, cardiorespiratory fitness and strength with insulin sensitivity independent of adiposity in children and adolescents. Experimental (intervention) and correlational (longitudinal and cross-sectional) studies on participants ages 18 years and younger were identified. A total of 42 studies were included in this review. Sample sizes in the studies ranged from 14 to 4955 participants, with individual ages ranging from 5 to 19 years. A significant relationship with insulin sensitivity existed in 78% of studies on physical activity, 69% of studies on cardiorespiratory fitness and 66% of studies on strength. In studies that examined both physical activity and cardiorespiratory fitness concurrently, evidence suggests that they are both correlated with insulin sensitivity independent of adiposity, especially when physical activity is at higher intensities. However, the strength of this relationship might be influenced by study design, measurement techniques and participant characteristics. This is the first review of its type to take research design into account and to examine study outcomes according to participant ethnicity, gender, age, pubertal status and weight status.

Rationale and study protocol for the supporting children's outcomes using rewards, exercise and skills (SCORES) group randomized controlled trial: a physical activity and fundamental movement skills intervention for primary schools in low-income communities

BACKGROUND

Many Australian children are insufficiently active to accrue health benefits and physical activity (PA) levels are consistently lower among youth of low socio-economic position. PA levels decline dramatically during adolescence and evidence suggests that competency in a range of fundamental movement skills (FMS) may serve as a protective factor against this trend.

METHODS/DESIGN

The Supporting Children's Outcomes Using Rewards Exercise and Skills (SCORES) intervention is a multi-component PA and FMS intervention for primary schools in low-income communities, which will be evaluated using a group randomized controlled trial. The socio-ecological model provided a framework for the 12-month intervention, which includes the following components: teacher professional learning, student leadership workshops (including leadership accreditation and rewards, e.g., stickers, water bottles), PA policy review, PA equipment packs, parental engagement via newsletters, FMS homework and a parent evening, and community partnerships with local sporting organizations. Outcomes will be assessed at baseline, 6- and 12-months. The primary outcomes are PA (accelerometers), FMS (Test of Gross Motor Development II) and cardiorespiratory fitness (multi-stage fitness test). Secondary outcomes include body mass index [using weight (kg)/height (m2)], perceived competence, physical self-esteem, and resilience. Individual and environmental mediators of behavior change (e.g. social support and enjoyment) will also be assessed. The System for Observing Fitness Instruction Time will be used to assess the impact of the intervention on PA within physical education lessons. Statistical analyses will follow intention-to-treat principles and hypothesized mediators of PA behavior change will be explored.

DISCUSSION

SCORES is an innovative primary school-based PA and FMS intervention designed to support students attending schools in low-income communities to be more skilled and active. The findings from the study may be used to guide teacher pre-service education, professional learning and school policy in primary schools.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry No: ACTRN12611001080910.

Rationale and study protocol for the supporting children's outcomes using rewards, exercise and skills (SCORES) group randomized controlled trial: a physical activity and fundamental movement skills intervention for primary schools in low-income communities

BACKGROUND

Many Australian children are insufficiently active to accrue health benefits and physical activity (PA) levels are consistently lower among youth of low socio-economic position. PA levels decline dramatically during adolescence and evidence suggests that competency in a range of fundamental movement skills (FMS) may serve as a protective factor against this trend.

METHODS/DESIGN

The Supporting Children's Outcomes Using Rewards Exercise and Skills (SCORES) intervention is a multi-component PA and FMS intervention for primary schools in low-income communities, which will be evaluated using a group randomized controlled trial. The socio-ecological model provided a framework for the 12-month intervention, which includes the following components: teacher professional learning, student leadership workshops (including leadership accreditation and rewards, e.g., stickers, water bottles), PA policy review, PA equipment packs, parental engagement via newsletters, FMS homework and a parent evening, and community partnerships with local sporting organizations. Outcomes will be assessed at baseline, 6- and 12-months. The primary outcomes are PA (accelerometers), FMS (Test of Gross Motor Development II) and cardiorespiratory fitness (multi-stage fitness test). Secondary outcomes include body mass index [using weight (kg)/height (m2)], perceived competence, physical self-esteem, and resilience. Individual and environmental mediators of behavior change (e.g. social support and enjoyment) will also be assessed. The System for Observing Fitness Instruction Time will be used to assess the impact of the intervention on PA within physical education lessons. Statistical analyses will follow intention-to-treat principles and hypothesized mediators of PA behavior change will be explored.

DISCUSSION

SCORES is an innovative primary school-based PA and FMS intervention designed to support students attending schools in low-income communities to be more skilled and active. The findings from the study may be used to guide teacher pre-service education, professional learning and school policy in primary schools.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry No: ACTRN12611001080910.

Association of body weight and physical activity with blood pressure in a rural population in the Dikgale village of Limpopo Province in South Africa

BACKGROUND

Africa is faced with an increasing burden of hypertension attributed mainly to physical inactivity and obesity. Paucity of population based evidence in the African continent hinders the implementation effective preventive and control strategies. The aim of this study was to determine the association of body weight and physical activity with blood pressure in a rural black population in the Limpopo Province of South Africa.

METHODS

A convenient sample of 532 subjects (396 women and 136 men) between the ages 20-95 years participated in the study. Standard anthropometric measurements, blood pressure, and physical activity were recorded by trained field workers.

RESULTS

Anthropometric measurements showed that a high percentage of women were significantly (p < 0.001) overweight and obese than men. Hypertension was significantly high among women (38.1%) compared to men (27.9%). In the univariate analysis mean body mass index (BMI), waist circumference (WC), hip circumference (HC) and waist hip ratio (WHR) showed a significant positive association (p ≤ 0.05) with systolic and diastolic BP in women, and only WHR was statistically significant in men. The odds of being hypertensive also increased with BMI, WC and WHR in both women and men, including HC in women. No relationship was found between physical activity and high blood pressure. In the multivariate analysis only increase in HC and WHR was consistently associated with increase in SBP in women and WHR with hypertension in men.

CONCLUSIONS

The study findings indicate that women in this black South African rural population are overweight and obese than men and are at higher risk of hypertension as determined by selected anthropometric parameters.

Non-traditional markers of metabolic risk in prepubertal children with different levels of cardiorespiratory fitness

OBJECTIVE

To assess classical and non-classical metabolic risk biomarkers in prepubertal children with different levels of cardiorespiratory fitness (CRF).

DESIGN

CRF was assessed by the 20 m shuttle run test. To estimate physical activity, participants were observed while engaged in an after-school programme. Additionally, a short test based on a validated questionnaire was used to obtain information about physical activity practice and sedentary habits. Anthropometric parameters, blood pressure, and classical and non-traditional metabolic risk biomarkers--plasma lipid profile, glucose and insulin, homeostasis model assessment-insulin resistance index (HOMA-IR), plasma uric acid, transaminases and C-reactive protein (CRP)--were measured.

SETTING

The study was conducted in local elementary schools in Córdoba, Spain.

SUBJECTS

One hundred and forty-one healthy children (eighty-eight boys, fifty-three girls) aged 7-12 years, in Tanner stage I, were recruited. They were divided into two groups after they performed the 20 m shuttle run test: equal or higher cardiovascular fitness (EHCF) group and low cardiovascular fitness (LCF) group.

RESULTS

The LCF group displayed significantly higher TAG (P = 0.004) and lower HDL cholesterol levels (P = 0.001), as well as significantly lower values for the non-traditional lipid marker apo-A1 (P = 0.001) compared with the EHCF group. The LCF children displayed higher plasma glucose (P = 0.003) and insulin levels, higher HOMA-IR scores (P < 0.001) and higher plasma uric acid and CRP levels (P < 0.05). After adjustment for BMI, age and sex, no statistically significant differences were found between groups for the biomarkers analysed.

CONCLUSIONS

The study provides new information to understand the role not only of weight status but also of the level of CRF on the metabolic health profile of prepubertal children.

Relationship of body fat and cardiorespiratory fitness with cardiovascular risk in Chinese children

Backgrounds/Objectives

Cardiorespiratory fitness (CRF) and body fat play an important role in elevated risk for cardiovascular disease (CVD). However, the combined effects of CRF and obesity on metabolic health in Chinese children are unclear. The purpose of this study was to investigate the independent and combined associations between body fat, CRF, and CVD risk in Chinese schoolchildren.

Methods

The study subjects comprised 676 schoolchildren (392 boys and 284 girls, aged 9.6±0.7 yrs old) in Wuhan, China. Their body mass index (BMI), waist circumference (WC), CRF, blood pressure (BP), lipids, glucose, and pubertal status were assessed. Children were categorized into different groups based on their BMI, WC, and CRF using Chinese obesity cut-off points and CRF sex-specific median points. Metabolic Risk Score (MRS) was computed based on the standardized scores of BP, lipids, and glucose.

Results

Multiple linear regression models showed that, in the separate models, body fat was positively associated with MRS while CRF was inversely associated with MRS (p<0.001). However, when assessed simultaneously, only body fat had a significant association with MRS (p<0.001). In general, low-fit children had a lower MRS compared to their counterparts, and a significant difference between the two extreme groups was observed (low CRF and high fat vs. high CRF and low fat, p<0.001).

Conclusions

These findings suggest that both body fat and CRF should be considered when interpreting CVD risk in Chinese children, while body fat may be correlated with CVD risk more than CRF.

Effect of energy expenditure on postprandial triacylglycerol in adolescent boys

This study examined the effects of 30 and 60 min of moderate intensity exercise on postprandial triacylglycerol concentration [TAG] in 11 healthy, 13-year-old boys. The boys completed three counterbalanced conditions. On day 1, they either rested (CON), or jogged for 30 min (EX30) or 60 min (EX60) at 55% peak [Formula: see text] Following a 12-h fast, on day 2 a capillary blood sample was taken for fasting [TAG] before a high fat milkshake was consumed. Further blood samples were taken every hour over a 6-h postprandial rest period for [TAG]. The estimated energy expenditure for EX30 (982 kJ) was doubled in EX60 (1967 kJ). Differences in fasting [TAG] between the conditions were small (ES = 0.23, P = 0.35). Differences in postprandial TAG over time between conditions were identified (ES = 0.41, P = 0.03). Mean [TAG] was lower in EX60 than CON (-33 to -3%, P = 0.03) with a similar strong trend for EX30 (-29 to 1%, P = 0.06); EX60 and EX30 were not different from each other (-21 to 14%, P = 0.62). The total area under the [TAG] versus time curve was different between conditions (ES = 0.42, P = 0.03). Again, EX60 was lower than CON (-31 to -2%, P = 0.02) with a strong trend for EX30 (-31 to 4%, P = 0.06); EX30 and EX60 were not different from each other (-17 to 16%, P = 0.58). This study shows for the first time that both 30 and 60 min of jogging, with energy expenditures equivalent to 982 and 1,967 kJ, attenuates postprandial [TAG] in adolescent boys, but not in a dose-dependent manner.

Micronutrient and anthropometric status indicators are associated with physical fitness in Colombian schoolchildren

Poor physical fitness is associated with increased health-related risks in children. The association of nutritional status indicators and physical fitness in children residing in developing countries is not well characterised. We conducted a cross-sectional study among 1945 children of age 5-12 years in Bogotá, Colombia, to assess whether anthropometric and micronutrient status indicators were associated with performance in the shuttle run and standing long jump tests. Stunted children scored significantly lower in the run (0·4 s; P = 0·0002) and jump (6 cm; boys only; P = 0·003) tests than non-stunted children, after adjustment for age and other factors. Children who were thin, overweight or obese ran slower than normal-weight children (P < 0·01). Lower jump scores were associated with overweight or obesity and greater arm fat area in boys only (P < 0·0001). Girls with low ferritin concentrations ran 0·6 s slower than girls with normal ferritin concentrations (P = 0·02). Erythrocyte folate concentrations were linearly related to higher run (P < 0·0001) and long jump scores (P = 0·0001). Boys with marginal or low vitamin B12 status had 4 cm lower long jump scores than children with normal status (P = 0·01). Suboptimal anthropometric and micronutrient status are related to poorer performance in fitness tests. The effects of improving nutritional status on physical fitness of children warrant investigation.

Elevated nocturnal blood pressure and heart rate in adolescent chronic fatigue syndrome

AIM

To compare ambulatory recordings of heart rate (HR) and blood pressure in adolescents with chronic fatigue syndrome (CFS) and healthy controls. We hypothesized both HR and blood pressure to be elevated among CFS patients.

METHODS

Forty-four CFS patients aged 12-18 years were recruited from our paediatric outpatient clinic. The controls were 52 healthy adolescents having similar distribution of age and gender. 24-h ambulatory blood pressure and HR were recorded using a validated, portable oscillometric device.

RESULTS

At night (sleep), HR, mean arterial blood pressure and diastolic blood pressure were significantly higher in CFS patients as compared with controls (p < 0.01). During daytime, HR was significantly higher among CFS patients (p < 0.05), whereas blood pressures were equal among the two groups.

CONCLUSIONS

The findings support previous experimental evidence of sympathetic predominance of cardiovascular control in adolescent CFS patients. Also, the findings prompt increased focus on cardiovascular risk assessment and suggest a possible target for therapeutic intervention.

Inverse but independent trends in obesity and fitness levels among Greek children: a time-series analysis from 1997 to 2007

OBJECTIVE

We examined secular trends in physical fitness and BMI status in 8- to 9-year-old Greek children during an 11-year period (1997-2007).

METHODS

Population data derived from a yearly health survey performed in over 85% of Greek schools. Anthropometric measurements and physical fitness tests from 651,582 children were analyzed. The gender- and age-specific BMI cut-off points by the International Obesity Task Force were used to define overweight/obesity.

RESULTS

Aerobic performance decreased by 4.9% (p < 0.001) for boys and 4.4% (p < 0.001) for girls between 1997 and 2007 while obesity increased by approximately 50% in both genders (p < 0.001). Time-series analyses revealed that the increasing trends in obesity were independent of the reduction in fitness levels. An increase from 21% in 1997 to 48.2% in 2007 was observed in the prevalence of the low quartile of aerobic performance for girls (p < 0.001) and from 25.7% in 1997 to 38.7% in 2007 (p < 0.001) for boys. Approximately 80% and 85% of obese boys and girls, respectively, failed to pass the low quartile of all aerobic tests in 2007.

CONCLUSIONS

Inverse but independent trends in obesity and fitness levels were observed among Greek children during an 11-year period (1997-2007), a fact that predisposes our children to serious health risks as they grow older.

Outcomes of a school-based intervention (RESCATE) to improve physical activity patterns in Mexican children aged 8-10 years

The aim of this study was to evaluate the impact of an intervention program on the patterns of physical activity in 8- to 10-year-old Mexican children from lower socioeconomic status. This study performed a randomized controlled field trial in 498 children aged 8-10 years from 10 public schools of low socioeconomic status in Mexico City. Schools were randomly assigned to intervention (n = 5) or control (n = 5) groups and followed up during 12 months. Physical and sedentary activities were assessed at the beginning of the program and after 6 and 12 months. At the end of follow-up, there was a significant increase in the performance of moderate physical activity (MPA) among children in intervention group who had not performed MPA at baseline any day of the week (40%, P = 0.04) but not in the control group (8%, P = not significant). The intervention group also showed a significant reduction in the proportion of children who spent more than 3 hours a day playing video games (from 23 to 13%, P = 0.01), while control group did not show significant changes. Given these findings, we conclude that intervention was able to modify positively physical activity and reduce time spent on such sedentary activities as video games among those at highest risk studied children.