Direct and indirect effects of physiological, psychological and cognitive variables on academic achievement in children.

BACKGROUND: Associations between cardiorespiratory fitness (CRF), screen time, psychological well-being, executive functions, and academic achievement have been reported, however, few studies have analysed models considering the effect of all these variables on academic achievement. This study aims to analyse the direct and indirect associations of mothers' education level, CRF, screen time, psychological well-being, executive functions, with academic achievement in schoolchildren, by sex. METHODS: This was a cross-sectional analysis of MOVI-daFit! study including 519 schoolchildren (49.52% girls) aged 9-11 years old. Executive functions were assessed with the NIH Toolbox, CRF with the 20-m shuttle run test, academic achievement through the final academic grades in language and mathematics and mother's education level, screen time and well-being by questionnaires. RESULTS: Structural equation modelling revealed that in boys cognitive flexibility had a significant direct effect on academic achievement and screen time a total significant effect on academic achievement. In girls, CRF was associated with inhibition and psychological well-being, and this was associated with academic achievement. CONCLUSIONS: Physiological, psychological, and behavioural variables act together to impact academic achievement, and that differences by sex might exist. Thus, strategies to enhance academic achievement in schoolchildren should consider psychological well-being, CRF, screen time, and sex differences. IMPACT: Physiological, psychological, and behavioural variables, such as cardiorespiratory fitness, screen time, psychological well-being, and cognition all together have an impact on academic achievement, with differences by sex. Previous studies have demonstrated the separate effect of these variables, however, to date, this is the first study that analyses all together in the same model their impact on academic achievement, by sex. This study shows that in boys cognitive flexibility and screen time impact academic achievement. In girls, cardiorespiratory fitness is highly associated with psychological well-being, and this, in turn, was associated with academic achievement.

Effectiveness of high-intensity interval training on peripheral brain-derived neurotrophic factor in adults: A systematic review and network meta-analysis.

BACKGROUND: High-intensity interval training (HIIT) has emerged as an alternative training method to increase brain-derived neurotrophic factor (BDNF) levels, a crucial molecule involved in plastic brain changes. Its effect compared to moderate-intensity continuous training (MICT) is controversial. We aimed to estimate, and to comparatively evaluate, the acute and chronic effects on peripheral BDNF levels after a HIIT, MICT intervention or a control condition in adults. METHODS: The CINAHL, Cochrane, PubMed, PEDro, Scopus, SPORTDiscus, and Web of Science databases were searched for randomized controlled trials (RCTs) from inception to June 30, 2023. A network meta-analysis was performed to assess the acute and chronic effects of HIIT versus control condition, HIIT versus MICT and MICT versus control condition on BDNF levels. Pooled standardized mean differences (SMDs) and their 95% confidence intervals (95% CIs) were calculated for RCTs using a random-effects model. RESULTS: A total of 22 RCTs were selected for the systematic review, with 656 participants (aged 20.4-79 years, 34.0% females) and 20 were selected for the network meta-analysis. Network SMD estimates were significant for HIIT versus control condition (1.49, 95% CI: 0.61, 2.38) and MICT versus control condition (1.08, 95% CI: 0.04, 2.12) for acutely BDNF increase. However, pairwise comparisons only resulted in a significant effect for HIIT versus control condition. CONCLUSIONS: HIIT is the best training modality for acutely increasing peripheral BDNF levels in adults. HIIT may effectively increase BDNF levels in the long term.

The Erasmus+ EUMOVE project-a school-based promotion of healthy lifestyles to prevent obesity in European children and adolescents.

The aim of this study was to describe the goals, activities, and methods of EUMOVE project in developing a set of resources targeting both primary and secondary schools that allow the entire educational community to promote healthy lifestyles (HL). The EUMOVE project is an Erasmus+ program based in the Creating Active Schools (CAS) framework. The project lasted 3 years and was developed by 14 academic and non-governmental institutions from Spain, Portugal, France, Italy, and the UK. EUMOVE was divided into three phases. In the first phase, several work packages were carried out aimed to ensure the coordination/management of the project activities. In the second phase, seven educational resources strengthened by rigorous scientific research were developed to promote HL from schools. During the last phase, all the resources were disseminated through scientific seminars, workshops with families and teachers, and the online promotion by the non-governmental institutions of each country. The EUMOVE project developed and promoted a smartphone APP, video/activity repository of physically active lessons, active break virtual platform, learning units, and parent/teachers/school-leaders' guidelines to promote physical activity, active commuting, active school playgrounds, healthy diet, and sleep habits. To our knowledge, EUMOVE is the first European project to provide a set of practical tools based on scientific evidence to help schools or future school-wide interventions implement a paradigm shift based on the CAS framework for the promotion of HL. Future research will need to investigate the implementation, effectiveness, and scalability of this proposal.

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.

Effectiveness of MOVI-KIDS programme on health-related quality of life in children: Cluster-randomized controlled trial.

OBJECTIVE: To test the effectiveness of an 8-month school-based multicomponent intervention (MOVI-KIDS) in improving health-related quality of life (HRQoL) in schoolchildren. STUDY DESIGN: A randomized cluster trial was conducted including 1168 children aged 4-6 years who attended 21 schools in two Spanish provinces (Cuenca and Ciudad Real). MOVI-KIDS study is a multicomponent physical activity intervention, which consisted of (i) 3 × 60-min sessions/week, (ii) educational materials for parents and teachers, and (iii) school playground modifications. The parent's proxy report of the KINDL-R Spanish version (6 subdimensions and a total score), and the KINDL-R self-reported by children (total score) was used to measure HRQoL. Mixed linear regression models were conducted to test differences in each HRQoL dimension between intervention and control groups, controlling for baseline values, cardiorespiratory fitness, and socioeconomic status, by gender. RESULTS: The boys in the intervention group presented better scores on total HRQoL than the control group in both the parent (ß = 1.46; 95% CI: 0.23-2.70) and self-reported (ß = 2.13; 95% CI: 0.53-3.74) versions, as well as on the emotional well-being dimension (ß = 2.43; 95% CI: 0.48-4.36). There was no significant effect of the intervention on physical well-being, self-esteem, family, and friends. In girls, no statistically significant differences were found between those who participated in MOVI-KIDS and those who did not. CONCLUSION: Our data support gender differences in the effect of MOVI-KIDS, such that while in boys the intervention was successful in increasing total scores of HRQoL, as well as emotional well-being scores, the intervention was not effective in improving girls' HRQoL.

Effect of different types of exercise on fitness in people with multiple sclerosis: A network meta-analysis.

BACKGROUND: It is assumed that people with multiple sclerosis (MS) who participate in programs of physical exercise improve their physical fitness. OBJECTIVE: The aim of this network meta-analysis (NMA) was to analyze the effect of different types of exercise on muscular fitness and cardiorespiratory fitness (CRF) among people with MS and to determine the best type of exercise according to disease severity. METHODS: MEDLINE, the Physiotherapy Evidence Database, the Cochrane Library, SPORTDiscus, Scopus, and Web of Science were searched from inception to April 2022 to identify randomized controlled trials (RCTs) concerning the effect of physical exercise on fitness in people with MS. We ranked the types of physical exercise by calculating the surface under the cumulative ranking (SUCRA). RESULTS: We included 72 RCTs involving 2543 MS patients in this NMA. A ranking of five types of physical exercise (aerobic, resistance, combined [aerobic and resistance], sensorimotor training, and mind-body exercises) was achieved. Combined and resistance training had the highest effect sizes (0.94, 95% CI 0.47, 1.41, and 0.93, 95% CI 0.57, 1.29, respectively) and the highest SUCRA (86.2% and 87.0%, respectively) for muscular fitness. The highest effect size (0.66, 95% CI 0.34, 0.99) and SUCRA (86.9%) for CRF was for aerobic exercise. CONCLUSIONS: Combined and resistance training seem to be the most effective exercises to improve muscular fitness and aerobic exercise for CRF in people with MS.

European fitness landscape for children and adolescents: updated reference values, fitness maps and country rankings based on nearly 8 million test results from 34 countries gathered by the FitBack network.

OBJECTIVES: (1) To develop reference values for health-related fitness in European children and adolescents aged 6-18 years that are the foundation for the web-based, open-access and multilanguage fitness platform (FitBack); (2) to provide comparisons across European countries. METHODS: This study builds on a previous large fitness reference study in European youth by (1) widening the age demographic, (2) identifying the most recent and representative country-level data and (3) including national data from existing fitness surveillance and monitoring systems. We used the Assessing Levels of PHysical Activity and fitness at population level (ALPHA) test battery as it comprises tests with the highest test-retest reliability, criterion/construct validity and health-related predictive validity: the 20 m shuttle run (cardiorespiratory fitness); handgrip strength and standing long jump (muscular strength); and body height, body mass, body mass index and waist circumference (anthropometry). Percentile values were obtained using the generalised additive models for location, scale and shape method. RESULTS: A total of 7 966 693 test results from 34 countries (106 datasets) were used to develop sex-specific and age-specific percentile values. In addition, country-level rankings based on mean percentiles are provided for each fitness test, as well as an overall fitness ranking. Finally, an interactive fitness platform, including individual and group reporting and European fitness maps, is provided and freely available online (www.fitbackeurope.eu). CONCLUSION: This study discusses the major implications of fitness assessment in youth from health, educational and sport perspectives, and how the FitBack reference values and interactive web-based platform contribute to it. Fitness testing can be conducted in school and/or sport settings, and the interpreted results be integrated in the healthcare systems across Europe.

The role of daytime napping on salivary cortisol in children aged 0-5 years: a systematic review and meta-analysis.

Cortisol levels are implicated in emotional and cognitive development in children. However, it is not clear whether daytime napping influences cortisol levels in early childhood. This systematic review and meta-analysis aimed to synthesize the available evidence regarding the association between daytime napping and salivary cortisol in early childhood. The Medline, Embase, Web of Science, PsycINFO, and Cochrane Collaboration databases were searched for observational and experimental studies reporting data about napping behavior and salivary cortisol in children 0-5 years of age. Salivary cortisol levels were analyzed in three situations: CAR, cortisol awakening response from nap awakening; PRE-POST, before and after a daytime nap; and DIURNAL, from morning awakening to bedtime. Five studies showed a significant CAR after napping (mean difference, MD: 0.11µg/mL; 95% confidence interval, CI: 0.04, 0.18). In the PRE-POST analysis, a small decrease was observed for at-home naps (MD: -0.05 µg/mL; 95% CI: - 0.09, - 0.02) but not for at-childcare naps (MD: 0.04 µg/mL; 95% CI: - 0.01, 0.09). A similar pattern of DIURNAL salivary cortisol decrease was observed when children took a nap (MD: - 0.34 µg/mL; 95% CI: - 0.41, - 0.28) and when they did not sleep during the day (MD: - 0.28 µg/mL; 95% CI: - 0.38, - 0.19). CONCLUSIONS: Daytime napping plays a minor role in the fluctuation of salivary cortisol levels during the day. The conditions of the home or the childcare environment under which napping occurs might have a greater influence on cortisol levels than daytime napping itself in early childhood. PROSPERO Identifier: CRD42020212249. WHAT IS KNOWN: • The regulation of sleep involves circadian rhythmicity of cortisol secretion via activation of the HPA axis and a subsequent release of cortisol upon morning awakening followed by a decline throughout the day. WHAT IS NEW: • The available evidence supports the occurrence of a cortisol awakening response after a daytime nap. • A small decrease in cortisol after napping was observed when the nap occurred at home but not at childcare. • The conditions of the home or childcare environment under which the nap occurs and the activities before and after napping may have a greater influence on cortisol levels than napping itself.

Effect of Exercise on Fatigue in Multiple Sclerosis: A Network Meta-analysis Comparing Different Types of Exercise.

OBJECTIVE: A network meta-analysis (NMA) of current evidence was conducted to determine if physical exercise has a positive influence on multiple sclerosis (MS) fatigue and type of exercise with the largest effect on fatigue also according to disease severity. DATA SOURCES: MEDLINE, Embase, SPORTDiscus, Physiotherapy Evidence Database, Cochrane Library, and Web of Science. The search strategy combined relevant terms related to (1) MS; (2) clinical trials; (3) exercise; and (4) fatigue from inception to February 2021. STUDY SELECTION: Randomized controlled trials concerning the effectiveness of different types of exercise on total and physical fatigue in people with MS were included. DATA EXTRACTION: The data were extracted into predesigned data extraction tables. Risk of bias was evaluated with the Cochrane Risk of Bias tool (RoB 2.0), and the Grading of Recommendations, Assessment, Development, and Evaluation tool was used to evaluate the quality of the evidence. DATA SYNTHESIS: A total of 58 studies were examined. Data were pooled using a random-effects model. A ranking of 7 and 8 different exercise interventions for physical and total fatigue scores, respectively, was achieved. The highest effects for pairwise comparisons were for combined exercise and resistance training vs control (ranging between -0.74 and -1.24). In the NMA, combined exercise (-1.51; 95% confidence interval [CI], -2.01 to -1.01) and resistance training (-1.15; 95% CI, -1.81 to -0.49) compared with the control group achieved the highest effects for physical and total fatigue, respectively. CONCLUSIONS: Exercise should be considered an effective fatigue management strategy. Among the different exercise modalities, combined exercise is the most effective exercise modality for improving both physical and total fatigue. Resistance training is also an effective exercise for total fatigue among people diagnosed with MS.

Mediators between physical activity and academic achievement: A systematic review.

BACKGROUND: Research has suggested the beneficial effects of physical activity (PA) on academic achievement (AA). However, the mechanisms underlying this influence remain unclear. Some proposed mechanisms include physiological, cognitive, psychological, and behavioral paths. This study aimed to analyze mediators between PA and AA in children and adolescents. METHODS: Systematic search in Medline, SPORTDiscuss, PsycInfo, Scopus, and Web of Science for observational and experimental studies, published up to March 2021. RESULTS: Twenty-eight studies (75237 participants, aged 4-16) were included. The designs of these studies were: 21 studies cross-sectional, 5 longitudinal, and 2 experimental. Eight out of nine studies analyzing fitness as a mediator reported positive results, and one reported null finding. Adiposity was a significant mediator in one study, in two only in girls, and two reported null results. Cognition as a mediator was supported by four studies, whereas two reported null results. Regarding mental well-being, 10 out of 14 studies reported positive effects, and one out of five behavioral studies found positive results. Although studies were too sparse to draw conclusions, overall, the results indicated that self-esteem, self-image, self-efficacy, stress, and health behaviors might be potential mediators in the relationship between PA and AA. All studies were rated as medium-high quality. CONCLUSION: Overall, the available evidence seems to suggest that cardiorespiratory fitness, cognition, mental well-being, and exercise-related behaviors play some role as mediators of the relationship between PA and AA. However, the cross-sectional nature of most of the reviewed studies prevents us from making any statement in terms of causal paths. Thus, well-designed follow-up and randomized controlled studies aimed not only to tests the effect of PA in AA, but also to examine the influence of mediators are required.

The effectiveness of a high-intensity interval games intervention in schoolchildren: A cluster-randomized trial.

The aim of this study was to assess the effectiveness of a high-intensity interval training (HIIT) intervention based on playground games (MOVI-daFit!) on improvements in adiposity, physical fitness, and cardiometabolic risk factors in schoolchildren. A cluster-randomized controlled trial (RCT) was performed that included 562 schoolchildren (9-11 years) from 10 schools in Cuenca, Spain. The intervention consisted of four 60-min sessions per week in the school setting. Analyses were conducted on the intention-to-treat basis. Changes in physical fitness parameters (cardiorespiratory fitness: main outcome), body composition, blood pressure, and biochemical cardiometabolic risk parameters were analyzed using both mixed linear and logistic regression models, controlling for baseline covariates, Tanner stages, health dietary score index, body mass index, and cluster factor school. In boys, no significant differences in any outcome measure were noted except for the standing long jump test (10.13 cm; 95% CI 2.94 to 17.32; p = 0.006) between the intervention group (IG) and the control group (CG). Improvements in mean arterial pressure (-1.68 mmHg; 95% CI -3.28 to -0.08; p = 0.039), the triglyceride/HDL-c ratio (-0.36 mg/dl; 95% CI -0.59 to -0.13; p = 0.002), C-reactive protein (-0.23 mg/L; 95% CI -0.43 to -0.03), VO2 max (1.44 ml/kg/min; 95% CI 0.52 to 2.36, p = 0.002), 20-m shuttle run test (3.64 laps; 95% CI 0.51 to 6.78), and standing long jump test (7.04 cm; 95% CI 1.21 to 12.87; p = 0.018) were observed in girls in the IG compared with those in the CG. Body composition parameters did not change significantly in either boys or girls. Additionally, children with lower fitness levels obtained greater improvements than children with higher fitness levels. In conclusion, MOVI-daFit! may represent a good strategy for incorporating HIIT into playground games, although its implementation may need to be improved to extend the benefits to children and enhance its adherence.

Sex differences on the relation among gross motor competence, cognition, and academic achievement in children.

An association between gross motor competence (GMC) and academic achievement (AA) has been described, but the potential mechanisms behind this association are still unknown. It is not known either whether these mechanisms are similar for boys and girls. The aim of this study was to analyse whether the association between GMC and AA is mediated by executive functions (EFs), and to investigate whether this mediation differs by sex. This cross-sectional study involved 451 children aged 8 to 10 (234 girls; mean age 9.95 ± 0.59). The Movement Assessment Battery for Children-Second Edition (MABC-2), NIH Toolbox, and grades in language and mathematics were used to test GMC, EFs, and AA, respectively. Multifactorial structural equation model (SEM) was used to evaluate a possible relation between variables, controlling for confounders. The differences by sex were examined using a multi-group SEM approach. The results showed that EFs acted as a full mediator of the relationship between GMC and AA in boys (ß = 0.14, p = 0.012) but not in girls (ß = 0.10, p = 0.326). These results show that the benefit of GMC on AA is mediated by EFs in boys but not in girls. Nevertheless, these conclusions should be carefully considered due to the cross-sectional nature of the study.

Maternal Education and Academic Achievement in Schoolchildren: The Role of Cardiorespiratory Fitness.

OBJECTIVES: To examine the relationship between maternal education, cardiorespiratory fitness, and academic achievement in schoolchildren, specifically whether the association between maternal education and academic achievement is mediated by cardiorespiratory fitness. STUDY DESIGN: This is a secondary analysis of a cross-sectional study including 478 Spanish schoolchildren aged 8-11 years. ANOVA was used to test differences in cardiorespiratory fitness by maternal education level. ANCOVA was used to test the differences in academic achievement by the educational level of mothers and the cardiorespiratory fitness of children, controlling for each other. A mediation analysis was used to test if the relationship between maternal education and academic achievement was explained by cardiorespiratory fitness. RESULTS: A higher level of maternal education was associated with a higher cardiorespiratory fitness level and academic achievement in children; moreover, the cardiorespiratory fitness level in children was associated with better academic achievement (P < .05). Finally, cardiorespiratory fitness acted as a partial mediator of the relationship between maternal education and academic achievement in boys (z = 1.81; P = .03) but not in girls (z = 0.86; P = .19), explaining 6.54% of this relationship for the total sample and 6.67% for boys. CONCLUSIONS: This study suggests that the benefits of maternal education on academic achievement are partially explained by the mediating role of cardiorespiratory fitness.

A Cluster Mediation Analysis Confirms the Validity of the "Fat but Fit" Paradigm in Children's Cognitive Function and Academic Achievement.

OBJECTIVE: To evaluate the fat but fit conceptual model, testing whether this paradigm for body mass index (BMI) and maximum rate of oxygen consumption (VO2max) exists in schoolchildren and whether executive functions mediate the relationship between fat but fit categories and academic achievement. STUDY DESIGN: Cluster cross-sectional analyses of data from 554 children aged 9-11 from Cuenca, Spain. BMI, VO2max, core executive functions (inhibition, working memory, and cognitive flexibility) and academic achievement (language and mathematics). RESULTS: Cluster analysis of BMI and VO2max z-scores resulted in a 4-cluster solution that could be interpreted according to fat unfit, unfat unfit, fat fit, and unfat fit categories. ANCOVA models confirmed an increasing trend by cluster category in terms of VO2max levels and, conversely, a decreasing trend in terms of adiposity variables. These models also confirmed that children in the fat fit and unfat fit categories scored higher than their peers in the fat unfit and unfat unfit categories. Mediation analyses using fat but fit clusters as multicategory independent variable, executive functions as mediators, and academic achievement as outcome variable showed that the positive association between the BMI-VO2max clusters and academic achievement was mediated by inhibition levels in fat fit and unfat fit individuals, by working memory levels only in those classified as fat fit, and by cognitive flexibility only in unfat fit individuals. CONCLUSIONS: This study confirms the validity of the 4-cluster conceptual model regarding BMI and VO2max and reinforces the predictive validity, proving that fitness levels are able to counteract the detrimental effect of obesity on academic achievement.

Relationship between both cardiorespiratory and muscular fitness and health-related quality of life in children and adolescents: a systematic review and meta-analysis of observational studies.

BACKGROUND: No review to date has evaluated the association between physical fitness and health-related quality of life (HRQoL) in healthy children and adolescents. The aims of this systematic review and meta-analysis were to examine the relationship between both cardiorespiratory fitness (CRF) and muscular fitness (MF) and HRQoL in healthy subjects under 18 years of age and to describe the dimensions of HRQoL in which these relationships are more robust. METHODS: The Medline, Embase, Cochrane Library, SCIELO, SPORTDiscus and PEDro databases were systematically searched to collect observational studies that examined the relationship between CRF and HRQoL and between MF and HRQoL in participants under 18 years of age without any diagnosed medical condition. Pooled effect sizes (ES) were estimated for the associations between both CRF and MF and the various HRQoL dimensions. RESULTS: The pooled ES (95% CI) estimates for the relationship between CRF and HRQoL were as follows: 0.19 (0.10 to 0.27) for physical well-being, 0.19 (0.07 to 0.32) for psychological well-being, 0.20 (- 0.14 to 0.55) for perceived health status, 0.10 (0.00 to 0.20) for self-perception/self-esteem, 0.07 (- 0.05 to 0.19) for quality of family relationship, 0.14 (0.04 to 0.25) for quality of peer relationship, 0.17 (0.04 to 0.29) for everyday functioning at school and 0.20 (0.12 to 0.28) for total HRQoL score. The pooled ES (95% CI) estimates for the relationship between MF and HRQoL were: 0.25 (0.12 to 0.37) for physical well-being, 0.11 (0.04 to 0.17) for psychological well-being, 0.08 (0.01 to 0.15) for quality of family relationship, 0.14 (0.03 to 0.25) for quality of peer relationship, and 0.09 (0.03 to 0.14) for total HRQoL score. CONCLUSIONS: Our data suggest that both CRF and MF are positively associated with HRQoL, mainly in physical, psychological and peer relationships. Moreover, CRF is positively associated with school dimensions and MF is positively associated with family relationships. Trail registration Protocol PROSPERO registration number: CRD42015025823.

School-based interventions modestly increase physical activity and cardiorespiratory fitness but are least effective for youth who need them most: an individual participant pooled analysis of 20 controlled trials.

OBJECTIVES: To determine if subpopulations of students benefit equally from school-based physical activity interventions in terms of cardiorespiratory fitness and physical activity. To examine if physical activity intensity mediates improvements in cardiorespiratory fitness. DESIGN: Pooled analysis of individual participant data from controlled trials that assessed the impact of school-based physical activity interventions on cardiorespiratory fitness and device-measured physical activity. PARTICIPANTS: Data for 6621 children and adolescents aged 4-18 years from 20 trials were included. MAIN OUTCOME MEASURES: Peak oxygen consumption (VO2Peak mL/kg/min) and minutes of moderate and vigorous physical activity. RESULTS: Interventions modestly improved students' cardiorespiratory fitness by 0.47 mL/kg/min (95% CI 0.33 to 0.61), but the effects were not distributed equally across subpopulations. Girls and older students benefited less than boys and younger students, respectively. Students with lower levels of initial fitness, and those with higher levels of baseline physical activity benefitted more than those who were initially fitter and less active, respectively. Interventions had a modest positive effect on physical activity with approximately one additional minute per day of both moderate and vigorous physical activity. Changes in vigorous, but not moderate intensity, physical activity explained a small amount (~5%) of the intervention effect on cardiorespiratory fitness. CONCLUSIONS: Future interventions should include targeted strategies to address the needs of girls and older students. Interventions may also be improved by promoting more vigorous intensity physical activity. Interventions could mitigate declining youth cardiorespiratory fitness, increase physical activity and promote cardiovascular health if they can be delivered equitably and their effects sustained at the population level.

Fitness and executive function as mediators between physical activity and academic achievement.

Physical activity is related with academic achievement in children. This cross-sectional study aimed to assess whether cardiorespiratory fitness (CRF) and executive function act as mediators of the association between moderate to vigorous physical activity (MVPA) and academic achievement. This study included 186 schoolchildren (9-11 years) from Cuenca, Spain. Sociodemographic variables, anthropometric variables, academic achievement, executive function (inhibition, cognitive flexibility and working memory), CRF (20-m shuttle run) and physical activity (by accelerometry) were measured. Serial mediation models were estimated using the Hayes´ PROCESS macro. The significant paths in the model mediating this relationship between MVPA and academic achievement were as follows: MVPA → CRF → academic achievement (IE = 0.068, 95% CI: [0.018; 0.127]; IE = 0.079, 95% CI: [0.029; 0.144]; and IE = 0.090, 95% CI: [0.032; 0.165], controlling for inhibition, cognitive flexibility and working memory, respectively), MVPA → CRF → inhibition → academic achievement (0.018, 95% CI: [0.001; 0.047]) and MVPA → cognitive flexibility → academic achievement (0.087, 95% CI: [0.012; 0.169]). The relationship between MVPA and academic achievement may not be direct but mediated by CRF, cognitive flexibility, and inhibition via CRF. Physical activity interventions to improve AA should be focused on improvements in CRF and executive function.

Relation between physical fitness and executive function variables in a preschool sample.

BACKGROUND: This study examined the association between key components of physical fitness with inhibition and cognitive flexibility in preschoolers. METHODS: This was a cross-sectional study of 362 Spanish preschoolers. The key components of physical fitness and executive functioning were measured. RESULTS: The partial correlation controlling for body mass index and family socioeconomic status showed that inhibition was positively related to cardiorespiratory fitness. No association was found between muscular strength (i.e., standing long jump and dynamometry) and speed/agility with inhibition or between physical fitness components and cognitive flexibility. The inhibition mean scores were significantly higher in preschoolers with higher cardiorespiratory than in their peers who were in lower categories, after adjustments were made for confounders. Additionally, the results showed that cardiorespiratory fitness was a significant predictor of inhibition, but for cognitive flexibility, age was the only significant predictor. CONCLUSIONS: Our data suggest that cardiorespiratory fitness is associated with inhibition in preschoolers. Likewise, our results also suggest that cognitive flexibility is an executive function that is more dependent on changes associated with age at this development stage. These findings are important for supporting initiatives that aimed at stimulating healthy brain development, and promote the improvement of cardiorespiratory fitness at early ages.

Obesity and thinness prevalence trends in Spanish schoolchildren: are they two convergent epidemics?

BACKGROUND: The objective of this study was to analyse the secular trends in body composition variables and weight status among Spanish schoolchildren from 1992 to 2017, and to examine the persistence in the same weight status category from 2013 to 2017 of the birth cohort in 2007-08. METHODS: The data for the prevalence/trend analysis were taken from cross-sectional analyses conducted in 1992 (n = 308), 1996 (n = 307), 1998 (n = 275), 2004 (n = 1119), 2010 (n = 912), 2013 (n = 352) and 2017 (n = 275) using similar procedure methods among schoolchildren (aged 4-6 y and 8-11 years) from 22 public schools in the province of Cuenca, Spain. The data for the longitudinal analysis were obtained from cross-sectional analyses of measurements gathered in 2013 and 2017 in the same cohort of children (n = 275) born in 2007 and 2008. Weight, height, body fat percentage (by electronic bioimpedance) and waist circumference were measured by trained personnel. Weight status was defined according to the BMI cut-offs proposed by the International obesity task force (IOTF) criteria. RESULTS: In schoolchildren, the overall prevalence of thinness increased from 5.9% in 1992 to 14.5% in 2017, P < 0.001. Whereas, the overall prevalence of obesity/overweight remained relatively steady between the same time period (from 25.2% to 26.9%), P = 0.599. In relation to the longitudinal analyses, we observed that 70.9% of schoolchildren in 2017 remained in the same weight status category as in 2013. CONCLUSIONS: The child obesity epidemic in Spain has remained relatively stable over the last two decades. However, the prevalence of thinness shows a worrying upward trend.

Effectiveness of a school-based physical activity intervention on adiposity, fitness and blood pressure: MOVI-KIDS study.

OBJECTIVE: To test a physical activity intervention (MOVI-KIDS) on obesity indicators, physical fitness and blood pressure (BP) in children. METHODS: A crossover randomised cluster trial was conducted, which comprised 1434 children (4-7 years old) from 21 schools in the provinces of Cuenca and Ciudad Real in the Castilla-La Mancha region of Spain. The intervention consisted of three 60 min sessions/week on weekdays between October 2013 and May 2014. Changes in anthropometric variables, physical fitness and BP parameters were measured. The analyses used were mixed regression models to adjust for baseline covariates under cluster randomisation. RESULTS: There was no significant improvement in overweight/obesity with the intervention compared with the control group in both sexes. Further, the intervention did not alter other adiposity indicators or BP parameters. Improvements in cardiorespiratory fitness were seen in girls (1.19; 95% CI 0.31 to 2.08; p=0.008), but not in boys. Finally, there was an improvement in velocity/agility in both girls (-2.51 s; 95% CI -3.98 to -1.05; p=0.001) and boys (-2.35 s; 95% CI -3.71 to -0.98; p=0.001), and in muscular strength in both girls (0.66; 95% CI 0.03 to 1.28; p=0.038) and boys (1.26; 95% CI 0.03 to 1.28; p<0.001). CONCLUSION: MOVI-KIDS was not successful in reducing the adiposity and maintained BP levels at previous healthy values in children. The intervention, however, showed significant improvements in cardiorespiratory fitness in girls, and muscular strength and velocity/agility in boys and girls. TRIAL REGISTRATION NUMBER: NCT01971840; Post-results.