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

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.

Relationships among motor skill, perceived self-competence, fitness, and physical activity in young adults

PURPOSE

This large-scale, exploratory study sought to examine the associations between motor skill proficiency (MSP), perceived self-competence (PC), physical fitness (PF), and self-reported physical activity (PA) to assess the assumption that relationships among these variables found in childhood and adolescence persist into young-adulthood. Specifically, predictors of PF and PA were assessed. Additionally, the contributions body mass index (BMI) and gender made to these relationships, as well as that of process- versus product-oriented motor skills data, were studied. Finally, how these relationships differed by gender was explored.

METHODS

Participants' (n = 448) MSP was assessed using select measures from the TGMD-2 and the BOT-2, while PF was evaluated using the FitnessGram. Participants also completed surveys to assess PC (SPPCS), PA (past-week MAQ), and demographic information. Height and weight were collected to calculate BMI.

RESULTS

Models predicting physical fitness had good fit to the observed data, with perceived athletic competence, locomotor skill, upper-limb coordination, BMI, and gender accounting for about 75% (R² = 0.748) of aerobic PF variance and about 48% (R² = 0.476) of variance in push-up performances. About 18% (R² = 0.178) of variance in curl-up performances was predicted by perceived athletic competence, locomotor skill, upper-limb coordination, and PA. The PA model demonstrated weaker predictive power, with only about 10% (R² = 0.097) of variance explained. When considering male and female models separately, female models demonstrated better fit when predicting all PF and PA outcome variables. BMI and gender operated as significant predictors to differing degrees across the various models.

CONCLUSIONS

There is compelling evidence to believe relationships found among MSP, PC, PF, and PA in childhood and adolescence also exist in early adulthood. However, differences in the roles of gender and physical fitness versus physical activity are likely to exist.

We Run This City: Impact of a Community-School Fitness Program on Obesity, Health, and Fitness

INTRODUCTION

The We Run This City (WRTC) Youth Marathon Program is a community-supported, school-based fitness program designed to increase physical activity in a large, urban school district by engaging middle school youth to train 12 to 14 weeks to run or walk 1.2 miles, 6.2 miles, or 13.1 miles of the Rite Aid Cleveland Marathon. The objective of our study was to evaluate the effect of the intervention on adolescent health.

METHODS

We assessed changes in obesity, health, and fitness, measured before training and postintervention, among 1,419 sixth- to eighth-grade students participating in WRTC for the first time, with particular interest in the program's effect on overweight (85th-94th body mass index percentile) or obese (≥95th percentile) students. We collected data from 2009 through 2012, and analyzed it in 2016 and 2017. Outcomes of interest were body mass index (BMI), waist-to-hip ratio (WHR), elevated blood pressure, and fitness levels evaluated by using the Progressive Aerobic Cardiovascular Endurance Run (PACER) test and the sit-to-stand test.

RESULTS

We saw significant improvements overall in fitness and blood pressure. Controlling for demographics, program event, and training dosage, BMI percentile increased among normal weight participants and decreased among overweight and obese participants (P < .001). WHR increased among obese participants, whereas reductions in blood pressure among those with elevated blood pressure were associated with higher amounts of training and lower baseline BMI.

CONCLUSION

Even small amounts of regular physical activity can affect the health and fitness of urban youths. School-community partnerships offer a promising approach to increasing physical activity by supporting schools and making a school-based activity inclusive, fun, and connected to the broader fitness community.

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.

International variability in 20 m shuttle run performance in children and youth: who are the fittest from a 50-country comparison? A systematic literature review with pooling of aggregate results

OBJECTIVES

To describe and compare 20 m shuttle run test (20mSRT) performance among children and youth across 50 countries; to explore broad socioeconomic indicators that correlate with 20mSRT performance in children and youth across countries and to evaluate the utility of the 20mSRT as an international population health indicator for children and youth.

METHODS

A systematic review was undertaken to identify papers that explicitly reported descriptive 20mSRT (with 1-min stages) data on apparently healthy 9-17 year-olds. Descriptive data were standardised to running speed (km/h) at the last completed stage. Country-specific 20mSRT performance indices were calculated as population-weighted mean z-scores relative to all children of the same age and sex from all countries. Countries were categorised into developed and developing groups based on the Human Development Index, and a correlational analysis was performed to describe the association between country-specific performance indices and broad socioeconomic indicators using Spearman's rank correlation coefficient.

RESULTS

Performance indices were calculated for 50 countries using collated data on 1 142 026 children and youth aged 9-17 years. The best performing countries were from Africa and Central-Northern Europe. Countries from South America were consistently among the worst performing countries. Country-specific income inequality (Gini index) was a strong negative correlate of the performance index across all 50 countries.

CONCLUSIONS

The pattern of variability in the performance index broadly supports the theory of a physical activity transition and income inequality as the strongest structural determinant of health in children and youth. This simple and cost-effective assessment would be a powerful tool for international population health surveillance.

International normative 20 m shuttle run values from 1 142 026 children and youth representing 50 countries

OBJECTIVE

To develop sex-specific and age-specific international norms for the 20 m shuttle run test (20mSRT) in children and youth (aged 9-17 years), and to estimate the prevalence meeting the FITNESSGRAM criterion-referenced standards for healthy cardiorespiratory endurance (CRE).

METHODS

A systematic review was undertaken to identify papers explicitly reporting descriptive 20mSRT (with 1 min stages) data on children and youth since 1981. Data were included on apparently healthy (free from known disease/injury) 9-17 years old. Following standardisation to a common metric and for protocol differences, pseudo data were generated using Monte Carlo simulation, with population-weighted sex-specific and age-specific normative centiles generated using the Lambda Mu and Sigma (LMS) method. Sex-related and age-related differences were expressed as per cent and standardised differences in means. The prevalence with healthy CRE was estimated using the sex-specific and age-specific FITNESSGRAM criterion-referenced standards for [Formula: see text].

RESULTS

Norms were displayed as tabulated centiles and as smoothed centile curves for the 20mSRT using 4 common metrics (speed at the last completed stage, completed stages/minutes, laps and relative [Formula: see text]). The final data set included 1 142 026 children and youth from 50 countries, extracted from 177 studies. Boys consistently outperformed girls at each age group (mean difference±95% CI: 0.86±0.28 km/h or 0.79±0.20 standardised units), with the magnitude of age-related increase larger for boys than for girls. A higher proportion of boys (mean±95% CI: 67±14%) had healthy CRE than girls (mean±95% CI: 54±17%), with the prevalence of healthy CRE decreasing systematically with age.

CONCLUSIONS

This study provides the most comprehensive and up-to-date set of international sex-specific and age-specific 20mSRT norms for children and youth, which have utility for health and fitness screening, profiling, monitoring and surveillance.

Lower extremity pain is associated with reduced function and psychosocial health in obese children

BACKGROUND

Childhood obesity is associated with reduced quality of life, physical fitness, and a higher prevalence of lower extremity (LE) pain; however, it is unclear whether and how these factors are related.

QUESTIONS/PURPOSES

For this study we asked if obese children with LE pain (LE+) had higher BMI-Z scores, lower physical function and psychosocial health, and lower physical fitness compared with obese children without LE pain (LE-). We determined the association of BMI-Z score with physical function, psychosocial health, or physical fitness in obese children.

METHODS

Medical charts of 183 obese children were reviewed. Recorded data included anthropometrics, demographics, reports of musculoskeletal pain, Pediatric Quality of Life (PedsQL)-Physical Function score, PedsQL-Psychosocial Health score, and physical fitness levels. Data from 175 individuals were included in the analysis, with 51 in the LE+ group and 124 in the LE- group. Statistical analysis included Mann-Whitney U tests and Spearman's rank order correlations.

RESULTS

Between the LE+ and LE- groups, BMI-Z and physical fitness scores were not different. The LE+ group scored worse on the PedsQL-Physical Function scale (LE+: 72.4 [17.1], LE-: 79.5 [15.0]) and PedsQL-Psychosocial Health scale (LE+: 70.0 [16.1], LE-: 75.8 [16.3]). BMI-Z scores negatively correlated with PedsQL-Physical Function scores, PedsQL-Psychosocial Health scores, and physical fitness scores.

CONCLUSIONS

Our findings indicate that LE pain should be considered in the evaluation and management of children who are obese.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Relationship of body mass index and fitness levels among schoolchildren

Childhood obesity is an epidemic in the U.S.A., and understanding aspects of fitness is critical in implementing effective interventions. The purpose of this study was to analyze the relationship of obesity levels with the fitness levels of public school children in Louisiana. Over 7,000 school children participated in body mass index (BMI) and Fitnessgram® subtests including the Progressive Aerobic Cardiovascular Endurance Run (aerobic capacity), curl-ups, trunk lifts, push-ups (strength and endurance), and shoulder stretches (flexibility). The fitness measures and BMI were analyzed using chi-square and logistic regression to test for any significant relationships. The results indicated that the participants with healthy BMIs have the highest levels of physical fitness. The differences between the fitness levels of obese and healthy children were statistically significant. This study demonstrated a direct relationship between BMI status and fitness levels as measured by the Fitnessgram® among study participants. This finding is not exceedingly surprising, as common sense tells us that the heavier a person is, the less likely he or she is to be physically fit. However, this study is an important first step in understanding weight issues in children. This information can be used to develop data-driven interventions to assist children in becoming healthier and more physically fit.

Physical fitness, activity, and insulin dynamics in early pubertal children

The objectives of this study were to identify the independent effect of physical activity and fitness on insulin dynamics in a cohort of European-, African-, and Hispanic-American children (n = 215) age 7-12 years and to determine if racial/ethnic in insulin dynamics could be statistically explained by racial/ethnic differences in physical activity or fitness. An intravenous glucose tolerance test and minimal modeling were used to derive the insulin sensitivity index (SI) and acute insulin response to glucose (AIRg). Fitness was assessed as VO2-170 and physical activity by accelerometer. Multiple regression models were tested for contributions of fitness and physical activity to SI and AIRg. Fitness was a stronger predictor of SI and AIRg than physical activity regardless of ethnicity; racial/ethnic differences in insulin dynamics were not accounted for by differences in fitness and/or physical activity.

Aptidão cardiorrespiratória de adolescentes de Florianópolis, SC

Níveis adequados de aptidão cardiorrespiratória durante a adolescência estão diretamente relacionados a um estilo de vida saudável na fase adulta. Este estudo objetivou identificar o comportamento da aptidão cardiorrespiratória durante a adolescência e descrever a prevalência de adolescentes que atenderam e não atenderam o critério recomendado para a saúde por sexo, idade e nível socioeconômico (NSE). A amostra foi composta de 963 adolescentes (513 moças e 450 rapazes), com idades de 10 a 15 anos. Na coleta de dados, foi aplicado um questionário para obtenção do NSE (A + B, C, D + E). Para análise da aptidão cardiorrespiratória, foi realizado o teste PACER (Progressive Aerobic Cardiovascular Endurance Run). Consideraram-se como parâmetros de desempenho cardiorrespiratório o número de voltas realizadas e o consumo máximo de oxigênio - VO2max (ml/kg/min). Na análise estatística, foram utilizadas médias e desvios padrões, análise de variância two-way com teste post-hoc de Tukey, e teste qui-quadrado (p < 0,05). Enquanto o número de voltas aumentou dos 10 aos 15 anos, o VO2max diminuiu, não havendo diferenças entre os sexos. Os escolares dos NSE menos favorecidos (D + E) obtiveram menor aptidão do que os demais. Identificou-se que 68% dos rapazes e 37,8% das moças não atingiram o mínimo proposto para a saúde. Verificou-se uma maior proporção de adolescentes dos NSE D + E que não atendeu o critério recomendado. Estes achados demonstram que, aproximadamente, dois terços dos rapazes e um terço das moças apresentaram baixa aptidão cardiorrespiratória. Os adolescentes de NSE menos favorecidos foram os que apresentaram menores níveis de aptidão cardiorrespiratória.

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.