Health-Related Criterion-Referenced Cut-Points for Cardiorespiratory Fitness Among Youth: A Systematic Review

Added predictive value of childhood physical fitness to traditional risk factors for adult cardiovascular disease

AIM

Childhood physical fitness is a predictor of cardiovascular (CV) health but is underutilised in health surveillance. This study determined the predictive utility of child physical fitness levels on obesity, hypertension, dyslipidaemia, and the metabolic syndrome (MetS) in adulthood over traditional CV risk factors in childhood.

METHODS

A longitudinal cohort study of Childhood Determinants of Adult Health Study participants who had their fitness (cardiorespiratory fitness (CRF): 1.6 km run/walk, physical work capacity at 170 beats per minute; muscular fitness: dominant handgrip strength, standing long jump) measured as children and their CV health assessed as children and adults (mean follow-up=27 years). Participants had their body mass index (BMI), waist circumference, blood pressure, fasting blood sample (lipids, glucose), and smoking status assessed as children in 1985 and in early adulthood (2004-06, 26-36 years) and/or middle adulthood (2014-19, 36-49 years) where obesity, hypertension, dyslipidaemia, and MetS were defined. Logistic regression was used to model associations (N range=578-5049).

RESULTS

Additionally considering childhood CRF or muscular fitness improved the ability to discriminate and fit models to predict adult obesity, low HDL-C and MetS when added to demographics (age, sex) and the corresponding measure in childhood (BMI, HDL-C, CV risk score), as reflected by increments in area under the curve (Δrange=0.003-0.022), net reclassification index (range=0.026-0.149), integrated discrimination index (range=0.003-0.027), reductions in deviance and Brier scores, and statistically significant likelihood ratio tests.

CONCLUSION

CRF and muscular fitness are independent health indicators that could complement other risk factors in childhood to identify individuals at increased long-term CV risk.

The Youth Fitness International Test (YFIT) battery for monitoring and surveillance among children and adolescents: A modified Delphi consensus project with 169 experts from 50 countries and territories

BACKGROUND

Physical fitness in childhood and adolescence is associated with a variety of health outcomes and is a powerful marker of current and future health. However, inconsistencies in tests and protocols limit international monitoring and surveillance. The objective of the study was to seek international consensus on a proposed, evidence-informed, Youth Fitness International Test (YFIT) battery and protocols for health monitoring and surveillance in children and adolescents aged 6-18 years.

METHODS

We conducted an international modified Delphi study to evaluate the level of agreement with a proposed, evidence-based, YFIT of core health-related fitness tests and protocols to be used worldwide in 6- to 18-year-olds. This proposal was based on previous European and North American projects that systematically reviewed the existing evidence to identify the most valid, reliable, health-related, safe, and feasible fitness tests to be used in children and adolescents aged 6-18 years. We designed a single-panel modified Delphi study and invited 216 experts from all around the world to answer this Delphi survey, of whom one-third are from low-to-middle income countries and one-third are women. Four experts were involved in the piloting of the survey and did not participate in the main Delphi study to avoid bias. We pre-defined an agreement of ≥80% among the expert participants to achieve consensus.

RESULTS

We obtained a high response rate (78%) with a total of 169 fitness experts from 50 countries and territories, including 63 women and 61 experts from low- or middle-income countries/territories. Consensus (>85% agreement) was achieved for all proposed tests and protocols, supporting the YFIT battery, which includes weight and height (to compute body mass index as a proxy of body size/composition), the 20-m shuttle run (cardiorespiratory fitness), handgrip strength, and standing long jump (muscular fitness).

CONCLUSION

This study contributes to standardizing fitness tests and protocols used for research, monitoring, and surveillance across the world, which will allow for future data pooling and the development of international and regional sex- and age-specific reference values, health-related cut-points, and a global picture of fitness among children and adolescents.

Tracking of Cardiorespiratory Fitness from Childhood to Mid-adulthood

High cardiorespiratory fitness (CRF) in adulthood is important for survival from major chronic diseases and preserving good health. We examined how childhood CRF tracks, or persists, into adulthood. Among a cohort of 748 school children followed over 34 years, we found child CRF correlated with young- (r = 0.30) and mid-adulthood (r = 0.16) CRF.

Normative-referenced values for health-related fitness among Czech youth: Physical fitness data from the study IPEN Adolescent Czech Republic

OBJECTIVES

The aim of this study was to developed sex- and age-specific normative-referenced percentile values for health-related fitness among 12 to 18 years old Czech youth.

METHODS

This study included cross-sectional data from 1,173 participants (50.7% boys) collected between 2013 and 2016. Participants were recruited from 32 elementary or secondary schools across eight cities located in the Czech Republic. Health-related fitness was objectively measured using both anthropometric (height, body mass, and sum of skinfolds) and performance (20-m shuttle run for cardiorespiratory endurance, modified push-ups for muscular strength/endurance, and V sit-and-reach for flexibility) tests. Sex- and age-specific normative values were calculated using the Lambda Mu Sigma method. Sex- and age-related differences in means were expressed as standardized effect sizes.

RESULTS

Normative percentiles were tabulated and displayed as smoothed curves. Among boys, measures of health-related fitness generally increased with age, except for an age-related decline in the sum of skinfolds and a plateau in V sit-and-reach. Among girls, most measures of health-related fitness increased from age 12 to 16 years before stabilizing, except for the sum of skinfolds, which remained stable from age 12 to 18 years. The sex-related differences were large with boys having higher cardiorespiratory endurance and muscular strength/endurance than girls. Girls compared to boys had higher flexibility.

CONCLUSIONS

This study presents the most up-to-date sex- and age-specific normative-referenced percentile values for health-related fitness among Czech youth. Normative values may be useful for fitness and public health screening and surveillance, for example, by helping to identify youth with low fitness who might benefit from a fitness-enhancing intervention.

Temporal Trends in the Physical Fitness of Hong Kong Adolescents Between 1998 and 2015

Low physical fitness in adolescence is linked with increased cardiometabolic risk and early all-cause mortality. This study aimed to estimate temporal trends in the physical fitness of Hong Kong adolescents aged 12-17 years between 1998 and 2015. Physical fitness (9-min run/walk, sit-ups, push-ups, and sit-and-reach) and body size data in a total of 28,059 adolescents tested across five population-representative surveys of Hong Kong secondary school pupils, were reported. Temporal trends in means were estimated at the gender-age level by best-fitting sample-weighted linear regression, with national trends estimated by a post-stratified population-weighting procedure. Overall, there were small declines in 9-min run/walk (effect size (ES)=-0.29 (95%CI: -0.32, -0.26)) and sit-ups performance (ES=-0.24 (95%CI: -0.27, -0.21)), with negligible changes in push-ups and sit-and-reach performance. There were small concurrent increases in both mean height and body mass, with a negligible increase in sum of skinfolds. Trends in mean physical fitness and body size/were not always uniform across the population distribution. The small declines in mean 9-min run/walk and sit-ups performance for Hong Kong adolescents are suggestive of corresponding declines in cardiorespiratory fitness and abdominal/core endurance, respectively. Increased national health promotion strategies are required to improve existing trends.

Trends in means and distributional characteristics of cardiorespiratory endurance performance for Italian children (1984-2010)

Cardiorespiratory endurance (CRE) is an important health marker. The aim of this study was to examine temporal trends of CRE performance for Italian children between 1984 and 2010. Using a repeated cross-sectional study design, 5303 CRE test results were available for 2520 children aged 11-13 years from a single Northern Italian middle-high school between 1984 and 2010. CRE was measured as 1000-m and 12-min run test performance. With adjustments for BMI, temporal trends in means were estimated using linear regression, with trends in distributional characteristics described visually and estimated as the ratio of coefficients of variation (CVs). There was a significant small increase in BMI (effect size (ES) [95%CI]: 0.40 [0.32, 0.48]) over the entire period. When adjusted for BMI, there were significant small to moderate declines in mean running speed (ES [95%CI]: 1000-m, - 0.34 [-0.39, - 0.29]); 12-min, - 0.65 [-0.70, - 0.60]). Declines were larger for boys compared to girls. Variability substantially increased over time (ratio of CVs: range, 1.7-2.9), with larger declines in children with low running speed compared to children with average or high running speed. Our findings may be important to public health because low CRE is significantly related to current and future health.

An Investigation of the Utility of Waist Circumference Predicting Cardiorespiratory Fitness in School Children: A Cross-Sectional Study

The early identification of modifiable risk factors and their monitoring, also within school physical education (PE) classes, are becoming indispensable in the context of public health. The aim of this study was to test whether making use of waist circumference (WC) measurements increases the possibility of predicting the results of cardiorespiratory fitness (CRF) in school-age children, as compared with body mass index (BMI) and other somatic indicators related to body fat. The cross-sectional study covered 190 children aged 10 to 15 years, participating in school PE classes. Body height (BH), body weight (BW), WC, hip circumference (HC) and percentage of body fat (BF%) were measured. BMI, waist to hip ratio (WHR) and waist to height ratio (WHtR) were calculated, and a CRF test was performed by means of a 20 m shuttle run test (20mSRT). The peak heart rate (HR_peak) of the children was also measured. The regression model that was developed showed that WC (R² = 47.1%), beyond BF% (R² = 50.3%) and WHtR (R² = 50.0%), was a useful measure of CRF, and stronger than BMI (R² = 45.8%) or WHR (R² = 39.2%). The risk of obtaining the CRF result classified below a good level (below the percentile range of P60-P80) was significantly higher in children with a larger WC (odds ratio (OR) for the WC change of 1 cm equals 1.14 (95% CI: 1.09-1.20; p < 0.001)). The simplicity of measuring WC and the possibility of using this measurement in the calculation of WHtR with reference to CRF indicate its usefulness in the prophylactic exams of school children.

Top 10 International Priorities for Physical Fitness Research and Surveillance Among Children and Adolescents: A Twin-Panel Delphi Study

BACKGROUND

The measurement of physical fitness has a history that dates back nearly 200 years. Recently, there has been an increase in international research and surveillance on physical fitness creating a need for setting international priorities that could help guide future efforts.

OBJECTIVE

This study aimed to produce a list of the top 10 international priorities for research and surveillance on physical fitness among children and adolescents.

METHODS

Using a twin-panel Delphi method, two independent panels consisting of 46 international experts were identified (panel 1 = 28, panel 2 = 18). The panel participants were asked to list up to five priorities for research or surveillance (round 1), and then rated the items from their own panel on a 5-point Likert scale of importance (round 2). In round 3, experts were asked to rate the priorities identified by the other panel.

RESULTS

There was strong between-panel agreement (panel 1: r_s = 0.76, p < 0.01; panel 2: r_s = 0.77, p < 0.01) in the priorities identified. The list of the final top 10 priorities included (i) "conduct longitudinal studies to assess changes in fitness and associations with health". This was followed by (ii) "use fitness surveillance to inform decision making", and (iii) "implement regular and consistent international/national fitness surveys using common measures".

CONCLUSIONS

The priorities identified in this study provide guidance for future international collaborations and research efforts on the physical fitness of children and adolescents over the next decade and beyond.