Youth Fitness Research Articles

Representative Percentile Curves of Physical Fitness From Early Childhood to Early Adulthood: The MoMo Study.

Introduction: Monitoring of physical fitness in youth is important because physical fitness is a summative indicator of health. From a developmental and preventive perspective, physical fitness levels are relatively stable from childhood to early adulthood. Thus, it is important to monitor physical fitness on a population based level being able to intervene at early stages (1). In order to reliably assess and evaluate the physical fitness of youth, a reliable system of standard values based on representative data is required. The aim of this analysis is to report sex- and age-specific physical fitness percentile curves from childhood to early adulthood in a nationwide sample in Germany.Methods: We use data from the nationwide representative Motorik Modul (MoMo) Study in Germany (data collection wave 1: 2009–2012; age: 4–23 years; n = 3,742; 50.1% female). Physical fitness was assessed by means of the MoMo test profile covering four dimensions of physical fitness (strength, endurance, coordination, and flexibility) and including eight physical fitness items. Percentile curves were fitted using the LMS transformation method of Cole and Green.Results: Standardized age- and sex-specific physical fitness percentiles were calculated for eight items: ergometric endurance testing, standing long jump, push-ups, sit-ups, jumping side-ways, balancing backwards, static stand, and stand and reach test. The physical fitness curves differ according to gender and the fitness dimension. Physical fitness improvements with age are linear (e.g., max. strength) or curvilinear (e.g., coordination) and have their stagnation points at different times over the course of adolescence.Discussion: Our results provide for the first time sex- and age-specific physical fitness percentile curves for Germany from 4 to 17 years. Differences in curve-shapes indicating a timed and capacity-specific physical fitness development. Nationwide German physical fitness percentiles can be useful in comparing different populations (e.g., cross-country), reporting secular trends, comparing special groups, and to evaluate physical fitness interventions.

Developmental Trajectories of Body Mass Index, Waist Circumference, and Aerobic Fitness in Youth: Implications for Physical Activity Guideline Recommendations (CHAMPS Study-DK).

Describe the trajectories of body mass index (BMI), waist circumference, and aerobic fitness in children and identify different outcomes of guideline-recommended physical activity (PA) in a subset of active children. We recruited students from 10 public primary schools and obtained repeated measures of BMI, waist circumference, and aerobic fitness over 30months. Aerobic fitness was measured with the Andersen test. We objectively measured physical activity behaviour with accelerometers and classified children as 'physically active' when they achieved ≥ 60min of moderate-to-vigorous PA per day (guideline concordance). Univariate trajectories of BMI, waist circumference, and aerobic fitness were calculated for all children, and we constructed a multi-trajectory model comprising all outcomes in the subgroup of physically active children. The construct validity of all models was investigated by examining for between-group differences in cardiovascular disease risk factors obtained from fasting blood samples. Data from 1208 children (53% female) with a mean (SD) age of 8.4 (1.4) years were included. The univariate trajectory models identified three distinct trajectories for BMI, waist circumference, and aerobic fitness. The multi-trajectory model classified 9.1% of physically active children as following an 'overweight/obese/low fitness' trajectory. There were moderate-to-large differences in cardiovascular risk factors between all trajectory groups (p < 0.001; d = 0.4-1.20). We identified distinct developmental trajectories of BMI, waist circumference, and aerobic fitness in children. Nearly one in 10 children who met PA guideline recommendations followed an unfavourable health trajectory. Health-related PA recommendations may be insufficient for some children.

An analysis of Chinese preservice physical education teachers’ attitudes toward school-based fitness testing in physical education settings

ABSTRACT Background: For over six decades, in many countries, youth fitness testing has been seen as a critical component of physical education programs. As such, preservice physical education teachers (PPETs) must be trained appropriately for effective youth fitness testing, with careful consideration dedicated to PPETs perceptions, since many purported attitudes to have an effect on behavior (Ajzen 1985. “From intentions to actions: A theory of planned behavior.” In Action control: From cognition to behavior, edited by J. Kuhl, and J. Beckmann. Berlin: Springer-Verlag). Our understanding on PPETs’ attitudes toward fitness testing is limited, with no research found on the topic for Chinese PPETs. Purposes: The primary purpose of the current study was to examine the overall attitudes of Chinese PPETs’ toward school-based fitness testing. The secondary purpose was to test differences of attitudes in gender and years in college, and interaction between these two independent variables. Method: A total of 1012 PPETs from 11 Chinese universities participated in the study. Participants consisted of 28.3% of freshmen, 37.0% of sophomore, 19.5% of junior, and 15.2% of senior, with an average age of 21.2. Participants were recruited via emails and asked to complete a previously validated 16-item survey in English, measuring PPETs’ attitudes toward fitness tests (Keating et al. 2008. “Physical Education Teacher Attitudes toward Fitness Tests Scale: Cross-Revalidation and Modification.” Measurement in Physical Education and Exercise Science 12 (2): 72. https://doi.org/10.1080/10913670801903969). The survey consisted of two domains (i.e. beliefs of the importance of fitness testing and effects of fitness test implementation with two subdomains: enjoyment of fitness test implementation and enjoyment of using fitness test results). The survey was translated into Chinese for distribution. ANOVA was performed to test overall attitude differences in gender and year in college, while two-way MANOVA was used to examine attitude subdomain differences in gender and year in college. Results: The overall attitudes of Chinese PPETs were slightly positive, and consistent with existing literature. Only significant gender differences in both overall attitudes and the three subdomains were found. It was also found that year in college was not significant, nor was the interaction between gender and year in college. These results may suggest that PETE programs have little effect on improving PPETs’ attitudes toward fitness testing. Conclusions: Chinese PPETs’ attitudes toward youth fitness testing were only slightly positive. Gender may affect Chinese PPETs’ attitudes, while surprisingly PETE programs may not focus on PPETs’ attitudes toward fitness testing. Future interventions on improving Chinese PPETs’ attitudes toward fitness tests are needed, with specialized interests targeting female candidates during PETE training programs.

Cardiorespiratory Fitness in Youth: An Important Marker of Health: A Scientific Statement From the American Heart Association.

Cardiorespiratory fitness (CRF) refers to the capacity of the circulatory and respiratory systems to supply oxygen to skeletal muscle mitochondria for energy production needed during physical activity. CRF is an important marker of physical and mental health and academic achievement in youth. However, only 40% of US youth are currently believed to have healthy CRF. In this statement, we review the physiological principles that determine CRF, the tools that are available to assess CRF, the modifiable and nonmodifiable factors influencing CRF, the association of CRF with markers of health in otherwise healthy youth, and the temporal trends in CRF both in the United States and internationally. Development of a cost-effective CRF measurement process that could readily be incorporated into office visits and in field settings to screen all youth periodically could help identify those at increased risk.

6-Minute Push Test in Youth Who Have Spina Bifida and Who Self-Propel a Wheelchair: Reliability and Physiologic Response

ObjectiveDespite the common occurrence of lower levels of physical activity and physical fitness in youth with spina bifida (SB) who use a wheelchair, there are very few tests available to measure and assess these levels. The purpose of this study was to determine reliability and the physiologic response of the 6-minute push test (6MPT) in youth with SB who self-propel a wheelchair.MethodsIn this reliability and observational study, a sample of 53 youth with SB (5–19 years old; mean age = 13 years 7 months; 32 boys and 21 girls) who used a wheelchair performed 2 exercise tests: the 6MPT and shuttle ride test. Heart rate, minute ventilation, respiratory exchange ratio, and oxygen consumption were measured using a calibrated mobile gas analysis system and a heart rate monitor. For reliability, intraclass correlation coefficients (ICCs), SE of measurement, smallest detectable change for total covered distance, minute work, and heart rate were calculated. Physiologic response during the 6MPT was expressed as percentage of maximal values achieved during the shuttle ride test.ResultsThe ICCs for total distance and minute work were excellent (0.95 and 0.97, respectively), and the ICC for heart rate was good (0.81). The physiologic response during the 6MPT was 85% to 89% of maximal values, except for minute ventilation (70.6%).ConclusionsFor most youth with SB who use a wheelchair for mobility or sports participation, the 6MPT is a reliable, functional performance test on a vigorous level of exercise.ImpactThis is the first study to investigate physiologic response during the 6MPT in youth (with SB) who are wheelchair using. Clinicians can use the 6MPT to evaluate functional performance and help design effective exercise programs for youth with SB who are wheelchair using.

Distribution Of Cardiorespiratory Fitness Among Children In The Hearts And Parks Study

One-third of children in the U.S. have an unhealthy body mass index (BMI). Vigorous activity improves BMI and reduces cardiovascular risk in children. Additionally, greater cardiorespiratory fitness (CRF) in youth may confer lower risks of poor cardiovascular and metabolic health in adulthood. The Hearts and Parks study utilizes a novel clinic-community intervention exploring how various types of physical activity, nutrition education and behavioral support affect the health of children (5-17 y) with a BMI ≥ the 95th percentile. PURPOSE: To explore 1-min post-exercise heart rate (HR) recovery following a physical fitness test and the distribution of CRF in children with obesity at baseline of enrollment in the Hearts and Parks study. METHODS: Participants aged 6-12 [n=109, Non-Hispanic: 59.1%, Boys: 47.8%] came to Duke’s Children Primary Care Clinic for anthropometric measures and an assessment of physical fitness. Physical fitness was assessed via the 3-min YMCA Bench Stepping Test, adapted for children 5-18. Heart rate recovery was measured via pulse-oximetry 1 minute after the test. RESULTS: The mean HR (bpm) for all age groups in this study showed a “very good” CRF [younger boys: 99.5, older boys: 98.2, younger girls: 109.0, older girls: 114.2]. Boys had a greater CRF with 39% at an “excellent” CRF compared to 24% for girls. Overall, girls tended to have a lower CRF compared to boys with 10% of girls in the “poor” category compared to the 4% for boys. CONCLUSION: Compared to normative values of children and considering their BMI, the participants of this study showed greater CRF values than expected. Irrespective of CRF levels, this study suggests children who are obese, in school and engage in some physical activity may still have a healthy level of CRF. Future studies should employ another measure such as VO2peak to examine CRF in children with obesity and how this may be related to the adiposity and health of the child. Funded by 17SFRN33700117

Association Between Strength Fitness And Gross Motor Function In Children: A Us National Study

It was believed that children with better motor function and skills will be likely more physically active. Yet, contribution of fitness, especially muscular strength, to children’s motor function and skill has not been well understood. PURPOSE: To examine the relationship between core and upper-body strength and gross motor function in children using a US national sample. METHODS: Three data sets in the 2012 National Youth Fitness Survey (NNYFS) were merged: Test of Gross Motor Development – Second Edition (TGMD-2), modified pull-up, and plank. TGMD-2 total score (TGMD-2 TS) was calculated by adding “Local motor subtest raw score” and “Object control subtest raw score” together. Descriptive statistics and correlations of TGMD-2 TS, “# of correctly completed modified pull-ups (M-Pull-up)”, and “# of seconds planks position is held (Planks)” were computed using the 2012 NNYFS data. RESULT: A total of 6375389 of boys and 6134317 of girls who aged between 3 and 5 yr. old participated in 2012 NNYFS, and their performances (M±SD) in gross motor function and fitness, as well as their correlations (r), are summarized below: Table CONCLUSION: As children become older, core and upper-body strength seems playing a positive impact on children’s gross motor function in both boys and girls.

Predicting Gross Motor Skills In Children: Data From The 2012 NHANES National Youth Fitness Survey

Predicting Gross Motor Skills In Children: Data From The 2012 NHANES National Youth Fitness Survey

Analysis Of The Current Situation Of Chinese Youth Science And Fitness

PURPOSE: The purpose of this study is to analyze the status of Chinese youth participation in scientific fitness activities and to provide reference for enhancing the scientific fitness activities of Chinese youth. METHODS: A total of 4663 healthy adolescents (age: 22.56 ± 5.81yrs, female: 54.5%) were investigated for the intervention from 33 provinces (central municipality, national autonomous region). Divided into three groups according to age: juvenile (12-17yrs), pre-youth (18-28yrs), and late youth (29-40yrs); divided into three regions based on the administrative districts: Eastern Region (ER), Central Region (CR) and Western Region (WR). RESULTS: The Questionnaire consists of two parts: (1) Knowledge and Skills (RRC 0.91), and (2) Cognitive, Attitude and Behavior (ICC 0.97, RRC 0.93). The content validity of the questionnaire was assessed by 11 experts. The structural validity was evaluated by the factor analyses. The results show that: (1) fitness location analysis: 70.6% of youth fitness venues in playground and park squares, gyms accounted for 12.1%, and other proportions of 9.1%. (2) Analysis of fitness METHODS: 81.5% of fitness methods tend to run and ball sports, the proportion of fitness and bodybuilding projects is 9.4%, the proportion of water projects is 2.5%, and the other proportion is 6.6%. (3) Analysis of fitness duration: 58.1% of young people's fitness time is 30-120 minutes, 30 minutes or less accounted for 33.0%, and more than two hours accounted for 8.9%. (4) Fitness frequency analysis: 62.1% of teenagers are not regular fitness, 17% have planned fitness, and 20.9% do not exercise very much. (5) Analysis of the number of fitness times in the week: 57.5% of the youth fitness no more than 2 times, 29.2% of the teenagers were 3-4 times and 13.3% of the teenagers were 5 times or more. CONCLUSIONS: Chinese youth participation in fitness activities is relatively concentrated; most of the youth fitness can be controlled within a relatively scientific range but the fitness activities are not regular. Relevant departments use a variety of strategies to promote the systematic and diverse participation of young people in fitness activities. (This study was supported by NPOPSS Grant 15CTY011)

Profiling the health-related physical fitness of Irish adolescents: A school-level sociodemographic divide.

Examining factors that may explain disparities in fitness levels among youth is a critical step in youth fitness promotion. The purpose of this study was twofold; 1) to examine the influence of school-level characteristics on fitness test performance; 2) to compare Irish adolescents' physical fitness to European norms. Adolescents (n = 1215, girls = 609) aged 13.4 years (SD .41) from a randomised sample of 20 secondary schools, stratified for gender, location and educational (dis)advantage, completed a series of field-based tests to measure the components of health-related physical fitness. Tests included: body mass index; 20 metre shuttle run test (20 m SRT); handgrip strength; standing broad jump (SBJ); 4 x 10 metre shuttle run; and back-saver sit-and-reach (BSR). Overall, boys outperformed girls in all tests, aside from the BSR (p < 0.005, t-test, Bonferroni correction). Participants in designated disadvantaged schools had significantly higher body mass index levels (p < 0.001), and significantly lower cardiorespiratory endurance (20 m SRT) (p < 0.001) and muscular strength (handgrip strength) (p = 0.018) levels compared to participants in non-disadvantaged schools. When compared to European norms, girls in this study scored significantly higher in the 20 m SRT, 4 x 10 metre shuttle run and SBJ tests, while boys scored significantly higher in the BSR test (Cohen's d 0.2 to 0.6, p < 0.001). However, European adolescents had significantly higher handgrip strength scores (Cohen's d 0.6 to 0.8, p < 0.001). Irish adolescents compared favourably to European normative values across most components of HRPF, with the exception of muscular strength. School socioeconomic status was a strong determinant of performance among Irish adolescents. The contrasting findings for different fitness components reiterate the need for multi-component testing batteries for monitoring fitness in youth.

THE PEDIATRIC INACTIVITY TRIAD: A TRIPLE JEOPARDY FOR MODERN DAY YOUTH

Apply It! • A majority of youth worldwide do not accumulate at least 60 minutes of moderate to vigorous physical activity daily. • The pediatric inactivity triad is a novel construct that consists of three interrelated determinants, namely, exercise deficit disorder, pediatric dynapenia, and physical illiteracy, that drive physical inactivity in youth. • Developmentally appropriate and inherently enjoyable exercise interventions are needed to move inactive youth toward the pediatric activity triad. • Youth fitness specialists who understand the science of pediatric exercise as well as the art of designing youth fitness programs are more likely to be successful.

Poverty Status Moderates the Relationship between Cardiorespiratory Fitness and Academic Achievement.

The purpose of the study was to examine the associations among cardiorespiratory fitness (CRF), weight status and academic achievement in youth, and to determine if these relationships are moderated by poverty status. The sample included 5th (N=27,791) and 8th grade (N=16,047) South Carolina students. Academic achievement was assessed using a state-wide assessment and classified into 2 categories (ie, does not meet/approaches standards vs meets/exceeds standards). CRF was assessed and expressed as Healthy Fitness Zone (HFZ) or Needs Improvement/Needs-Improvement-Health Risk. Students' demographics and poverty status were reported. Multilevel logistic regression analyses were used to examine the association between CRF, weight status and academic achievement. Interaction terms were introduced into the final models. Analyses were performed separately by grade level and academic subject. The CRF was significantly associated with the odds of meeting/exceeding academic standards after controlling for covariates and adjusting for weight status. The relationship between CRF and academic achievement varied significantly by poverty status. After adjustment for CRF, weight status was not significantly associated with academic achievement. The odds of achieving academic standards were significantly higher among students achieving CRF HFZ regardless of poverty status. CRF may partially mitigate the adverse effect of poverty on academic achievement.

Skeletal Muscle Mass Is Linked to Cardiorespiratory Fitness in Youth.

Cardiorespiratory fitness (CRF) measured by oxygen consumption (V˙O2) during exercise is an important marker of health. The traditional method of indexing V˙O2 to total body mass is suboptimal because skeletal muscle mass (SMM), rather than fat and extracellular fluid, is the main contributor to CRF. The traditional estimating equations for peak V˙O2 in youth do not account for this. Bioelectric impedance analysis (BIA) is a noninvasive method to accurately measure body composition. The objectives of this study were to 1) examine the relationship of body composition indices and peak V˙O2 in healthy children, adolescents, and young adults, and 2) derive an optimized estimating equation incorporating BIA and compare its performance with traditional estimating equations. A retrospective, cross-sectional, single-center study of patients <21 yr old referred for exercise testing who did not have underlying cardiovascular disease. All patients underwent BIA immediately before exercise testing. Univariable and multivariable linear regression models were constructed and tested for model performance. A total of 165 young healthy people (mean age 14 yr, 48% male) were studied. There was a strong and linear relationship between peak V˙O2 and SMM (R = 0.79). The sex difference in SMM explained the most variability in CRF between boys and girls. A generalized equation using SMM (peak V˙O2 = 302 - (23.7 × age) - (50.3 × [female = 1, male = 0]) + (81.8 × SMM)) had superior performance (R = 0.80) compared with estimating equations currently used in clinical practice (R = 0.67). SMM is a stronger correlate of CRF than is total body mass in youth and may be a better scaling variable to estimate expected peak V˙O2.

Resistance Training for Children and Adolescents

Resistance training is becoming more important as an integral part of comprehensive sport training regimens, school physical education classes, and after-school fitness programs. The increasing number of youth who are involved in sport activities, coupled with the health problems of inactivity and being overweight, have resulted in increased interest in resistance training. Secular declines in measures of muscular fitness in modern-day youth highlight the need for participation in youth resistance training for nonathletes as well as athletes. Parents often ask pediatricians to offer advice regarding the safety, benefits, and implementation of an effective resistance-training program. This report is a revision of the 2008 American Academy of Pediatrics policy statement and reviews current information and research on the benefits and risks of resistance training for children and adolescents.

PHYSICAL FITNESS OF BOYS PERTAINING TO UNDERWEIGHT, OVERWEIGHT AND OBESITY

Together with the changing socio-economic status of the Polish society, differences in the nutritional status of children and youth and their lower physical fitness levels are becoming more noticeable. The aim of this research was to define changes that occurred over a 10-year period regarding physical fitness of boys with proper weight-height proportions and of their underweight, overweight and obese counterparts. In 2004/05, somatic features and physical fitness were examined in 16116 and 9507 boys, respectively, aged 10-18. Ten years later somatic features and physical fitness assesmensts were repeated in 6972 and 6834 boys aged 10 to 18. The participants performed Eurofit tests and their body height and body mass were measured in order to calculate the Body Mass Index (BMI). The ten-year differences in physical fitness were expressed on a T point scale, while their extent was estimated with the Student’s t-test for independent data. The frequency of occurrence of underweight and overweight was expressed in percentage values and verified with the use of the χ² test. In the analysed decade, an increase in the frequency of occurrence of both overweight and serious underweight was noted. It resulted in a lower level of physical fitness in children and youth belonging to the aforementioned groups. The most serious negative changes were noted in boys aged 13-15. It can be concluded that unless remedial programmes are implemented, the young generation will experience biological deterioration in the decades to come, which may result in an epidemic of lifestyle diseases in younger and younger individuals.

Socioeconomic and Familial Factors Associated with Gross Motor Skills among US Children Aged 3-5 Years: The 2012 NHANES National Youth Fitness Survey.

The first aim of this study was to examine the prevalence of below average gross motor skills in a representative sample of US children aged 3 to 5 years. The second aim was to identify socioeconomic and familial characteristics that are associated with below average gross motor skills. Secondary analysis was conducted using the datasets from the 2012 National Health and Examination Survey National Youth Fitness Survey (NNYFS). The NNYFS assessed gross motor skills among 329 children aged 3–5 years, using the Test of Gross Motor Development-Second Edition (TGMD-2). Socioeconomic and familial characteristics of interest, such as family income and family structure, were asked in an in-person interview. This study estimated that one in three US children age 3 to 5 years old (33.9%) scored below average for gross motor quotient. In the gross motor subsets, one in four (24.4%) scored below average for locomotion and two in five (39.9%) scored below average for object control. Children living below the poverty threshold were more likely to have a higher gross motor quotient (odds ratio, OR = 2.76; 95% confidence interval, CI = 1.09–7.00). Girls were more likely to have a higher locomotor score (OR = 2.17; 95% CI = 1.10–4.25). Those living with other child(ren) aged ≤5 years were more likely to have a higher locomotor score (OR = 2.36; 95% CI = 1.01–5.54), while those living with child(ren) aged 6–17 years were more likely to have a higher object control score (OR = 1.83; 95% CI = 1.24–2.69). This study revealed risk factors associated with poor gross motor development, furthering our understanding of gross motor development in early childhood.

Testing validity of FitnessGram in two samples of US adolescents (12–15 years)

Background/ObjectiveThis study examined the validity of the FitnessGram® criterion-reference cut-points for cardiorespiratory fitness (CRF) based on two samples of US adolescents (aged 12–15 years). This study also established the CRF cut-points for metabolically healthy weight status based on a recent national fitness survey for the purposes of cross-validating with pre-existing cut-points including FitnessGram. MethodsTwo cross-sectional data from the 2003–2004 National Health and Nutrition Examination Survey (NHANES) (n = 378) and 2012 NHANES National Youth Fitness Survey (NNYFS) (n = 451) were used. CRF (estimated V˙O2max in mL/kg/min) was estimated from a submaximal exercise test. CRF categories based on FitnessGram cut-points, a clustered cardiometabolic risk factors score and weight status were used. A series of Receiver Operating Characteristic (ROC) curve analyses were conducted to identify age- and sex-specific CRF cut-points that were optimal for metabolically healthy weight status. ResultsBased on FitnessGram cut-points, having high risk CRF, but not low risk CRF, was associated with high cardiometabolic risk (OR = 3.17, 95% CI = 1.14–8.79) and unhealthy weight status (OR = 5.81, 95% CI = 3.49–9.68). The optimal CRF cut-points for 12-13-year-olds and 14-15-year-olds were 40 and 43 mL/kg/min in males and 39 and 34 mL/kg/min in females, respectively. Compared to meeting new CRF cut-points, not meeting new CRF cut-points was associated with higher odds of showing high cardiometabolic risk (OR = 2.91, 95% CI = 1.47–5.77) and metabolically unhealthy weight status (OR = 4.47, 95% CI = 2.83–7.05). ConclusionFitnessGram CRF cut-point itself has rarely been scrutinized in previous literature. Our findings provide partial support for FitnessGram based on two samples of US adolescents. CRF cut-points established in this study supports international criterion-referenced cut-points as well as FitnessGram cut-points only for males. FitnessGram should be continuously monitored and scrutinized using different samples.

Bidirectional associations between fitness and fatness in youth: A longitudinal study.

The aim was to examine the bidirectional association between cardiorespiratory fitness (CRF) and fatness in a 2-year longitudinal study conducted in young people. A total of 1082 children (512 females) and 727 adolescents (342 females) with complete data at baseline and follow-up were included. CRF was determined by the 20-m shuttle run test. Height and weight were measured, and body mass index and fat mass index (kg/m2 ) were calculated. Triceps and subscapular skinfolds were assessed to compute body fat percentage. Bidirectionality was tested by including CRF and each fatness index as exposures and outcomes, alternatively, in different regression models. CRF was prospectively associated with fatness index levels (ß from -0.186 to -0.528; P<.001), remaining significant in children after adjusting for baseline fatness indices. Fatness indices were prospectively associated with CRF (ß from -0.207 to -0.479; P<.001), with no substantial changes observed in children and female adolescents when baseline CRF was considered. Changes in CRF were prospectively associated with several fatness indices, regardless of body fatness at baseline (ß from -0.062 to -0.220; P<.05). Body fatness changes were associated with future CRF levels, independently of baseline CRF, especially in children of both sexes and male adolescents (ß from -0.079 to -0.260; P<.05). Overall, a bidirectional association was observed between CRF and fatness in children and adolescents. The attainment of optimal CRF and fatness levels in early ages should be promoted since it could result in favorable future fatness and CRF levels, respectively, which are two key determinants of health status.

A Pilot Study of Cardiorespiratory Fitness, Adiposity, and Cardiometabolic Health in Youth With Overweight and Obesity.

To conduct a preliminary assessment of the relationships between cardiorespiratory fitness, adiposity, and cardiometabolic health using gold standard measures in diverse youth ranging from overweight to severe obesity. Twenty of 30 participants (mean [SD]; age 13.2 [1.8] y, 55% female, 45% African American) met the criteria for VO2peak during a graded cycle ergometer test to volitional fatigue. The body composition was measured by dual-energy X-ray absorptiometry (percentage of body fat, fat mass index, and fat-free mass) and magnetic resonance imaging (abdominal visceral and subcutaneous [SAT] adipose tissue). The VO2peak was expressed relative to fat-free mass. Fasting lipid levels, glycemic biomarkers, and vital signs were examined individually and used in a composite cardiometabolic risk score. Accelerometer-measured physical activity and sedentary time were included as covariates. VO2peak was negatively associated with abdominal SAT (r = -.49, P < .05), but not visceral adipose tissue or markers of cardiometabolic health. The association between SAT and VO2peak was partly explained by habitual sedentary time. We demonstrated a significant negative association between cardiorespiratory fitness and SAT in a diverse group of high-risk youth. The inclusion of rigorous, laboratory-based measures and youth with severe obesity extends the previous work in pediatric populations.

Physical fitness disparities among New York City public school youth using standardized methods, 2006-2017.

Standardized physical fitness monitoring provides a more accurate proxy for youth health when compared with physical activity. Little is known about the utilization of broad-scale individual-level youth physical fitness testing to explore health disparities. We examined longitudinal trends in population-level fitness for 4th-12th grade New York City youth during 2006/7-2016/17 (average n = 510,293 per year). Analyses were performed in 2019. The primary outcome was whether or not youth achieved sex-/age-specific performance levels (called the Healthy Fitness Zone) on the aerobic capacity, muscular strength and muscular endurance tests using the NYC FITNESSGRAM. The Cooper Institute’s most recent Healthy Fitness Zone criteria were applied to all tests and years. Prevalence estimates were weighted, accounted for school clustering, adjusted for student-level sociodemographics, and run by sociodemographic subgroups and year. The overall prevalence for meeting 3 Healthy Fitness Zones increased from 15.5% (95%CI: 13.9%-17.0%) in 2006/7 to 23.3% (95%CI: 22.2%-24.4%) in 2016/17 for students in grades 4–12. Fitness for all student groups increased over time, although Hispanic and non-Hispanic black girls consistently had the lowest prevalence of meeting 3 Healthy Fitness Zones as compared to all other race/sex subgroups. Also, 9th-12th graders had a lower prevalence of meeting 3 Healthy Fitness Zones as compared to 4th-8th graders. Given forecasted sharp increases in cardiovascular disease prevalence, routine youth fitness surveillance using standardized, criterion referenced methods can identify important fitness disparities and inform interventions.