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.

Are Physical Activity Interventions Effective in Improving Health-Related Quality of Life in Children and Adolescents? A Systematic Review and Meta-Analysis.

CONTEXT: Physical activity (PA) interventions improve well-being and positive mental health in children and adolescents, but the results of previous systematic reviews included participants with chronic medical conditions and did not accurately assess the multidimensional nature of health-related quality of life (HRQoL). OBJECTIVE: The aims of this meta-analysis were to (1) evaluate the effects of PA interventions on several domains of HRQoL in healthy <18-year-olds and (2) examine the effectiveness of interventions on HRQoL according to whether they were successful in increasing PA, the type of intervention delivered, and the duration of the intervention. DATA SOURCES: PubMed (Medline), EMBASE, the Cochrane Library, SCIELO, SPORTDiscus, and PEDro databases were systematically searched from inception to September 30, 2022. STUDY SELECTION: Experimental studies that examined the effectiveness of PA interventions on HRQoL participants aged <18 years. STUDY DESIGN: Systematic review with meta-analysis and meta-regression. LEVEL OF EVIDENCE: Level 1. METHODS: Random-effects models were used to calculate pooled effect size (ES) for total HRQoL score and its dimensions. Subgroup analyses were conducted to examine the effect of PA program characteristics. RESULTS: A total of 17 studies were included. Pooled ES (95% CI) estimations were as follows: 0.179 (0.045, 0.002) for total HRQoL score, 0.192 (0.077, 0.306) for physical well-being, 0.158 (0.080, 0.237) for psychological well-being, 0.118 (0.044, 0.192) for autonomy and parent relation, 0.135 (0.043, 0.227) for social support and peers, and 0.129 (-0.013, 0.270) for school environment. Subgroup analyses suggested there were no differences in the effectiveness of the interventions by category of PA increase or by type and duration of intervention. CONCLUSION: Exercise interventions are an effective strategy for improving overall HRQoL and its most significant domains in children and adolescents.

Parents' Perceptions of Children's and Adolescents' Use of Electronic Devices to Promote Physical Activity: Systematic Review of Qualitative Evidence.

BACKGROUND: The use of physical activity (PA) electronic devices offers a unique opportunity to engage children and adolescents in PA. For this age group (2-17 years), parents play a key role in promoting healthy lifestyles and regulating the use of electronic devices. Therefore, parents' perceptions of the use of electronic devices for PA in children and adolescents are critical for efficient intervention. OBJECTIVE: The aim of this qualitative systematic review was to improve the understanding of parents' perceptions of the use of electronic devices for PA in children and adolescents. METHODS: A systematic search of electronic databases (Medline/PubMed, SPORTDiscus, Web of Science, Scopus, OpenGrey, and Deep Blue) was conducted. Studies from inception (2010) to May 2022 were identified. Qualitative studies on the perceptions of healthy children's and adolescents' (aged 2-17 years) parents regarding PA interventions performed on electronic devices were included according to the Cochrane Qualitative and Implementation Methods Group Guidance Series and the Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) statement. The Joanna Briggs Institute Qualitative Assessment and Review Instrument was used for methodological validity. RESULTS: In total, 18 studies with 410 parents, mostly mothers, were included. Parents' perceptions were grouped into 4 categories: usefulness, advantages, general perceptions (electronic devices for health promotion, preferences for real-life PA, and concerns), and acceptability (barriers and facilitators) of electronic devices for PA. Parents perceived electronic devices as useful for increasing PA, learning new skills, and increasing motivation for PA and valued those devices that promoted socialization and family and peer bonding. In terms of general perceptions, parents had positive attitudes toward PA electronic devices; however, they preferred outdoor and real-life PA, especially for preschoolers and children. Concerns, such as physical and psychological harm, addiction, conflicts, and compliance difficulties, were found. Facilitators were identified as ease of use, appropriate feedback, promotion of socialization, and motivational strategies, such as rewards, challenges, and attractiveness. Barriers, such as discomfort, price, and difficulties in using or understanding electronic devices, were also identified. For older children and adolescents, parents were more concerned about high levels of screen time and setting limits on electronic devices and therefore preferred PA electronic devices rather than traditional ones. CONCLUSIONS: Overall, the participants had positive attitudes toward electronic devices for PA and perceived them as an effective way to promote PA in children and adolescents. They also perceived several benefits of using electronic devices, such as health promotion, increased awareness and motivation, and socialization, as well as barriers, facilitators, and age differences. The results of this study could provide researchers with insights into designing more effective, age-appropriate PA electronic devices for children and adolescents and improving adherence to their use. TRIAL REGISTRATION: PROSPERO CRD42021292340; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=292340.

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.

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.

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.

Validity and reliability of the International fItness scale (IFIS) in preschool children.

Objectives: Examine the validity and reliability of parent-reported International FItness Scale (IFIS) in preschoolers. Method: A cross-sectional study of 3051 Spanish preschoolers (3-5 years). Fitness was measured by PREFIT battery and reported by parents using an adapted version of the IFIS. Waist circumference was evaluated, and the waist-to-height ratio (WHtR) was calculated. Seventy-six parents of randomly selected schoolchildren completed the IFIS twice for a reliability assessment. Results: ANCOVA, adjusted for sex, age and WHtR, showed that preschoolers who were scored by their parents as having average-to-very good fitness had better levels of measured physical fitness than those preschoolers who were classified as having "very poor/poor" fitness levels (18.1laps to 22.1laps vs 15.6laps for cardiorespiratory fitness; 6.6 kg to 7.5 kg vs 5.3 kg for muscular fitness-handgrip-; 71.7 cm to 76.4 cm vs 62.0 cm for muscular fitness-standing long jump-; 17.2s to 16.2s vs 18.2s for speed/agility; and 11.2s to 15.6s vs 8.7s for balance; p < 0.001). The weighted kappa for concordance between parent-reported fitness levels and objective assessment was poor (κ ≤ 0.18 for all fitness measures). Overall, the mean values of the abdominal adiposity indicators were significantly lower in high-level fitness categories reported by parents than in low-level fitness categories (p < 0.05). The test-retest reliability ranged from 0.46 to 0.62. Conclusions: The reliability of the parent-reported IFIS are acceptable, but the concordance between parents reported and objectively measures fitness levels is poor, suggesting that parents' responses may not be able to correctly classify preschoolers according to their fitness level.HighlightsThe convergent validity and reliability (test-retest) values of the IFIS parent scale are moderately acceptable for assessing physical fitness in children aged 3-5 years.However, the results of concordance show that criterion validity is poor suggesting that parents' responses may not be able to correctly classify preschoolers according to their fitness level.Considering that the fitness level at these ages is fairly homogeneous, it seems difficult for parents to discriminate between the fitness levels of their children. Therefore, it seems necessary to recalibrate the scale in future work.

Active Commuting to School among Spanish Preschool Children: A Temporal Change Study between 2013 and 2017.

BACKGROUND: Active commuting to school may increase the total daily physical activity and achieve health benefits among preschool children. Rates of active commuting to school among Spanish children and adolescents have been widely analysed, while the rates of active commuting to school among Spanish preschool children are unknown. AIM: The main objective of this study was to examine the changes in the rates of active commuting to school in a sample of Spanish preschool children between 3 and 6 years old from 2013 to 2017. METHODS: Data were found from five studies carried out across Spain. The study sample comprised 4787 preschool children (4.59 ± 0.77 years old; 51% males). The overall changes in active commuting to school were assessed using multilevel logistic regression analysis. RESULTS: The rates of active commuting to school in Spanish preschool children are around 52%, and the active commuting to school rates have stayed stable throughout the period assessed (odds ratio from 0.40 to 0.58, all p > 0.05). CONCLUSION: In preschool children, the present study obtained a favourable result on active commuting to school, showing a pattern stability in the examined period similar to other ages. It will be of great importance to promote this behaviour to obtain high levels of active commuting to school.

The moderating role of physical fitness in the relationship between sugar-sweetened beverage consumption and adiposity in schoolchildren.

The mediating and moderating associations of cardiorespiratory fitness (CRF) and handgrip strength on the association between dietary patterns and several health outcomes have been previously studied. For instance, handgrip strength has been found as a moderator of the relationship between excess weight and cardiometabolic risk factors in young adults. Similarly, CRF has been shown as a mediator of the association between diet and obesity in children. However, to our knowledge, the role of CRF and handgrip strength on the association between sugar-sweetened beverage (SSB) consumption and adiposity is still unclear. The aim of this study was to determine whether CRF and handgrip strength moderate the association between SSB consumption and adiposity in a population-based sample of Spanish schoolchildren. This cross-sectional study involved 475 schoolchildren (52.0% girls), aged 8-12, from ten schools in Cuenca (Spain). Adiposity was determined as body fat (in kg), which was measured using a bioimpedance analysis system. Data on SSB consumption were gathered by 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 Nevill's curvilinear allometric model. Handgrip strength was determined using a digital dynamometer with adjustable grip. For each unit (in ml/kg/min) of CRF increased, the association between SSB consumption and adiposity was moderated (B = - 0.09, CI 95% - 0.14 to - 0.04). This significant moderation was also found for each 0.01 unit of increased normalized handgrip strength (B = - 0.07; CI 95% - 0.11 to - 0.02). Similarly, the Johnson-Neymann technique established three different regions. The first region shows that the association of SSB consumption on adiposity in participants who had levels of CRF < 43.4 ml/kg/min or handgrip strength < 0.34 was greater and statistically significant. The second region (43.4-57.4 ml/kg/min for CRF; 0.34-0.58 for normalized handgrip strength) depicted that the association between SSB consumption and adiposity was not statistically significant in those with a CRF level or normalized handgrip strength between the lower and upper thresholds. The third region was found at > 57.4 ml/kg/min (for CRF level) and > 0.58 (for normalized handgrip strength), indicating that the association between SSB consumption and adiposity was lower and statistically significant in children above these moderator values. Our results showed that certain levels of CRF and normalized handgrip strength moderate the association between SSB consumption and adiposity in a sample of Spanish schoolchildren. It might be possible that higher physical fitness level in childhood may contribute to reducing the association between SSB consumption and adiposity.

Obesity risk in 10-year-old children, based on attributes observed at 4 years of age, provides evidence on how to target interventions to lower obesity rates in mid-childhood.

Introduction: Introduction: although in Chile 75 % of obese preschool children participate in a primary health intervention, obesity rates have increased. Objective: to determine the risk of children being obese in 5th grade (10 yrs), according to biological and social attributes observed when they attended prekindergarten (PK) at 4 yrs, to determine which preschoolers should be prioritized for targeting. Method: a retrospective cohort study including 55,623 participants. The variables collected when children attended PK were age, sex, weight, height, maternal educational level and employment status, the child´s relationship with persons living at home, person in charge of the child after school, and number of household members, plus weight, height, and age in 5th grade. To determine the risk of being obese in 5th grade we did two logistic regression models-the first one included all PK children and the above variables, while the second model considered additionally the presence of obesity in PK. The rest of the variables were the same. Results: the risk of children being obese in 5th grade (10 yrs) was 1.43 times higher if their mothers had ≤ 8 yrs of schooling, 1.13 times higher if they lived with a grandparent, and slightly higher if their mothers had an occupation (1.04 times). Boys had a significantly higher risk (1.74 times). Obesity at 4 yrs constituted the highest obesity risk later on (5.3 times). Conclusions: targeting obese 4-year-old boys who participate in a primary health intervention, whose mothers have low education and who live with a grandparent, may lower obesity rates in mid-childhood.

Introducción: Introducción: aunque, en Chile, el 75 % de los preescolares obesos participan en un programa de salud primaria, la obesidad infantil ha aumentado. Objetivo: determinar el riesgo de obesidad en escolares de 5º básico (10 años), según las características biológicas y sociales observadas en prekínder (PK) a los 4 años, para determinar qué preescolares debieran ser priorizados para intervenir. Método: cohorte retrospectiva de 55.623 participantes. Las variables recolectadas en PK fueron: edad, sexo, peso, estatura, nivel educacional y situación laboral de la madre, relación del preescolar con miembros del hogar, persona que cuida al escolar y número de miembros del hogar, además de peso, estatura y edad en 5º básico. El riesgo de obesidad en 5º básico se determinó a través de 2 modelos de regresión logística: el primero incluyó a todos los preescolares en PK y las variables mencionadas anteriormente, y el segundo consideró adicionalmente la presencia de obesidad en PK. El resto de las variables fueron las mismas. Resultados: el riesgo de que los escolares presenten obesidad en 5º básico (10 años) fue 1,43 veces mayor si sus madres tenían ≤ 8 años de escolaridad, 1,13 veces mayor si vivían con un abuelo y ligeramente mayor si sus madres estaban ocupadas (1,04 veces). Los hombres tenían un riesgo significativamente mayor (1,74 veces). La obesidad a los 4 años constituyó el mayor riesgo de obesidad posteriormente (5,3 veces). Conclusión: centrar la atención en los niños obesos de 4 años que participen en una intervención de atención primaria, cuyas madres tengan menor educación y que vivan con un abuelo podría reducir la prevalencia de la obesidad.

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.

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.

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.

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.

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.

Health-related quality of life in developmental coordination disorder and typical developing children.

PURPOSE: To analyse: 1) the differences in health-related quality of life (HRQoL) between typically developing (TD) children and children with developmental coordination disorder (DCD) according to parents' and children's perception, and 2) the differences and level of agreement between parents and children's perceptions in HRQoL in both children's samples. METHODS: Cross-sectional analysis in 115 Spanish schoolchildren 4-to-7 years. Motor competence and HRQoL were assessed using the MACB-2 and the KINDL-R questionnaire, respectively. RESULTS: ANCOVA model showed that children with DCD children obtained lower scores in physical well-being, friends, school and total HRQoL dimensions than TD peers after controlling for covariates (p < 0.05). Moreover, parents' perception scores in HRQoL were lower in children with DCD than in TD peers (79.7 vs 84.8; p = 0.022). Student T-tests for repeated-measures showed non-significant differences between children and parents' perceptions in mean HRQoL scores, by motor competence categories. The intraclass correlations coefficients between parents and children's perception of HRQoL was moderate in DCD category (0.62; p = 0.024) and small in TD category (0.29; p = 0.049). CONCLUSIONS: Children under 6 years old with DCD have lower HRQoL scores than their TD peers. No differences were found between children's and parents' perceptions in total HRQoL, although the perceptions of children and parents in DCD category showed a significantly higher level of agreement than TD children. Interventions aimed at promoting motor skills in school settings during the preschool age seem necessary to improve children's quality of life.

The "Fat but Fit" Paradigm from a Children's Health-Related Quality of Life Perspective.

Background: The fat but fit paradigm originally argues that the detrimental influence of obesity on cardiovascular risk and mortality could be counterbalanced by normal to high cardiorespiratory fitness (CRF) levels. The aim of the study was to determine whether there is a relationship between categories of the fat but fit conceptual model and health-related quality of life (HRQoL) in children. Materials and Methods: Cross-sectional cluster analyses of the MOVI-daFit! baseline data were conducted in 507 children aged 9 to 11 years in Cuenca, Spain. BMI, body fat percentage, VO2 max estimate, and HRQoL (measured by the KIDSCREEN questionnaire) were assessed. Results: The cluster analysis of BMI/body fat percentage and VO2 max estimate z-scores resulted in a four-cluster solution that fit the four categories included in the fat but fit paradigm: fat unfit (FU), unfat unfit (UU), fat but fit (FF), and unfat fit (UF). Analysis of variance (ANOVA) models showed the expected mean trends by cluster category: an increasing trend (FUFF>UU>UF) in terms of adiposity (p < 0.05). These models also indicated, in the whole sample, that schoolchildren in the FF and UF clusters scored higher on physical well-being, psychological well-being, and total HRQoL scores than their peers in the FU and UU clusters (p < 0.05). The results were similar regardless of gender and whether BMI or body fat percentage was used for clustering. Conclusions: This study reinforces the fat but fit paradigm with respect to a previously unexplored outcome, HRQoL, by indicating that CRF may be mediating in the relationship between obesity and HRQoL. Clinical Trial Registration number: NCT03236337.

Parents' Perceptions on Barriers and Facilitators of Physical Activity among Schoolchildren: A Qualitative Study.

Given that physical activity (PA) plays an important role in early childhood, understanding the factors that affect the practice of PA at an early age could help develop effective strategies for overcoming barriers and increasing activity levels in this age group. A qualitative study was conducted based on grounded theory aimed at exploring the perceptions of mothers and fathers from Cuenca and Ciudad Real (Castilla La Mancha, Spain) regarding barriers and facilitators of physical activity of their children during the adiposity rebound period. Data were collected using focus groups involving 46 parents of children in the 3rd grade of pre-school and 1st grade of elementary school. During the analysis, the socio-ecological model and grounded theory were used. The barriers encountered were the preferences of children for sedentary activities (individual factors), academic tasks as a main priority of parents, the influence of older siblings and the unfavorable school environment (microsystem), the lack of family conciliation (mesosystem), and barriers related to the built environment or lack of facilities for physical activity (exosystem). Facilitators were the preferences for active games (individual factors), parental models including the co-participation of parents in activities, the influence of friends, living in large homes, the support provided by teachers and the school (microsystem), living in rural areas, having sufficient facilities, favorable weather conditions (exosystem), and the existence of free or subsidized activities (macro system). Programs aimed at promoting PA in early childhood should include strategies that address contextual factors and not only focus on individual factors related to the child.

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.