The effects of a physical fitness program on low-fit children

Inverse Association of High-Density Lipoprotein Cholesterol Concentration with Muscle Mass in Children

Background: Obesity was often associated with low high-density lipoprotein (HDL) cholesterol concentration, which is an established cardiovascular risk factor. Objectives: To evaluate the association of HDL-cholesterol concentration with fat and muscle mass in children and adolescents. Methods: Data of the National Health and Nutrition Examination Survey (1999-2004) were used to estimate fat and muscle mass by dual-energy X-ray absorptiometry (DXA) of the participants who had also an examination of their lipid profiles. Fat mass was assessed by DXA-determined fat mass index (FMI). Muscle mass was operationalized by appendicular lean mass index (LMI). Low HDL-cholesterol concentration was defined as <40 mg/dL. Results: For the evaluation of the association of HDL-cholesterol concentration with FMI and LMI Z-scores, the data of 6288 children and adolescents (age 8-19 years) (2535 females) were eligible. In the study population, the prevalence of low HDL-cholesterol concentration increased with rising FMI and appendicular LMI Z-scores. Conclusions: The study results suggested that there is a counterintuitive, inverse association of muscle mass and HDL-cholesterol concentration.

Regular physical education class enhances sociality and physical fitness while reducing psychological problems in children of multicultural families

This study investigated the influence of physical education class (PEC) as an intervention method for aggression, sociality, stress, and physical fitness levels in children from multicultural families. The hypothesis was that participating in PEC would result in reduced aggression and stress and improved sociality and physical fitness in multicultural children. A three-item questionnaire, a body composition test, and physical fitness tests were given three times. Eighty-four subjects were divided into four groups: multicultural children who participated in PEC (multi-PEG, n=12), multicultural children who did not participate in PEC (multi-NPEG, n=13), single-cultural children who participated in PEC (sing-PEG, n=11), and single-cultural children who did not participate in PEC (sing-NPEG, n=12), respectively. Parametric and nonparametric statistical methods were conducted on the collected data with a significance level set a priori at P<0.05. After 8 weeks of PEC, fat mass (F=2.966, P=0.045) and body mass index (F=3.654, P=0.021) had significantly different interaction effects. In the aspect of interaction effects from physical fitness variables, cardiopulmonary endurance (F=21.961, P=0.001), flexibility (F=8.892, P=0.001), muscular endurance (F=31.996, P=0.001), muscular strength (F=4.570, P=0.008), and power (F=24.479, P=0.001) were significantly improved in the multi-PEG compared to those of the other three groups. Moreover, sociality (F=22.144, P=0.001) in the multi-PEG was enhanced, whereas aggression (F=6.745, P=0.001) and stress (F=3.242, P=0.033) levels were reduced. As conclusion, the PEC reduced aggression and stress levels, and improved sociality and physical fitness levels after 8 weeks. This study confirmed that PEC for children from multicultural families can improve psychosocial factors and physical health.

Perceptions about Exercise and Intrinsic Motivation of Students Attending a Health-Related Physical Education Program

The present study examined effects of sex, attitude towards physical activity, perceived barriers for participation in physical activity, and students' perception of their parents' participation in physical activity on the intrinsic motivation of students participating in a health related program in physical education. 643 students (303 boys and 340 girls) responded to questionnaires measuring intrinsic motivation, attitudes towards physical activity, perceived barriers to exercise and perceived parents' participation in physical activity. Mean age was 12.9 yr. ( SD=1.2, range 11–14 years). Analysis indicated that students' intrinsic motivation towards the program was influenced by perceived barriers to exercise. Sex, attitudes towards physical activity, and perceived parents' participation in physical activity seem to be less important.

Effects of a Circuit Training Program on Muscular and Cardiovascular Endurance and their Maintenance in Schoolchildren

The purpose of this study was to evaluate the effects of a circuit training program along with a maintenance program on muscular and cardiovascular endurance in children in a physical education setting. Seventy two children 10–12 years old from four different classes were randomly grouped into either an experimental group (n = 35) or a control group (n = 37) (two classes for each group). After an eight-week development program carried out twice a week and a four-week detraining period, the experimental group performed a four-week maintenance program once a week. The program included one circuit of eight stations of 15/45 to 35/25 seconds of work/rest performed twice. Abdominal muscular endurance (sit-ups in 30 seconds test), upper-limbs muscular endurance (bent arm hang test), and cardiovascular endurance (20-m endurance shuttle run test) were measured at the beginning and at the end of the development program, and at the end of the maintenance program. After the development program, muscular and cardiovascular endurance increased significantly in the experimental group (p < 0.05). The gains obtained remained after the maintenance program. The respective values did not change in the control group (p > 0.05). The results showed that the circuit training program was effective to increase and maintain both muscular and cardiovascular endurance among schoolchildren. This could help physical education teachers design programs that permit students to maintain fit muscular and cardiovascular endurance levels.

Cardiorespiratory fitness relates more strongly than physical activity to cardiovascular disease risk factors in healthy children and adolescents: the European Youth Heart Study

BACKGROUND

Physical activity and cardiorespiratory fitness are closely related to health variables in adults, especially those considered to be among risk factors for cardiovascular diseases. The possible tracking of cardiovascular disease risk factors from childhood to adulthood makes it important to increase our understanding of the complex relationships between physical activity, cardiorespiratory fitness and cardiovascular risk factors early in life.

DESIGN

A cross-sectional, school-based study on healthy children and adolescents, aged 9-10 years (295 girls, 295 boys) and 15-16 years (302 girls, 233 boys) was performed during a school year in Sweden and Estonia, as part of the European Youth Heart Study.

METHODS

Total physical activity, and minutes spent in inactivity and activity of moderate or higher intensity were measured by accelerometry. A maximal ergometer bike test was used for estimation of cardiorespiratory fitness. The risk factors included blood pressure and fasting blood levels of insulin, glucose, triglycerides, total cholesterol and high-density lipoprotein cholesterol.

RESULTS

Canonical correlations between physical activity and cardiorespiratory fitness versus cardiovascular disease risk factors showed significant associations in both age and sex groups (rc=0.46-0.61, P<0.0001). The cardiorespiratory fitness was found to be the strongest contributor to these relationships. In girls high values of the physical activity variables were also associated with a favourable cardiovascular profile.

CONCLUSIONS

Cardiorespiratory fitness relates more strongly to cardiovascular risk factors than components of objectively measured physical activity in children and adolescents. Physical activity becomes more important in the 15-year-old adolescents, indicating that these modifiable lifestyle factors increase in importance with age.

Body fat is associated with blood pressure in school-aged girls with low cardiorespiratory fitness: The European Youth Heart Study

OBJECTIVE

To examine the association between anthropometric measurements of total and central adiposity and blood pressure in school-aged children, and to study whether these associations are modified by the levels of cardiorespiratory fitness.

METHODS

Systolic and diastolic blood pressure, weight, height, skinfold thickness and waist circumference were measured in 873 children aged 9-10 years participating in the Estonian and Swedish part of the European Youth Heart Study. Mean arterial pressure was calculated. Body mass index and skinfold thickness were used as markers of total adiposity, whereas waist circumference and waist-height ratio were used as markers of central adiposity. Cardiorespiratory fitness was estimated by a maximal ergometer bike test, and dichotomized into low and high levels.

RESULTS

Markers of total and central adiposity were positively associated with blood pressure. The results from the regression models showed that the markers of total and central adiposity were significantly associated with systolic blood pressure in girls with low levels of cardiorespiratory fitness. Similar results were observed when mean arterial pressure was the outcome variable. None of the markers of total and central adiposity were significantly associated with blood pressure in girls with high levels of cardiorespiratory fitness or in boys with low or high levels of cardiorespiratory fitness.

CONCLUSIONS

The results show a positive influence of simple anthropometric measurements of total and central adiposity on blood pressure, and suggest that higher cardiorespiratory fitness may attenuate the association between body fat and blood pressure in school-aged children.

Associations of low-grade inflammation with physical activity, fitness and fatness in prepubertal children; the European Youth Heart Study

OBJECTIVE

To examine the associations of low-grade inflammation with objectively measured physical activity, cardiovascular fitness (CVF) and fatness in prepubertal children.

DESIGN

Cross-sectional study.

SUBJECTS

One hundred and forty-two children (74 boys and 68 girls) aged 9-10 years (pubertal stage I and II) from the Swedish part of the European Youth Heart Study.

MEASUREMENTS

Total physical activity and its intensity levels (moderate, vigorous, moderate + vigorous) were measured by accelerometry. CVF was measured with a maximal ergometer bike test. Body fat was derived from the sum of five skinfold thicknesses. The measured low-grade inflammatory markers include C-reactive protein, fibrinogen, complement factors C3 and C4.

RESULTS

C-reactive protein and C3 were negatively associated with CVF (beta=-0.254 and -0.267, respectively, P<0.05) and positively associated with body fat (beta=0.439 and 0.446, respectively, P<0.001), after controlling for sex, age and pubertal development. C-reactive protein and C3 were not significantly associated with CVF once body fat was in the model. Low-grade inflammation was not associated with physical activity, but physical activity was associated with CVF.

CONCLUSIONS

The results showed that low-grade inflammatory markers were negatively associated with CVF and positively associated with body fat in prepubertal children. For most of the variables, the influence of fatness was slightly higher than the influence of CVF. The findings suggest that the potential beneficial effects of physical activity on low-grade inflammation may be explained by its association with CVF. Understanding the interplay between physical activity, CVF and fatness may be of importance to reducing cardiovascular disease risk in young people.

Markers of insulin resistance are associated with fatness and fitness in school-aged children: the European Youth Heart Study

AIMS/HYPOTHESIS

Our aim was to examine the association between markers of insulin resistance and: (1) body fat and waist circumference, taking into account cardiorespiratory fitness in school-aged children; and (2) cardiorespiratory fitness at differing levels of body fat and waist circumference.

SUBJECTS AND METHODS

This was a cross-sectional study of 873 children aged 9.6 +/- 0.4 years from Estonia and Sweden. Weight, height and waist circumference were measured. Body fat was expressed as the sum of five skinfold thicknesses. Cardiorespiratory fitness was estimated by a maximal cycle-ergometer test. The studied markers of insulin resistance were fasting insulin and glucose, and homeostasis model assessment (HOMA).

RESULTS

HOMA and fasting insulin were positively associated with body fat and waist circumference after adjusting for cardiorespiratory fitness, age, pubertal status and study location. HOMA and fasting insulin were negatively associated with cardiorespiratory fitness in children in the third (highest) tertile of body fat and waist circumference after controlling for sex, age, pubertal status and study location. Fasting glucose was negatively associated with cardiorespiratory fitness in children in the third (highest) tertile of waist circumference, but it was not associated when body fat was taken into account.

CONCLUSIONS/INTERPRETATION

In school-aged children, HOMA and fasting insulin are significantly associated with body fat and waist circumference. In addition, cardiorespiratory fitness explains a significant proportion of the HOMA and fasting insulin variance in those children with high levels of body fat and waist circumference. The findings suggest that the deleterious consequences ascribed to high fatness could be counteracted by having high levels of cardiorespiratory fitness.

High cardiovascular fitness is associated with low metabolic risk score in children: the European Youth Heart Study

The aim of the present study was to examine the associations of cardiovascular fitness (CVF) with a clustering of metabolic risk factors in children, and to examine whether there is a CVF level associated with a low metabolic risk. CVF was estimated by a maximal ergometer bike test on 873 randomly selected children from Sweden and Estonia. Additional measured outcomes included fasting insulin, glucose, triglycerides, HDLC, blood pressure, and the sum of five skinfolds. A metabolic risk score was computed as the mean of the standardized outcomes scores. A risk score <75th percentile was considered to indicate a low metabolic risk. CVF was negatively associated with clustering of metabolic risk factors in children. Receiver operating characteristic curve analysis showed a significant discriminatory accuracy of CVF in identifying the low/high metabolic risk in girls and boys (p < 0.001). The CVF level for a low metabolic risk was 37.0 and 42.1 mL/kg/min in girls and boys, respectively. These levels are similar to the health-related threshold values of CVF suggested by worldwide recognized organizations. In conclusion, the results suggest a hypothetical CVF level for having a low metabolic risk, which should be further tested in longitudinal and/or intervention studies.

A meta-analytic review of obesity prevention programs for children and adolescents: the skinny on interventions that work

This meta-analytic review summarizes obesity prevention programs and their effects and investigates participant, intervention, delivery, and design features associated with larger effects. A literature search identified 64 prevention programs seeking to produce weight gain prevention effects, of which 21% produced significant prevention effects that were typically pre- to post effects. Larger effects emerged for programs that targeted children and adolescents (vs. preadolescents) and females, programs that were relatively brief, programs that solely targeted weight control versus other health behaviors (e.g., smoking), programs evaluated in pilot trials, and programs wherein participants must have self-selected into the intervention. Other factors, including mandated improvements in diet and exercise, sedentary behavior reduction, delivery by trained interventionists, and parental involvement, were not associated with significantly larger effects.

Reducing obesity and related chronic disease risk in children and youth: a synthesis of evidence with 'best practice' recommendations

Childhood obesity is a global epidemic and rising trends in overweight and obesity are apparent in both developed and developing countries. Available estimates for the period between the 1980s and 1990s show the prevalence of overweight and obesity in children increased by a magnitude of two to five times in developed countries (e.g. from 11% to over 30% in boys in Canada), and up to almost four times in developing countries (e.g. from 4% to 14% in Brazil). The goal of this synthesis research study was to develop best practice recommendations based on a systematic approach to finding, selecting and critically appraising programmes addressing prevention and treatment of childhood obesity and related risk of chronic diseases. An international panel of experts in areas of relevance to obesity provided guidance for the study. This synthesis research encompassed a comprehensive search of medical/academic and grey literature and the Internet covering the years 1982-2003. The appraisal approach developed to identify best practice was unique, in that it considered not only methodological rigour, but also population health, immigrant health and programme development/evaluation perspectives in the assessment. Scores were generated based on pre-determined criteria with programmes scoring in the top tertile of the scoring range in any one of the four appraisal categories included for further examination. The synthesis process included identification of gaps and an analysis and summary of programme development and programme effectiveness to enable conclusions to be drawn and recommendations to be made. The results from the library database searches (13,158 hits), the Internet search and key informant surveys were reduced to a review of 982 reports of which 500 were selected for critical appraisal. In total 158 articles, representing 147 programmes, were included for further analysis. The majority of reports were included based on high appraisal scores in programme development and evaluation with limited numbers eligible based on scores in other categories of appraisal. While no single programme emerged as a model of best practice, synthesis of included programmes provided rich information on elements that represent innovative rather than best practice under particular circumstances that are dynamic (changing according to population subgroups, age, ethnicity, setting, leadership, etc.). Thus the findings of this synthesis review identifies areas for action, opportunities for programme development and research priorities to inform the development of best practice recommendations that will reduce obesity and chronic disease risk in children and youth. A lack of programming to address the particular needs of subgroups of children and youth emerged in this review. Although immigrants new to developed countries may be more vulnerable to the obesogenic environment, no programmes were identified that specifically targeted their potentially specialized needs (e.g. different food supply in a new country). Children 0-6 years of age and males represented other population subgroups where obesity prevention programmes and evidence of effectiveness were limited. These gaps are of concern because (i) the pre-school years may be a critical period for obesity prevention as indicated by the association of the adiposity rebound and obesity in later years; and (ii) although the growing prevalence of obesity affects males and females equally; males may be more vulnerable to associated health risks such as cardiovascular disease. Other gaps in knowledge identified during synthesis include a limited number of interventions in home and community settings and a lack of upstream population-based interventions. The shortage of programmes in community and home settings limits our understanding of the effectiveness of interventions in these environments, while the lack of upstream investment indicates an opportunity to develop more upstream and population-focused interventions to balance and extend the current emphasis on individual-based programmes. The evidence reviewed indicates that current programmes lead to short-term improvements in outcomes relating to obesity and chronic disease prevention with no adverse effects noted. This supports the continuation and further development of programmes currently directed at children and youth, as further evidence for best practice accumulates. In this synthesis, schools were found to be a critical setting for programming where health status indicators, such as body composition, chronic disease risk factors and fitness, can all be positively impacted. Engagement in physical activity emerged as a critical intervention in obesity prevention and reduction programmes. While many programmes in the review had the potential to integrate chronic disease prevention, few did; therefore efforts could be directed towards better integration of chronic disease prevention programmes to minimize duplication and optimize resources. Programmes require sustained long-term resources to facilitate comprehensive evaluation that will ascertain if long-term impact such as sustained normal weight is maintained. Furthermore, involving stakeholders in programme design, implementation and evaluation could be crucial to the success of interventions, helping to ensure that needs are met. A number of methodological issues related to the assessment of obesity intervention and prevention programmes were identified and offer insight into how research protocols can be enhanced to strengthen evidence for obesity interventions. Further research is required to understand the merits of the various forms in which interventions (singly and in combination) are delivered and in which circumstances they are effective. There is a critical need for the development of consistent indicators to ensure that comparisons of programme outcomes can be made to better inform best practice.

Health outcomes of elementary school students in New Brunswick. The education perspective

With data from the New Brunswick School Climate Study (N = 6,883 students from 147 schools), this study examined individual differences in and school effects on health outcomes of students. Results of hierarchical linear modeling showed that females reported experiencing more physical health problems, eating less healthy food, and doing fewer exercises than males. Students of high socioeconomic status (SES) reported eating more healthy food and doing more exercises than students of low SES. Native students reported experiencing more physical health problems and eating less healthy food than nonnative students. Students of single parents reported eating more healthy food and exercising more than students of both parents. Schools showed effects on health outcomes over and above the effects of students. Students in schools with high SES and positive disciplinary climate reported fewer physical and mental health problems. Students in large schools reported less healthy food intake and fewer physical exercises.

School-based interventions improve heart health in children with multiple cardiovascular disease risk factors

OBJECTIVE

To determine the immediate effects of two types of elementary school-based interventions on children with multiple cardiovascular disease (CVD) risk factors.

DESIGN

Randomized, controlled field trial.

SETTING

Conducted in 18 randomly selected elementary schools across North Carolina.

STUDY PARTICIPANTS

Four hundred twenty-two children age 9 +/- 0.8 years with at least two risk factors at baseline: low aerobic power and either high serum cholesterol or obesity.

INTERVENTION

Both 8-week interventions consisted of a knowledge and attitude program and an adaptation of physical education. The classroom-based intervention was given by regular teachers to all children in the 3rd and 4th grades. The risk-based intervention was given in small groups only to children with identified risk factors. Children in the control group received usual teaching and physical education.

OUTCOME MEASURES

The primary outcome measure was cholesterol; additional measures were blood pressure, body mass index, body fat, eating and activity habits, and health knowledge.

RESULTS

Both interventions produced large reductions in cholesterol (-10.1 mg/dL and -11.7 mg/dL) compared with a small drop (-2.3 mg/dL) in the controls. There was a trend for systolic blood pressure to increase less in both intervention groups than in the controls. Both intervention groups had a small reduction in body fat and higher health knowledge than the control group.

CONCLUSIONS

Both brief interventions can improve the CVD risk profile of children with multiple risk factors. The classroom-based approach was easier to implement and used fewer resources. This population approach should be considered as one means of early primary prevention of CVD.

Guidelines for school and community programs to promote lifelong physical activity among young people. National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and prevention

Regular physical activity is linked to enhanced health and to reduced risk for all-cause mortality and the development of many chronic diseases in adults. However, many U.S. adults are either sedentary of less physically active than recommended. Children and adolescents are more physically active than adults, but participation in physical activity declines in adolescence. School and community programs have the potential to help children and adolescents establish lifelong, healthy physical activity patterns. This report summarizes recommendations for encouraging physical activity among young people so that they will continue to engage in physical activity in adulthood and obtain the benefits of physical activity throughout life. These guidelines were developed by CDC in collaboration with experts from universities and from national, federal, and voluntary agencies and organizations. They are based on an in-depth review of research, theory, and current practice in physical education, exercise science, health education, and public health. The guidelines include recommendations about 10 aspects of school and community programs to promote lifelong physical activity among young people policies that promote enjoyable physical activity and social environments that encourage and enable physical activity; physical education curricula and instruction; health education curricula and instruction; extracurricular physical activity programs that meet the needs and interests of students; involvement of parents and guardians on physical activity instruction and programs for young people; personnel training; health services for children and adolescents; developmentally appropriate community sports and recreation programs that are attractive to young people; and regular evaluation of physical activity instruction, programs, and facilities.

Self-concept and health status in elementary-school-aged children

The purpose of this descriptive, correlational study was to measure the relationship between self-concept and physical fitness, health indicators, and health habits in elementary-school-aged children. Instruments included the Martinek-Zaichowsky Self-Concept Scale for Children and a self-administered questionnaire for parents pertaining to family health habits and health history. Children (N = 61) were screened for health and fitness indicators: height, weight, body mass index, 1-mile walk-run time, shuttle run time, and number of curl-ups. Results showed a positive relationship between self-concept and regular exercise and between self-concept and curl-ups. No gender difference was noted in the relationship between self-concept and physical fitness.

Effects of an aerobic activity program on the cholesterol levels of adolescents

The purpose of this study was to determine the effects of a 15-week aerobic activity program on the total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels of 25 high school students, ages 14-17 years (experimental group = 14, control group = 11). Participants in the activity program exercised 4 days per week in a specially designed physical education class, while the control group participated in the regular physical education program. Results of the analysis of covariance found significant reductions in TC in the training group (control group Adj M = 190.2 mg/dl, experimental group Adj M = 173.1 mg/dl, p < .05), but no significant changes in HDL-C (control group Adj M = 49.8 mg/dl, experimental group Adj M = 50 mg/dl). While the exercise program appeared to have a beneficial effect on TC in 12 of 14 participants (86%), HDL-C also dropped in 12 of 14 participants (86%).

Effects of a school-based intervention to reduce cardiovascular disease risk factors in elementary-school children: the Cardiovascular Health in Children (CHIC) study

OBJECTIVE

To test a classroom-based intervention to reduce cardiovascular disease risk factors in elementary school children.

STUDY DESIGN

This was a randomized, controlled field trial in 12 schools across North Carolina, stratified by geographic region and urban/rural setting. Subjects were 1274 third and fourth graders (48% boys). The intervention, taught by regular classroom and physical education teachers, provided all children an 8-week exercise program and 8 weeks of classes on nutrition and smoking. Data were analyzed at the school level with survey regression models and at the individual level with multivariate analysis of variance and analysis of covariance models; 95% confidence intervals were computed.

RESULTS

Children in the intervention group had significantly greater knowledge (7.9% more correct) and a significant increase in self-reported physical activity than children in the control group. Trends for the intervention group were a reduction in total cholesterol level (-5.27 mg/dl), an increase in aerobic power, a reduction in body fat, and smaller rise in diastolic blood pressure than control children.

CONCLUSIONS

This classroom-based, public health approach improved children's cardiovascular disease risk profiles; it is practical and fairly easy to incorporate into the school day. All children directly receive the potential benefits of the intervention without a risk of labeling. This program can improve health knowledge, habits, and health outcomes of young children at a time when health habits are being formed.