Background: The role of muscle fitness in controlling cardiometabolic risk factors during childhood is incompletely understood. Methods: A prospective observational design including 6- to 11-year-old children (n = 512) was used to study associations between 1.5-year changes in handgrip strength, standing vertical jump displacement, the short shuttle run, and a composite of these with changes in composite and single cardiometabolic risk markers. The authors modeled sequential mixed linear regressions controlling for changes in cardiorespiratory fitness, waist circumference, and other putative confounding variables. Results: Statistically significant associations, standardized beta (95% confidence intervals), were observed between changes in composite muscle fitness −0.19 (−0.30 to −0.07), muscular strength −0.15 (−0.25 to −0.06), and agility 0.14 (0.04 to 0.23), but not muscular power −0.06 (−0.14 to 0.03) with changes in the composite risk score. In sex-stratified analysis, associations were robust in girls, but not in boys. Control for changes in cardiorespiratory fitness and waist circumference greatly attenuated associations. Changes in muscle fitness were strongly associated with changes in waist circumference in both girls −0.21 (−0.37 to −0.05) and boys −0.23 (−0.35 to −0.11) after controlling for cardiorespiratory fitness. Conclusions: Our data support a unique role of muscle fitness in the promotion of metabolic health and prevention of excess adipose tissue accumulation in children.
Jakob Tarp, Anna Bugge, Niels Christian Møller, Heidi Klakk, Christina Trifonov Rexen, Anders Grøntved and Niels Wedderkopp
Rodrigo Antunes Lima, Lisbeth Runge Larsen, Anna Bugge and Lars Bo Andersen
Purpose: The current investigation aimed to investigate the longitudinal association between physical fitness and academic performance over 3 years in adolescents. A secondary aim was to determine to what extent waist circumference mediated the association between physical fitness and academic performance. Methods: For the current study, 1020 students from first grade [mean age: 7.87 (0.34) y] to fifth grade [mean age: 11.87 (0.37) y] were monitored annually for 3 years (2010–2013). Physical fitness was assessed using the Andersen test, 5 × 5-m shuttle run, jump height, and grip strength tests and by constructing a composite score combining all 4 fitness tests. Academic performance was assessed by national standardized tests in Danish language and math. Generalized structural equation modeling was used to evaluate the relationships between these variables. Results: The Andersen test (standardized β = 0.15 SD), shuttle run (β = −0.18 SD), jump height (β = 0.10 SD), and the fitness composite score (β = 0.23 SD) were positively associated with academic performance over 3 years. In addition, waist circumference partially mediated the association between physical fitness and academic performance. Conclusion: Thus, physical fitness abilities should be stimulated during childhood and early adolescence because of their positive association with academic performance.
Glen Nielsen, Anna Bugge, Bianca Hermansen, Jesper Svensson and Lars Bo Andersen
This study investigates the influence of school playground facilities on children’s daily physical activity.
Participants were 594 school children measured at preschool (age 6 to 7 years) and 3 years later in third grade (518 children age 9 to 10 years) from 18 schools in 2 suburban municipalities in Denmark. Physical activity data were obtained using accelerometers. These were related to the number of permanent play facilities in school grounds and the school playground area (m2).
The number of play facilities in the school grounds was positively associated with all measures of children’s activity. In preschool every 10 additional play facilities the children had access to was associated with an increase in the average accelerometer counts of 14% (r = .273, P < .001) in school time and 6.9% (r = .195, P < .001) overall. For the children in third grade, access to 10 additional play facilities was associated with an increase in school time activity level of 26% (r = .364, P < .001) and an increase in overall activity level of 9.4% (r = .211, P < .001). School playground area did not affect activity levels independently of the number of permanent play facilities.
Increasing the number of play facilities in primary school playgrounds may increase the level of children’s daily physical activity.
Rodrigo Antunes Lima, Karin A. Pfeiffer, Niels Christian Møller, Lars Bo Andersen and Anna Bugge
Background: To analyze the longitudinal association between academic performance and moderate to vigorous physical activity (MVPA), vigorous physical activity (VPA), and sedentary (SED) in a 3-year longitudinal study. A secondary aim was to determine whether MVPA and VPA were indirectly related with academic performance via waist circumference (WC). Methods: Physical activity (PA) and SED were measured by accelerometers. Academic performance was assessed by national tests in Danish and Math. Structural equation modeling was performed to evaluate whether MVPA, VPA, and SED were associated with academic performance and the potential PA–academic performance indirect relationship via WC. Results: MVPA and VPA were associated with academic performance, mediated via WC (β = 0.036; 95% confidence interval [CI], 0.002 to 0.070 and β = 0.096; 95% CI, 0.027 to 0.164, respectively). SED was directly associated with academic performance (β = 0.124; 95% CI, 0.030 to 0.217, MVPA model and β = 0.132; 95% CI, 0.044 to 0.221, VPA model). WC was negatively associated with academic performance. Conclusions: Both PA and SED time were positively associated with academic performance. Based on this, PA should be encouraged in children and youth not only to promote physical health but also to promote academic performance. Future studies should distinguish between school-related SED and other SED activities and their relationship with academic performance.
Magnus Dencker, Bianca Hermansen, Anna Bugge, Karsten Froberg and Lars B. Andersen
This study investigated the predictors of aerobic fitness (VO2PEAK) in young children on a population-base. Participants were 436 children (229 boys and 207 girls) aged 6.7 ± 0.4 yrs. VO2PEAK was measured during a maximal treadmill exercise test. Physical activity was assessed by accelerometers. Total body fat and total fat free mass were estimated from skinfold measurements. Regression analyses indicated that significant predictors for VO2PEAK per kilogram body mass were total body fat, maximal heart rate, sex, and age. Physical activity explained an additional 4–7%. Further analyses showed the main contributing factors for absolute values of VO2PEAK were fat free mass, maximal heart rate, sex, and age. Physical activity explained an additional 3–6%.
Kyle M. Morrison, Anna Bugge, Bianca El-Naaman, Joey C. Eisenmann, Karsten Froberg, Karin A. Pfeiffer and Lars Bo Andersen
This study examined the interrelationships among physical activity (PA), percent body fat (%BF), and motor performance (MP) in 498 6- to 8-year-old Danish children. PA was assessed by accelerometer, %BF was calculated from skinfolds, and the Koordinations Test für Kinder along with a throwing accuracy test was used to assess MP. PA was not correlated with %BF, but was significantly correlated with MP. The strongest correlations existed between %BF and MP. Low %BF/High PA had higher MP scores compared with High %BF/Low PA, and within the High %BF groups MP was higher in the High PA versus Low PA group. When comparing PA by %BF and MP groups, boys in the Low %BF/High MP had higher PA than both the Low %BF/Low MP and High %BF/Low MP groups. In girls, PA was highest in the High %BF/High MP group. This study highlights the complex interrelationships among PA, %BF, and MP in children and the need to develop fundamental motor skills during childhood.
Rodrigo A. Lima, Karin Pfeiffer, Lisbeth R. Larsen, Anna Bugge, Niels C. Moller, Lars B. Anderson and David F. Stodden
The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years.
This was a 7-year longitudinal study, the Copenhagen School Child Intervention Study (CoSCIS), with 3 measuring points [mean ages (in years) and respective sample size: 6.75 ± 0.37, n = 696; 9.59 ± 1.07, n = 617; 13.35 ± 0.34, n = 513]. PA was assessed using accelerometers. MC was evaluated by the Körperkoordinationstest für Kinder (KTK) test battery. Cardiorespiratory fitness (VO2peak) was evaluated using a continuous running protocol until exhaustion. Structural equation modeling was performed to evaluate the longitudinal associations.
Vigorous PA (VPA) and MC presented reciprocal longitudinal association during the 7-year follow-up (VPA → MC; β = 0.18; 95% CI: 0.10, 0.26; MC → VPA; β = 0.14; 95% CI: 0.08, 0.21). In addition, VO2peak mediated the relationship in both directions (VPA → MC; β = 0.09; 95% CI: 0.06, 0.12; MC → VPA; β = 0.06; 95% CI: 0.03, 0.09).
PA and MC presented a positive reciprocal relationship across childhood through early adolescence and VO2peak mediated the association in both directions. Interventions targeting to increase PA in children and adolescents should also address the development of MC skills because of the clear positive feedback loop between PA and MC.