The association between aerobic fitness and physical activity in children and adolescents: the European youth heart study

Motor skills and capacities in developmental dyslexia: A systematic review and meta-analysis

In recent decades, the connections between academic skills, such as reading, writing, and calculation, and motor skills/capacities have received increasing attention. Many studies provided evidence for motor difficulties in children and adolescents with dyslexia, prompting the need for a meta-analysis to combine these multiple findings. Therefore, we conducted a meta-analysis using PsycINFO, Pubmed, and SportDiscus as scientific databases. A total of 572 studies were analyzed following several stringent inclusion criteria, resulting in the inclusion of 23 peer-reviewed studies in the final analysis. Our results showed that children and adolescents with dyslexia displayed significant different performances in multiple motor tasks and these differences persisted also when the type of motor task was considered as moderator in the analysis. The present findings are in accordance with the literature that supports a close connection between reading disabilities and difficulties in motor skills/capacities.

Effects of adding high-intensity training during an 8-week period on maximal oxygen uptake in 12-year-old youth athletes

PURPOSE

Maximal oxygen uptake (V̇O2max ) increases during adolescence parallel to the increase in fat-free mass (FFM). How much endurance training adds to this effect is still controversial. Our aim was to investigate if inclusion of high-intensity training (HIT) during an 8-week training period was superior to low-intensity strength and coordination training in 12-year-old youth athletes concerning the effect on V̇O2max .

METHODS

Thirty-five cross-country skiers were randomized into a HIT group (ET) and a strength and coordination group (SC), while 29 less active peers served as controls for growth and maturation (C). Anthropometrics and V̇O2max were assessed before and after the training period, and level of physical activity and training were monitored with accelerometers, training logs and a questionnaire.

RESULTS

The number of weekly training sessions were higher for ET (4.6 ± 1.2) and SC (4.1 ± 1.0) compared with C (1.8 ± 2.0) (p < 0.01), with only ET conducting HIT sessions (1.9 ± 0.2 per week). C spent more time sedentary and less time in moderate and vigorous activity compared with ET (p < 0.05). All groups had a similar %-change pre-post in absolute V̇O2max (mL min-1 ) of 6% ± 6% for ET (p < 0.01), 5% ± 7 for SC (p = 0.14), and 5% ± 13% for C (p = 0.03), with no significant differences between groups. V̇O2max relative to FFM did not change significantly for any groups.

CONCLUSION

The change in V̇O2max paralleled the change in FFM for all groups, questioning the effect of HIT on V̇O2max over an 8-week period in youth athletes.

Influence of Volume and Bouts of Sedentary Time and Physical Activity on School-Aged Youth's Physical Fitness: The UP & DOWN Longitudinal Study

BACKGROUND

The aim of this study was to examine associations of total volume and bouts of sedentary time (ST) and moderate to vigorous physical activity (MVPA) with physical fitness (PF) in youth.

METHODS

This was a 2-year follow-up study with 1418 children and adolescents (51.7% boys). Accelerometers were used to assess ST and MVPA. Cardiorespiratory and muscular fitness values were objectively measured and combined in a global PF variable. Weight status was objectively obtained. Linear regression analyses were used to examine the cross-sectional (using scores at baseline) and longitudinal associations (using the change in the variables) of total volume and bouts of ST and MVPA with PF.

RESULTS

Total ST was negatively associated with global PF (β = -0.488, P < .001 in cross-sectional analysis; β = -0.234, P = .003 in longitudinal analysis). However, this association was not independent of MVPA. Total volume of MVPA showed a positive association with global PF independently of ST and weight status (β = 0.285, P < .001 in cross-sectional analysis; β = 0.119, P = .001 in longitudinal analysis). Longitudinal associations found between ST and MVPA accumulated in bouts of various lengths and global PF became nonsignificant when their respective total volumes are included in the model.

CONCLUSIONS

These results underline the need to accumulate minutes of MVPA, regardless of the bout duration, to increase PF levels in youth.

Is cardiorespiratory fitness a moderator of the relationship between sugar-sweetened beverage consumption and insulin resistance in schoolchildren?

PURPOSE

The aim of this study was to determine whether cardiorespiratory fitness (CRF) decreases the association between insulin resistance and sugar-sweetened beverage (SSB) consumption in a population-based sample of Spanish schoolchildren.

METHODS

This is a cross-sectional study including 430 schoolchildren (51.4% girls), aged 8-12 years, from 10 schools in Cuenca (Spain). Blood samples were drawn to measure fasting insulin levels. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) was also assessed. Data on SSB consumption were gathered using the Children's Eating Habits Questionnaire, which was completed by parents. The CRF level was determined by the 20 m Shuttle Run test and a curvilinear allometric model.

RESULTS

Our conditional regression estimates showed that CRF moderated the association of SSB consumption on insulin levels or HOMA-IR. In children who had levels of CRF < 34.4 ml/kg/min ml/kg/min (for insulin levels) or < 33.6 ml/kg/min (for HOMA-IR), the association between SSB consumption and fasting insulin levels or HOMA-IR raised. Among children with CRF levels between 34.4 and 52.1 ml/kg/min (for insulin levels) or 33.6-55.4 ml/kg/min (for HOMA-IR), the association of SSB consumption on insulin level or HOMA-IR neither increased nor decreased. Among children with CRF levels > 52.1 ml/kg/min (for insulin levels) or > 55.4 ml/kg/min (for HOMA-IR), the association of SSB consumption on fasting insulin levels or HOMA-IR decreased.

CONCLUSIONS

Our results showed that certain levels of CRF moderate the association between SSB consumption and insulin resistance in a population-based sample of Spanish schoolchildren.

Sex-Related Differences in the Relationship between Sugar-Sweetened Beverage Consumption and Cardiorespiratory Fitness: Results from Chinese Cross-Sectional Study on Children

Sugar-sweetened beverage (SSB) consumption continues to increase among children, with adverse health effects, and China is no exception. Our study investigates the association between SSB consumption and cardiopulmonary fitness. We used stratified whole group sampling to investigate and test SSB consumption and cardiopulmonary fitness in 21,055 children aged 13−15 years in China. A chi-square test and one-way ANOVA were used to compare different categories of SSB consumption. General linear regression analysis and logistic regression analysis were used to analyze the relationship between different SSB consumption and cardiopulmonary fitness in Chinese children. Our research results show the proportions of Chinese children with SSB consumption ≤ 1 time/week, 2−4 times/week, and ≥5 times/week were 33.3%, 52.8%, and 13.9%, respectively. VO2max in children consuming ≥ 5 times/week was lower than those consuming 2−4 times/week and ≤2 times/week of SSB by 0.15 and 0.301 mL·kg−1·min−1, with statistically significant differences (F-value 18.807, p < 0.001). After relevant confounders were adjusted, children in the SSB consumption ≥ 5 times/week group had a higher risk of developing poorer cardiopulmonary fitness than those in the SSB consumption ≤ 1 time/week group (OR: 1.336, 95% CI: 1.181, 1.511) (p < 0.001). In conclusion, the consumption of SSBs among children aged 13−15 in China is higher than the recommended intake by the World Health Organization, and boys are higher than girls. In addition, after adjusting for relevant confounders, the association between SSB consumption and an increased risk of poor cardiorespiratory fitness remained. The relationship between SSB consumption and cardiopulmonary fitness was higher in girls compared with boys.

Associations between Sedentary Time and Sedentary Patterns and Cardiorespiratory Fitness in Chinese Children and Adolescents

The increase in sedentary behavior in children and adolescents has become a worldwide public health problem. This study aimed to explore the associations between sedentary time (ST) and sedentary patterns (SP) and the cardiorespiratory fitness (CRF) of Chinese children and adolescents. The CRF of 535 participants was determined using a 20-m shuttle run test. ST and SP were measured with accelerometers. Questionnaires were used to investigate the different types of ST. Multiple linear regression models were used to test the associations between ST and SP and CRF. In this study, only some ST and SP indicators were found to be significantly associated with CRF in girls. With each additional 10 min of screen time or passive traffic time, VO2max decreases by 0.06 mL/kg/min (B = −0.006, 95% CI: −0.010~−0.001) and 0.31 mL/kg/min (B = −0.031, 95% CI: −0.061~−0.002), respectively, with MVPA control. With each additional 10 min of breaks in ST or duration of breaks in ST, VO2max increases by 0.41 mL/kg/min (B = 0.041, 95% CI: 0.007~0.076) and 0.21 mL/kg/min (B = 0.021, 95% CI: 0.007~0.035), respectively, with control total ST. Breaks in ST (B = 0.075, 95% CI: 0.027~0.123) and the duration of breaks in ST (B = 0.021, 95% CI: 0.012~0.146) were positively correlated with CRF when controlling for LPA, but these associations were not significant when controlling for MVPA (B = 0.003, 95% CI: −0.042~0.048; B = 0.001, 95% CI: −0.024~0.025). The total ST of children and adolescents was found to not be correlated with CRF, but when ST was divided into different types, the screen time and passive traffic time of girls were negatively correlated with CRF. More breaks in ST and the duration of breaks in ST were positively associated with higher CRF in girls. MVPA performed during breaks in ST may be the key factor affecting CRF. Schools and public health departments should take all feasible means to actively intervene with CRF in children and adolescents.

Development of Cardiorespiratory Fitness in Children in the Transition From Kindergarten to Basic School According to Participation in Organized Sports

Purpose: This study examined the development of cardiorespiratory fitness (CRF) in children in the transition from kindergarten to basic school according to participation in organized sports and estimated the associations of CRF and body composition indices during the transition from childhood to preadolescence.

Methods: Children participated in the three-staged study (kindergarten, 6.6 years, n = 212; 1st grade, 7.6 years, n = 136; and 5th grade, 11.5 years, n = 142) for 5 years and were categorized into three groups according to their participation in organized sports in the study period (whole period, episodically, and never). Cardiorespiratory fitness was assessed by performing a 20-m shuttle run test, while body composition was measured by skinfold thicknesses, and physical activity was registered with an accelerometer. International gender- and age-specific CRF reference normativities were also used to characterize the participants.

Results: Children who participated consistently in organized sports had significantly higher CRF levels and lower body fatness (31.3 ± 13.5 laps in 20 m shuttle run; 21.1% ± 6.3% body fat) in 11.5 years than in children who had never participated in sports clubs (20.7 ± 12.0 laps in 20-m shuttle run; 26.1% ± 6.8% body fat). Body composition and CRF did not associate in consistently trained children. The proportion of 5th grade children demonstrating age-appropriate healthy CRF was almost threefold higher in the group of consistent sports training among both boys and girls than among non-members of sports clubs.

Conclusion: Consistent attendance in organized sports in childhood and early preadolescence ensures higher CRF and healthier body composition than in children who had no experience of organized sports.

Physical Activity in Paediatric Long QT Syndrome Patients

Background

Physical activity (PA) is important for cardiovascular health as well as social and emotional well-being of children. Patients with long QT syndrome (LQTS) often face PA restrictions and are often prescribed beta-blockers for disease management. The aim of this study was to determine if PA levels were lower in patients with LQTS compared with healthy controls.

Methods

Participants with LQTS from an inherited arrhythmia clinic completed the Physical Activity Questionnaire for Children and Adolescents (PAQ-C/A) and an exercise stress test. PAQ score (a general measure of PA for youth, unitless) and endurance time were compared with healthy controls.

Results

Twenty-three patients with LQTS completed the PAQ and had an exercise stress test within a year of having completed the PAQ. No difference was observed in PAQ scores between LQTS and control groups (LQTS: 2.3 ± 0.15 vs controls: 2.3 ± 0.18; P = 0.78). There was no effect of age on PA in patients with LQTS (P > 0.05), whereas PA significantly decreased in controls with age (eg, 11-12 vs 17-20 years: 3.2 ± 0.07 vs 1.5 ± 0.08, P = 0.005). Endurance time and heart rate at peak exercise were significantly lower in patients with LQTS compared with controls (11 ± 0.5 vs 15 ± 0.5 minutes, P < 0.0001; 169 ± 5 vs 198 ± 2 beats per minute, P < 0.0001).

Conclusions

Despite guideline recommendations restricting PA, risk of sudden cardiac death, and use of beta-blockers, our cohort of patients with LQTS reported similar PA levels as healthy controls.

Associations of Motor Competence, Cardiorespiratory Fitness, and Physical Activity: The Mediating Role of Cardiorespiratory Fitness

Purpose: Supporting children's physical activity (PA) behavior is imperative in order to safeguard their health. In an attempt to gain a deeper understanding about children's PA behavior, the aim of this study was to investigate the associations among motor competence (MC), cardiorespiratory fitness (CRF) and ambulatory PA during middle and late childhood. Method: A cross-sectional design was adopted and a total of 576 8-12-year-old children (M_age = 10.2 years, SD = 1.3) were examined. MC was assessed by the Canadian Agility and Movement Skill Assessment; daily PA (steps/day) was obtained by pedometers; CRF was measured by the Progressive Aerobic Cardiovascular Endurance Run. The associations among the key study variables were investigated by correlation and mediation analyses. Using a bootstrap method, two mediation models were tested: (a) MC predicting PA through CRF, (b) PA predicting MC through CRF. Results: MC, CRF, and PA present significant and positive associations both in boys and girls (p < .05). CRF fully mediates the relationship between MC and PA in both directions [Model 1: b = .138, 95% CI (.0952, .1869), Model 2: b = .108, 95% CI (.0752, .1445)]. The pathway leading from PA to MC (R² = .375, p < .0001) has stronger predictive utility than the reverse pathway (R² = .124, p < .0001). Conclusion: MC and CRF are important predictors of children's PA participation; therefore, systematic and targeted interventions focused on the enhancement of these two factors should be used as a mechanism to reinforce children's PA behavior.

Longitudinal Associations of Healthy Behaviors on Fitness in Adolescents: DADOS Study

INTRODUCTION

This study aims to investigate the individual and combined associations of physical activity, sedentary time, diet, and sleep at baseline on cardiorespiratory fitness at 24-month follow-up in adolescents.

METHODS

The DADOS (Deporte, ADOlescencia y Salud) prospective cohort study was performed between 2015 and 2017. Analyses were conducted in 2020 and included 189 adolescents aged 13.9 (SD=0.3) years at baseline. Vigorous physical activity, total sedentary time, and sleep duration were evaluated by GENEActiv accelerometer. Sleep quality and adherence to a Mediterranean diet were evaluated by questionnaires. Cardiorespiratory fitness was assessed by the 20-meter shuttle run test. A healthy lifestyle index was created by including positive scores for each individual behavior, and 3 categories of achievement (≤1, 2, ≥3) were established.

RESULTS

Performing high vigorous physical activity and low screen time at baseline were individually associated with the likelihood of achieving high cardiorespiratory fitness at follow-up (OR=3.33 and 3.09, respectively). ANCOVA indicated that adolescents with a healthy lifestyle index ≥3 at baseline showed higher cardiorespiratory fitness at follow-up than those with a healthy lifestyle index of 2 and ≤1 (74.4 [SE=1.5] vs 68.9 [SE=1.4] and 67.8 [SE=1.5] laps, respectively; p<0.01). Adolescents with a healthy lifestyle index ≥3 at baseline were more likely to have high cardiorespiratory fitness at follow-up (OR=3.10) than their peers with ≤1.

CONCLUSIONS

The results showed a cumulative impact of baseline health-related behaviors on cardiorespiratory fitness at 24-month follow-up in adolescents. These findings underline the key role of promoting a healthy lifestyle to improve adolescents' health.

The Indirect Role of Executive Functions on the Relationship between Cardiorespiratory Fitness and School Grades

PURPOSE

The aim of this study was to investigate the indirect effects of cardiorespiratory fitness on scholastic performance through executive functions. More precisely, we examined the contribution of the different domains of executive functions, and whether this relationship was specific to certain school topics.

METHODS

Children 8-12 yr old completed nine cognitive tests and the multistage fitness test. Structural equation modeling techniques were used to analyze the role of different domains of executive functions (inhibition, working memory, cognitive flexibility, and a common factor to all tasks) in the relationship between cardiorespiratory fitness and school grades in three domains: (i) mathematics; (ii) grammar, spelling, and vocabulary; and (iii) text comprehension and expression. Covariate analyses included age and socioeconomic status.

RESULTS

The results of this study showed that an indirect effect of the various domains of executive functions explained, in part, the relationship between cardiorespiratory fitness and (i) mathematics (β = 0.12, SE = 0.03, P < 0.001), and between cardiorespiratory fitness and (ii) grammar, spelling, and vocabulary (β = 0.12, SE = 0.03, P < 0.001). No relationship between cardiorespiratory fitness and (iii) text comprehension and expression was observed. Although executive functions correlated with school grades, cognitive flexibility drove the indirect effect when all executive function domains were simultaneously taken into account.

CONCLUSIONS

These results show the role that executive functions play in understanding the relationship between cardiorespiratory fitness and scholastic performance. Importantly, not all executive function domains contributed equally because cognitive flexibility played a leading role in this wide age range. Furthermore, the relationship between cardiorespiratory fitness and scholastic performance was strongest for mathematics and for low-level language topics but nonsignificant for higher-level language topics, providing a more modulated view of the effect of cardiorespiratory fitness on language.

The Relationship between Students' Physical Self-Concept and Their Physical Activity Levels and Sedentary Behavior: The Role of Students' Motivation

This study aimed to analyze the association between specific dimension (i.e., fitness, appearance, physical competence, physical strength, and self-esteem) of students’ physical self-concept (PSC) and their physical activity (PA) levels (i.e., intentions to be physically active and out-of-school PA levels perceived by students) and sedentary behavior (SB) (i.e., total sitting and screen time perceived by students). We also tested the role of students’ motivation (i.e., intrinsic motivation and amotivation) towards PA in these relationships. A total of 1998 Spanish male (n = 1003) and female (n = 995) secondary students, aged between 13 and 17 years (M = 14.92, SD = 0.87) from 22 schools, enrolled in third grade (n = 1081) and fourth grade (n = 917), completed the self-reported questionnaires. Five independent structural equation modeling (SEM) adjusted by students’ sex was used to examine the association between specific dimension of students’ PSC (i.e., fitness, appearance, physical competence, physical strength, and self-esteem) and self-reported PA and SB variables, and to test the role of students’ motivation in these relationships. Overall, most of students’ PSC dimension positively predicted students’ PA outcomes, and were negatively associated with SB. In addition, most of students’ PSC dimension were positively associated with intrinsic motivation, and negatively predicted amotivation. In turn, intrinsic motivation was a positive predictor of PA outcomes, and a negative predictor of SB, whereas amotivation was a negative predictor of PA outcomes and sitting time, and a positive predictor of screen time. Finally, from PSC dimensions, sex as a covariate was a positive predictor of intrinsic motivation and PA outcomes, and was a negative predictor of amotivation and sitting time. These findings suggest the importance of the specific dimensions of PSC perceived by adolescents on their motivational processes, and in turn, on their PA and SB outcomes.

Changes in Physical Fitness during Summer Months and the School Year in Austrian Elementary School Children-A 4-Year Longitudinal Study

Even though physical fitness is an important component in children's health and well-being, there has been a decline in physical fitness over the last several decades. The present study examined potential differences in the development of physical fitness during the academic year and summer vacation in Austrian elementary-school children. A total of 214 children (52.3% boys) completed the German motor test in the fall (after summer vacation) and spring (prior to summer vacation) of every grade throughout their elementary school years. This resulted in eight assessments of cardio-respiratory endurance, muscular fitness, flexibility, speed, agility, and balance over a 4-year period. As expected, physical fitness increased with age but the improvement in cardio-respiratory endurance and muscular fitness was more pronounced during summer vacation (p < 0.01), while the improvement in speed was more pronounced during the academic year (p < 0.01). These results indicate an influence of weather conditions on health-enhancing physical activity in addition to structural and social support. Particularly in geographical regions with cold winters and shorter days, health-enhancing physical activity may be limited. Accordingly, schools need to provide additional opportunities to ensure an adequate amount of physical activity that stimulates the development of physical fitness.

Wearable Technologies for Children with Chronic Illnesses: An Exploratory Approach

OBJECTIVE

To determine the utility of wearable technologies in physical activity assessment in three paediatric diseases, namely, Niemann-Pick C (NP-C), Juvenile Idiopathic Arthritis (JIA) and Duchenne Muscular Dystrophy (DMD).

DESIGN

Exploratory study SETTING AND PATIENTS: Thirty children were recruited across three UK hospitals (Royal Manchester's Children Hospital, Great Ormond Street Children's Hospital, and the Great North Children's Hospital). Ten were diagnosed with NP-C, eight with DMD and twelve with JIA.

INTERVENTION

All participants completed the 6-min walk test (6MWT) at enrolment. Patients were provided with disease-specific smartphone apps paired with a wearable device via Bluetooth. Ambulation was recorded in 30-min epochs measuring average daily maximum (ADM), average daily steps (ADS) and average daily steps per 30-min epoch (ASE).

RESULTS

Median 6MWT results were 450 m, 325 m and 434.5 m for the NP-C, DMD and JIA cohorts, respectively. Wearable data capture was feasible in all three disease cohorts, although complete data capture was not sustained. A statistically significant between-cohort difference was identified for ADM, ADS and ASE. Statistically significant differences were found between DMD/JIA for ADM; NP-C/DMD for ADS and DMD/JIA for ASE.

DISCUSSION

Wearable sensor technologies have the potential to provide additional information for our understanding of ambulation in chronic paediatric disease. The wearable devices were easy to use and popular with patients although key features need to be addressed to appropriately meet study objectives. As the technology continues to evolve at a rapid pace, opportunities to implement child friendly solutions are already available.

Activity patterns of primary school children during participation in The Daily Mile

The Daily Mile is a popular physical activity initiative in primary schools, yet little is known regarding the activity patterns of children during The Daily Mile. Eighty children (10.4 ± 0.7 years) participated in The Daily Mile (20-min). Activity patterns were assessed using global positioning systems (total distance and age-specific speed zones), alongside heart rate. Cardiorespiratory fitness was assessed using the Multi-Stage Fitness Test. Participants covered a distance of 2511 ± 550 m during The Daily Mile, and heart rate was 163 ± 27 beats^.min^-1. Participants travelled the furthest distance, and were most intermittent, during the first 5 min (main effect of time, both p < 0.001). Boys ran further and their activity was more intermittent compared to girls (main effect of sex, both p < 0.001). Moreover, the highest fit children ran further than less fit children (main effect of fitness, p < 0.001). This study provides novel evidence of the nature of physical activity during The Daily Mile; demonstrating that children covered, on average, 1.5-miles and exercised at a moderate-to-vigorous intensity. Furthermore, boys covered a greater distance and were more intermittent than girls; whilst higher fit children ran further than lower fit children. In summary, The Daily Mile makes a valuable contribution to in-school physical activity targets in all children.

Isotemporal substitution of sedentary behavior for physical activity on cardiorespiratory fitness in children and adolescents

Both sedentary behavior (SB) and physical activity (PA) are associated with cardiorespiratory fitness (CRF) and independent of each other. Due to the limited time during school for children and adolescents, it is necessary to explore the isotemporal substitution of SB for PA on CRF.A total 536 eligible participants selected from the 7 traditional administrative regions of China were included in this study. The outcome was CRF, determined using a 20-meter shuttle run test, and exposures were SB, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) measured with accelerometers. We analyzed the cross-sectional associations of substituting SB with LPA, MVPA, and combinations of LPA and MVPA with CRF, using an isotemporal substitution model.Reallocating SB into MVPA was associated with higher CRF for male (P < .01) and female (P < .01) children and female adolescents (P < .05). In the mixed redistribution, the ratio of LPA to MVPA for male children and female adolescents started from 16:4 and 14:6, respectively, tended toward improvements in CRF. For female children, regardless of the ratio of LPA to MVPA, it was always associated with higher CRF.Reallocating SB into MVPA isotemporally was positively associated with CRF for male and female children and female adolescents but not for male adolescents. MVPA is the key factor to improve CRF when combinations of LPA and MVPA replace SB. The combined approach can provide basis for the selection of target and monitoring variables in intervention studies, and has more flexible choices for improving CRF that are more consistent with the daily PA habits of children and adolescents.

Effects of an Alternative Sports Program Using Kin-Ball in Individuals with Intellectual Disabilities

The first aim of the present work was to examine the effects of a physical activity sports program, specifically Kin-Ball, within a group of individuals with intellectual disabilities, on decreasing sedentary behavior and improving basic physical skills. The second aim was to evaluate social validity and acceptability of the intervention. In this pre-experimental study, 47 individuals participated (46.8% male and 53.2% female) with an average age of 29.85 (SD = 10.41). All participants were administered an intervention program based on the alternative sport of Kin-Ball. BMI was calculated for body composition and age-related Z-scores were interpreted with the tables provided by the WHO. Endurance was measured through a modified six-minute test, speed was analyzed using a 50 m test, and strength was estimated according to a hand-grip dynamometer. Likewise, balance and coordination were examined in line with adaptations proposed by the scientific literature. Results indicated that all cases experienced statistically significant differences following the intervention program (p = 0.000). Improvement effects were detected in all post-intervention tests (endurance, strength, speed, balance, and coordination). As a main conclusion, it is indicated that an alternative sports-based program improves physical ability and motor skills in individuals with intellectual disabilities.

Effects of aerobic exercise and cognitively engaging exercise on cardiorespiratory fitness and motor skills in primary school children: A cluster randomized controlled trial

This paper examined effects of two interventions on cardiorespiratory fitness and motor skills, and whether these effects are influenced by baseline levels, and dose of moderate-to-vigorous physical activity (MVPA) during the intervention. A cluster randomized controlled trial was implemented in 22 schools (n = 891; 9.2 ± 07 years). Intervention groups received aerobic or cognitively engaging exercise (14-weeks, four lessons per week). Control groups followed their regular physical education programme. Cardiorespiratory fitness, motor skills and MVPA were assessed. Multilevel analysis showed no main effects on cardiorespiratory fitness and motor skills although the amount of MVPA was higher in the aerobic than in the cognitively engaging and control group. Intervention effects did not depend on baseline cardiorespiratory fitness and motor skills. Children with a higher dose of MVPA within the intervention groups had better cardiorespiratory fitness after both interventions and better motor skills after the cognitively engaging intervention. In conclusion, the interventions were not effective to enhance cardiorespiratory fitness and motor skills at a group level, possibly due to large individual differences and to a total dose of MVPA too low to find effects. However, the amount of MVPA is an important factor that influence the effectiveness of interventions.

Public health surveillance of habitual physical activity in adolescents and adults in Namibia: a cross-sectional validation of activity questionnaires against accelerometry

BACKGROUND

Monitoring population-level physical activity is crucial for examining adherence to global guidelines and addressing obesity. This study validated self-reported moderate-to-vigorous physical activity (MVPA) against an accurate device-based method in Namibia.

METHODS

Adolescent girls (n = 52, mean age 16.2 years [SD 1.6]) and adult women (n = 51, mean age 31.3 years [SD 4.7]) completed the PACE+/GPAQ self-report questionnaires and were asked to wear an Actigraph accelerometer for 7 days. Validity of self-reported MVPA was assessed using rank-order correlations between self-report and accelerometry, and classification ability of the questionnaires with Mann-Whitney tests, kappa's, sensitivity and specificity.

RESULTS

In the adolescents, Spearman's rank coefficients between self-reported MVPA (days/week) and accelerometry measured MVPA were positive but not significant (r = 0.240; P = 0.104). In the adults, self-reported MVPA (minutes/day) was moderately and significantly correlated with accelerometer-measured MVPA (r = 0.396; P = 0.008). In both groups, there was fair agreement between accelerometry and questionnaire-defined tertiles of MVPA (adolescents κ = 0.267; P = 0.010; adults κ = 0.284; P = 0.008), and measured MVPA was significantly higher in the individuals self-reporting higher MVPA than those reporting lower MVPA.

CONCLUSIONS

The PACE+ and GPAQ questionnaires have a degree of validity in adolescent girls and adult females in Namibia, though more suitable for population than individual level measurement.

Relationship between breakfast consumption, BMI status and physical fitness of Ghanaian school-aged children

BACKGROUND

Good nutrition and physical activity of school-aged children are important for ensuring optimum growth and reducing obesity. This present study assessed associations between breakfast consumption, BMI-for-Age (BMI) and physical fitness in a cross-section of school-aged children attending government-owned primary schools in Kumasi, Ghana.

METHOD

The sample consisted of 438 pupils (boys = 213; girls = 225; mean age 11.1 ± 1.1), attending 10 randomly selected schools. Weight (kg), height (cm) and Mid Upper Arm Circumference (MUAC) were measured for each participant, and BMI-for-age z-scores determined using the World Health Organisation (WHO) anthroplus software. Participants were stratified into thinness, normal weight, overweight/obese using WHO cut offs. Physical fitness was assessed using forward jump, left and right handgrips, flexibility, sit-ups and 50 metre run following standard procedures and converted to scores of 1 to 10 following Japanese standards, based on which percentiles were derived. Total fitness score for each pupil was computed by adding all scores. A questionnaire was used to assess meal intake patterns.

RESULTS

The mean BMI-for-age z-score for participants was - 0.24 ± 0.99. Thinness, normal weight and overweight/obesity were 2.7, 86.5, and 10.5% respectively among the pupils. Overweight was higher in girls (14.2%) compared to boys (4.2%), p = 0.003. Similarly, mean MUAC was significantly (p = 0.021) higher in the girls (22.0 ± 3.2 cm) than the boys (20.7 ± 7.3 cm). For physical fitness, the girls scored higher in forward jump (p < 0.0001), 50-m run (p = 0.002) and overall fitness score than the boys (21.0 ± 6.2 versus 19.2 ± 8.3, p = 0.012). However, a larger proportion of boys performed excellently and poorly than girls (p = 0.019). A positive correlation was observed between BMI z-score and hand grip (r = 0.21, p < 0.001), while sit up (r = - 0.11, p = 0.018) showed a negative correlation with BMI z-score. No other fitness test varied by BMI. Overweight children performed best in handgrip. Majority of children said they engaged in exercise (89.9%) and consumed breakfast (78.9%). Breakfast consumption was not associated with BMI z-score (x2 0.0359, p = 0.549) but non-breakfast consumers performed better in 50 m run compared to consumers (7.0 seconds ± 2.3 vrs 6.3 seconds ± 2.5, p = 0.022). Children who reported to exercise were physically fitter than those who did not.

CONCLUSION

Underweight levels were low while overweight was over 10% in these children. Girls were more than 3 times affected by overweight than boys, and were also physically fitter than boys. Breakfast consumption was not related to weight or fitness.

Effects of the Active Smarter Kids (ASK) physical activity intervention on cardiometabolic risk factors in children: A cluster-randomized controlled trial

The onset of cardiometabolic diseases are recognized to occur in childhood. We aimed to investigate the effect of a school-based cluster-randomized controlled trial of physical activity (PA) on single and clustered cardiometabolic risk factors. We included 1129 fifth-grade children from 57 schools (≥seven children in each class) in Sogn and Fjordane County, Norway, randomized to 28 intervention schools and 29 control schools. The PA intervention was conducted between November 2014 and June 2015. Cardiometabolic risk factors were waist circumference (WC), systolic blood pressure (SBP), total cholesterol (TC):high-density lipoprotein (HDL)-ratio, triglycerides (TG), homeostatic model assessment (HOMA)-score, and cardiorespiratory fitness (CRF). PA was measured by accelerometry. No significant intervention effects were found for single or clustered cardiometabolic risk factors. However, in children with the less favorable baseline values, beneficial effects were found for SBP (p = 0.07 for group ∗ tertile interaction), TC:HDL ratio (p = 0.03 for group ∗ tertile interaction) and the clustered cardiometabolic risk score (p = 0.01 for group ∗ tertile interaction). Compared to boys, girls had a greater effect of the intervention on WC (p = 0.03 for group ∗ sex interaction) and CRF (p < 0.001 for group ∗ sex interaction). The majority of the children had high PA levels, thus limited potential for change, and we found no effects of the PA intervention on cardiometabolic risk in the total sample. However, the intervention had a significantly enhanced effect on fatness and fitness of girls compared to boys. Furthermore, the data suggest that children with the least favorable cardiometabolic risk profile and therefore most in need of change can benefit from school-based PA interventions. Trial registration number: Clinicaltrials.gov ID no.: NCT02132494.

Physical activity maintenance and metabolic risk in adolescents

Aim

Examine the association between child and adolescent physical activity maintenance categories and metabolic profile in adolescence.

Methods

This cross-sectional study was conducted with 1152 adolescents (57.4% female) aged 10-16 years from Londrina, Brazil. Physical activity was self-reported in childhood (7-10 years old, retrospective data) and adolescence through questionnaires. Cardiorespiratory fitness (20 m shuttle-run test), body fat (skinfolds), waist circumference, blood pressure (automatic instrument) and blood variables (fasting glucose, HDL-cholesterol and triglycerides) were measured at adolescence.

Results

Frequency of physical activity in childhood and adolescence was 50.3 and 17.2%, respectively, and only 25.7% of boys and 10.9% of girls were active at both ages. Adolescents who were physically active in childhood alone were less likely [OR = 0.71 (95% CI: 0.52-0.97)] to present low cardiorespiratory fitness in adolescence compared to those who were non-active in childhood. Regardless of controlled, actives in childhood and adolescence were less likely to present low cardiorespiratory fitness [OR = 0.50 (95% CI: 0.34-0.73)], high blood pressure [OR = 0.52 (95% CI: 0.32-0.85)] and high metabolic risk score [OR = 0.44 (95% CI: 0.22-0.90)] compared to the non-actives at both ages.

Conclusions

Actives through childhood to adolescence are less likely to present low cardiorespiratory fitness, high blood pressure and high metabolic risk.

A Combined EEG-fNIRS Study Investigating Mechanisms Underlying the Association between Aerobic Fitness and Inhibitory Control in Young Adults

The current evidence suggests that aerobic fitness is associated with inhibitory control of executive functioning in children and older adults. However, the relative contributions of different neurophysiological mechanisms to this relation remain unclear and have not yet been examined in young adults. The present study aimed to compare inhibitory control between high and low-fit young adult men, and to investigate a possible mediation of fitness effects by conflict monitoring (N450 component of event-related potentials) and lateralized oxygenation difference (LOD) in the DLPFC. For the present cross-sectional study, participants with different physical activity levels were recruited and divided into low-fit and high-fit participants based on relative power on the PWC170. A Stroop Color-Word task was administered and combined EEG-fNIRS was simultaneously utilized to assess the N450 and LOD, because these parameters are linked with behavioral performance. The results of the statistical analysis showed that high-fitcompared to low-fit participants showed less Stroop interference and lower negativity of the N450, whereas no difference was found for LOD. Path-analyses further revealed that the relation between aerobic fitness levels and Stroop interference was indirect and mediated by N450. In contrast, LOD was inversely correlated with Stroop interference, but did not explain the relation of aerobic fitness with behavioral performance. The present findings indicate that greater inhibitory control in high- compared to low-fit young men can be explained by more effective conflict monitoring. Moreover, young adults with left-lateralizedDLPFC oxygenation also show higher inhibitory control, but this oxygenation pattern is not influenced by aerobic fitness.

Physical fitness of children and adolescents with moderate to severe intellectual disabilities

Background: Low levels of physical fitness are associated with low physical and mental health. The aims of this study were to assess the health-related physical fitness of children with intellectual disability (ID), and study the association of physical activity and motor development with physical fitness.Methods: One hundred and twenty-eight children with moderate to severe ID (83 boys; age 2-18 years) visiting specialised day programme centres engaged in field-based physical fitness tests (body composition, muscular strength, muscular endurance, and cardiorespiratory fitness). Scores were compared to reference values, and with linear regression analysis the association between the fitness outcomes and physical activity and motor development was studied.Results: High rates of overweight (23-25%) and obesity (10-15%) were found. A majority of the participants (71-91%) scored below reference values for muscular strength, endurance, and cardiorespiratory fitness tests. Physical activity and motor development were positively associated with scores on several fitness test (β = 0.27-0.44; p < 0.05).Conclusions: Children with moderate to severe ID visiting specialised day programme centres have strikingly low physical fitness levels. Policies and interventions to increase the physical fitness for this specific group of children are urgently needed, in which increasing physical activity and motor skills are expected to be effective components.Implications for rehabilitationStrikingly low levels of physical fitness were seen in children and adolescents with moderate to severe intellectual disabilities.This vulnerable group is in need of appropriate interventions to increase their physical fitness levels.Increasing the physical activity is a potential component in these interventions.Improving motor development will most likely lead to improved physical fitness as well.

Enhancing fitness, enjoyment, and physical self-efficacy in primary school children: a DEDIPAC naturalistic study

BACKGROUND

Physical activity (PA) (e.g., sport, physical education) promotes the psychophysical development of children, enhances health and wellbeing, offers opportunities for enjoyable experiences, and increases self-efficacy.

METHODS

In the DEDIPAC framework, we conducted a naturalistic, cross-sectional study to evaluate the effects of a school-based, long-term intervention on fitness (i.e., cardiovascular endurance, muscular strength, flexibility, speed, and finger dexterity), body mass index (BMI), PA levels, sedentary levels, enjoyment, and physical self-efficacy in primary school children. A group of Italian children (41 boys and 39 girls, aged 10-11 years) involved in the project-named "Più Sport @ Scuola" (PS@S)-was compared with a group of children (41 boys and 39 girls) of the same age not involved in the project.

RESULTS

After a four-year long attendance to the PS@S project, participants reported higher scores of cardiovascular endurance, muscular strength, enjoyment, and physical self-efficacy compared to children not involved in the project. Correlation analysis results showed that muscular strength scores correlated positively with BMI, PA levels, and enjoyment. Flexibility of the upper body was positively related to physical self-efficacy, and negatively related to speed and BMI.

CONCLUSIONS

Findings suggest that the PS@S project enhanced fitness level, enjoyment, and physical self-efficacy of children.

Physically active academic lessons and effect on physical activity and aerobic fitness. The Active School study: A cluster randomized controlled trial

The Active School program was designed to positively impact health and academic-related outcomes in school. The core intervention component was physically active academic lessons, a teaching activity that combines physical activity and educational content. The purpose of this study was to investigate the effect of a 10-month, cluster-randomized controlled trial on physical activity level and aerobic fitness conducted in the city of Stavanger, Norway, in 2014-15. The physical activity level during physically active academic lessons was also studied. A total of 447 children (9-10 years) participated. The weekly intervention consisted of physically active academic lessons, physically active homework and physically active recess. Physical activity level and aerobic fitness were measured objectively by accelerometry and a 10-minute interval running test. Intervention effects were found for time in moderate to vigorous physical activity (MVPA) (adjusted mean difference of 8 min/day, 95% CI: 3.4-13, p < 0.001) and total physical activity (60 counts/min, 95% CI: 15-105, p = 0.009). Children with low aerobic fitness increased their running distance compared to controls (d = 0.46; p = 0.001). During physically active academic lessons children spent 26% of the time in MVPA, which was comparable to physical education lessons. The Active School program successfully increased physical activity for the intervention group and aerobic fitness for the least fit children. The activity level during physically active academic lessons was as high as in physical education lessons. Clinicaltrail.gov ID identifier: NCT03436355.

Reference values for cardiometabolic risk scores in children and adolescents: Suggesting a common standard

BACKGROUND AND AIMS

International reference values for cardiometabolic risk variables, to allow for standardization of continuous risk scores in children, are not currently available. The aim of this study was to provide international age- and gender-specific reference values for cardiometabolic risk factors in children and adolescents.

METHODS

Cohorts of children sampled from different parts of Europe (North, South, Mid and Eastern) and from the United States were pooled. In total, 22,479 observations (48.7% European vs. 51.3% American), 11,234 from girls and 11,245 from boys, aged 6-18 years were included in the study. Linear mixed-model regression analysis was used to analyze the associations between age and each cardiometabolic risk factor.

RESULTS

Reference values for 14 of the most commonly used cardiometabolic risk variables in clustered risk scores were calculated and presented by age and gender: systolic blood pressure (SBP), diastolic blood pressure (DBP), waist circumference (WC), body mass index (BMI), sum of 4 skinfolds (sum4skin), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), TC:HDL-C ratio, glucose, insulin, homeostatic model assessment-score (HOMA-score), and cardiorespiratory fitness (CRF).

CONCLUSIONS

This study suggests a common standard to define cardiometabolic risk in children. Adapting this approach makes single risk factors and clustered cardiometabolic disease risk scores comparable to the reference material itself and comparable to cardiometabolic risk values in studies using the same strategy. This unified approach therefore increases the prospect to estimate and compare prevalence and trends of cardiometabolic risk in children when using continuous cardiometabolic risk scores.

Cardiorespiratory fitness is associated with physical literacy in a large sample of Canadian children aged 8 to 12 years

BACKGROUND

The associations between cardiorespiratory fitness (CRF) and physical literacy in children are largely unknown. The aim of this study was to assess the relationships between CRF, measured using the 20-m shuttle run test (20mSRT), and components of physical literacy among Canadian children aged 8-12 years.

METHODS

A total of 9393 (49.9% girls) children, with a mean (SD) age of 10.1 (±1.2) years, from a cross-sectional surveillance study were included for this analysis. The SRT was evaluated using a standardized 15 m or 20 m protocol. All 15 m SRTs were converted to 20mSRT values using a standardized formula. The four domains of physical literacy (Physical Competence, Daily Behaviour, Motivation and Confidence, and Knowledge and Understanding) were measured using the Canadian Assessment of Physical Literacy. Tertiles were identified for 20mSRT laps, representing low, medium, and high CRF for each age and gender group. Cohen's d was used to calculate the effect size between the low and high CRF groups.

RESULTS

CRF was strongly and favourably associated with all components of physical literacy among school-aged Canadian children. The effect size between low and high CRF tertile groups was large for the Physical Competence domain (Cohen's d range: 1.11-1.94) across age and gender groups, followed by moderate to large effect sizes for Motivation and Confidence (Cohen's d range: 0.54-1.18), small to moderate effect sizes for Daily Behaviour (Cohen's d range: 0.25-0.81), and marginal to moderate effect sizes for Knowledge and Understanding (Cohen's d range: 0.08-0.70).

CONCLUSIONS

This study identified strong favourable associations between CRF and physical literacy and its constituent components in children aged 8-12 years. Future research should investigate the sensitivity and specificity of the 20mSRT in screening those with low physical literacy levels.

A cross-sectional study exploring the relationship between age, gender, and physical measures with adequacy in and predilection for physical activity

BACKGROUND

Physical literacy is a complex construct influenced by a range of physical, behavioural, affective, and cognitive factors. Researchers are interested in relationships among these constituent factors. The purpose of this study was to investigate how age, gender, and physical competence components of physical literacy relate to a child's adequacy in and predilection for physical activity.

METHODS

A sample of 8530 Canadian youth (50% girl) aged 8.0 to 12.9 years participated in the study. Participants completed the Canadian Assessment of Physical Literacy (CAPL) protocol, which assesses physical literacy in four domains: Physical Competence, Daily Behaviour, Motivation and Confidence, and Knowledge and Understanding. Stepwise multiple regression analyses were conducted to investigate the relationship between physical competence components of physical literacy (Progressive Aerobic Cardiovascular Endurance Run [PACER], Canadian Agility and Movement Skill Assessment [CAMSA], sit and reach, handgrip, plank, and body mass index) and children's perceived adequacy and predilection toward physical activity as measured by subscales from the Children's Self-Perceptions of Adequacy in and Predilection for Physical Activity scale (CSAPPA).

RESULTS

The variable most strongly associated with adequacy and predilection was the PACER shuttle run score. The PACER accounted for 10.9% of the variance in adequacy and 9.9% of the variance in predilection. Participants' age was inversely related to adequacy (β = - 0.374) and predilection (β = - 0.621). The combination of other variables related to adequacy brought the total variance explained to 14.7%, while the model for predilection explained a total of 13.7%.

CONCLUSIONS

Results indicate an association between cardiorespiratory fitness and measures of physical activity adequacy and predilection. These findings suggest that practitioners should consider the physiological and psychological makeup of the child, and ways to enhance adequacy and predilection among children with limited cardiorespiratory fitness, in order to create the best possible environment for all children to participate in physical activity.

Cross-sectional and prospective associations between sleep, screen time, active school travel, sports/exercise participation and physical activity in children and adolescents

BACKGROUND

The aim of this study was to investigate how sleep, screen time, active school travel and sport and/or exercise participation associates with moderate-to-vigorous physical activity (MVPA) in nationally representative samples of Norwegian 9- and 15-y-olds, and whether these four behaviors at age nine predict change in MVPA from age nine to 15 years.

METHOD

We pooled cross-sectional accelerometer and questionnaire data from 9- (n = 2366) and 15-y-olds (n = 1554) that participated in the first (2005/06) and second (2011/12) wave of the Physical Activity among Norwegian Children Study to investigate cross-sectional associations. To investigate prospective associations, we used data from a sub-sample that participated in both waves (at age nine and 15 years, n = 517).

RESULTS

Cross-sectional analyses indicated a modest, inverse association between screen time and MVPA among 9- (- 2.2 min/d (95% CI: -3.1, - 1.3)) and 15-y-olds (- 1.7 min/d (95% CI: -2.7, - 0.8)). Compared to their peers with 0-5 min/d of active travel to school, 9- and 15-y-olds with ≥16 min/d accumulated 7.2 (95% CI: 4.0, 10.4) and 9.0 (95% CI: 3.8, 14.1) more min/d of MVPA, respectively. Nine-y-old boys and 15-y-olds reporting ≥8 h/week of sports and/or exercise participation accumulated 14.7 (95% CI: 8.2, 21.3) and 17.9 (95% CI: 14.0, 21.8) more min/d of MVPA, respectively, than those reporting ≤2 h/week. We found no cross-sectional association between sleep duration and MVPA in either age group. None of the four behaviors predicted change in MVPA from age nine to 15 years (p ≥ 0.102).

CONCLUSION

Active travel to school and sport/exercise participation may be important targets for future interventions aimed at increasing MVPA in children and adolescents. However, future studies are needed to determine causality.

Individual calibration of accelerometers in children and their health-related implications

This study compared children's physical activity (PA) levels, the prevalence of children meeting current guidelines of ≥60 minutes of daily moderate to vigorous PA (MVPA), and PA-health associations using individually calibrated (IC) and empirical accelerometer cutpoints. Data from 75 (n = 32 boys) 10-12 year old children were included in this study. Clustered cardiometabolic (CM) risk, directly measured cardiorespiratory fitness (CRF), anthropometric and 7 day accelerometer data were included within analysis. PA data were classified using Froude anchored IC, Evenson et al. (Evenson, K. R., Catellier, D. J., Gill, K., Ondrak, K. S., & McMurray, R. G. (2008). Calibration of two objective measures of physical activity for children. Journal of Sports Sciences, 26(14), 1557-1565. doi:10.1080/02640410802334196) (Ev) and Mackintosh et al. (Mackintosh, K. A., Fairclough, S. J., Stratton, G., & Ridgers, N. D. (2012). A calibration protocol for population-specific accelerometer cutpoints in children. PLoS One, 7(5), e36919. doi:10.1371/journal.pone.0036919) (Mack) cutpoints. The proportion of the cohort meeting ≥60mins MVPA/day ranged from 37%-56% depending on the cutpoints used. Reported PA differed significantly across the cutpoint sets. IC LPA and MPA were predictors of CRF (LPA: standardised β = 0.32, p = 0.002, MPA: standardised β = 0.27 p = 0.013). IC MPA also predicted BMI Z-score (standardised β = -0.35, p = 0.004). Ev VPA was a predictor of BMI Z-score (standardised β = -0.33, p = 0.012). Cutpoint choice has a substantial impact on reported PA levels though no significant associations with CM risk were observed. Froude IC cutpoints represent a promising approach towards classifying children's PA data.

Systematic review of the relationships between objectively measured physical activity and health indicators in school-aged children and youth

Moderate-to-vigorous physical activity (MVPA) is essential for disease prevention and health promotion. Emerging evidence suggests other intensities of physical activity (PA), including light-intensity activity (LPA), may also be important, but there has been no rigorous evaluation of the evidence. The purpose of this systematic review was to examine the relationships between objectively measured PA (total and all intensities) and health indicators in school-aged children and youth. Online databases were searched for peer-reviewed studies that met the a priori inclusion criteria: population (apparently healthy, aged 5-17 years), intervention/exposure/comparator (volumes, durations, frequencies, intensities, and patterns of objectively measured PA), and outcome (body composition, cardiometabolic biomarkers, physical fitness, behavioural conduct/pro-social behaviour, cognition/academic achievement, quality of life/well-being, harms, bone health, motor skill development, psychological distress, self-esteem). Heterogeneity among studies precluded meta-analyses; narrative synthesis was conducted. A total of 162 studies were included (204 171 participants from 31 countries). Overall, total PA was favourably associated with physical, psychological/social, and cognitive health indicators. Relationships were more consistent and robust for higher (e.g., MVPA) versus lower (e.g., LPA) intensity PA. All patterns of activity (sporadic, bouts, continuous) provided benefit. LPA was favourably associated with cardiometabolic biomarkers; data were scarce for other outcomes. These findings continue to support the importance of at least 60 min/day of MVPA for disease prevention and health promotion in children and youth, but also highlight the potential benefits of LPA and total PA. All intensities of PA should be considered in future work aimed at better elucidating the health benefits of PA in children and youth.

Motor Performance as Predictor of Physical Activity in Children: The CHAMPS Study-DK

PURPOSE

Physical activity (PA) is associated with several health benefits in children, and PA habits developed in childhood tend to persist into adulthood. PA may be the foundation of a healthy lifestyle, and motor performance has been shown to be positively associated with PA in cross-sectional studies. The purpose of this study was to explore the longitudinal relation between motor performance and PA in a 3-yr follow-up study.

METHODS

Longitudinal analyses were performed using data from 673 participants (44% boys, 6-12 yr old) who had been included in the Childhood Health Activity and Motor Performance School study-DK. Baseline motor performance tests consisted of vertical jump, shuttle run, hand grip strength, backward balance, precision throw, and cardiovascular fitness. Composite z-scores were generated to express health-related fitness and performance-related fitness. PA was measured by accelerometer at baseline and at 3-yr follow-up and was expressed as a percentage of time in moderate-to-vigorous PA.

RESULTS

Cardiovascular fitness, vertical jump, health-related fitness, and performance-related fitness showed significant positive associations with 3-yr follow-up measures of PA in both sexes. Furthermore, shuttle run showed significant inverse associations with follow-up measures of PA for both sexes.

CONCLUSIONS

Cardiorespiratory fitness, shuttle run, vertical jump, health-related fitness, and performance-related fitness were significantly associated with time spent in moderate-to-vigorous PA at 3-yr follow-up. The clinical relevance of the results indicates that cardiorespiratory fitness and shuttle run in childhood may be important determinants of PA in adolescence.

Effect of Physically Active Academic Lessons on Body Mass Index and Physical Fitness in Primary School Children

BACKGROUND

Preventing overweight and improving physical fitness in primary school children is a worldwide challenge, and physically active intervention programs usually come with the cost of academic instruction time. This study aimed to investigate effects of physically active academic lessons on body mass index (BMI) and physical fitness in primary school children.

METHODS

Dutch children attending second- or third-grade class from 12 primary schools (N = 376; 8.1 ± 0.7 years) were randomly assigned to a 22-week intervention program or to the control group. In addition to measuring BMI before and after the intervention, physical fitness was measured with 5 items of the Eurofit test battery, measuring cardiovascular and muscular fitness.

RESULTS

Multilevel analysis showed a significant interaction effect between condition (intervention vs control) and grade (B = -0.47; p < .05). For third-grade children, BMI of the intervention group did not change significantly during the intervention period, whereas a significant increase was found in the control group. No significant main or interaction effects were found for cardiovascular or muscular fitness.

CONCLUSIONS

The current physically active academic lessons had positive effects on BMI in third-grade children, but had no effects on cardiovascular and muscular fitness.

Long-term effects of physically active academic lessons on physical fitness and executive functions in primary school children

Integrating physical activity into the curriculum has potential health and cognitive benefits in primary school children. The aim of this study was to investigate the effects of physically active academic lessons on cardiovascular fitness, muscular fitness and executive functions. In the current randomized controlled trial, 499 second and third graders within 12 primary schools (mean age = 8.1 ± 0.7) were randomized to the intervention (n = 249) or control condition (n = 250). The physically active academic lessons were given for 2 consecutive school years, 22 weeks per year, three times a week, with a duration of 20-30 min per lesson. Multiple tests were administered before, between and after the intervention period, measuring cardiovascular fitness, muscular fitness and executive functions. Multilevel analysis accounted for the nested structure of the children within classes and schools. Results showed a larger improvement in speed-coordination (B = -0.70,P = 0.002) and a lower improvement in static strength (B = -0.92,P < : 0.001) for the intervention group compared with the control group. The current lessons did not result in a significant change in executive functions.

Physical activity and its correlates in children and adolescents post-liver transplant

The health benefits of PA are well established for healthy and chronically ill children. This study objectively measures physical fitness and PA levels in children PLT and explores potential correlates and perceived barriers impacting their PA. A total of 23 children (16 females, mean 14.01 ± 2.49 yrs) >1 yr PLT were assessed for peak oxygen consumption (VO2 peak), muscle strength, endurance, and flexibility. MVPA and steps/day were determined with accelerometry. Additionally, SE, perceived fatigue, and barriers and benefits of PA were examined. VO2 peak (mean 33. 2 ± 7.61 mL/kg/min; 77.0 ± 15.6% predicted) and PA (average 6841 ± 2299 steps/day) were below healthy norms. MVPA (31.6 ± 16.1 min/day) was lower than national guidelines. Six participants (30%) attained criterion standards for abdominal strength and one participant (5%) for push-ups. Fatigue and SE were lower than reported levels in healthy children. A commonly perceived barrier to PA was "I am tired." A positive correlation was shown between SE and MVPA (r = 0.57, p = 0.007), SE and fatigue (r = 0.54, p = 0.01), and PELD score and fatigue (r = 0.66, p = 0.007). Children PLT demonstrate below normal levels of PA and aerobic capacity. SE is a modifiable correlate of their PA. Further investigation of the impact of PA correlates can guide the development of future innovative PA intervention strategies in children PLT.

Associations of Physical Activity, Sports Participation and Active Commuting on Mathematic Performance and Inhibitory Control in Adolescents

Objectives

To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents.

Methods

The design was cross-sectional. A convenient sample of 869 sixth and seventh grade students (12–14 years) was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical activity was assessed with GT3X and GT3X+ accelerometers presented in sex-specific quartiles of mean counts per minute and mean minutes per day in moderate-to-vigorous physical activity. Active commuting and sports participation was self-reported. Mixed model regression was applied. Total physical activity level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer.

Results

Non-cyclists in the 2^nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2^nd and 3^rd quartile of moderate-to-vigorous physical activity relative to the least active quartile. Non-cyclists in the 3^rd quartile of counts per minute had an improved reaction time and cyclists in the 2^nd quartile of counts per minute and moderate-to-vigorous physical activity displayed an improved accuracy, whereas non-cyclists in the 2^nd quartile of counts per minute showed an inferior accuracy relative to the least active quartile. Bicycling to school and organized sports participation were positively associated with mathematic performance.

Conclusions

Sports participation and bicycling were positively associated with mathematic performance. Results regarding objectively measured physical activity were mixed. Although, no linear nor dose-response relationship was observed there was no indication of a higher activity level impairing the scholastic or cognitive performance.

Better Movers and Thinkers (BMT): An Exploratory Study of an Innovative Approach to Physical Education

Recent research has confirmed a positive relationship between levels of physical activity and academic achievement. Some of these studies have been informed by neurological models of Executive Functioning (EF). There is a general consensus within the literature that the three core EF skills are; working memory, inhibitory control and cognitive flexibility. The development of these core EF skills has been linked with learning and academic achievement and is an essential component in the delivery of PE using a new and innovative approach called ‘Better Movers and Thinkers (BMT).’ A mixed methods design was used to investigate the effectiveness and feasibility of a 16-week intervention programme using BMT where 46 children were tested on two separate occasions for coordination and balance control, academic skills, working memory and non-verbal reasoning skills. One school acted as the control condition (21 students, aged 9 – 10 years) and another school acted as the intervention condition (25 students, aged 9 – 10 years). Quantitative data revealed an effect between pre and post-test conditions in the areas of phonological skills (p = .042), segmentation skills (p = .014) and working memory (p = .040) in favour of the intervention condition. Further analysis identified a gender-interaction with male students in the intervention condition making significant gains in phonological skills (p = .005) segmentation skills (p = .014) and spelling (p = .007) compared to boys in the control condition. Analysis of qualitative data from a sample of students from the intervention condition and their class teacher indicated good acceptability of BMT as an alternative approach to PE.

Correlates of sports practice, occupational and leisure-time physical activity in Brazilian adolescents

OBJECTIVES

To analyze the relationship between different physical activity (PA) domains and sociodemographic, psychological, behavioral and biological factors in Brazilian adolescents.

METHODS

1,220 adolescents (55.1% female) aged between 10 and 16 years-old participated in this study. The Baecke questionnaire was used to evaluate different PA domains, namely occupational, sports and leisure-time. Socioeconomic status, number of siblings, friendships satisfaction, mother's and father's PA level and previous experience with sports were self-reported. Cardiorespiratory fitness, waist circumference, and somatic maturity were estimated by objective indicators. Linear regression was used for the main statistical analysis.

RESULTS

The variables consistently related to all of the PA domains were gender (boys more active), friendship satisfaction (positive with sports and leisure-time PA and negative with occupational PA) and cardiorespiratory fitness (positive). There were also domain-specific relationships for occupational (number of siblings [β = 0.02] and father's PA [β = 0.13]), sport practice (previous experience with sports [β = 0.33], waist circumference [β = 0.01] and somatic maturity [β = -0.12]) and leisure-time PA (chronological age [β = -0.15], mother's PA [β = 0.47] and previous experience with sports [β = 0.17]).

CONCLUSIONS

The different domains of PA are related to specific variables in adolescence. This information may be helpful in formulating strategies for physical activity promotion, particularly in adolescents from low-to-middle income countries.

The influence of aerobic fitness on obesity and its parent-offspring correlations in a cross-sectional study among German families

BACKGROUND

Overweight/obesity is an important public health burden worldwide, increasing the risk for the development of cardiovascular diseases or the metabolic syndrome. This risk may be reduced by a good aerobic fitness (AF) that can be improved by physical activity but is also influenced by genetic factors. The aim of this study was to test for familial aggregation of AF measured by maximal oxygen uptake (VO2max) and to estimate its heritability. Furthermore, an exploratory analysis of the association between overweight/obesity and AF was performed. In contrast to previous studies, all analyses were adjusted for additional environmental and behavioral factors, in particular for objectively measured physical activity (PA) in addition to body mass index (BMI).

METHODS

79 families (157 parents, 132 children) performed a maximum exercise test (spiroergometry) to assess maximum oxygen uptake. PA was measured by accelerometry. Familial aggregation of AF was determined using a two-step design: AF was adjusted for age, sex and age*sex using linear regression. Afterwards, the residuals were used to determine the intraclass correlation coefficient (ICC) by ANOVA. Heritability and associations were estimated by generalized linear mixed models.

RESULTS

Familial aggregation of AF (ICC = 0.22, p < 0.001) was significant but decreased when adjusted for PA or BMI. Its heritability was estimated as 40% (adjusted for PA) using the mid-parent-offspring design. Relative to the middle quintile of AF residuals, the odds of being overweight/obese were three- to tenfold reduced in the upper quintile (adjusted for age, sex, age*sex, PA).

CONCLUSIONS

AF clustered in families after controlling for PA, BMI and parental smoking. Heritability was stronger for mother-child pairs as compared to father-child pairs after controlling for PA and BMI. Above average AF was negatively associated with overweight/obesity.

Assessment of physical activity and energy expenditure: an overview of objective measures

The ability to assess energy expenditure (EE) and estimate physical activity (PA) in free-living individuals is extremely important in the global context of non-communicable diseases including malnutrition, overnutrition (obesity), and diabetes. It is also important to appreciate that PA and EE are different constructs with PA defined as any bodily movement that results in EE and accordingly, energy is expended as a result of PA. However, total energy expenditure, best assessed using the criterion doubly labeled water (DLW) technique, includes components in addition to physical activity energy expenditure, namely resting energy expenditure and the thermic effect of food. Given the large number of assessment techniques currently used to estimate PA in humans, it is imperative to understand the relative merits of each. The goal of this review is to provide information on the utility and limitations of a range of objective measures of PA and their relationship with EE. The measures discussed include those based on EE or oxygen uptake including DLW, activity energy expenditure, physical activity level, and metabolic equivalent; those based on heart rate monitoring and motion sensors; and because of their widespread use, selected subjective measures.

Physical activity, cardiorespiratory fitness, and clustered cardiometabolic risk in 10- to 12-year-old school children: the REACH Y6 study

OBJECTIVES

(1) Investigate whether clustered cardiometabolic risk score, cardiorespiratory fitness (CRF), sedentary time (ST), and body mass index Z-scores (BMI Z-scores), differed between participants that met and did not achieve ≥60 min of daily moderate to vigorous intensity physical activity (MVPA). (2) Compare clustered cardiometabolic risk score, BMI Z-score, ST, and MVPA by CRF status.

METHODS

One hundred and one (n = 45 boys) 10- to 12-year-old participants took part in this cross-sectional study, conducted in Liverpool (Summer 2010) and Ulster (Spring 2011) UK. Assessments of blood markers, stature, sitting stature, body mass, waist circumference, flow mediated dilation (FMD), and resting blood pressure (BP) were completed. CRF (VO2 peak) was estimated using an individually calibrated treadmill protocol. Habitual MVPA and ST were assessed using an individually calibrated accelerometer protocol. Clustered cardiometabolic risk scores were calculated using blood markers, FMD (%), BP and anthropometric measures. Participants were classified as active (≥60 min MVPA) or inactive and as fit or unfit. Multivariate analysis of covariance (MANCOVA) was used to investigate differences in cardiometabolic risk, BMI Z-score, CRF, and ST by activity status. MANCOVA was also completed to assess differences in cardiometabolic risk, MVPA, ST, and BMI Z-score by fitness status.

RESULTS

Inactive children exhibited significantly higher clustered cardiometabolic risk scores and ST, and lower CRF than active children. Unfit participants exhibited significantly higher clustered cardiometabolic risk scores, BMI Z-scores and ST and lower MVPA in comparison to fit participants.

CONCLUSIONS

This study highlights the importance of children achieving 60 min MVPA daily and provides further evidence surrounding the importance of CRF for health.

Objectively measured activity in 8-10-year-old Turkish children: relationship to health-related fitness

BACKGROUND

No objective data regarding the physical activity (PA) levels of young Turkish children currently exist. Furthermore, whether habitual PA is associated with the components of health-related fitness among children is unclear. The aim of this study was to evaluate the patterns and levels of objectively measured PA in prepubertal Turkish children and its relationship with body fatness, aerobic and anaerobic fitness.

METHODS

Eighty-nine 8-10-year-old children (47 boys and 42 girls) participated in this study. The intensity, duration and frequency of PA were assessed from 4 days of heart rate monitoring with 15 s sampling intervals. Body fatness was determined by measuring skinfold thickness. Anaerobic fitness was evaluated using the Wingate test. All the children performed the shuttle run test to assess aerobic fitness.

RESULTS

The PA of boys was significantly higher than that of girls (P < 0.05). Gender difference is more marked for vigorous PA. Instead of sustained PA, short bouts of PA, lasting up to 1 min, were characteristic of PA patterns of children. The duration and frequency of PA were positively related to aerobic fitness and negatively related to fatness for both gender groups (P < 0.05). These relationships were more prominent for accumulated PA than for other measures of PA. No relationship was obtained between PA and anaerobic fitness in either gender group (P > 0.05).

CONCLUSIONS

Intermittent, accumulated moderate intensity PA may be more important than sustained vigorous intensity PA in influencing children's fitness and fatness levels. Detailed studies are needed to clarify which dimension of PA is more beneficial for health-related fitness in children.

Screen time viewing behaviors and isometric trunk muscle strength in youth

PURPOSE

The objective of this study was to examine the association of screen time viewing behavior with isometric trunk muscle strength in youth.

METHODS

A cross-sectional study was carried out including 606 adolescents (14-16 yr old) participating in the Danish European Youth Heart Study, a population-based study with assessments conducted in either 1997/1998 or 2003/2004. Maximal voluntary contractions during isometric back extension and abdominal flexion were determined using a strain gauge dynamometer, and cardiorespiratory fitness (CRF) was obtained using a maximal cycle ergometer test. TV viewing time, computer use, and other lifestyle behaviors were obtained by self-report. Analyses of association of screen use behaviors with isometric trunk muscle strength were carried out using multivariable adjusted linear regression.

RESULTS

The mean (SD) isometric strength was 0.87 (0.16) N·kg-1. TV viewing, computer use, and total screen time use were inversely associated with isometric trunk muscle strength in analyses adjusted for lifestyle and sociodemographic factors. After further adjustment for CRF and waist circumference, associations remained significant for computer use and total screen time, but TV viewing was only marginally associated with muscle strength after these additional adjustments (-0.05 SD (95% confidence interval, -0.11 to 0.005) difference in strength per 1 h·d-1 difference in TV viewing time, P = 0.08). Each 1 h·d-1 difference in total screen time use was associated with -0.09 SD (95% confidence interval, -0.14 to -0.04) lower isometric trunk muscle strength in the fully adjusted model (P = 0.001). There were no indications that the association of screen time use with isometric trunk muscle strength was attenuated among highly fit individuals (P = 0.91 for CRF by screen time interaction).

CONCLUSIONS

Screen time use was inversely associated with isometric trunk muscle strength independent of CRF and other confounding factors.

Seasonal variations in physical fitness among elementary school children

There is empirical evidence that children's physical activity is dependent on climatic conditions. In addition, a correlation between physical activity level and physical fitness has been identified. In this longitudinal study, we investigate whether seasons have an influence on physical fitness. A total of 145 German elementary school children were tested every six months over a two-year period. We used the German Motor Test 6-18 to assess physical fitness. Performance in the 6-min endurance run (P < 0.001), bidirectional jumping (P < 0.001), the standing long jump (P = 0.026), the 20 m sprint (P = 0.006) and the stand-and-reach task (P = 0.017) was significantly better in summer than in winter. There were no differences in the ability to balance backwards (P = 0.120); in the winter, the results for push-ups (P < 0.001) and sit-ups (P < 0.001) were better than those in the summer. We have shown that physical fitness is significantly influenced by the season. Consequently, when children's fitness tests are used (e.g. as the basis for intervention programs, for classifying health-risk groups or for recognising talent), the season in which testing occurred should be reported and accounted for in future studies.