One-Mile Run/Walk and Body Mass Index of an Ethnically Diverse Sample of Youth

Relationship between body mass index and physical fitness index in Chinese college students: Results from a cross-sectional survey

BACKGROUND

To explore the cross-sectional relationship between the body mass index (BMI) and physical fitness index (PFI) of Chinese college students.

METHODS

In total, 30 497 (male 16 197, 55.5%) Chinese college students aged 19-22 were tested for height, weight and five physical fitness indicators (50-m sprint, sit and reach, standing long jump, 1000/800-m run, pull-up/bent-leg sit-up). Stratified according to age and gender, according to BMI percentile, divided into BMI < 10th Percentile (A), 10th ≤ BMI < 25th Percentile (B), 25th ≤ BMI < 75th Percentile (C), 75th ≤ BMI < 90th Percentile (D), BMI ≥ 90th Percentile (E), a total of 5 groups, and the PFI composed of 5 indicators of physical fitness was calculated according to age and gender. The comparison of PFI between different BMI groups was carried out using the effect size, and the non-linear relationship between BMI-Z and PFI was analyzed.

RESULTS

The relationship between BMI-Z and PFI of male and female college students in China showed an inverted "U"-shaped curve. With comparable BMI, PFI change was greater in males than in females.

CONCLUSION

The relationship between BMI and PFI of Chinese college students is nonlinear. The physical fitness level of college students who are underweight or overweight and those with obesity is lower than that of normal-weight students.

Relationship between body mass index and physical fitness of children and adolescents in Xinjiang, China: a cross-sectional study

Background

Xinjiang is an economically underdeveloped area in China, but the obesity rate of children and adolescents is increasing year by year. Physical fitness and body mass index (BMI) are very important factors for healthy development, whereas few studies focus on the relationship between them in this region. This study aimed to explore the relationship between physical fitness and BMI of children and adolescents aged 7 to 18 in Xinjiang.

Method

A total of 17,356 children and adolescents aged 7–18 years were involved. BMI was divided into five levels by percentiles, from very low to very high. Physical fitness was evaluated by five indicators: grip strength, standing long jump, sit-and-reach, 50 m dash, and endurance running. Single-factor analysis of variance was used to compare the Z-scores of the five physical fitness indicators among different BMI levels for the four age groups by gender. A nonlinear quadratic regression model was used to evaluate the relationship between BMI and each indicator in the four age groups.

Result

There is a significant correlation between the five health-related indicators (grip strength, standing long jump, sit and reach, 50 m dash, endurance run) at two age groups (13-15 yrs., 16-18 yrs) of children and adolescents in Xinjiang, China. The range of the Pearson coefficient is 0.048 ~ 0.744. For the other two age groups (7-9 yrs., 10-12 yrs.,) significant correlations are found only in some indicators, and the Pearson coefficient ranges from 0.002 to 0.589. The relationship between BMI and physical fitness presents an U-shaped or inverted U-shaped curve in most age groups(R² ranges from − 0.001 to 0.182. Children and adolescents with normal BMI score higher on physical fitness tests, and boys (R² ranges from − 0.001 to 0.182) are more pronounced than girls (R² ranges from 0.001 to 0.031).

Conclusion

Children and adolescents with a BMI above or below the normal ranges have lower physical fitness than those with normal BMI. BMI and physical fitness have an U-shaped or inverted U-shaped curve relationship, and the impact is more evident in boys than girls. Targeted actions such as improving the quality of physical education classes, advocating students to keep a balanced diet and physical exercise should be taken designedly.

Impact of a year-round school calendar on children's BMI and fitness: Final outcomes from a natural experiment

BACKGROUND

Structure may mitigate children's accelerated summer BMI gain and cardiorespiratory-fitness (CRF) loss.

OBJECTIVES

Examine BMI and CRF change during school and summer for year-round and traditional calendar school children.

METHODS

Three schools (N = 2279, 1 year-round) participated in this natural experiment. Children's BMI z-score (zBMI) and CRF (PACER laps) were measured from 2017 to 2019 each May/August. Mixed effects regression estimated monthly zBMI and CRF change during school/summer. Secondary analyses examined differences by weight status and race. Spline regression models estimated zBMI and CRF growth from kindergarten-sixth grade.

RESULTS

Compared to traditional school, children attending a year-round school gained more zBMI (difference = 0.015; 95CI = 0.002, 0.028) during school, and less zBMI (difference = -0.029; 95CI = -0.041, -0.018), and more CRF (difference = 0.834; 95CI = 0.575, 1.093) monthly during summer. Differences by weight status and race were observed during summer and school. Growth models demonstrated that the magnitude of overall zBMI and CRF change from kindergarten-sixth grade was similar for year-round or traditional school children.

CONCLUSIONS

Contrary to traditional school children zBMI increased during the traditional 9-month school calendar and zBMI decreased during the traditional summer vacation for year-round school children. Structured summer programming may mitigate accelerated summer BMI gain and CRF loss especially for overweight or obese, and/or Black children.

The potential of a year-round school calendar for maintaining children's weight status and fitness: Preliminary outcomes from a natural experiment

Purpose

To evaluate the potential of a year-round school calendar (180-day school year distributed across 12 months) as an intervention compared to a traditional school calendar (180-day school year distributed across 9 months) for mitigating children's weight gain and fitness loss via a natural experiment.

Methods

Height, weight, and cardiorespiratory fitness (CRF) (i.e., Fitnessgram Progressive Aerobic Cardiovascular Endurance Run) were measured in children (5-12 years old) in 3 schools (2 traditional, 1 year-round, n = 990 students, age = 8.6 ± 2.4 years, 53.1% male, 68.9% African American) from 1 school district. Structure (represented by the presence of a school day) was the independent variable. Changes in body mass index (BMI), age- and sex-specific BMI z-scores (zBMI), BMI percentile, percent of overweight or obese children, and CRF (Progressive Aerobic Cardiovascular Endurance Run laps completed) were assessed for summer 2017 (May-August 2017), school year 2017/2018 (August 2017-May 2018), and summer 2018 (May-August 2018). Primary analyses examined the overall change in weight and CRF from summer 2017 until summer 2018 via multilevel mixed effects regression, with group (traditional vs. year-round calendar), time, and a group-by-time interaction as the independent variables. Secondary regression analyses estimated differences in change within and between groups during each time period, separately.

Results

Year-round students gained less BMI (difference in ∆ = -0.44, 95% confidence interval (CI): -0.67 to -0.03) and less CRF (difference in ∆ = -1.92, 95%CI: -3.56 to -0.28) than students attending a traditional school overall. Compared with traditional students, during both summers, year-round students gained less BMI (summer 2017 difference in ∆ = -0.15, 95%CI: -0.21 to -0.08; summer 2018 difference in ∆ = -0.16, 95%CI: -0.24 to -0.07) and zBMI (summer 2017 difference in ∆ = -0.032, 95%CI: -0.050 to -0.010; summer 2018 difference in ∆ = -0.033, 95%CI: -0.056 to -0.009), and increased CRF (summer 2017 difference in ∆ = 0.40, 95%CI: 0.02-0.85; summer 2018 difference in ∆ = 0.23, 95%CI: -0.25 to 0.74). However, the opposite was observed for the school year, with traditional students gaining less BMI and zBMI and increasing CRF compared with year-round students (difference in BMI ∆ = 0.05, 95%CI: 0.03-0.07; difference in zBMI ∆ = 0.012, 95%CI: 0.005-0.019; difference in Progressive Aerobic Cardiovascular Endurance Run laps ∆ = -0.43, 95%CI: -0.58 to -0.28).

Conclusion

The year-round school calendar had a small beneficial impact on children's weight status but not CRF. It is unclear if this benefit to children's weight would be maintained because gains made in the summer were largely erased during the school year. Trajectories of weight and CRF gain/loss were consistent with the structured days hypothesis.

Benefits of normal body mass index on physical fitness: A cross-sectional study among children and adolescents in Xinjiang Uyghur Autonomous Region, China

OBJECTIVE

To assess the association between body mass index (BMI) and physical fitness index (PFI) among children and adolescents in Xinjiang Uyghur Autonomous Region, China.

METHODS

In total, 17,618 children and adolescents aged 7-18 years from the selected region were enrolled in this cross-sectional study (8,800 boys and 8,818 girls). Participants were stratified by age and sex and divided into five groups by BMI percentiles: very low (BMI <5th percentile); low, (5th ≤ BMI < 15th percentile); normal (15th ≤ BMI < 85th percentile); high (85th ≤ BMI < 95th percentile); and very high (BMI ≥95th percentile). PFI was assessed by height, weight, and five health-related fitness indicators (grip strength, standing long jump, sit and reach, 50 m dash, and endurance run).

RESULTS

BMI was significantly associated with PFI during adolescence (13-18 years) in boys and pre-adolescence (7-12 years) in girls. Between the ages of 13 and 18 years, an increase in BMI had a greater impact on PFI in boys than girls. PFI showed a parabolic curvilinear relationship with BMI.

CONCLUSION

Children and adolescents in China's Xinjiang Uyghur Autonomous Region with a normal BMI demonstrated good physical fitness. A BMI below or above the normal range may contribute to poor physical fitness. The relationship between BMI and PFI shows an inverted U-shaped curve.

A systematic review and meta-analysis of cardiorespiratory fitness among Indigenous populations in North America and circumpolar Inuit populations

Indigenous populations experience health disparities including increased obesity, diabetes and cardiovascular disease rates. Cardiorespiratory fitness is beneficial for maintaining positive health outcomes. The objective of this systematic review is to evaluate cardiorespiratory fitness among Indigenous populations including comparisons across genders, Indigenous identities, age groups, decades, socio-demographic variables and in comparison to non-Indigenous groups. Included articles reported various cardiorespiratory fitness measures using maximal treadmill or cycle ergometer tests, 20 m shuttle run, 1 mile run/walk test and 6 min walk test. From 14 databases searched in March 2017, including MEDLINE, EMBASE and Scopus, 1069 citations were evaluated and 39 articles included, representing 32 investigations and 10,579 individuals. First Nations/American Indian (FN/AI) adults have greater cardiorespiratory fitness than Inuit. Inuit and FN/AI men and boys have higher cardiorespiratory fitness than women and girls. Lower cardiorespiratory fitness is associated with obesity, metabolic syndrome and a western lifestyle. Cardiorespiratory fitness has declined among Inuit adults, averaging 51.7 ± 7.9 mL·kg^-1·min^-1 in 1970 to 37.7 ± 6.9 mL·kg^-1·min^-1 in 2000. Among men, FN/AI have greater cardiorespiratory fitness compared to European-descents, and European-descents have greater cardiorespiratory fitness compared to Inuit. The 1 mile run/walk time showed that FN/AI boys, girls, and youth had faster times compared to European-descendants, but 20 m shuttle run showed that European-descent boys and youth advanced to further stages compared to FN/AI populations. Cardiorespiratory fitness is declining, and among some Indigenous populations to lower levels than European-descent populations. Improving cardiorespiratory fitness for Indigenous populations should be considered a primary health strategy.

Twelve Weeks of Plyometric Training Improves Motor Performance of 7- to 9-Year-Old Boys Who Were Overweight/Obese: A Randomized Controlled Intervention

Nobre, GG, de Almeida, MB, Nobre, IG, dos Santos, FK, Brinco, RA, Arruda-Lima, TR, de-Vasconcelos, KL, de-Lima, JG, Borba-Neto, ME, Damasceno-Rodrigues, EM, Santos-Silva, SM, Leandro, CG, and Moura-dos-Santos, MA. Twelve weeks of plyometric training improves motor performance of 7- to 9-year-old boys who were overweight/obese: a randomized controlled intervention. J Strength Cond Res 31(8): 2091-2099, 2017-The prevalence of childhood overweight/obesity has increased, and physical training at school may to be effective to combat this scenario. We analyzed the effects of a protocol of plyometric training on body composition and motor performance of boys who were overweight/obese aged 7-9 years. The sample was randomly assigned into 2 groups: plyometric training group (T, n = 40) and control group (C, n = 19). Training consisted of 20 min·d (twice a week, during 12 weeks) of lower extremity plyometric exercise. Health-related physical fitness was measured by handgrip strength, standing long jump (SLJ), curl-ups, sit and reach, square test, running speed, and mile run test. Gross motor coordination was evaluated by means of the Körperkoordinations-test für Kinder (KTK) tests. Baseline and postintervention differences were investigated, and effect size was estimated through Cohen's d coefficient. Both groups showed increased body weight, height, and sitting height after intervention with a negligible effect size. Only T group showed increased fat-free mass (p = 0.011) compared with baseline values with small effect size. Plyometric training improved handgrip strength (d = 0.23), sit and reach (d = 0.18), curl-ups (d = 0.39), SLJ (d = 0.80), agility (d = 0.48), and time in the mile run test (d = 0.38). For gross motor coordination results, T group showed better performance in all tests after plyometric training with moderate/large effect size. Thus, 12 weeks of PT improved health-related physical fitness components and motor coordination acquisition of 7- to 9-year-old boys who were overweight/obese.

School and Neighborhood Predictors of Physical Fitness in Elementary School Students

BACKGROUND

We assessed the associations of 5 school and 7 neighborhood variables with fifth-grade students achieving Healthy Fitness Zone (HFZ) or Needs Improvement-Health Risk (NI-HR) on aerobic capacity (AC) and body composition (BC) physical fitness components of the state-mandated FITNESSGRAM^® physical fitness test.

METHODS

Data for outcome (physical fitness) and predictor (school and neighborhood) variables were extracted from various databases (eg, Data Quest, Walk Score^® ) for 160 schools located in San Diego, California. Predictor variables that were at least moderately correlated (|r| ≥ .30) with ≥1 outcome variables in univariate analyses were retained for ordinary least squares regression analyses.

RESULTS

The mean percentages of students achieving HFZ AC (65.7%) and BC (63.5%) were similar (t = 1.13, p = .26), while those for NI-HR zones were significantly different (AC = 6.0% vs BC = 18.6%; t = 12.60, p < .001). Correlations were greater in magnitude for school than neighborhood demographics and stronger for BC than AC. The school variables free/reduced-price lunch (negative) and math achievement (positive) predicted fitness scores. Among neighborhood variables, percent Hispanic predicted failure of meeting the HFZ BC criterion.

CONCLUSIONS

Creating school and neighborhood environments conducive to promoting physical activity and improving fitness is warranted.

Developmental differences between boys and girls result in sex-specific physical fitness changes from fourth to fifth grade

To better understand how developmental differences impact performance on a broad selection of common physical fitness measures, we examined changes in boys and girls from fourth to fifth grade. Subjects included 273 boys (age, 9.5 ± 0.6 years; height, 139.86 ± 7.52 cm; mass, 38.00 ± 9.55 kg) and 295 girls (age, 9.6 ± 0.5 years; height, 139.30 ± 7.19 cm; weight, 37.44 ± 9.35 kg). We compared anthropometrics, cardiorespiratory and local muscular endurance, flexibility, power, and strength. A mixed-method analysis of variance was used to compare boys and girls at the 2 time points. Pearson correlation coefficients were used to examine relationships between anthropometric and fitness measurements. Significance was set at p ≤ 0.05. Weight increased significantly (>10%) in both sexes, and girls became significantly taller than boys after growing 4.9% by fifth grade (vs. 3.5%). Both groups improved cardiorespiratory endurance and power, although boys performed better than girls at both time points. Boys were stronger in fourth grade, but girls improved more, leading to similar fifth-grade values. Girls were more flexible in fourth grade, but their significant decreases (∼32.4%) coupled with large improvements in boys (∼105%) resulted in similar fifth-grade scores. Body mass index (BMI) was positively correlated with run time regardless of grade or sex. Power was negatively correlated with BMI and run time in fourth grade. In conclusion, sex-specific differences in physical fitness are apparent before pubescence. Furthermore, this selection of measures reveals sexually dimorphic changes, which likely reflect the onset of puberty in girls. Coaches and teachers should account these developmental differences and their effects on anthropometrics and fitness in boys and girls.

Self-efficacy, physical activity, and aerobic fitness in middle school children: examination of a pedometer intervention program

Physical activity in children has been associated with a number of health benefits. Unfortunately, physical inactivity continues to increase. The purpose of this study was to examine the relationships among self-efficacy levels, physical activity, aerobic fitness, and body composition (relative body mass index [RBMI]) and to determine whether a school-based pedometer intervention program would improve those variables. The sample consisted of 116 rural 11- to 13-year-old students. Weakly positive correlations between self-efficacy, physical activity, and aerobic fitness and weakly correlated inverse relationships between self-efficacy, physical activity, aerobic fitness and RBMI were found. There was no statistical significance between the intervention and control group when analyzing outcome variables. These findings suggest that those with optimal RBMI levels have higher self-efficacy, physical activity and aerobic fitness levels. Although not statistically significant, the intervention group had greater improvements in mean self-efficacy scores, aerobic fitness levels, and RBMI.

Relationship between socioeconomic status and physical fitness in junior high school students

BACKGROUND

Research on physical fitness often regards socioeconomic status (SES) as a confounding factor. However, few studies investigate the impact of SES on fitness. This study investigated the impact of SES on physical fitness in both males and females, with an economic-based construct of SES.

METHODS

The sample consisted of 954 6th, 7th, and 8th graders from a public, urban, Illinois middle school. The students participated in the FITNESSGRAM battery of fitness assessments as part of physical education. Descriptive statistics were calculated for height, weight, age, and sex. Students were grouped as high or low SES depending on whether they qualified for the federal free lunch program. A multivariate analysis of variance controlled for age and stratified by sex compared the raw scores from the fitness test for low and high SES students. Odds ratios stratified by sex were calculated for the likelihood of not achieving the FITNESSGRAM Healthy Fitness Zone standards among SES groups.

RESULTS

Girls of the low SES group had significantly lower scores on the FITNESSGRAM assessments and were significantly less likely to achieve Healthy Fitness Zone status than the girls from the high SES groups. For boys, SES was a significant main effect for body composition but not for the other fitness tests conducted.

CONCLUSION

SES is related to physical fitness in girls but not in boys. A potential explanation for this is that boys are more likely to engage in vigorous leisure time activity regardless of SES than girls.

Distribution of health-related physical fitness in Texas youth: a demographic and geographic analysis

This study examined demographic and geographic variability in aggregated school-level data on the percentage of students achieving the FITNESSGRAM Healthy Fitness Zones (HFZ). Three-way analyses of variance were used to examine differences in fitness achievement rates among schools that had distinct diversity and socioeconomic status profiles. The results revealed age-related declines in the percentage of youth who achieved the HFZ standard for cardiovascular fitness (elementary school: 70%; middle school: 46%; high school: 34%). Interestingly, there was little evidence of age-related declines in other fitness dimensions. School-level attainment of fitness was consistently higher in schools categorized as low diversity and high socioeconomic status. Clear spatial patterns in fitness achievement were also evident when data were analyzed at the region and county level using geodemographic information system software.

Low aerobic fitness and obesity are associated with lower standardized test scores in children

OBJECTIVE

To investigate whether aerobic fitness and obesity in school children are associated with standardized test performance.

STUDY DESIGN

Ethnically diverse (n = 1989) 5th, 7th, and 9th graders attending California schools comprised the sample. Aerobic fitness was determined by a 1-mile run/walk test; body mass index (BMI) was obtained from state-mandated measurements. California standardized test scores were obtained from the school district.

RESULTS

Students whose mile run/walk times exceeded California Fitnessgram standards or whose BMI exceeded Centers for Disease Control sex- and age-specific body weight standards scored lower on California standardized math, reading, and language tests than students with desirable BMI status or fitness level, even after controlling for parent education among other covariates. Ethnic differences in standardized test scores were consistent with ethnic differences in obesity status and aerobic fitness. BMI-for-age was no longer a significant multivariate predictor when covariates included fitness level.

CONCLUSIONS

Low aerobic fitness is common among youth and varies among ethnic groups, and aerobic fitness level predicts performance on standardized tests across ethnic groups. More research is needed to uncover the physiological mechanisms by which aerobic fitness may contribute to performance on standardized academic tests.

Technical report--racial and ethnic disparities in the health and health care of children

OBJECTIVE

This technical report reviews and synthesizes the published literature on racial/ethnic disparities in children's health and health care.

METHODS

A systematic review of the literature was conducted for articles published between 1950 and March 2007. Inclusion criteria were peer-reviewed, original research articles in English on racial/ethnic disparities in the health and health care of US children. Search terms used included "child," "disparities," and the Index Medicus terms for each racial/ethnic minority group.

RESULTS

Of 781 articles initially reviewed, 111 met inclusion criteria and constituted the final database. Review of the literature revealed that racial/ethnic disparities in children's health and health care are quite extensive, pervasive, and persistent. Disparities were noted across the spectrum of health and health care, including in mortality rates, access to care and use of services, prevention and population health, health status, adolescent health, chronic diseases, special health care needs, quality of care, and organ transplantation. Mortality-rate disparities were noted for children in all 4 major US racial/ethnic minority groups, including substantially greater risks than white children of all-cause mortality; death from drowning, from acute lymphoblastic leukemia, and after congenital heart defect surgery; and an earlier median age at death for those with Down syndrome and congenital heart defects. Certain methodologic flaws were commonly observed among excluded studies, including failure to evaluate children separately from adults (22%), combining all nonwhite children into 1 group (9%), and failure to provide a white comparison group (8%). Among studies in the final database, 22% did not perform multivariable or stratified analyses to ensure that disparities persisted after adjustment for potential confounders.

CONCLUSIONS

Racial/ethnic disparities in children's health and health care are extensive, pervasive, and persistent, and occur across the spectrum of health and health care. Methodologic flaws were identified in how such disparities are sometimes documented and analyzed. Optimal health and health care for all children will require recognition of disparities as pervasive problems, methodologically sound disparities studies, and rigorous evaluation of disparities interventions.

Cardiovascular fitness in obese versus nonobese 8-11-year-old boys and girls

The purpose of this study was to compare cardiovascular fitness between obese and nonobese children. Based on body mass index, 118 were classified as obese (boys [OB] = 62, girls [OG] = 56), while 421 were nonobese (boys [NOB] = 196, girls [NOG] = 225). Cardiovascular fitness was determined by a 1-mile [1.6 km] run/walk (MRW) and estimated peak oxygen uptake (VO2peak) and analyzed using two-way analyses of variance (Gender x Obese/Nonobese). MRW times were significantly faster (p < .05) for the NOB (10 min 34 s) compared to the OB (13 min 8 s) and the NOG (13 min 15 s.) compared to the OG (14 min 44 s.). Predicted VO2peak values (mL x kg(-1) x min(-1)) were significantly higher (p < .05) for the NOB (48.29) compared to the OB (41.56) and the NOG (45.99) compared to the OG (42.13). MRW was compared between obese and nonobese participants on the President's Challenge (2005), the National Children and Youth Fitness Study, and FITNESSGRAM HFZ standards. The nonobese boys and girls scored higher on all three, exhibiting better cardiovascular fitness as compared to obese counterparts.

Asthma prevalence among US children in underrepresented minority populations: American Indian/Alaska Native, Chinese, Filipino, and Asian Indian

OBJECTIVES

The purpose of this work was to estimate asthma prevalence among US children in racial minority subgroups who have been historically underrepresented in the pediatric asthma literature. These subgroups include American Indian/Alaska Native, Chinese, Filipino, and Asian Indian children. We also explored the association between these race categories and asthma after adjusting for demographic and sociodemographic characteristics and explored the effect of place of birth as it relates to current asthma.

PATIENTS AND METHODS

Data on all 51944 children aged 2 to 17 years from the 2001-2005 National Health Interview Survey were aggregated and analyzed to estimate the prevalence of current asthma, lifetime asthma, and asthma attacks according to race and place of birth. Logistic regression was used to determine adjusted odds ratios for current asthma according to race and place of birth while controlling for other demographic and sociodemographic variables.

RESULTS

National estimates of current asthma prevalence among the children in the selected minority subgroups ranged from 4.4% in Asian Indian children to 13.0% in American Indian/Alaska Native children. Overall, children born in the United States had greater adjusted odds of reporting current asthma than did children born outside of the United States.

CONCLUSIONS

Smaller racial and ethnic minority groups are often excluded from asthma studies. This study reveals that, among children from different Asian American subgroups, wide variation may occur in asthma prevalence. We also found that children born in the United States were more likely than children born outside of the United States to have current asthma.

Reducing sedentary behavior in minority girls via a theory-based, tailored classroom media intervention

OBJECTIVE

To develop, implement and test an innovative, theory-based classroom media intervention known as Get Moving! to increase physical activity and decrease sedentary behaviors in predominantly Latina middle school girls.

RESEARCH METHODS AND PROCEDURES

School-based intervention on five to seven consecutive school days in seven schools (four intervention and three control) with high Latino populations (above 60%). Intervention schools were matched to control schools by ethnic makeup and socioeconomic status (SES). Measures conducted 3 months before and 3 months after intervention included height, weight, percentage body fat (bioimpedance analysis), physical activity and psychosocial aspects of activity by questionnaire. Subjects were middle school girls, mean age 12.5 years old, 73% Latina (N=459 girls).

RESULTS

Get Moving! significantly reduced time spent on sedentary behavior (beta+/- standard error, SE=-0.27+/-0.14, p<0.05) and significantly increased intrinsic motivation (beta+/-SE=0.11+/-0.05, p<0.05). There was a trend for mediation effects of intrinsic motivation, but this did not reach significance.

DISCUSSION

Get Moving! is a promising school-based approach that specifically targets physical activity and sedentary behavior in Latina girls, a population at high risk for obesity and related diseases.

Sports participation and physical education in American secondary schools: current levels and racial/ethnic and socioeconomic disparities

BACKGROUND

The purpose of this study was to determine the current levels of physical education (PE) and sports participation among American secondary school students, and to establish the extent to which they vary by grade level, racial/ethnic background, and socioeconomic status (SES) of the students.

METHODS

Nationally representative data were used from over 500 schools and 54,000 students surveyed in 2003, 2004, and 2005 as part of the Youth, Education, and Society (YES) study and the Monitoring the Future (MTF) study. As part of YES, school administrators completed questionnaires on physical activity (including rates of sports and PE participation) of students in their schools. Students in the same schools completed self-administered questionnaires in the same year as part of MTF, providing individual background data, including their gender, racial/ethnic identification, and parents' education level. Data were analyzed in 2006.

RESULTS

Physical education requirements, and actual student participation rates, decline substantially between 8th and 12th grades. About 87% of 8th graders were in schools that required them to take PE, compared to only 20% of 12th graders. Principals estimate that over 90% of 8th graders actually take PE, compared to 34% of 12th graders. Subgroup differences in PE participation rates were small. Only a fraction of all students participate in varsity sports during the school year, with girls participating only slightly less than boys (33% vs 37%). Participation correlates negatively with SES and was lower among black and Hispanic students than white students, even after controlling for other variables. Participation rates in intramural sports were even lower, declined in higher grades, and were lower among low-SES and Hispanic students (after controlling for other variables).

CONCLUSIONS

Physical education is noticeably lacking in American high schools for all groups. Racial/ethnic minorities and low-SES youth, who are at higher than average risk of being overweight in adolescence, are getting less exercise due to their lower participation in school sports. Disparities in resources available to minorities and lower-SES youth may help explain the differences in participation rates.

BMI and health-related physical fitness in Taiwanese youth 9-18 years

PURPOSE

The purpose of the study was to evaluate the cross-sectional relationship between BMI and a physical fitness index (PFI) based on four indicators of fitness in a national sample of Taiwanese youth.

METHODS

Height, weight, and four measures of physical fitness (sit-ups completed in 60 s, standing long jump, sit and reach, and 800- or 1600-m run/walk) were measured in a national sample of 102,765 Taiwanese youth 9-18 yr of age: 50,940 girls and 51,825 boys. BMI was calculated for each subject. Within each sex-specific half-year age group, students were classified into five BMI categories based on national percentiles: very low, BMI < 5th percentile; low, BMI >or= 5th but < 15th percentiles; normal, BMI >or= 15th but < 85th percentiles; high, BMI >or= 85th but < 95th percentiles; and very high, BMI >or= 95th percentiles. Z-scores based on sex- and age-specific means and standard deviations were calculated, and the sum of z-scores for the four fitness tests was used as a PFI. Differences in PFI between BMI categories within each sex-specific half-year age group were compared with ANOVA with Bonferroni adjustments. Sex-specific regressions of PFI on BMI, using a nonlinear quadratic model, were done in four broader age categories.

RESULTS

Relationships between BMI and PFI are nonlinear and vary with age from late childhood through adolescence. With increasing age during adolescence, the relationship becomes parabolic, and the peaks of the parabola are sharper in adolescent boys than girls.

CONCLUSION

PFI declines in a curvilinear manner with increasing BMI among youth 9-18 yr of age, but the slope of the relationship varies with age.

The nutrition transition in American Indians

The purpose of this article was to examine whether a nutritional transition has occurred among American Indians (AI) by evaluating related articles and government health statistics. Findings indicate that although the primary health risk for the AI population around 1970 was undernutrition, now there is an obesity epidemic among all age groups that is associated with a loss of traditional food practices and reduced physical activity. Deaths caused by cardiovascular disease, diabetes mellitus, and cancer have outpaced death from infectious disease. With abundant high-energy foods and limited physical activity, the acculturated environment has resulted in obesity and increased mortality from chronic diseases. To improve AI health and survival, the obesity epidemic must be approached in a concerted, culturally appropriate manner with encouragement of traditional foods and safe opportunities for physical activity.

Ethnic and socioeconomic comparisons of fitness, activity levels, and barriers to exercise in high school females

The purpose of this study was to determine if high school females differed in individual measures of health-related physical fitness, barriers to exercise, or activity level based on ethnicity or socioeconomic status. A cross-sectional sample consisting of African American (28%), Hispanic (23%), and white (49%) female high school students, 46% from low socioeconomic groups and 54% from moderate or high socioeconomic groups (n = 1314, age = 16.2 +/- 0.9) participated in this study. A 15-question survey instrument assessed barriers to exercise and activity level. The FITNESSGRAM fitness test assessed aerobic capacity and body mass index (BMI), and skinfold calipers were used to assess percent body fat. Significant differences between African Americans, Hispanics, and whites were found on the following dependent variables: BMI, percent fat, mile run, perceived barriers to exercise, and activity level. Significant differences between socioeconomic groups were found on the following dependent variables: percent fat, mile run, activity level, and perceived barriers to exercise. These results suggest that students of minority and low socioeconomic groups should be given separate and different interventions regarding health-related fitness.

Progressive aerobic cardiovascular endurance run and body mass index among an ethnically diverse sample of 10-15-year-olds

This study examined the cardiovascular fitness (CVF, Progressive Aerobic Cardiovascular Endurance Run [PACER], number of laps completed) and the prevalence of at risk of overweight (AR) and overweight (OW) among 10-15-year-olds (48% girls)from the following ethnic backgrounds: African American (n = 2,604), Asian-Pacific Islander (n = 3,888), Hispanic (n = 11,680); and White non-Hispanic (n = 16,352). Hierarchal multiple linear regression analysis, controlling for height and weight, with White non-Hispanics serving as the comparison group, revealed a limited number of significant differences among PACER performances, with no values exceeding +/- 4.43 laps. Odds ratios (OR) for being classified as AR or OW were significantly greater (p < .01) in African American (OR = 1.25, 1.65) and Hispanic (OR = 2.33, 2.28) boys and girls, respectively, and Asian boys (OR = 1.43). The results of this cross-sectional analysis indicated negligible differences in CVF among ethnic groups, while AR and OW were consistent with previous reports for ethnic populations.