Criterion-related validity of the 20-m shuttle run test in youths aged 13–19 years

Reliability and validity of the modified shuttle test-paeds to measure cardiorespiratory fitness in children

BACKGROUND

The Modified Shuttle Test-Paeds (Paeds), a recently developed 10-meter Shuttle run test for aerobic capacity in children. This study aims to investigate the construct validity (known-group and convergent validity) and test-retest reliability of the recently developed test for cardiorespiratory fitness, the Modified Shuttle Test-Paeds (Paeds).

METHODS

A total of 144 participants (6-12 y) were tested on the Paeds test, and 84 children were tested on the 20-meter Shuttle Run test (20 m-SRT) to assess construct validity. To evaluate test-retest reliability, 46 children were tested twice on the Paeds.

RESULTS

No sex differences were found, but there was an age effect. A strong correlation was found between Paeds and the 20 m-SRT (rs=0.78, p < 0.001). The test-retest reliability was good (ICC 0.84; 95% CI 0.74-0.91).

CONCLUSION

Paeds appears to be a reliable and valid tool for estimating cardiorespiratory fitness in typically developing children aged 6-12 years and has the advantages of being shorter, needing less space, not requiring pacing and being self-motivational. More studies are needed to assess whether children reach an aerobic steady state in three minutes and how much of the results of the Paeds test can be explained by the agility component of the task (turning and grasping or aiming a bean bag). For clinical use, psychometric properties should be studied in various patient groups (e.g., ADHD, DCD, and children with intellectual disabilities).

Cardiorespiratory fitness has declined among French children since 1999, although the decline appears to be getting smaller

BACKGROUND

Cardiorespiratory fitness (CRF) is a strong marker of current and future health. The aim of this study was to assess the national temporal trends in CRF for French children and adolescents between 1999 and 2022.

METHODS

CRF data were obtained from several cross-sectional studies on 15 420 (51.1% boys) French children and adolescents aged 9-16 years between 1999 and 2022. The 20-m shuttle run test (20mSRT) estimated CRF. Body mass index (BMI) was calculated from measured height and body mass, with BMI z-scores (BMIz) calculated using WHO growth curves. The 20mSRT results were corrected for protocol and converted to z-scores (20mSRTz) using international sex- and age-specific norms. With additional adjustment for BMIz, temporal trends in mean 20mSRT performance (20mSRTz) were estimated using linear regression, with the distance max (Dmax) method used to locate a breakpoint and linear segments fitted to points below and above the breakpoint. Trends in distributional characteristics were assessed visually and described as the ratio of the coefficients of variation (CVs).

RESULTS

After adjustment for protocol, age, sex, and BMIz, a large decline in mean 20mSRT performance (trend per decade (95% CI): -1.42 SDs (-1.45, -1.39) or -18.4% (95% CI: -18.8, -18.0)) between 1999 and 2022 was found. Dmax located a breakpoint for the two-linear-segment model in year 2010. There was a large decline in mean 20mSRT performance pre-2010 (trend per decade (95% CI): -2.31 SDs (-2.39, -2.24)), which reduced 0.06-fold to a negligible decline post-2010 (trend per decade (95% CI): -0.15 SD (-0.20, -0.10)). We also found that the trend in mean 20mSRT performance was not uniform across the population distribution. Between 1999 and 2022, there was a small trend in distributional asymmetry, with slightly smaller declines experienced by the high performers (above the 75th percentile).

CONCLUSIONS

Our data suggest a large decline in the 20mSRT performance of French children and adolescents since 1999. This declining trend seems to have diminished considerably since 2010. Such declines in CRF could translate into declines in health status. Although a slowing in the declining trend in CRF in recent years is encouraging, more data are needed to confirm these findings.

Proposed Protocol for Field Testing of Endurance Fitness of Young Labrador Retrievers

The number of dogs and, with it, dog sports are growing in popularity, and the training of dogs begins at an early age. Although fitness testing is an imperative part of purposeful training and sports, to our knowledge, no objective field tests are available for measuring young dogs' endurance fitness. The aim of this study is to describe a simple, easy-to-repeat, and inexpensive way to test training intervention effects on endurance fitness in young Labrador Retrievers. Healthy client-owned 16-week-old Labrador Retrievers will be recruited and divided into test and control groups. The test group will have an eight-week training program followed by a four-week detraining period, while the control group will live a normal puppy life. All dogs will be tested for endurance fitness four times at four-week intervals: at baseline, one month later, two months later at the end of the training period, and one month after ending the training program. Each of the four testing sessions will be identical and will consist of four measurements of heart rate (HR) and blood lactate (BL): at baseline, after trotting 1000 m, after sprinting 200 m, and at recovery 5-8 min after the sprint. The training-induced changes in endurance fitness are evaluated by changes in HR and heart rate recovery times (HRR), BL, and running times.

Does incorporating high intensity interval training in physical education classes improve fitness outcomes of students? A cluster randomized controlled trial

The aim of this study was to determine the efficacy of a high intensity interval training (HIIT) intervention lasting 12 weeks on fitness (cardiorespiratory fitness, muscular strength, muscular endurance, power, speed, flexibility, and balance) and adiposity of 10- to 15-year-old students implemented during their physical education (PE). The focus of this study was to compare two approaches to increasing fitness level among school-aged children, one approach focusing on regular PE sessions in accordance with the curriculum and another one on regular PE classes augmented by HIIT. A cluster-randomized controlled trial was conducted (February-May 2022, Zagreb, Croatia). The total number of students across both groups was 207. General linear models were used to compare fitness and adiposity changes in both groups based on Eurofit test battery. A significant effect of the HIIT intervention was present for the 20-meter shuttle run test (p = 0.001; d = 0.31). The effect of the intervention compared to the control was estimated as an additional 181.2 m, 95 %CI (70.4 to 292.0). An additional intention-to-treat (ITT) analysis showed that the effect of the HIIT intervention on 20-meter shuttle run test remained statistically significant (p = 0.011), though the magnitude of the estimated effect was reduced from 181.2 m; SE = 55.4 to 119.6 m; SE = 46.4. Whilst it appears HIIT had the opposite of the expected effect on body fat percentiles, the effect on body composition was inconsistent. The intervention is registered at the Australian New Zealand Clinical Trials Registry (ANZCTR) [ACTRN12622000209796].

Performance factors that negatively influence shooting efficiency in women's basketball

The purpose of the present study was to examine the influence of selected factors (possession duration, game quarter, defensive pressure, shooting distance from the basket, and heart rate level) on shooting efficiency on Under-19 (U19) and senior level of women's basketball competition (second division). The analysis procedures included five U19 and six senior-level games, containing 224 and 252 shooting attempts, respectively. Binary logistic regression identified the opponent's defensive pressure and shooting distance from the basket as significant predictors of shooting efficiency in both categories. When defensive pressure was high, the chance for the missed shot was 3.5 (95% CI; 1.43-8.52) and 3.19 (95% CI; 1.4-7.26) times more likely than it was under the minimum defensive pressure for U19 and senior category, respectively. Shooting efficiency significantly decreased when the horizontal distance from the basket increased. In U19, a chance for a missed shot was 4.63 (95% CI; 2-10.712) and 5.15 (95% CI; 1.91-13.86) times higher for medium and long-distance (respectively), compared to short-range shooting. In the senior category, the chance for the missed shot was 3.9 (95% CI; 1.83-8.31) and 3.27 (95% CI; 1.43-7.52) times higher for medium and long-distance (respectively) when compared to a short distance. The possession duration, game quarter, and heart rate level were identified as insignificant predictors. Therefore, the aforementioned findings suggest that basketball players and coaches may benefit from designing training sessions where the defender puts pressure on the shooting player as in a real game situation and balanced the frequency of shooting from different distances from the basket.

Increase in peak oxygen uptake and Andersen test performance in children from age six to ten: The Health Oriented Pedagogical Project (HOPP)

The increased prevalence of non-communicable disease risk factors among children because of lack of physical activity is concerning. The Health Oriented Pedagogical Project was set up to combine learning activities and physical activity, thus reducing sedentariness during school time. The current study aimed to measure and describe the longitudinal and cross-sectional development of oxygen uptake and running performance in children at ages six and ten. The validity of the Andersen Test in predicting V̇O2peak in these age groups was also evaluated. Eighty-six children (53 boys, 33 girls) with complete datasets at ages 6 and 10 years were included in the longitudinal study, while 192 children (106 boys, 86 girls) were included in the cross-sectional analysis because they missed data from 1 year. Oxygen uptake was measured using a metabolic analyser and maximal treadmill running, while the distance covered during the AT determined running performance. Body mass, height, and waist-to-height ratios were recorded. Multiple regression analysis was used to assess the association between oxygen uptake and running performance. The cross-sectional results did not differ from the longitudinal data for anthropometrical data, oxygen uptake and running performance. Height, body mass and waist-to-height ratio did not differ between the sexes at ages six or ten. Boys had significantly higher peak oxygen uptake than girls at 6 years of age, irrespective of how oxygen uptake was expressed. Allometric scaling of oxygen uptake revealed differences between sexes at both ages. Longitudinal running performance increased in both sexes from 6 to 10 years. Boys ran significantly longer only at age ten. The association between oxygen uptake and running performance varied according to how the oxygen uptake was expressed and with sex and age. Ten-year-old girls had the highest correlations in the longitudinal investigation, from r2 = 0.48 (fV̇O2peak) to 0.65 (rV̇O2peak) between AT and V̇O2peak. The AT was found to be as valid as the 20-m shuttle run test in estimating peak oxygen uptake, with a random measurement error of approximately 11% of mean values.

Cluster randomised controlled trial to determine the impact of an activity enabling uniform on primary school student's fitness and physical activity: study protocol for the Active WeAR Everyday (AWARE) study

IntroductionMulticomponent school-based physical activity (PA) interventions can improve students' cardiorespiratory fitness (CRF) and PA. Due to the complex nature of such interventions when delivered at scale their effect sizes markedly reduce. Modifying student school uniforms, so that they are more PA enabling, may be a simple intervention that could enhance student health. The primary aim of this trial is to assess the effectiveness of an activity enabling uniform intervention (shorts, polo shirt and sports shoes) in improving children's CRF.

METHODS AND ANALYSIS

A cluster randomised controlled trial will be conducted in 24 primary schools in New South Wales (NSW), Australia. Schools will be randomly allocated to either intervention or usual practice following baseline data collection. Active WeAR Everyday intervention schools will allow students in grades 4-6 (aged approx. 9-12 years) to wear their existing sports uniform (shorts, polo shirt and sports shoes) every day. To avoid any financial cost to students they will be provided with two additional sports shirts and one pair of shorts. Study outcomes will be assessed at baseline and 9 months postbaseline. The primary outcome is students' CRF measured using the 20 m multistage fitness test. Secondary outcomes include students': mean daily steps and steps/minute measured via accelerometer, quality of life, mental well-being and perceived PA self-efficacy. The acceptability, feasibility and cost of the intervention will be assessed. Analyses will be performed using an intention-to-treat framework. Linear mixed effects regression models will be used to assess intervention effects on the primary outcome at follow-up. Planned exploratory analyses will examine effects by subgroups (eg, gender).

ETHICS AND DISSEMINATION

This study has received approval from Hunter New England Local Health District Human Ethics Committee (2020/ETHO2602) the University of Newcastle, Human Research Ethics Committee (H-2021-0013), NSW Department of Education (SERAP: 2020387) and Catholic School Offices.

TRIAL REGISTRATION NUMBER

ACTRN12621000201875.

The Multistage 20-m Shuttle Run Test for Predicting VO2Peak in 6–9-Year-Old Children: A Comparison with VO2Peak Predictive Equations

Simple Summary

Cardiorespiratory fitness is one of the main components of physical fitness. For children, a simple test that can be used to assess cardiorespiratory fitness is the multistage 20-m shuttle run test (20mSRT). Research has often used a portable gas analyzer to measure cardiorespiratory fitness in clinical and scientific settings; however, this may not be practical due to the high cost of the device. Moreover, the use of such a device with children is almost impracticable in school environments. Thus, to avoid using such a device, one possibility is to use equations for predicting peak oxygen consumption, which is recognized as one of the best indicators of aerobic fitness. In the present study, 22 equations were used to determine which predictive equations had greater agreement with VO₂peak values measured by direct oximetry through performance of the 20mSRT. Furthermore, we verified if wearing and carrying a portable gas analyzer constrained the children’s performances. To accomplish these aims, 67 boys and 63 girls were included in the analysis. Our results showed that only six predictive equations correctly predicted the peak oxygen consumption. In addition, for girls, higher values of maximal speed, total laps, and total time were found when a portable gas analyzer was used. This information is helpful to strength and conditioning professionals and to schoolteachers if portable gas analyzers are unavailable or if the environment is not suitable for such assessments.

Abstract

This study aimed (i) to verify if using and carrying a portable gas analyzer (PGA) constrained the performance of school children on the multistage 20-m shuttle run test (20mSRT), (ii) to verify which peak oxygen consumption (VO₂peak) predictive equations have greater agreement with VO₂peak values measured by direct oximetry using the 20mSRT. The study participants were 130 children ((67 boys (age 7.76 ± 0.97 years) and 63 girls (age 7.59 ± 0.91 years)), who performed two randomized trials of the 20mSRT with and without a PGA. Twenty-two predictive equations predicted the VO₂peak values through the performance of the test with and without a PGA. Without a PGA, lower values of maximal speed (MS), total laps (TL), and total time (TT) were found for girls than for boys with a PGA. Only six equations were considered to correctly predict VO₂peak. In general, higher MS, TL, and TT values were found with the use of a PGA. The predicted VO₂peak values from the 20mSRT varied significantly among the published predictive equations. Therefore, we suggest that the six equations that presented satisfactory accuracy could be practically used to examine cardiorespiratory fitness in schools and in research with large populations when direct measurement of VO₂peak is not feasible.

Making a HIIT: study protocol for assessing the feasibility and effects of co-designing high-intensity interval training workouts with students and teachers

Background

High-intensity interval training (HIIT) is an effective strategy for improving a variety of health outcomes within the school setting. However, there is limited research on the implementation of school-based HIIT interventions and the integration of HIIT within the Health and Physical Education (HPE) curriculum. The aims of the Making a HIIT study are to: 1) describe the methodology and evaluate the feasibility of co-designing HIIT workouts with students and teachers in HPE; 2) determine the effect of co-designed HIIT workouts on cardiorespiratory and muscular fitness, and executive function; 3) understand the effect of co-design on students’ motivation, enjoyment, and self-efficacy towards the workouts; and 4) evaluate the implementation of the intervention.

Methods

Three schools will participate. Within each school, three different groups will be formed from Year 7 and 8 classes: 1) Co-Designers; 2) HIIT Only; and 3) Control. The study will include two phases. In phase one, Group 1 will co-design HIIT workouts as part of the HPE curriculum using an iterative process with the researcher, teacher, and students as collaborators. This process will be evaluated using student discussions, student surveys, and teacher interviews. In phase two, Groups 1 and 2 will use the co-designed 10-minute HIIT workouts in HPE for 8-weeks. Group 3 (control) will continue their regular HPE lessons. All students will participate in cardiorespiratory fitness, muscular fitness, and executive function assessments before and after the HIIT program or control period. Students will complete questionnaires on their motivation, enjoyment, and self-efficacy of the workouts. Differences between groups will be assessed using linear regressions to account for covariates. Heart rate and rating of perceived exertion will be collected during each HIIT session. The implementation will be evaluated using the Framework for Effective Implementation. Ethical approval was granted by the University of Queensland Human Research Ethics Committee and other relevant bodies.

Discussion

This study will be the first to co-design HIIT workouts with teachers and students within the HPE curriculum. As this study relies on co-design, each HIIT workout will differ, which will add variability between HIIT workouts but increase the ecological validity of the study.

Trial registration

ACTRN, ACTRN12622000534785, Registered 5 April 2022 – Retrospectively registered, https://www.anzctr.org.au/ACTRN12622000534785.aspx

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03440-w.

Intensity and Duration of Physical Activity and Cardiorespiratory Fitness

OBJECTIVES

There is no clear guidance on the intensity and duration of physical activity (PA) that adolescents require to maximise cardiorespiratory fitness (CRF). We aimed to determine the strength of associations between each PA intensity and CRF, independently of other intensities, and the PA duration at each intensity associated with maximal CRF.

METHODS

PA and CRF were assessed in 339 adolescents aged 13 to 14 years by wrist-worn accelerometers and 20-m shuttle runs, respectively. Partial regression modeling was used to construct residualized PA variables at each PA intensity that were uncorrelated with each other. Moving average models were optimally fitted to determine relationships between residualized PA variables and CRF. Threshold regression models determined the duration of PA above which CRF improvement was minimal.

RESULTS

Greater vigorous PA (VPA) was associated with better CRF until about 20 minutes of daily VPA, when the relationship plateaued. Moderate and light PA, and sedentary time were not associated with CRF in partial models. Adolescents performing 14 (range 12-17) minutes of daily VPA had median CRF. Participants in the upper quartile of VPA had 1.03 z-scores higher CRF than those in the lowest quartile (95% confidence interval: 0.75 to 1.30).

CONCLUSIONS

Our data suggest that 20 minutes of daily VPA may be best for maximizing CRF in adolescence. As moderate-to-vigorous PA guidelines can be satisfied by only undertaking moderate PA, with no apparent independent benefit, we suggest that future guidelines focus on VPA alone, simplifying public health messaging.

Comparison of VO2peak from the Progressive Aerobic Cardiovascular Endurance Run (PACER) and treadmill in children

Background/Objectives

Methods

Results

Conclusions

Obesity and Cardiometabolic Risk Factors: From Childhood to Adulthood

Obesity has become a major epidemic in the 21st century. It increases the risk of dyslipidemia, hypertension, and type 2 diabetes, which are known cardiometabolic risk factors and components of the metabolic syndrome. Although overt cardiovascular (CV) diseases such as stroke or myocardial infarction are the domain of adulthood, it is evident that the CV continuum begins very early in life. Recognition of risk factors and early stages of CV damage, at a time when these processes are still reversible, and the development of prevention strategies are major pillars in reducing CV morbidity and mortality in the general population. In this review, we will discuss the role of well-known but also novel risk factors linking obesity and increased CV risk from prenatal age to adulthood, including the role of perinatal factors, diet, nutrigenomics, and nutri-epigenetics, hyperuricemia, dyslipidemia, hypertension, and cardiorespiratory fitness. The importance of 'tracking' of these risk factors on adult CV health is highlighted and the economic impact of childhood obesity as well as preventive strategies are discussed.

The Cardiorespiratory fitness of children and adolescents in Tibet at altitudes over 3,500 meters

BACKGROUND

Cardiorespiratory fitness (CRF) is the core element of health-related physical fitness evaluation. High pressure and low oxygen in Tibet (over 3,500 m above sea level) may negatively impact the residents' CRF. The 20-m shuttle run test (20mSRT) is the most popular field-based assessment and estimate of CRF in children and adolescents worldwide. However, normative CRF data for the children and adolescents residing in China's plateau region are unavailable, which prevents comparability among those living at high-altitudes around the world.

PURPOSE

To measure the CRF of Chinese children and adolescents aged 9-18 years living in Tibet at altitudes exceeding 3,500 m, and to identify correlations between this metric and demographic characteristics (age, sex, and ethnicity). These data were then compared with those generated in the lowland (Shanghai, China) and various global regions.

METHODS

20mSRT performance (number of completed laps) and predicted peak oxygen consumption (VO2peak) were used as indicators of CRF. We measured the CRF of 1,717 healthy children and adolescents aged 9-18 years living in Tibet. The CRF data from school-age subjects in Shanghai (2,437 boys and 2,396 girls) and worldwide (1,142,026 students from 50 countries/regions in Africa, Asia, Europe, Latin America, North America, and Oceania) were collated from published papers.

RESULTS

The average CRF of the participants from Tibet was 39.8 mL/kg/min. The male subjects (n = 876; 41.1 ± 4.42 mL/kg/min) had a higher average CRF than their female counterparts (n = 841; 37.8 ± 5.40 mL/kg/min). CRF decreased with age in both sexes at statistical significance (F = 1249.9, p for trend 0.05). The indigenous Tibetans (n = 1289; 40.1 ± 3.71 mL/kg/min) had a significant higher average CRF than those of Han descent (n = 394; 38.9 ± 4.70 mL/kg/min) (p < 0.05).

CONCLUSIONS

Children and adolescents aged 7-18 years residing above 3,500 m in Tibet displayed lower CRF traits compared with their counterparts from the plains area and other high altitude places. CRF varied according to age, sex, and ethnic group. Given the importance of CRF in children and adolescents, effective intervention strategies should be implemented to improve CRF in children and adolescents on the plateau.

Concurrent Validity and Reliability of a Novel Visual Analogue Fitness Perception Scale for Adolescents (FP VAS A)

Introduction: Self-reported physical fitness (PF) provides an accurate measure of PF, specifically for young people. The Visual Analogue Scale (VAS) is one of the most used psychosocial measurement methods. The main arguments in favor of VAS are its ease of use and comprehension, particularly for less educated participants. There are some scales that assess self-perception of PF, but the VAS presented in this study covers a higher range of responses and a number of variables than other already validated measures. Aims: The aim was to determine the concurrent validity of the Visual Analogue Fitness Perception Scale for Adolescents (FP VAS A) (Sub-study 1) and check its reliability (Sub-study 2). Methods: Anthropometric and body composition measurements were performed, as well as PF tests (manual dynamometry, Course Navette, 4 × 10 m, and sit and reach). The International Fitness Scale (IFIS) and FP VAS A were used to assess self-reported PF. Results: Two sub-studies were carried out: in sub-study 1 a total of 67 students (26 males and 41 females aged 12–16 years) participated. The results showed a significant direct correlation between the level of PF and self-perception of PF (IFIS and FP VAS A), with the FP VAS A obtaining a higher correlation with PF (r = 0.444 to 0.666) than the IFIS and PF (r = 0.154 to 0.557). In sub-study 2 (test–retest of the FP VAS A), a total of 217 students (120 males and 97 females aged 12–17 years) participated. It showed a moderate reliability for all items; the intraclass correlation coefficient (ICC) was between 0.800 and 0.870, and kappa values ranged from 0.622 (endurance) to 0.458 (flexibility). In addition, Cronbach’s α for the total was 0.860. Conclusion: This study showed good validity and reliability for the FP VAS A in adolescents.

Determinants of Dribbling and Passing Skills in Competitive Games of Women's Basketball

This work aimed to identify the influence of selected endogenous (internal load) and exogenous (possession duration, game quarter, and defensive pressure) factors in natural game conditions on the efficiency of dribbling and passing skills. Dribbling and passing skills were assessed during four games of U19 female basketball players and five games of senior (2nd division) female basketball players. In total, 551 dribbling and 914 passing executions were evaluated. Binary logistic regression identified defensive pressure of the opponent as a predictor of dribbling and passing skills effectivity. When the defensive pressure of the opponent was medium, the chances for the ineffective pass were 1.997 times more likely (95% CI; 1.179-3.383), as it is at the minimum defensive pressure. When the defensive pressure of the opponent was high, the chances for ineffective dribbling were 7.45 times more likely (95% CI; 3.672-15.113) and for ineffective pass were 8.419 times more likely (95% CI; 4.6-15.409), as it is at minimum defensive pressure. The game quarter and the internal load were not identified as the predictors influencing the dribbling and passing effectivity. Possession duration was also an insignificant predictor of dribbling and passing skills effectivity. However, the passing skill effectivity decreases when the shot clock is winding down. These findings confirm the importance of transferring game situations into the training process. Coaches should take into account these factors when they want to stimulate determinants of player performance in a balanced and systematic way.

Normative Data and Physical Determinants of Multiple Sprint Sets in Young Soccer Players Aged 11-18 Years: Effect of Maturity Status

Selmi, MA, Sassi, RH, Yahmed, MH, Giannini, S, Perroni, F, and Elloumi, M. Normative data and physical determinants of multiple sprint sets in young soccer players aged 11-18 years: Effect of maturity status. J Strength Cond Res 34(2): 506-515, 2020-The aims of the study were: (a) to establish normative data for repeated-sprint sets (RSS) test based on the maturity status (age at peak height velocity [PHV]) and (2) to investigate the relationship between anthropometrical variables (stature, sitting height, body mass, and body fat percentage), RSS (2 × 5 × 20 m with 15-second recovery between sprints and 1-minute recovery between sets), and fitness tests {squat jump, countermovement jump, standing long jump, standing triple jump, 5-jump test, and 20-m shuttle run (multistage shuttle run test [MSRT])}. Young male soccer players (n = 262; age: 14.5 ± 2.9 years) were evaluated and classified into 4 groups according to their maturity status: pre-PHV, circum-PHV1, circum-PHV2, post-PHV. An analysis of variance and Bonferroni post hoc were used to determine maturity group differences (p ≤ 0.05), whereas Pearson's correlation was used between variables. Repeated-sprint sets' indices (sum of sprint times [SST] and best sprint time [BST]) were significantly different between the maturity groups. Significant correlations between SST with body mass (from -0.73 to -0.33) and MSRT (from -0.49 to -0.30) among each maturity group were found. With the different maturity groups, correlations between SST (s), BST (s), and vertical jump (cm) (r = -0.63 to -0.25 and r = -0.68 to -0.23) and horizontal jump (m) (r = -0.70 to -0.38 and r = -0.63 to -0.43) were observed. Repeated-sprint sets' values improve during maturation of young soccer players and the correlations between RSS and fitness tests vary through the maturity groups. This information could be useful for the coach to identify talent and to prescribe specific physical training to improve performance.

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.

Influence of Body Composition on Physical Fitness in Adolescents

Background and objectives: Childhood obesity is one of the main public health issues facing advanced societies. The Spanish population presents 28.6% overweight or obese adolescents, and Extremadura, 22.3%. Physical fitness is considered one of the most important health markers and a common predictor of morbidity and mortality caused by cardiovascular diseases. Thus, fitness tests are needed for health monitoring, especially in overweight and obese adolescents. Therefore, this study aimed to explore the relationship between body composition and physical fitness in adolescents and to analyse if there are differences in physical condition and body composition between the sexes, as well as to compare the different body mass index (BMI) categories to each other. This project also tried to find regression equations to predict the physical fitness test results. Materials and Methods: A total of 225 adolescents were recruited. Weight status was classified according to WHO 2007 standards. Body composition variables (i.e., BMI, fat mass (FM), FM percentage (FM%), and fat-free mass (FFM)) and physical fitness (standing long jump (SLJ), speed–agility (SA), cardiorespiratory fitness (CF), and handgrip strength (HS)) were assessed. Results: Significant differences were found between the sexes in body composition (FM%, FM, and FFM) and physical fitness (SLJ, SA, CF, and HS) (p < 0.001) in favour of males. Significant differences were also found in speed (p = 0.002), CF (p < 0.001), and SLJ (p = 0.004) in favour of normal-weight adolescents compared to overweight and obese adolescents. Contrarily, the outcomes revealed a significantly greater HS (p = 0.014) in favour of overweight and obese participants compared to normal-weight adolescents. Moreover, the results showed that CF and SLJ correlated inversely with BMI, FM%, and total FM. There was also a direct relationship between SA and FM percentage, as well as between HS and FFM. Finally, four fitness test predictive models are proposed based on body composition, age, sex, and BMI. Conclusions: Overweight and obese adolescents have lower levels of physical fitness than their normal-weight peers, regardless of their sex. Normal-ranged body composition values are related to a greater physical fitness in adolescents. Furthermore, this study presents several equations that can help to predict the performance of different fitness tests in adolescents.

Well-Being, Obesity and Motricity Observatory in Childhood and Youth (WOMO): A Study Protocol

Background: Childhood obesity is one of the greatest public health problems facing advanced societies, and Spain is one of the countries with the highest incidence. There are many studies that monitor at the national level, but given the lack of specificity, lack of updating and scarcity of epidemiological data on overweight, obesity, physical condition and well-being of children and adolescents in Extremadura, it seems necessary to create a Well-being, Obesity and Motricity Observatory in Childhood and Youth (WOMO) in Extremadura in order to follow up on the evolution of this problem and to propose strategies to combat it. Therefore, this project aims (1) to obtain information on the physical condition, body composition and well-being of children and youth in Extremadura every year and (2) to evaluate the relationship between obesity, overweight, physical condition, well-being, self-perceived physical fitness, physical activity adherence, physical literacy, health-related quality of life (HRQoL), happiness and satisfaction with life, connection with nature, barriers to sports practice, self-concept and bullying in children and youth. Methods: An annual monitoring cross-sectional and follow-up study will be performed. Primary outcome measures will be (1) personal data and anthropometric measurements, (2) family and school information, (3) physical condition, (4) obesity and overweight level, and (5) well-being. Secondary outcome measures will be (1) self-perceived physical fitness, (2) physical activity adherence, (3) physical literacy, (4) HRQoL, (5) happiness and satisfaction with life, (6) connection with nature, (7) barriers to sports practice, (8) self-concept and (9) bullying. Discussion: This project will provide valuable information to adopt appropriate strategies to reduce the level of overweight and obesity in children and youth. Furthermore, orientations will be given to transfer the results obtained to the business sector or to the public sector to evaluate or change the policies adopted.

Validation of Maximal, Submaximal, and Nonexercise Indirect [Formula: see text]O2max Estimations at 2600 m Altitude

Aim: To study the criterion validity of three indirect maximal oxygen uptake ([Formula: see text]O₂max) assessment equations at altitude. Methods: We studied 64 young adults (53% men) at Bogota, Colombia (2600 m altitude). Direct [Formula: see text]O₂max was measured by indirect calorimetry using a maximal incremental treadmill protocol. Indirect [Formula: see text]O₂max was estimated by two exercise field tests (the 20-m shuttle-run test [20-MST] and the 2-km walking test (UKK)) and one nonexercise method (the perceived functional ability-physical activity rating questionnaire [PFA-PAR]). Altitude-adjusted PFA-PAR was estimated as a 13% linear reduction in PFA-PAR. We calculated Lin concordance coefficients (LCC) and standard error of the estimates (SEEs), and we performed Bland-Altman analyses for each indirect method. Results: Mean [Formula: see text]O₂max was 41.2 ± 5.8 mL/kg/min in men and 32.2 ± 3.6 mL/kg/min in women. We found the highest agreement with direct [Formula: see text]O₂max for the 20-MST (LCC = 0.79, SEE = 3.91 mL/kg/min), followed in order by the altitude-adjusted PFA-PAR (LCC = 0.71, SEE = 4.12 mL/kg/min), the UKK (LCC = 0.67, SEE = 5.48 mL/kg/min), and the unadjusted PFA-PAR (LCC = 0.57, SEE = 4.75 mL/kg/min). The unadjusted PFA-PAR tended to overestimate [Formula: see text]O₂max, but Bland-Altman analysis showed that this bias disappeared after altitude adjustment. Conclusion: Several maximal, submaximal, and nonexercise methods provide estimates of [Formula: see text]O₂max with acceptable validity for use in epidemiological studies of populations living at moderate altitude.

Test-Retest Reliability of Student-Administered Health-Related Fitness Tests in School Settings

PURPOSE

To examine the test-retest reliability of student-administered (SA) health-related fitness tests in school settings and to compare indices of reliability with those taken by trained research-assistants.

METHODS

Participants (n = 86; age: 13.43 [0.33] y) were divided into 2 groups, SA (n = 45, girls = 26) or research-assistant administered (RA; n = 41, girls = 21). The SA group had their measures taken by 8 students (age: 15.59 [0.56] y, girls = 4), and the RA group had their measures taken by 8 research-assistants (age: 21.21 [1.38], girls = 5). Tests were administered twice by both groups, 1 week apart. Tests included body mass index, handgrip strength, standing broad jump, isometric plank hold, 90° push-up, 4 × 10-m shuttle run, back-saver sit and reach, and blood pressure.

RESULTS

Intraclass correlation coefficients for SA (≥.797) and RA (≥.866) groups were high, and the observed systematic error (Bland-Altman plot) between test 1 and test 2 was close to 0 for all tests. The coefficient of variation was less than 10% for all tests in the SA group, aside from the 90° push-up (24.3%). The SA group had a marginally lower combined mean coefficient of variation across all tests (6.5%) in comparison with the RA group (6.8%).

CONCLUSION

This study demonstrates that, following familiarization training, SA health-related fitness tests in school-based physical education programs can be considered reliable.

Comparing levels of fitness of police Officers between two United States law enforcement agencies

BACKGROUND

The general physical task demands of law enforcement may suggest that police Officers are of similar fitness levels across cities, states and countries.

OBJECTIVE

To investigate whether fitness levels of police Officers from two different United States (U.S.) Law Enforcement Agencies (LEA) are similar.

METHODS

Retrospective data were analysed from two LEAs (LEA1 n = 79 and LEA2 n = 319). The data for Officers included: age, mass, 1-minute push-up repetitions, 1-minute sit-up repetitions, vertical jump height, 2.4 km run time (LEA 1) and 20-meter Multi-Stage Fitness Test results (LEA 2). Independent samples t-tests were used to compare anthropometric and fitness data between LEA with significance set at 0.05.

RESULTS

Officers from LEA1 weighed significantly less and performed significantly better than Officers from LEA2 on all fitness measures. When comparing male Officers alone, there was no statistical difference in age and mass; nonetheless, Officers from LEA1 significantly outperformed Officers from LEA2 on all fitness measures.

CONCLUSION

While similarities / differences in job tasks performed between these two LEA are not known, the results from this study suggest differences in fitness between these two different U.S. LEA. Fitness standards and training protocols need to be developed and contextualized to each LEA's specific population and needs.

Cardiorespiratory fitness and health-related quality of life in adolescents: A longitudinal analysis from the LabMed Physical Activity Study

OBJECTIVE

The purpose of this study was to examine the longitudinal associations between cardiorespiratory fitness and health-related quality of life (HRQoL) in a sample of adolescents, and to determine whether changes in cardiorespiratory fitness were associated with HRQoL over a 2-year follow-up.

METHODS

This is a longitudinal analysis with 571 Portuguese adolescents (274 boys and 297 girls) aged 12-18 years. HRQoL was measured with the Kidscreen-10 questionnaire; the 20 m shuttle-run was used to estimate cardiorespiratory fitness; socioeconomic status was assessed with the Family Affluence Scale; and pubertal stage was assessed with Tanner stages. Linear regression and analysis of covariance (ancovas) were used to examine the associations between cardiorespiratory fitness and HRQoL.

RESULTS

HRQoL decreased over a 2-year period both in boys and girls (P < .05). Moreover, girls at baseline and at follow-up reported significantly lower HRQoL values than boys (between subjects P < .001). After adjustments for potential confounders, regression analyses showed significant cross-sectional associations between cardiorespiratory fitness and HRQoL both at baseline (B = 0.095; P = .023) and at follow-up (B = 0.090; P = .012). ancova showed that adolescents whose cardiorespiratory fitness decreased over time exhibited lower scores of HRQoL at follow-up, compared to those with persistent high cardiorespiratory fitness; this held after adjustments for age, sex, socioeconomic status, and pubertal stage.

CONCLUSIONS

Changes in cardiorespiratory fitness during adolescence were associated with HRQoL over a 2-year period. This study suggests that improving cardiorespiratory fitness could be an important strategy in improving the HRQoL of adolescents.

The Incidence and Occurrence of Injuries To Junior Rugby League Players in a Tropical Environment

This study investigated the effect of the environment, jersey color and ground conditions on injury rates in junior rugby-league players in a tropical environment. Injury, environment and ground condition data were collected during each game, over one season (n = 12 rounds). The study investigated three teams (n = 64): one under-16 team in striped jerseys and two under-14 teams in black and orange jerseys. The injury rates for the under-16 team (83.3/1000 hrs) were higher than for the under-14 teams in black (69.9/1000 hrs) and orange (59.9/1000 hrs) jerseys. In the under-16 team, a negative correlation (r = -0.66, p < 0.05) was found between players' injuries and heat index, while in the under-14 team in black jerseys, a positive correlation was observed (r = 0.90, p < 0.01), although in the under-14 team in orange, no significant correlation was found (r = 0.140, p > 0.05). In the under-14 team in black, a significant correlation (r = 0.80, p < 0.01) between players' injuries and the temperature was observed. However, no correlations were found with any other variables per group (p > 0.05) and injury rates were not different between the teams (p > 0.05). While ground conditions had no effect on injury rates, it appears that the heat acted as a protection against injury for teams with striped and orange jerseys. However, black jerseys may put players at an increased risk of injury during hot and humid day games.

New 20 m Progressive Shuttle Test Protocol and Equation for Predicting the Maximal Oxygen Uptake of Korean Adolescents Aged 13-18 Years

Background: Although several equations for predicting VO_2max in children and adolescents have been reported, the validity of application of these equations to the Korean population has not been verified. The purpose of study was to develop and validate regression models to estimate maximal oxygen uptake (VO_2max) using a newly developed 20 m progressive shuttle test (20 m PST) protocol in Korean male (n = 80, 15.3 ± 1.86 years) and female (n = 81, 15.5 ± 1.73 years) adolescents aged 13-18 years. Methods: The modified 20 m PST was performed and the VO_2max was assessed in a sample of 161 participants. The participants underwent a treadmill test (TT) in the laboratory and the modified 20 m PST in a gymnasium. For the validation study, the participants performed the TT with a stationary metabolic cart and the 20 m PST with a portable metabolic cart once. In addition, they performed the 20 m PST two more times to establish test-retest reliability. Results: The mean VO_2max (49.6 ± 8.7 mL·kg^-1·min^-1) measured with the potable metabolic cart was significantly higher than that measured in the graded exercise test with the stationary metabolic cart (46.6 ± 8.9 mL·kg^-1·min^-1, p < 0.001) using the new 20 m PST protocol. The standard error of the estimate (SEE) between these two measurements was 1.35 mL·kg^-1·min^-1. However, the VO_2max derived from the newly developed equation was 46.7 ± 7.3 mL·kg^-1·min^-1 (p > 0.05) and the SEE was 2.90 mL·kg^-1·min^-1. The test and retest trials of the 20 m PST yielded comparable results (laps, r = 0.96; last speed, r = 0.93). Conclusions: Our data suggest that the new 20 m PST protocol is valid and reliable and that the equation developed in this study provides a valid estimate of VO_2max in Korean male and female adolescents aged 13-18 years.

Development and Validation of a PACER Prediction Equation for VO2peak in 10- to 15-Year-Old Youth

Previous progressive aerobic cardiovascular endurance run (PACER) equations were developed to estimate peak oxygen consumption (VO₂peak) from data collected during treadmill running. No equation has been developed using VO₂peak assessed during the PACER. Purpose: To develop and validate a prediction equation to estimate VO₂peak from the PACER in 10- to 15-year-olds. Methods: A sample of 163 youth were recruited to develop (n = 101) and validate (n = 62) a prediction equation. VO₂peak was measured using a portable metabolic unit. Regression analysis yielded a prediction equation that included laps, body mass index, and interaction between sex and age. Correlations and repeated-measures analysis of variances were used to compare the measured and estimated VO₂peak from the new Scott et al equation and 2 commonly used FitnessGram™ (Mahar et al 2011 and Mahar et al 2018) equations, and the impact of sex on predicted VO₂peak. Results: Predicted VO₂peak from the Mahar et al 2011 and 2018 equations was significantly lower compared with measured values, and the Scott et al prediction was not different. The Mahar et al 2018 equation tended to overestimate VO₂peak in males but worked well for females. The Mahar et al 2011 and Scott et al equations revealed no sex differences. Conclusions: The Scott et al equation resulted in a more accurate estimate of VO₂peak, performing equally well for both sexes.

The 20-m Shuttle Run: Assessment and Interpretation of Data in Relation to Youth Aerobic Fitness and Health

Cardiorespiratory fitness (CRF) is a good summative measure of the body's ability to perform continuous, rhythmic, dynamic, large-muscle group physical activity, and exercise. In children, CRF is meaningfully associated with health, independent of physical activity levels, and it is an important determinant of sports and athletic performance. Although gas-analyzed peak oxygen uptake is the criterion physiological measure of children's CRF, it is not practical for population-based testing. Field testing offers a simple, cheap, practical alternative to gas analysis. The 20-m shuttle run test (20mSRT)-a progressive aerobic exercise test involving continuous running between 2 lines 20 m apart in time to audio signals-is probably the most widely used field test of CRF. This review aims to clarify the international utility of the 20mSRT by synthesizing the evidence describing measurement variability, validity, reliability, feasibility, and the interpretation of results, as well as to provide future directions for international surveillance. The authors show that the 20mSRT is an acceptable, feasible, and scalable measure of CRF and functional/exercise capacity, and that it has moderate criterion validity and high to very high reliability. The assessment is pragmatic, easily interpreted, and results are transferable to meaningful and understandable situations. The authors recommend that CRF, assessed by the 20mSRT, be considered as an international population health surveillance measure to provide additional insight into pediatric population health.

PREDICTIVE EQUATIONS OF MAXIMUM OXYGEN CONSUMPTION BY SHUTTLE RUN TEST IN CHILDREN AND ADOLESCENTS: A SYSTEMATIC REVIEW

ABSTRACT Objective: To systematically review the literature as for the level of evidence of predictive equations of VO2peak through the 20-meter shuttle run test (20m-SRT) in children and adolescents. Data sources: Searches were conducted independently by two researchers, according to the procedures adopted by PRISMA, in the electronic databases MEDLINE via PubMed, ScienceDirect, Web of Science, LILACS and SciELO, for articles published until September 2017 in English and Portuguese. The inclusion criteria were: original studies, abstract available, using predictive equations of VO2peak through 20m-SRT, conducted with adolescents and/or children, non-athletes, and mentioning correlation analysis between predicted and measured VO2peak. The level of evidence of equations was based on the risk of bias of the studies using the following criteria: sample number, sample characteristics, and statistical analysis. Data synthesis: Eighteen studies were selected, in which fifteen equations were found and analyzed. The studies had been conducted with samples composed of subjects of both sexes, aged 8 to 19 years. Equations of Léger and Matsuzaka had their level of evidence classified as high, and estimation ranged between r=0.54-0.90 and r=0.65-0.90. Equations by Ruiz, Barnett and Matsuzaka had their level of evidence classified as moderate, and estimation ranged between r=0.75-0.96, r=0.66-0.84 and r=0.66-0.89, respectively. Conclusions: Matsuzaka’s equation presented satisfactory parameters for estimates of VO2peak in children and adolescents. Although not explored in equations, body adiposity and pubertal stage are significantly associated with cardiorespiratory fitness in children and adolescents.

Making a Case for Cardiorespiratory Fitness Surveillance Among Children and Youth

We review the evidence that supports cardiorespiratory fitness (CRF) as an important indicator of current and future health among school-aged children and youth, independent of physical activity levels. We discuss the merit of CRF measurement for population health surveillance and propose the development of CRF guidelines to help support regional, national, and international surveillance efforts.

Peak oxygen uptake cut-points to identify children at increased cardiometabolic risk - The PANIC Study

We aimed to develop cut-points for directly measured peak oxygen uptake ( V ˙ O 2 peak ) to identify boys and girls at increased cardiometabolic risk using different scaling methods to control for body size and composition. Altogether 352 children (186 boys, 166 girls) aged 9-11 years were included in the analyses. We measured V̇O_2peak directly during a maximal cycle ergometer exercise test and lean body mass (LM) by bioelectrical impedance. We computed a sex- and age-specific cardiometabolic risk score (CRS) by summing important cardiometabolic risk factors and defined increased cardiometabolic risk as >1 standard deviation above the mean of CRS. Receiver operating characteristics curves were used to detect V̇O_2peak cut-points for increased cardiometabolic risk. Boys with V̇O_2peak <45.8 mL kg body mass (BM)^-1  min^-1 (95% confidence interval [CI] = 45.1 to 54.6, area under the curve [AUC] = 0.86, P < 0.001) and <63.2 mL kg LM^-1  min^-1 (95% CI =52.4 to 67.5, AUC = 0.65, P = 0.006) had an increased CRS. Girls with V̇O_2peak <44.1 mL kg BM^-1  min^-1 (95% CI = 44.0 to 58.6, AUC = 0.67, P = 0.013) had an increased CRS. V̇O_2peak scaled by BM^-0.49 and LM^-0.77 derived from log-linear allometric modeling poorly predicted increased cardiometabolic risk in boys and girls. In conclusion, directly measured V ˙ O 2 peak <45.8 mL kg BM^-1  min^-1 among boys and <44.1 mL kg BM^-1  min^-1 among girls were cut-points to identify those at increased cardiometabolic risk. Appropriately controlling for body size and composition reduced the ability of cardiorespiratory fitness to identify children at increased cardiometabolic risk.

VALIDITY OF FIELD TESTS TO ESTIMATE CARDIORESPIRATORY FITNESS IN CHILDREN AND ADOLESCENTS: A SYSTEMATIC REVIEW

Objective:

To systematically review the literature to verify the validity of field-tests to evaluate cardiorespiratory fitness (CRF) in children and adolescents.

Data sources:

The electronic search was conducted in the databases: Medline (PubMed), SPORTDiscus, Scopus, Web of Science, in addition to the Latin American databases LILACS and SciELO. The search comprised the period from the inception of each database until February 2015, in English and Portuguese. All stages of the process were performed in accordance with the PRISMA flow diagram.

Data synthesis:

After confirming the inclusion criteria, eligibility, and quality of the studies, 43 studies were analyzed in full; 38 obtained through the searches in the electronic databases, and 5 through private libraries, and references from other articles. Of the total studies, only 13 were considered high quality according to the adopted criteria. The most commonly investigated test in the literature was the 20-meter shuttle run (SR-20 m), accounting for 23 studies, followed by tests of distances between 550 meters and 1 mile, in 9 studies, timed tests of 6, 9, and 12 minutes, also 9 studies, and finally bench protocols and new test proposals represented in 7 studies.

Conclusions:

The SR-20-m test seems to be the most appropriate to evaluate the CRF of young people with the equation of Barnett, recommended to estimate VO₂ peak. As an alternative for evaluating CRF, the 1-mile test is indicated with the equation proposed by Cureton for estimating VO₂ peak.

The efficacy of two activity-based interventions in adolescents with Developmental Coordination Disorder

BACKGROUND

Adolescents with Developmental Coordination Disorder (DCD) usually experience psychomotor difficulties that affect their participation in everyday tasks and sports. Without effective intervention, adolescents show persistent motor deficits through adulthood. It is therefore critical to develop interventions to address the specific needs of this population. Studies evaluating the impact of motor interventions among adolescents with DCD are limited.

AIM

The study evaluated the efficacy of two activity-based motor interventions in female adolescents with DCD.

METHODS AND PROCEDURES

Forty-three female participants (Mean±SD: 14.3±1.1years) were identified as having DCD using the DSM-5 criteria. They were randomly assigned to either Task-oriented Functional Training (TFT) or Wii training. Both groups received 45min training per week for 14 weeks. Outcome measures included isometric muscular strength, motor proficiency, functional performance and participation in activities of daily living (ADL).

OUTCOMES AND RESULTS

At the conclusion of the intervention, the two groups had significant improvement in muscular strength, motor proficiency, running and agility, predilection for physical activity and generalized self-efficacy. However, there was no difference in outcomes for the two interventions.

CONCLUSIONS AND IMPLICATIONS

The findings highlight the potential benefits of activity-based motor interventions in reducing impairments, improving functional performance, and enhancing participation. These results support previous findings on the efficacy of task-oriented interventions and demonstrate the value of these approaches at all levels of functioning.

Temporal trends in the cardiorespiratory fitness of children and adolescents representing 19 high-income and upper middle-income countries between 1981 and 2014

OBJECTIVE

To estimate international and national temporal trends in the cardiorespiratory fitness (CRF) of children and adolescents and to examine relationships between temporal trends in CRF and temporal trends in broad socioeconomic and health-related indicators across countries.

METHODS

Data were obtained from a systematic search of studies that explicitly reported 20 m shuttle run test (a validated measure of CRF) descriptive data on apparently healthy individuals aged 9-17 years. Following the estimation of relative peak oxygen uptake (mL/kg/min) as a measure of CRF, sample-weighted temporal trends were estimated at the country-sex-age level using best-fitting linear or polynomial regression models relating the year of testing to mean CRF. Poststratified population-weighted mean changes in absolute and per cent CRF were estimated. Pearson's correlations were used to describe the association between linear temporal trends in CRF and linear temporal trends in broad socioeconomic and health-related indicators.

RESULTS

Temporal trends were estimated from 965 264 children and adolescents from 19 high-income and upper middle-income countries between 1981 and 2014, using data from 137 studies. Collectively, there was a moderate decline in CRF of 3.3 mL/kg/min (95% CI -3.5 to -3.1), equivalent to a decline of 7.3% (95% CI -7.8% to -6.7%) over the 33-year time period. This international decline diminished with each decade and stabilised near zero around 2000. The decline was larger for boys than girls and was similar for children and adolescents. Trends also differed in magnitude and direction between countries, with most showing declines. There was a strong negative association between country-specific trends in income inequality (Gini index) and trends in CRF across 18 countries; meaning, countries approaching income equality had more favourable trends in CRF.

CONCLUSIONS

There has been a substantial decline in CRF since 1981, which is suggestive of a meaningful decline in population health. However, the international trend in CRF has not followed the anticipated trajectory, diminishing and stabilising with negligible change since 2000. CRF data are needed from children in low-income and middle-income countries to more confidently determine true international trends and determine whether temporal trends are similar to those observed in high-income and upper middle-income countries.

[Body composition and physical fitness in Colombian high school students from Ibagué]

INTRODUCTION

Body composition and other components of physical fitness have proved to be important markers of health condition.

OBJECTIVE

To analyze body composition and physical fitness in Colombian students from public high schools of Ibagué, as well as to study differences between sexes and age groups, and establish correlations between some of the variables.

MATERIALS AND METHODS

The sample consisted of 1,253 students (601 males; 652 females), with an age range of 10-20 years. The ALPHA-Fitness test (extended version) was applied. Body Mass Index (BMI), waist circumference and fat percentage were assessed.

RESULTS

Differences between sexes were found in the variables studied, with greater BMI and fat percentage among females (20.6 kg/m2 vs. 19.4 kg/m2 and 26.1% vs. 16.8%, respectively); however, waist circumference was greater in males (69.6 cm vs. 67.9 cm), who also showed better fitness in the rest of the physical tests (p<0.05). In both sexes, age was associated to increases in BMI (p<0.05), and among females to fat percentage as well (p<0.05); among males it was the opposite, as in them, age was inversely associated to fat percentage (p<0.05). For the rest of the physical tests, age was positively associated to fitness both in men and women, except for maximal oxygen uptake (VO2 max). Correlations were found between some of the variables studied.

CONCLUSIONS

Adiposity was significantly greater in females than in males (p<0.05). Males showed better levels of aerobic, musculoskeletal and motor capacities.

Review of criterion-referenced standards for cardiorespiratory fitness: what percentage of 1 142 026 international children and youth are apparently healthy?

PURPOSE

To identify criterion-referenced standards for cardiorespiratory fitness (CRF); to estimate the percentage of children and youth that met each standard; and to discuss strategies to help improve the utility of criterion-referenced standards for population health research.

METHODS

A search of four databases was undertaken to identify papers that reported criterion-referenced CRF standards for children and youth generated using the receiver operating characteristic curve technique. A pseudo-dataset representing the 20-m shuttle run test performance of 1 142 026 children and youth aged 9-17 years from 50 countries was generated using Monte Carlo simulation. Pseudo-data were used to estimate the international percentage of children and youth that met published criterion-referenced standards for CRF.

RESULTS

Ten studies reported criterion-referenced standards for healthy CRF in children and youth. The mean percentage (±95% CI) of children and youth that met the standards varied substantially across age groups from 36%±13% to 95%±4% among girls, and from 51%±7% to 96%±16% among boys. There was an age gradient across all criterion-referenced standards where younger children were more likely to meet the standards compared with older children, regardless of sex. Within age groups, mean percentages were more precise (smaller CI) for younger girls and older boys.

CONCLUSION

There are several CRF criterion-referenced standards for children and youth producing widely varying results. This study encourages using the interim international criterion-referenced standards of 35 and 42 mL/kg/min for girls and boys, respectively, to identify children and youth at risk of poor health-raising a clinical red flag.

[Analysis of adiposity and physical fitness in young Colombian students]

INTRODUCTION

Body mass index and physical fitness are important markers of a healthy life style. Objective: To analyze adiposity and physical fitness in young students from public schools in Armenia, Colombia, and examine differences between sex and age groups. Materials and methods: We analyzed 1,150 students: 46.6% (n=536) males and 53.4% (n=614) females, with an age range of 10 to 20 years (15.45 ± 2.52). Physical fitness was evaluated by the Course-Navette test, the Horizontal Jump test, the 20-meter run test and the Sit-and-Reach test. Body mass index and body fat were also assessed. Results: Compared with males, females had significantly higher adiposity levels, body mass index (20.4 vs. 19.5) and body fat (23% vs. 11%). Males had higher levels of physical fitness in all the variables analyzed, with statistically significant differences (p<0.001), except in flexibility, where females achieved better results (3.1cm vs.1 3cm; p=0.003). In both sexes, body mass index increased with age (p<0.001). However, body fat decreased with age in males (p<0.001) and increased in females (p<0.001). In males, physical fitness improved with age in all variables. In females, no significant differences were found between age groups except in the maximal oxygen uptake (VO2max, p<0.001). Conclusion: Adiposity was significantly higher in women than in men. Males had a better level of physical fitness than females, except in flexibility. Physical fitness improved significantly with age in males, but did not change in females.

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.

Sprint interval training (SIT) is an effective method to maintain cardiorespiratory fitness (CRF) and glucose homeostasis in Scottish adolescents

The present study examined the physiological impact of a school based sprint interval training (SIT) intervention in replacement of standard physical education (SPE) class on cardio-respiratory fitness (CRF) and glucose homeostasis during the semester following summer vacation. Participants (n=49) were randomly allocated to either intervention (SIT; n=26, aged 16.9 ± 0.3 yrs) or control group who underwent standard physical education (SPE; n=23, aged 16.8 ± 0.6 yrs). CRF (VO₂max) and glucose homeostasis were obtained prior-to and following 7 weeks of SIT exercise. Significant group x time interaction was observed for CRF (P < 0.01) with non-significant trends for fasting insulin (P= 0.08), and HOMA-IR (P=0.06). CRF decreased (P < 0.01) in SPE such that POST intervention CRF was significantly lower (P< 0.05) in SPE. Fasting plasma glucose (P < 0.01), insulin (P< 0.01) and HOMA-IR (P< 0.01) increased significantly amongst SPE. The main finding of the present study is that 7-weeks of SIT exercise is an effective method of maintaining (but not improving) CRF and fasting insulin homeostasis amongst school-going adolescents. SIT exercise demonstrates potential as a time efficient physiological adjunct to standard PE class in order to maintain CRF during the school term.

Geographical variation in health-related physical fitness and body composition among Chilean 8th graders: a nationally representative cross-sectional study

PURPOSE

In addition to excess adiposity, low cardiorespiratory fitness (CRF) and low musculoskeletal fitness (MSF) are important independent risk factors for future cardio-metabolic disease in adolescents, yet global fitness surveillance in adolescents is poor. The objective of this study was to describe and investigate geographical variation in levels of health-related physical fitness, including CRF, MSF, body mass index (BMI), and waist circumference (WC) in Chilean 8th graders.

METHODS

This cross-sectional study was based on a population-based, representative sample of 19,929 8th graders (median age = 14 years) in the 2011 National Physical Education Survey from Chile. CRF was assessed with the 20-meter shuttle run test, MSF with standing broad jump, and body composition with BMI and WC. Data were classified according to health-related standards. Prevalence of levels of health-related physical fitness was mapped for each of the four variables, and geographical variation was explored at the country level by region and in the Santiago Metropolitan Area by municipality.

RESULTS

Girls had significantly higher prevalence of unhealthy CRF, MSF, and BMI than boys (p<0.05). Overall, 26% of boys and 55% of girls had unhealthy CRF, 29% of boys and 35% of girls had unhealthy MSF, 29% of boys and 44% of girls had unhealthy BMI, and 31% of adolescents had unhealthy WC. High prevalence of unhealthy fitness levels concentrates in the northern and middle regions of the country and in the North and Southwest sectors for the Santiago Metropolitan Area.

CONCLUSION

Prevalence of unhealthy CRF, MSF, and BMI is relatively high among Chilean 8th graders, especially in girls, when compared with global estimates. Identification of geographical regions and municipalities with high prevalence of unhealthy physical fitness presents opportunity for targeted intervention.

Critical measurement issues/challenges in assessing aerobic capacity in youth

We discuss current measurement issues related to tests of aerobic capacity in the FITNESSGRAM. Interpretation of tests of aerobic capacity is difficult because the criterion measure of aerobic capacity, maximal rate of oxygen uptake (VO2(max)) expressed relative to body weight, is inversely related to body fatness and body mass index (BMI). This association cannot be easily be eliminated in a way that maintains the units commonly used to express aerobic capacity (i.e., mL x kg(-1) x min(-1)) and is understandable to typical test users. Requiring the measurement of BMI to predict VO2(max) creates practical problems for users by: (a) uncoupling the relation of predicted VO2(max) to physical performance on the 1-mile run/walk (MRW) and the Progressive Aerobic Cardiovascular Endurance Run (PACER) tests, (b) making explicit the influence of body composition on the ability of children to achieve the aerobic capacity healthy fitness zone, and (c) creating a barrier for users who cannot measure height and weight. The use of test equating improved classification agreement between the MRW and PACER tests but required measurement of BMI to estimate aerobic capacity from the PACER. A new equation to predict aerobic capacity that does not require BMI was recently introduced to address user concerns. This change will improve ease of use of the Fitnessgram with little effect on prediction accuracy but will likely result in poorer classification agreement between the MRW and PACER tests. Although considerable progress has been made in addressing issues related to assessment of aerobic capacity in youth, future work is needed to carefully balance the issues of prediction accuracy, test feasibility, and test agreement.

Desenvolvimento de equações para estimativa do VO2PICO pelo teste de 9 minutos

OBJETIVO: Desenvolver e validar modelos matemáticos para predição do VO2pico em crianças e adolescentes, por meio da utilização do teste de campo de corrida/caminhada de 9 minutos.MÉTODOS: Foram avaliados 211 escolares, de sete a 12 anos de idade, de ambos os sexos, regularmente matriculados em duas escolas do Município de Londrina - PR, sendo 141 escolares separados para amostra de desenvolvimento e 70 para validação das equações desenvolvidas. As medidas avaliadas foram: massa corporal, estatura, espessuras de dobras cutâneas (tricipital e subescapular), além da maturação biológica. Os testes de corrida/caminha de 9 minutos foram realizados em pista de atletismo e a análise direta do VO2pico (mL/kg/min ) realizada em laboratório, com analisador de gás portátil, através um teste incremental em esteira rolante. O desenvolvimento das equações foi realizado através da análise de regressão linear pelo método stepwise e a validação foi realizada pelos testes matemáticos específicos levando em consideração uma significância de 5% para todas as análises.RESULTADOS: A equação geral para a amostra total foi VO2pico= 24,506+16,672 (maturação, 0=pré e 1=púbere e pós) - 0,346 (Σ DC) + 5,187 (sexo, 0=F e 1=M) + 0,009 (distância) com um r=0,742 e EPE=9,149 mL/kg/min e sua validação apresentou r=0,570, CCI= 0,68, limites de concordância de -1,4 mL/kg/min, EPE=8,39 mL/kg/min e CV= 21,94%.CONCLUSÃO: Conclui-se que a equação generalizada desenvolvida fornece uma estimativa válida do VO2pico em crianças e adolescentes de sete a 12 anos de idade.

Measurement agreement between estimates of aerobic fitness in youth: the impact of body mass index

PURPOSE

The purpose of this study was to examine the impact of body mass index (BMI) on the agreement between aerobic capacity estimates from different Progressive Aerobic Cardiorespiratory Endurance Run (PACER) equations and the Mile Run Test.

METHOD

The agreement between 2 different tests of aerobic capacity was examined on a large data set from 2 suburban school districts (n = 1,686 youth in Grades 3-10). Difference estimates between the Mile Run Test and several PACER equations were computed, and residuals were examined using cluster analysis. The implication of the discrepancy between these tests was also examined using FITNESSGRAM health-related standards for BMI. Comparisons were made against corresponding estimates of peak oxygen consumption from the Mile run because this equation is more established.

RESULTS

Results supported a 2-cluster solution. The discrepancy between tests was higher in participants with higher BMI scores (Z scores for residuals in this group ranged from -0.07 to 1.57). BMI was able to explain 30% to 34% of the disagreement between the Mile and different PACER equations of aerobic fitness. Classification analyses revealed that kappa scores were lower among PACER equations that do not include a BMI term (kappa = .12-.34 vs. .59-.81). Overall, the test-equating approach used in the Fitnessgram program to process PACER data had better agreement than alternative PACER equations that included BMI.

CONCLUSION

The results support the inclusion of BMI in prediction equations used to estimate aerobic capacity from the PACER.

The ability of the PACER to elicit peak exercise response in youth [corrected]

PURPOSE

A graded exercise test (GXT) is the standard laboratory method of determining peak aerobic fitness (V˙O2peak). The FITNESSGRAM's Progressive Aerobic Cardiovascular Endurance Run (PACER) test is commonly used to estimate the peak oxygen consumption in the youth in the field.The objective of this study is to compare the peak physiological variables and RPEpeak during a treadmill GXT and the PACER test in 10- to 15-yr-old youths.

METHODS

Participants (20 boys and 25 girls, 12.7 ± 1.7 yr) completed the PACER and treadmill GXT in a randomized order, separated by at least 24 h. HRpeak was measured via telemetry, V˙O2peak and RERpeak were measured using a portable metabolic system, and participants reported RPEpeak at the end of each test.

RESULTS

No significant differences were found between the GXT and PACER HRpeak (197 vs 197 beats·min), RERpeak (1.13 vs 1.12), V˙O2peak (45.0 vs 45.9 mL·kg·min), and RPEpeak (8.4 vs 8.3). The SE of the measurement between the GXT V˙O2peak and PACER V˙O2peak was 1.4 mL·kg·min.

CONCLUSIONS

It appears that the PACER elicits similar peak exercise responses compared with a treadmill GXT. The PACER can also be administered for fitness and functional capacity assessments in healthy and clinical populations.