Objective measured physical activity and metabolic syndrome score in children and adolescents: The UP&DOWN longitudinal study.

INTRODUCTION: We aimed to analyze the cross-sectional and longitudinal association of physical activity (PA) levels and PA patterns with metabolic syndrome score (MetS) in children and adolescents. METHODS: A total of 175 children (82 females) and 188 adolescents (95 females) were included. Objective PA levels and patterns were determined by accelerometry. MetS was computed from waist circumference, systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, and glucose levels. Different linear regression models were implemented to examine the associations of PA with MetS. RESULTS: Vigorous PA, moderate-vigorous PA, number of bouts per day in 10 min (N10), and total time in bouts per day in 10 min (T10) were negatively associated with MetS in male children and adolescents at cross-sectional level (ß ranging from -0.005 to -0.164, all p < 0.05). Total time in bouts per day in 20 min in male children, and vigorous PA and N10 in female children were longitudinally and negatively associated with MetS (ß ranging from -0.011 to -0.247, all p < 0.05). CONCLUSIONS: Associations of PA and MetS were observed at cross-sectional level in males and longitudinally in female children. The associations in PA patterns were found when patterns were grouped into bouts of 10 min. Therefore, for future studies of PA with health markers in the pediatric population, it would be advisable to choose bouts of shorter duration.

Health and fitness trends in Southern Europe for 2023: A cross-sectional survey.

The physical activity, exercise and wellness sector is rapidly growing and seems to be an exciting field for business and professional development with great potential globally. The purpose of this observational and cross-sectional study was to determine the most popular health and fitness trends in Southern Europe for the first time, including data from Italy, Spain, Portugal, Greece and Cyprus, and to investigate any potential differences in this area compared to the Pan-European and global fitness trends for 2023. A national online survey was conducted in five Southern European countries, using the methodology of similar regional and worldwide surveys conducted by the American College of Sports Medicine since 2007. In total, a web-based questionnaire was sent to 19,887 professionals who worked in the Southern European physical activity, exercise and wellness sector. A total of 2645 responses were collected from five national surveys with an overall mean response rate of 13.3%. The ten most important fitness trends in Southern Europe for 2023 were personal training, licensure for fitness professionals, exercise is medicine, employing certified fitness professionals, functional fitness training, small group training, high-intensity interval training, fitness programs for older adults, post-rehabilitation classes and body weight training. The present findings are aligned with those reported for the European and worldwide fitness trends.

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.

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 (ß = -0.488, P < .001 in cross-sectional analysis; ß = -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 (ß = 0.285, P < .001 in cross-sectional analysis; ß = 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.

Fitness, body composition, and metabolic risk scores in children and adolescents: the UP&DOWN study.

We aimed to analyse the longitudinal association between physical fitness (PF) and body composition (BC) with a metabolic risk score (Met4) in children and adolescents and to elucidate whether the association between PF and Met4 differs when using relativized or absolute fitness variables. A total of 188 children (86 females) and 195 adolescents (97 females) were included. Cardiorespiratory fitness (CRF) was determined by the 20-m shuttle run test, and muscular fitness (MF) was determined by hand grip and standing long jump tests. Height and weight were measured, and the body mass index (Kg/m2) was calculated. Triceps and subscapular skinfolds were assessed to compute body fat percentage. Met4 was computed from systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, and glucose levels. Relative CRF was longitudinally and negatively associated with Met4 in female children (ß = -0.031, p = 0.025), while absolute CRF was positively associated with Met4 in male children and adolescents (ß = 0.000, p < 0.05). Relative upper and lower-body MF were longitudinally and negatively associated with Met4 in female adolescents (ß = -1.347, ß = -0.005, p < 0.05), while absolute lower-body MF was positively associated with Met4 in male children (ß = 0.000, p = 0.019). BC was longitudinally and positively associated with Met4 in male children (ß-ranging from 0.011 to 0.055, all p < 0.05) and male adolescents (ß-ranging from 0.011 to 0.046, all p < 0.05).  Conclusion: BC is more strongly associated with Met4 than PF in children and adolescents. An optimal body weight status should be considered the main objective of health-promoting programs at childhood and adolescence. Furthermore, the way of expressing the fitness variables determines the direction of the association with Met4. What is Known: • Physical fitness is an important health indicator in children and adolescents, with great amount of previous evidence supporting the preventive role of maintaining optimal levels of both cardiorespiratory and muscular fitness for future cardiometabolic issues. What is New: • The way of reporting physical fitness variables can affect the associations between physical fitness features and cardiometabolic outcomes. Since body composition variables have a great impact on both physical fitness and cardiometabolic health, relativizing physical fitness performance by body composition could lead to erroneous conclusions.

Comparison of Adherence to Mediterranean Diet between Spanish and German School-Children and Influence of Gender, Overweight, and Physical Activity.

BACKGROUND: Poor dietary habits and low levels of physical activity (PA) have a strong tendency to track from childhood into adulthood. The Mediterranean Diet (MD) is known to be extremely healthy, associated with lower BMI and a lower risk of obesity in children and adolescents. Therefore, adherence to the MD was compared between Spanish (n = 182) and German (n = 152) children aged 10 to 13 years to examine a possible more "westernized" diet in Spain with a non-Mediterranean country, that traditionally prefers a "Western diet" and to determine the association between adherence to the MD and gender, body composition, and PA levels. METHODS: In the German observational longitudinal cohort study and the Spanish cohort study, body composition and questionnaires (KIDMED, Diet Quality (IAES)) were obtained, and accelerometers (Actigraph) were applied to detect PA. RESULTS: Girls had higher BMI-standard deviation score (SDS) than boys and Spanish girls were less active than boys. Differences were detected in MD habits, such as favorable fruit-, vegetables-, fish-intakes, and dairy products in Spanish children and unfavorable consumptions of fast food, processed bakery goods, candies, and sweet beverages in German children. Independently of country, girls, children with lower BMI-SDS and children with higher PA level were related with better diet quality. CONCLUSION: Spanish children showed higher adherence to MD and diet quality (IAES) compared to German children, but there was a trend toward a more "westernized" diet. Gender, body composition, and PA influenced nutrition regardless of country.

Family-reported barriers and predictors of short-term attendance in a multidisciplinary intervention for managing childhood obesity: A psycho-family-system based randomised controlled trial (ENTREN-F).

OBJECTIVE: This study was aimed to examine patient enrolment in the pre-intervention stage, family-reported barriers, attendance rates and underlying predictors of short-term attendance in a family-system-based randomised controlled trial for managing childhood obesity in children aged 8-12-years-old (ENTREN-F). METHOD: Psychosocial and anthropometric measures were collected through primary health referral. The data were used for descriptive analyses of sample characteristics and linear regression analyses. RESULTS: Low enrolment rates and several family-reported barriers were observed in the pre-intervention stage. Logistical barriers were the most frequent family-reported reason for attrition in the different stages of the study. Having a first face-to-face orientation session with the families and the use of motivational interviewing helped to improve adherence in the initial phases of the study. After 6 months of intervention, family based treatments (FBTs) under consideration achieve greater adherence compared with the standard intervention. Moreover, family involvement was a predictor of success for better treatment adherence rates. By contrast, participants who attended a brief standard intervention, mothers with primary education, greater body mass index, higher levels of depressive symptomatology and more critical comments towards their children, children with higher weight status and lower levels of self-reported depressive symptoms at baseline attended interventions less frequently. CONCLUSIONS: In future programmes a comprehensive screening of modifiable factors related to family and their setting characteristics is paramount prior to intervention, identifying key barriers related to drop-out, especially in the case of less-advantaged families.

Objectively measured physical activity and academic performance in school-aged youth: The UP&DOWN longitudinal study.

To examine the longitudinal relationships between objectively measured total volume and specific intensities of physical activity (PA) with academic performance in a large sample of youth aged 6-18 years. A longitudinal study of 1046 youth (10.04 ± 3.10 years) from Spain was followed over 2 years. PA (volume and intensity) was measured by accelerometry. Academic performance was assessed through grades reported on the transcript at the end of the academic year (Mathematics, Language, an average of these two core subjects, and grade point average [GPA]). Longitudinal relationships between PA and four indicators of academic performance were examined using covariance and regression analyses, adjusted for a variety of confounders. Youth Quartile 2 for PA volume at baseline obtained better scores than those who participated in Quartiles 1 or 4 volumes of PA in GPA 2 years later (p = 0.006). There were generally no longitudinal associations between specific PA intensities and any of the academic performance indicators (all p > 0.170). However, a change in light PA over 2 years was inversely associated with three academic indicators in youth (ßrange , -.103 to - 090; all P < 040). Findings suggest that participants in Quartile 2 volume of PA had a better GPA in comparison with Quartiles 1 and 4 volumes of PA during youth, but there was no association with changes in PA volume over time. PA intensity was generally unrelated to academic performance during youth. However, there was an inverted u-shape relationship between light PA changes and GPA.

Prospective Associations of Physical Activity and Health-Related Physical Fitness in Adolescents with Down Syndrome: The UP&DOWN Longitudinal Study.

(1) Background: Numerous studies have focused on examining the association between PA levels and health-related physical fitness components in children or adolescents without disabilities. However, research on the association between PA and health-related physical fitness in adolescents with DS (Down syndrome) is limited, and most of the previous studies have been developed with a cross-sectional perspective. Therefore, the aim of the present study was to assess the prospective association of accelerometer-based PA at baseline with health-related physical fitness at a 2-year follow-up in a relatively large sample of adolescents with DS from the UP&DOWN study. (2) Methods: A total of 92 adolescents with DS (58 males) between 11 and 20 years old with full data were eligible from an initial sample of 110 participants. Fitness was assessed by the ALPHA health-related fitness test battery for youth, and physical activity was assessed by Actigraph accelerometers. (3) Results: The high tertile of total PA was related to decreased motor (Beta [95% CI] = -1.46 [-2.88; -0.05]) and cardiorespiratory fitness (Beta [95% CI] = -2.22 [-4.42; 0.02]) in adolescents with DS. (4) Conclusions: In adolescents with DS, (i) PA level was not prospectively associated with muscular fitness and (ii) high levels of total PA at the baseline were inversely associated with motor and cardiorespiratory fitness at the 2-year follow-up. For comparative purposes, these relationships were also examined in a subsample of adolescents without DS.

Activity-related typologies and longitudinal change in physical activity and sedentary time in children and adolescents: The UP&DOWN Study.

BACKGROUND: Children and adolescents can be distinguished by different typologies (clusters) of physical activity and sedentary behavior. How physical activity and sedentary behaviors change over time within different typologies is not known. This study examined longitudinal changes in physical activity and sedentary time among children and adolescents with different baseline typologies of activity-related behavior. METHODS: In this longitudinal study (3 annual time points) of children (n = 600, age = 9.2 ± 0.4 years (mean ± SD), 50.3% girls) and adolescents (n = 1037, age = 13.6 ± 1.7 years, 48.4% girls), participants were recruited in Spain in 2011-2012. Latent class analyses identified typologies based on self-reported screen, educational, social and relaxing sedentary behaviors, active travel, muscle strengthening activity, and sport at baseline. Within each typology, linear mixed growth models explored longitudinal changes in accelerometer-derived moderate-to-vigorous physical activity and sedentary time, as well as time by class interactions. RESULTS: Three typologies were identified among children ("social screenies", 12.8%; "exercisers", 61.5%; and "non-sporty active commuters", 25.7%) and among adolescents ("active screenies", 43.5%; "active academics", 35.0%; and "non-sporty active commuters", 21.5%) at baseline. Sedentary time increased within each typology among children and adolescents, with no significant differences between typologies. No changes in physical activity were found in any typology among children. In adolescents, physical activity declined within all typologies, with "non-sporty active commuters" declining significantly more than "active screenies" over 3 years. CONCLUSION: These results support the need for intervention to promote physical activity and prevent increases in sedentary time during childhood and adolescence. Adolescents characterized as "non-sporty active commuters" may require specific interventions to maintain their physical activity over time.

Fitness, waist circumference and their association with future blood pressure in youth: The UP&DOWN Longitudinal Study.

OBJECTIVES: The aim was to determine the independent associations of muscular fitness (MF), cardiorespiratory fitness (CRF) and waist circumference (WC) with blood pressure (BP) levels over 2 years in children and adolescents. METHODS: 1089 children (517 females) and 787 adolescents (378 females) with complete data on fitness, WC and BP (systolic [SBP] and diastolic [DBP]) were included. Upper MF was assessed through the handgrip strength test, and lower MF using the standing long jump test. The 20-m shuttle run test was used to assess CRF. WC was obtained following standardized methods. Different regression models were fitted by introducing fitness and WC at baseline and their changes as exposures and BP at follow-up and their changes as outcomes. RESULTS: WC at baseline was positively and independently associated with each BP variable at follow-up in children and adolescents (ß=0.094-0.260; p≤0.05), and CRF was negatively associated with DBP in adolescents (ß=-0.096; p=0.034). WC changes were associated with BP variables 2 years later in children (ß=0.121-0.142; p<0.01). In adolescents, changes in upper MF (ß=-0.116; p=0.001) and WC (ß=0.080-0.098; p<0.05) were associated with SBP at follow-up. WC changes were independently associated with changes in each BP variable in children (ß=0.111-0.145; all p<0.05) and SBP changes in adolescents (ß=0.103 to 0.117; all p<0.01). CONCLUSIONS: WC, but neither MF nor CRF, is independently associated with BP and its changes over 2 years. The attainment or maintenance of optimal fatness levels in the pediatric population should be highly encouraged for the prevention of future hypertension.

A longitudinal gender perspective of well-being and health in spanish youth: the UP&DOWN study.

Previous studies have observed a link between gender and well-being and health in young populations. The purpose of this research was twofold: (1) to analyse the cross-sectional relationship between gender status with well-being indicators and self-perceived health in adolescents at baseline and at 2-year follow-up and (2) to evaluate the prospective associations between gender at baseline and well-being indicators/self-perceived health assessed at 2-year follow-up. Well-being was measured using the KIDSCREEN-10 questionnaire (as a measure of health-related quality of life (HR-QoL)), the Children's Hope Scale and the Positive and Negative Affect Schedule. Health status of the adolescents was assessed using self-perceived health. Multilevel mixed-effects linear/logistic regression models were carried out to assess the associations between gender status and well-being and health of a sample of 1590 Spanish adolescents. Adolescent girls were shown to have lower HR-QoL scores and higher negative affect scores, and had a higher risk of reporting poor health than boys, in both cross-sectional and longitudinal analyses. Adolescent girls seem to be more vulnerable to poorer well-being and self-reported health than boys. When looking at hedonic and eudemonic well-being separately, longitudinal differential evolution of boys and girls seems to indicate greater deterioration of hedonic well-being among girls as compared to boys. Overall, gender may have a relevant impact on mental and physical health during adolescence.

Correlates of dual trajectories of physical activity and sedentary time in youth: The UP & DOWN longitudinal study.

Trajectories of physical activity and sedentary time (SED) may differ between subgroups of youth. The aim of this study was to identify group-based dual trajectories of physical activity and SED and explore individual, social, and environmental correlates of these trajectories. Longitudinal data (three time points, baseline 2011-2012) of Spanish youth (n = 1597, mean age = 11.94 ± 2.52, 50.9% boys) were used. Moderate-to-vigorous physical activity (MVPA) and SED were assessed objectively at each time point, and 21 potential correlates were self-reported at baseline. Parallel process growth mixture models identified shared categorical latent groups, adjusting for school and age. Multinomial logistic regression models identified baseline correlates of a given trajectory. Four shared categorical latent groups were identified: (1) stable MVPA and decreasing SED (4%); (2) stable MVPA and increasing SED (3%); (3) consistently higher MVPA (18%); and (4) stable low MVPA and slight increase in SED (75%). Multinomial logistic regression models with group 3 as reference found: negative affect (RRR = 0.90, 95% CI 0.84-0.97), parental screen-time rules (RRR = 1.15, 95% CI 1.00-1.33), and household media equipment (RRR = 1.17, 95% CI 1.05-1.30) predicted likelihood of group 1 membership; cons of reducing SED (RRR = 2.70, 95% CI 1.77-4.10) predicted likelihood of group 2 membership; and co-participation in physical activity with friends (RRR = 0.80, 95% CI 0.69-0.94), fathers' modeling of TV viewing (RRR = 1.22, 95% CI 1.02-1.47), and household media equipment (RRR = 1.16, 95% CI 1.02-1.31) predicted likelihood of group 4 membership. Results suggest that strategies to improve MVPA and SED behaviors among youth may need to be multifaceted, targeting all levels of influence.

Bidirectional longitudinal associations of fatness with physical fitness in adolescents with Down syndrome. The UP&DOWN Longitudinal study.

BACKGROUND: The aim of this study was to examine the bidirectional longitudinal associations of several markers of fatness and physical fitness in adolescents with Down syndrome. METHODS: This study comprised a total of 111 adolescents (41 females), aged from 11 to 20 years with complete data at the baseline. We had a drop-out of <10% from the baseline to the 2-year follow-up. The ALPHA health-related fitness test battery for youth was used. RESULTS: Our results show that all fatness variables at the baseline were associated with a 2-year change in cardiorespiratory fitness (ß ranging from -0.32 to -0.38; all p < .05), but not with muscular and motor fitness (p > .05). However, no associations were found between physical fitness components as predictors and fatness indicators (p > .05). CONCLUSIONS: Results suggest that reducing fatness during adolescence might represent a modifiable factor to improve cardiorespiratory fitness at the 2-year follow-up, but not vice versa since associations were not bidirectional.

A cross-sectional association of physical fitness with positive and negative affect in children and adolescents: the up & down study.

BACKGROUND: Affect and physical fitness play an important role in psychological and physical health; however, the association between those variables in youth remains unknown. The aim of the present study was to examine the influence of physical fitness on positive and negative affect in Spanish children and adolescents. METHOD: Healthy young Spanish people (n = 1,490) were recruited for the present study: 542 children (n = 272 girls; mean age 9.6 years) and 948 adolescents (n = 454 girls; mean age 14.1 years) with complete baseline data on health-related fitness tests (20 m shuttle run test, 4 × 10 m test, muscular fitness index, and physical fitness index), and positive and negative affect (Positive and Negative Affect Schedule). RESULTS: Higher performance on physical fitness components was associated with positive affect (ß = -0.176-0.118, all P < 0.05). There was no association between all physical fitness components and negative affect (ß = -0.100-0.15, all P > 0.05). There were differences on positive affect between the lowest and the highest quartile of the physical fitness index in boys (P = 0.037, Cohen's d 0.60) and girls (P = 0.004, Cohen's d = 0.69), and between the lowest and the highest quartile of muscular fitness index in girls (P < 0.001, Cohen's d = 0.76). CONCLUSIONS: Promoting physical activity during the school years, including strength exercises to increase muscular fitness, could improve positive affect levels and thus psychological health.

Longitudinal associations of physical fitness and body mass index with academic performance.

No studies have analyzed the longitudinal associations of change in physical fitness components and obesity with academic performance. The aim of the study was to examine longitudinal associations of changes in physical fitness components and body mass index with academic performance among youth, and whether the physical fitness components are moderators of the longitudinal association between obesity and academic performance in youth. Longitudinal analyses (2 years) included 1802 youths. Physical fitness components were assessed following the ALPHA health-related fitness test battery. Academic performance was assessed via school records. Youth in the persistently high cardiorespiratory fitness and motor ability categories (ie, fit at baseline and at 2-year follow-up) had higher academic performance at follow-up than those in the persistently low category. Further, youth with normal weight at baseline and overweight/obesity at follow-up had lower academic performance scores at follow-up compared to those with normal weight. Also, cardiorespiratory fitness may ameliorate the negative influence of excess body mass index on academic performance at follow-up. Promoting physical activity programs at school that include both aerobic exercise and motor tasks to improve physical fitness and reduce body mass index may not only improve physical health, but also contribute toward successful academic development.

The Investigation of Gender Differences in Subjective Wellbeing in Children and Adolescents: The UP&DOWN Study.

OBJECTIVE: Based on a three-factor model of subjective wellbeing (evaluative, hedonic and eudemonic), the purpose of this study was to analyze gender differences in children and adolescents through three different subjective wellbeing indicators. METHOD: The sample comprised 1.407 children and adolescents from Cadiz and Madrid (Spain), in the framework of the UP&DOWN study. Life satisfaction was measured with the subjective happiness scale, positive and negative affect were measured with the positive and negative affect schedule, and purpose in life was assessed with the children's hope scale. RESULTS: Linear regression models indicate the existence of significant gender differences only in adolescents, with higher scores among girls in positive affect (p = 0.016) and negative affect (p < 0.001) but with lower scores in purpose in life (p = 0.024). CONCLUSIONS: These results highlight the role of gender as an important factor in explaining differences in subjective wellbeing. Additionally, results indicate that gender differences in subjective wellbeing are observed in adolescents, but not in children, suggesting that the gender gap in subjective wellbeing begins at the age of 12. Mental health practitioners should pay attention to these findings in order to implement screening methods and interventions focused on these needs.

Bidirectional associations between fitness and fatness in youth: A longitudinal study.

The aim was to examine the bidirectional association between cardiorespiratory fitness (CRF) and fatness in a 2-year longitudinal study conducted in young people. A total of 1082 children (512 females) and 727 adolescents (342 females) with complete data at baseline and follow-up were included. CRF was determined by the 20-m shuttle run test. Height and weight were measured, and body mass index and fat mass index (kg/m2 ) were calculated. Triceps and subscapular skinfolds were assessed to compute body fat percentage. Bidirectionality was tested by including CRF and each fatness index as exposures and outcomes, alternatively, in different regression models. CRF was prospectively associated with fatness index levels (ß from -0.186 to -0.528; P < .001), remaining significant in children after adjusting for baseline fatness indices. Fatness indices were prospectively associated with CRF (ß from -0.207 to -0.479; P < .001), with no substantial changes observed in children and female adolescents when baseline CRF was considered. Changes in CRF were prospectively associated with several fatness indices, regardless of body fatness at baseline (ß from -0.062 to -0.220; P < .05). Body fatness changes were associated with future CRF levels, independently of baseline CRF, especially in children of both sexes and male adolescents (ß from -0.079 to -0.260; P < .05). Overall, a bidirectional association was observed between CRF and fatness in children and adolescents. The attainment of optimal CRF and fatness levels in early ages should be promoted since it could result in favorable future fatness and CRF levels, respectively, which are two key determinants of health status.

Does modality matter? A latent profile and transition analysis of sedentary behaviours among school-aged youth: The UP&DOWN study.

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8-18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.

Changes in and the mediating role of physical activity in relation to active school transport, fitness and adiposity among Spanish youth: the UP&DOWN longitudinal study.

BACKGROUND: Longitudinal changes in child and adolescent active school transport (AST), and the mediating role of different intensities of daily physical activity (PA) levels in relation to AST and physical fitness and adiposity indicators is unclear. This study aimed to: 1) describe longitudinal changes in AST, light PA (LPA), moderate- to vigorous-intensity PA (MVPA), physical fitness and adiposity indicators over three time-points; and 2) investigate the mediating role of LPA and MVPA levels on associations between AST and physical fitness and adiposity indicators over three time-points among children and adolescents. METHODS: This longitudinal study comprised 1646 Spanish children and adolescents (48.8% girls, mean age 12.5 years ±2.5) at baseline, recruited from schools in Cádiz and Madrid. Mode of commuting to school was self-reported at baseline (T0, 2011-12), 1-year (T1) and 2-year follow-up (T2). PA was assessed using accelerometers. Handgrip strength, standing long jump and cardiorespiratory fitness (CRF) assessed physical fitness. Height, weight, body mass index, waist circumference, and triceps and subscapular skinfold thickness were measured. Multilevel linear regression analyses assessed changes in AST, PA levels, physical fitness and adiposity indicators over three time-points (T0-T1-T2). Additionally, longitudinal path analysis (n = 453; mean age [years] 12.6 ± 2.4) was used to test the mediating effects of LPA and MVPA levels on the association between AST and physical fitness and adiposity indicators. RESULTS: Multilevel analyses observed decreases in LPA between T0-T1 (ß = - 11.27; p < 0.001) and T0-T2 (ß = - 16.27; p < 0.001) and decreases in MVPA between T0-T2 (ß = - 4.51; p = 0.011). Moreover, changes over time showed increases in handgrip between T0-T1 (ß = 0.78; p = 0.028) and T0-T2 (ß = 0.81; p = 0.046). Path analyses showed that AST was directly positively associated with MVPA at T1 (all, ß ≈ 0.33; p < 0.001). MVPA at T1 mediated associations between AST and CRF at T2 (ß = 0.20; p = 0.040), but not the other outcomes. LPA did not mediate any associations. CONCLUSIONS: Results from longitudinal path analysis suggest that participation in more AST may help attenuate declines in MVPA that typically occur with age and improve CRF. Therefore, we encourage health authorities to promote AST, as a way to increase MVPA levels and CRF among youth.