Low physical fitness is associated with increased risk of cardiovascular disease (CVD) in adults and a higher incidence of CVD risk factors in children. Our aim was to compare the aerobic performance of Canadian children in 2004 with that of children measured 2 decades ago. We conducted a cross-sectional comparison of 2 data sets: (a) a 2004 cohort (n = 252) and (b) data from Leger’s 1981 cohort (n = 2,151). Performance was assessed using Leger’s 20 m Shuttle Run Test. First, we compared VO2max by cohort (in age and sex subgroups). Second, we used 1981 derived data, to re-create the original distribution curves, then calculated a 1981 equivalent percentile for each 2004 cohort child. We found that aerobic performance was lower at all ages in 2004 compared with 1981 (p < .01). Thus, the 50th percentile for fitness of children in 2004 was equivalent to that of children in the lowest 20% of fitness in 1981. We support the view that the performance of children on aerobic fitness tests is declining.
Search Results
Secular Changes in Shuttle-Run Performance: A 23-Year Retrospective Comparison of 9- to 11-Year-Old Children
Katharine E. Reed, Darren E.R. Warburton, Crystal L. Whitney, and Heather A. McKay
Developmental Coordination Disorder and Cardiorespiratory Fitness in Children
John Cairney, John A. Hay, Brent E. Faught, Andreas Flouris, and Panagiota Klentrou
It is not known whether children with Developmental Coordination Disorder (DCD) have lower cardiorespiratory fitness (CRF) than children without the disorder, or whether this relationship varies by age and gender. These issues are examined using a cross-sectional assessment of children 9-14 years of age (N = 549). Participants were screened for DCD using the short form Bruininks-Oseretsky Test of Motor Proficiency (BOTMP-SF). A BOTMP-SF age-adjusted standard score at or below the 10th percentile rank on the BOTMP-SF was required to classify a diagnosis for probable DCD. CRF was determined from each participant’s predicted peak-aerobic power using the Léger 20-m shuttle-run test. Children with DCD report lower CRF than children without the disorder and are more likely to be in a high-risk group (≤ 20th percentile in peak VO2). Moreover, 70% of boys with DCD scored at or below the 20th percentile in peak VO2. Further research in a laboratory setting should be conducted to confirm these findings.
Number of Daily Steps to Discriminate Abdominal Obesity in a Sample of Brazilian Children and Adolescents
Alex Pinheiro Gordia, Teresa Maria Bianchini de Quadros, Jorge Mota, and Luciana Rodrigues Silva
Purpose:
Weight status-referenced pedometer step-count guidelines for young people have been developed for populations from high-income countries and may not be applicable to middle- and low-income countries. The objectives of this study were 1) to develop cut-off points for pedometer-determined step count in young Brazilians using waist circumference (WC) as a reference criterion, and 2) to analyze the capacity of previous recommendations to discriminate abdominal obesity in the sample studied.
Methods:
A cross-sectional study was conducted on 1,044 schoolchildren (456 boys) aged 6–17 years from Northeastern Brazil. WC was measured and daily step counts were determined with a pedometer.
Results:
The area under the curve (AUC) of step count was significant for boys (AUC = 0.55; 95%CI: 0.50–0.59) and girls (AUC = 0.57; 95%CI: 0.53–0.61). Our cut-off points (14,414 and 11,355 steps for boys and girls, respectively) were more balanced in terms of sensitivity and specificity compared with previous recommendations. The use of previous guidelines to classify step count in the sample provided very low sensitivity or specificity and wide variation in the prevalence of insufficient physical activity (39.3–77.0%).
Conclusions:
A universal step-count recommendation for young people may not be adequate and specific guidelines seem to be necessary for different countries or regions.
Active School Lesson Breaks Increase Daily Vigorous Physical Activity, but Not Daily Moderate to Vigorous Physical Activity in Elementary School Boys
Andrew N. Wilson, Timothy Olds, Kurt Lushington, Somayeh Parvazian, and James Dollman
Purpose:
Brief classroom-based episodes of physical activity (active lesson breaks, ALBs) have improved schoolchildren’s classroom behaviors in some studies, and may also increase the likelihood of children meeting the recommended daily minutes of moderate to vigorous physical activity (MVPA). However, there is emerging evidence that increases in physical activity at particular times of the day may lead to compensatory declines at other times. This study explored evidence for compensatory declines in response to a 10 min ALB during the school day.
Method:
Thirty-eight 12-year-old boys from a single elementary school completed intervention and control conditions in a cross-over design, with each phase lasting one week. The intervention consisted of a single 10-min active lesson break delivered on each of three days in the intervention week. Twenty-four hour accelerometry was used to quantify moderate and vigorous physical activity.
Results:
ALBs increased in-school MVPA by 5.8 min (p < .0001), but overall daily MVPA was similar between intervention and control conditions (77.2 vs 77.4 min/d, p > .05), However, vigorous physical activity increased significantly over the whole day (11.2 vs 8.9 min, p = .0006).
Conclusion:
A brief episode of classroom-based play led to a modest increase in vigorous physical activity in elementary school students, but did not increase MVPA across the day.
Normative Values for Cardiorespiratory Fitness Testing Among US Children Aged 6-11 years
Jaime J. Gahche, Brian K. Kit, Janet E. Fulton, Dianna D. Carroll, and Thomas Rowland
Background:
Nationally representative normative values for cardiorespiratory fitness (CRF) have not been described for US children since the mid 1980s.
Objective:
To provide sex- and age-specific normative values for CRF of US children aged 6–11 years.
Methods:
Data from 624 children aged 6–11 years who participated in the CRF testing as part of the 2012 National Health and Nutrition Examination Survey National Youth Fitness Survey, a cross-sectional survey, were analyzed. Participants were assigned to one of three age-specific protocols and asked to exercise to volitional fatigue. The difficulty of the protocols increased with successive age groups. CRF was assessed as maximal endurance time (min:sec). Data analysis was conducted in 2016.
Results:
For 6–7, 8–9, 10–11 year olds, corresponding with the age-specific protocols, mean endurance time was 12:10 min:sec (95% CI: 11:49–12:31), 11:16 min:sec (95% CI: 11:00–11:31), and 10:01 min:sec (95% CI: 9:37–10:25), respectively. Youth in the lowest 20th percentile for endurance time were more likely to be obese, to report less favorable health, and to report greater than two hours of screen time per day.
Conclusions:
These data may serve as baseline estimates to monitor trends over time in CRF among US children aged 6–11 years.
Physiological, Perceptual and Performance Responses Associated With Self-Selected Versus Standardized Recovery Periods During a Repeated Sprint Protocol in Elite Youth Football Players: A Preliminary Study
Neil Gibson, Callum Brownstein, Derek Ball, and Craig Twist
Purpose:
To examine the physiological and perceptual responses of youth footballers to a repeated sprint protocol employing standardized and self-selected recovery.
Methods:
Eleven male participants (13.7 ± 1.1 years) performed a repeated sprint assessment comprising 10 × 30 m efforts. Employing a randomized cross-over design, repeated sprints were performed using 30 s and self-selected recovery periods. Heart rate was monitored continuously with ratings of perceived exertion (RPE) and lower body muscle power measured 2 min after the final sprint. The concentration of blood lactate was measured at 2, 5 and 7 min post sprinting. Magnitude of effects were reported using effect size (ES) statistics ± 90% confidence interval and percentage differences. Differences between trials were examined using paired student t tests (p < .05).
Results:
Self-selected recovery resulted in most likely shorter recovery times (57.7%; ES 1.55 ± 0.5; p < .01), a most likely increase in percentage decrement (65%; ES 0.36 ± 0.21; p = .12), very likely lower heart rate recovery (-58.9%; ES -1.10 ± 0.72; p = .05), and likely higher blood lactate concentration (p = .08–0.02). Differences in lower body power and RPE were unclear (p > .05).
Conclusion:
Self-selected recovery periods compromise repeated sprint performance.
Serum Adiponectin Levels and Cardiorespiratory Fitness in Nonoverweight and Overweight Portuguese Adolescents: The LabMed Physical Activity Study
César Agostinis-Sobrinho, Carla Moreira, Sandra Abreu, Luís Lopes, José Oliveira-Santos, Jostein Steene-Johannessen, Jorge Mota, and Rute Santos
Purpose:
This study examined the independent associations between cardiorespiratory fitness and circulating adiponectin concentration in adolescents, controlling for several potential covariates.
Methods:
This is a cross-sectional study in Portuguese adolescents. A sample of 529 (267 girls) aged 12–18 years were included and categorized as overweight and nonoverweight. Cardiorespiratory fitness was assessed by 20 meters shuttle run test. We measured serum adiponectin, high-sensitivity C-reactive protein, fasting glucose, insulin and HDL-cholesterol.
Results:
After adjustment for age, sex, pubertal stage, adherence to the Mediterranean diet, socioeconomic status, body fat percentage, insulin resistance, HDL-cholesterol and C-reactive protein, regression analysis showed a significant inverse association between adiponectin and cardiorespiratory fitness in nonoverweight participants (B=-0.359; p < .042). Analysis of covariance showed a significant difference between the highest cardiorespiratory fitness Healthy zone (above healthy zone) and the Under and the Healthy cardiorespiratory fitness zones in nonoverweight adolescents (p = .03) (F (2, 339) = 3.156, p < .001).
Conclusion:
Paradoxically, serum adiponectin levels are inversely associated with cardiorespiratory fitness in nonoverweight, but not in overweight adolescents. In nonoverweight adolescents, those with highest levels of cardiorespiratory fitness (above healthy zone) presented lower levels of adiponectin compared with those in Under and Healthy cardiorespiratory fitness zones.
Assessment of the 5-Minute Oxygen Uptake Efficiency Slope in Children With Obesity
Katrin A. Dias, Concetta E Masterson, Matthew P. Wallen, Arnt E. Tjonna, Mansoureh S. Hosseini, Peter S.W. Davies, Peter A. Cain, Gary M. Leong, Ross Arena, Charlotte B. Ingul, and Jeff S. Coombes
Purpose:
Poor cardiorespiratory fitness is associated with increased all cause morbidity and mortality. In children with obesity, maximum oxygen uptake (V̇O2max) may not be achieved due to reduced motivation and peripheral fatigue. We aimed to identify a valid submaximal surrogate for V̇O2max in children with obesity.
Method:
Ninety-two children with obesity (7–16 years) completed a maximal exercise treadmill test and entered a three-month exercise and/or nutrition intervention after which the exercise test was repeated (n = 63). Participants were required to reach V̇O2max to be included in this analysis (n = 32 at baseline and n = 13 at both time-points). The oxygen uptake efficiency slope (OUES) was determined as the slope of the line when V̇O2 (L/min) was plotted against log V̇E. Associations between the maximal OUES, submaximal OUES (at 3, 4, 5 and 6 min of the exercise test) and V̇O2max were calculated.
Results:
In the cross-sectional analysis, V̇O2max (L/min) was strongly correlated with 5-min OUES independent of Tanner puberty stage and sex (R 2 = .80, p < .001). Longitudinal changes in V̇O2max were closely reflected by changes in 5-min OUES independent of change in percent body fat (R 2 = .63, p < .05).
Conclusion:
The 5-min OUES is a viable alternative to V̇O2max when assessing children with obesity.
Physical Activity, Sedentary Behavior and the Risk of Overweight and Obesity in School-Aged Children
Eimear Keane, Xia Li, Janas M. Harrington, Anthony P. Fitzgerald, Ivan J. Perry, and Patricia M. Kearney
Purpose:
Globally, public health policies are targeting modifiable lifestyle behaviors. We explore the independent association of moderate-to-vigorous physical activity (MVPA) and sedentary behavior on the risk of childhood overweight/obesity.
Method:
A cross-sectional survey of children aged 8–11 years (N = 826). Objective body mass index was used to classify children as normal weight or overweight/obese. Children wore wrist-worn Geneactiv accelerometers for 7-days and thresholds were applied to categorize MVPA and sedentary time. Screen time (ST) was parent reported. Poisson regression examined the independent association of (1) MVPA (2), objective sedentary time and (3) ST on the risk of overweight/obesity.
Results:
Overall, 23.7% (95% CI, 20.8–26.6%) of children were overweight/obese. On average, children spent 10.8% of waking time at MVPA and 61.3% sedentary. One-fifth (22.1%, 95% CI, 19.3–25.0%) of children achieved MVPA recommendations (≥ 60 min each day) and 17.5% (95% CI, 14.9–20.1%) met ST recommendations (<2 hr per day). Time spent at MVPA was inversely associated with the risk of overweight/obese independent of total sedentary time. Total time spent sedentary was not associated with overweight/obese independent of MVPA. ST was associated with an increased risk of overweight/obese independent of physical activity.
Conclusion:
Few schoolchildren met physical activity and screen time recommendations suggesting population based measures are needed.
Longitudinal Associations Between Sedentary Behavior of Adolescent Girls, Their Mothers, and Best Friends
Lennart Raudsepp and Eva-Maria Riso
Purpose:
The objective of this study was to examine the prospective relationship and changes in sedentary behavior between adolescent girls, their mothers and best friends over time.
Method:
The results are based on 122 girls aged 11–12 years at baseline measurement, their mothers and best friends who completed ecological momentary assessment diary for the assessment of sedentary behavior. All measurements were taken at 3 time points separated by one year. We used structural equation modeling to examine associations among sedentary behavior of adolescent girls, their mothers and best friends.
Results:
A linear growth model for adolescent girls’ and their best friends’ sedentary behavior fit the data well, revealing an overall significant increase in sedentary behavior across time. Initial levels of mothers’ and best friends’ sedentary behavior were positively related with sedentary behavior of adolescent girls. The changes of adolescent girls’ and best friends’ sedentary behavior across 3 years were positively related. Cross-lagged panel analysis demonstrated significant reciprocal effects between adolescent girls’ and best friends’ sedentary behavior. Mothers’ sedentary behavior at baseline predicted daughters’ sedentary behavior at 1-year follow-up and vice versa.
Conclusion:
From early to midadolescence, changes in adolescent girls’ sedentary behavior were associated with changes in best friends’ sedentary behavior. These findings suggest reciprocal associations between sedentary behavior of adolescent girls and their best friends.