Secular trends in skill-related physical fitness among Slovenian children and adolescents from 1983 to 2014.

It is vital from the public health and educational perspective to be familiar with changes in the fitness levels of individuals and populations since fitness is associated with several health outcomes and cognition. Skill-related physical fitness refers to performance in sports or occupation and is associated with motor skill performance. The aim of the present study was to examine secular trends in skill-related physical fitness of 16 678 participants in four youth generations of Slovenian children and adolescents in years 1983 (n = 3128), 1993/94 (n = 3413), 2003/04 (n = 5497), and 2013/14 (n = 4640). Using repeated cross-sectional design, we observed fitness level of all participants divided into three age groups: 6-10, 11-14, and 15-19 years. Skill-related physical performance was measured with seven fitness tests for speed, coordination, balance, and flexibility. Analysis of covariance was used to compare differences in fitness performance between decades in each age and sex group, adjusted for body height, body weight, and body mass index. Overall, large but inconsistent changes in coordination, a small improvement in speed, and a decline in flexibility were seen. The trends over the whole examined period were not linear throughout decades. Generally, positive trends were noticed in periods 1983-1993 (range 1.4%-17.9%; except flexibility) and 2003/04-2013/14 (range 0.2%-36.4%; except age group 15-19 years) while in the period 1993/94-2003/04 there are some particularities in secular trends according to individual components as well as age groups. In general, the secular trend showed a positive direction for both genders (p < 0.05), except for gross motor coordination, which demonstrated positive trends in 1993 and 2013 compared with a decade earlier (p < 0.05) and from 1983 to 2013/14, except for the youngest boys in 2003 and the youngest girls from 1993 to 2003 (p < 0.05). Our findings call for exercise programs aimed at improving speed and gross motor coordination in both sexes and all age groups, especially in the group of 15-19 years old.

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.

Secular trends in muscular fitness from 1983 to 2014 among Slovenian children and adolescents.

Low physical fitness has been found to be associated with many chronic diseases and medical conditions. Knowledge of secular trends in physical fitness is important to initiate countermeasures for addressing negative trends. The aim of this study was to analyze secular trends in health-related muscular fitness in Slovenian children and adolescents between 1983 and 2014. Data were collected as part of "The Analysis of Children's Development in Slovenia (ACDSi)" study in 1983, 1993/94, 2003/04, and 2013/14. Anthropometry (body weight, height, BMI, and triceps skinfold) and muscular fitness (standing long jump, bent-arm hang, and sit-ups 60 s test) of 18730 (9168 female) students from primary and secondary schools were recorded. The secular trend was analyzed considering anthropometry. The results showed that anthropometric measures had an increasing trend and overall muscular fitness had a decreasing trend. Leg muscle power decreased over the decades in all age groups (relative difference between -1.5% and -2.6%), being more pronounced in boys. Arm muscle strength decreased in two younger age groups (range -21.1% to -42.7%, 6-10, and 11-14 years), but not in the oldest group (15-19 years), where the increase occurred in both genders (0.4% to 9.3%). In terms of decades, the largest negative changes (-30.1%) occurred from 1993/94 to 2003/04 and the smallest changes (-4.2%) from 2003/04 to 2013/14. The overall trend in repetitive core strength surprisingly increased (1.1% to 18.3%). There is a need to promote healthy lifestyles, raise parental awareness and use all government resources to redirect the negative trend in physical fitness.

Associations of mode and distance of commuting to school with cardiorespiratory fitness in Slovenian schoolchildren: a nationwide cross-sectional study.

BACKGROUND: It is unclear whether active commuting has the potential to improve children's health. This study examined the association of commuting mode and distance with children's cardiorespiratory fitness (CRF). METHODS: We conducted a cross-sectional study, including 713 Slovenian schoolchildren aged 12 to 15 years. Commuting modes were self-reported, and four commuting groups were constructed, while CRF was determined with a 20-m shuttle run test. The distance from home to school was calculated using the Geographic Information System. Effects of commuting mode and distance, controlling for age, gender and amount of total physical activity, were evaluated using general two linear models (one for each direction of commuting to/from school). RESULTS: The main effect of commuting group on CRF and its interaction with distance were significant in the direction from school to home (P = 0.013 and P = 0.028, respectively), but not in the opposite direction. Predicted differences in CRF between commuting groups were moderate and generally higher in males than in females. When comparing commuting group median distance from home to school, males driven by car had around 4 ml/min/kg lower predicted CRF than those who walked (P = 0.01) or used wheels commuting (e.g., bicycle, skateboard). CONCLUSIONS: The distance of commuting had a small effect on CRF, except in the Car group where children who live close to school had significantly lower CRF than those living further away. Children driven by car who live within wheels or walk distance from school should be targeted by interventions promoting active transport.

An inventory of national surveillance systems assessing physical activity, sedentary behaviour and sport participation of adults in the European Union.

BACKGROUND: Physical inactivity has been recognised as a global public health problem that requires concerted action. This calls for systematic physical activity (PA) surveillance as a mechanism for assessing the problem and evaluating the effectiveness of related policies. Because countries tend to design their policy measures based on national surveillance data, here we present an inventory of existing national surveillance systems on PA, sedentary behaviour (SB) and sport participation (SP) among adult population in all European Union (EU) Member States. METHODS: As a part of the European Physical Activity and Sports Monitoring System (EUPASMOS) project, a questionnaire was constructed in the form of an on-line survey to collect detailed information on existing national surveillance systems on either PA, SB, or SP. National HEPA focal points from all 27 EU Member States were invited to answer the on-line questionnaire and data collection took part in the period May 2018-September 2019. RESULTS: National monitoring of PA or SB or SP for adults has been established in 16/27 EU Member States, that host 33 different PA/SB/SP monitoring systems. Apart from 3 countries that are using accelerometers (Finland, Ireland and Portugal), surveillance is typically based on questionnaires. In most Member States these questionnaires have not been validated in the particular language and cultural setting. Next, specific domains and dimensions of PA, SB and SP assessed vary a lot across countries. Only 3 countries (the Netherlands, Portugal and Slovenia) are monitoring all three behaviours while covering most of the domains and dimensions of PA/SB/SP. Lastly, as half of the existing surveillance systems set an upper age limit, in 9/16 countries that are monitoring PA/SB/SP, no data for people older than 80 years are available. CONCLUSIONS: Systematic surveillance of PA is lacking among 11/27 EU countries, with even few monitoring SB and SP. Besides, existing surveillance systems typically fail to assess all dimensions and domains of PA/SB/SP with only three countries maintaining monitoring systems that encompass all three behaviours while covering most of the domains and dimensions of PA/SB/SP. Hence, additional efforts in advocacy of systematic PA surveillance in the EU are called for.

Agreement between the SHAPES Questionnaire and a Multiple-Sensor Monitor in Assessing Physical Activity of Adolescents Using Categorial Approach: A Cross-Sectional Study.

This study aimed to evaluate the agreement between a 7-day recall questionnaire and multiple-sensor monitor in identifying sufficiently active adolescents. A total of 282 students involved in the CRO-PALS study were randomly selected for a device-based measurement of physical activity (PA) using the SenseWear Armband device (SWA) no more than three weeks before or after having fulfilled the SHAPES questionnaire. Valid data was obtained from 150 participants (61 boys; 89 girls) and included in the analysis. In boys, SHAPES exhibited high specificity (92.3%), overall percent agreement (85.0%), and significant agreement (κ = 0.32, p = 0.014) with the SWA in recognising sufficiently active individuals. Conversely, no agreement was detected for quartiles of PA, although boys that were classified in the first and in the fourth quartile by SHAPES differed in device-based measured duration of MVPA (134 [95%CI: 109-160] vs. 87 [95%CI: 65-108], p = 0.032); and VPA (39 [95%CI: 23-56] vs. 14 [95%CI: 6-22], p = 0.011). In girls, no significant agreement between the two methods was found in any of the analyses. It appears that the SHAPES questionnaire is effective to identify individuals that comply with PA recommendations and to distinguish between the most active and the least active individuals for adolescent boys, but not for girls.

Can Injuries Be Predicted by Functional Movement Screen in Adolescents? The Application of Machine Learning.

ABSTRACT: Karuc, J, Misigoj-Durakovic, M, Sarlija, M, Markovic, G, Hadzic, V, Trost-Bobic, T, and Soric, M. Can injuries be predicted by functional movement screen in adolescents? The application of machine learning. J Strength Cond Res 35(4): 910-919, 2021-This study used machine learning (ML) to predict injuries among adolescents by functional movement testing. This research is a part of the CRO-PALS study conducted in a representative sample of adolescents and analyses for this study are based on nonathletic (n = 364) and athletic (n = 192) subgroups of the cohort (16-17 years). Sex, age, body mass index (BMI), body fatness, moderate-to-vigorous physical activity (MVPA), training hours per week, Functional Movement Screen (FMS), and socioeconomic status were assessed at baseline. A year later, data on injury occurrence were collected. The optimal cut-point of the total FMS score for predicting injury was calculated using receiver operating characteristic curve. These predictors were included in ML analyses with calculated metrics: area under the curve (AUC), sensitivity, specificity, and odds ratio (95% confidence interval [CI]). Receiver operating characteristic curve analyses with associated criterium of total FMS score >12 showed AUC of 0.54 (95% CI: 0.48-0.59) and 0.56 (95% CI: 0.47-0.63), for the nonathletic and athletic youth, respectively. However, in the nonathletic subgroup, ML showed that the Naïve Bayes exhibited highest AUC (0.58), whereas in the athletic group, logistic regression was demonstrated as the model with the best predictive accuracy (AUC: 0.62). In both subgroups, with given predictors: sex, age, BMI, body fat percentage, MVPA, training hours per week, socioeconomic status, and total FMS score, ML can give a more accurate prediction then FMS alone. Results indicate that nonathletic boys who have lower-body fat could be more prone to suffer from injury incidence, whereas among athletic subjects, boys who spend more time training are at a higher risk of being injured. Conclusively, total FMS cut-off scores for each subgroup did not successfully discriminate those who suffered from those who did not suffer from injury, and, therefore, our research does not support FMS as an injury prediction tool.

The epidemiological burden of obesity in childhood: a worldwide epidemic requiring urgent action.

BACKGROUND: In recent decades, the prevalence of obesity in children has increased dramatically. This worldwide epidemic has important consequences, including psychiatric, psychological and psychosocial disorders in childhood and increased risk of developing non-communicable diseases (NCDs) later in life. Treatment of obesity is difficult and children with excess weight are likely to become adults with obesity. These trends have led member states of the World Health Organization (WHO) to endorse a target of no increase in obesity in childhood by 2025. MAIN BODY: Estimates of overweight in children aged under 5 years are available jointly from the United Nations Children's Fund (UNICEF), WHO and the World Bank. The Institute for Health Metrics and Evaluation (IHME) has published country-level estimates of obesity in children aged 2-4 years. For children aged 5-19 years, obesity estimates are available from the NCD Risk Factor Collaboration. The global prevalence of overweight in children aged 5 years or under has increased modestly, but with heterogeneous trends in low and middle-income regions, while the prevalence of obesity in children aged 2-4 years has increased moderately. In 1975, obesity in children aged 5-19 years was relatively rare, but was much more common in 2016. CONCLUSIONS: It is recognised that the key drivers of this epidemic form an obesogenic environment, which includes changing food systems and reduced physical activity. Although cost-effective interventions such as WHO 'best buys' have been identified, political will and implementation have so far been limited. There is therefore a need to implement effective programmes and policies in multiple sectors to address overnutrition, undernutrition, mobility and physical activity. To be successful, the obesity epidemic must be a political priority, with these issues addressed both locally and globally. Work by governments, civil society, private corporations and other key stakeholders must be coordinated.

School day and weekend patterns of physical activity in urban 11-year-olds: a cross-cultural comparison.

OBJECTIVES: This multi-center study was conducted to objectively evaluate energy expenditure and physical activity (PA) patterns on school days and weekends in urban 11-year-olds. METHODS: The sample consisted of 241 children from three cities: Zagreb, Ljubljana (both in Central Europe) and Ann Arbor (United States). Energy expenditure and PA were assessed during two school days and two weekend days using a multiple-sensor body monitor. RESULTS: Differences between the cities were observed for all PA variables. The highest level of moderate to vigorous PA (MVPA) was noted in Ljubljana boys [284 (98) min/day] and the lowest in Zagreb girls [179 (95) min/day]. In Zagreb and Ljubljana, boys were more physically active than girls, while in Ann Arbor the opposite was observed. In contrast, no gender difference in sedentary behavior was observed in any of the cities. A decline in PA from school days to weekends was noted in all city groups in both genders. However, the magnitude of the reduction in daily energy expenditure differed between the cities, with the largest differences being observed in Ljubljana and the smallest in Ann Arbor. In all three city groups, the great majority of boys and girls achieved current recommendations of 60 min of MVPA either during school days or weekends. CONCLUSIONS: Weekends seem to be an appropriate target when promoting PA in 11-year-olds in all the cities included in the study. Increasing vigorous activity on weekends seems to be of particular importance in Zagreb and Ljubljana.

Associations of objectively assessed sleep and physical activity in 11-year old children.

AIM: Objective methods were used to evaluate children's sleep and physical activity over several days in order to test the hypotheses that: (1) low average sleep duration and/or sleep efficiency are linked to a low amount of physical activity; and (2) a reduction in sleep quantity and/or sleep efficiency during the night is followed by a decrease in physical activity the following day. METHODS: This is a multi-centre, observational study involving 276 children, aged 10.5-12 years, from diverse urban settings in Croatia, Slovenia and the US. Sleep and activity were monitored for 2-6 days (median = 4) using the Sensewear Armband™ multi-sensor body monitor. RESULTS: While average sleep duration and efficiency were unrelated to physical activity, within-subjects associations revealed that an extra hour spent in bed during the night was followed by a 16-minute decrease in moderate-to-vigorous physical activity (p < 0.001). This was accompanied by a 4.5 kJ/kg and 5.9 kJ/kg lower total daily energy expenditure in boys and girls, respectively (p < 0.001). CONCLUSIONS: This study found no evidence for a link between short sleep and low or reduced physical activity.

Tracking of BMI, fatness and cardiorespiratory fitness from adolescence to middle adulthood: the Zagreb Growth and Development Longitudinal Study.

BACKGROUND: Effective intervention strategies aiming to improve cardiorespiratory fitness and to decrease body fatness are needed. However, long-term stability of these traits is not well understood. AIM: To assess long-term tracking of cardiorespiratory fitness and body fatness from late adolescence to middle adulthood. SUBJECTS AND METHODS: The sample consisted of 50 participants (31 boys) from the Zagreb Growth and Development Longitudinal Study who were followed up in adulthood (median age = 43). Fatness was evaluated through BMI and skin-folds, while cardiorespiratory fitness was assessed using a cardiopulmonary exercise test. Inter-age partial correlation coefficients were calculated to evaluate tracking. RESULTS: Body mass index and skin-folds showed moderate tracking from age 15 years to middle adulthood (partial r = 0.55, p < 0.001 and partial r = 0.52, p < 0.001, respectively), while tracking of subcutaneous fat distribution was somewhat lower (partial r = 0.38, p < 0.01). At the same time, the observed tracking of peak oxygen uptake was low-to-moderate (partial r = 0.30, p = 0.03), while ventilatory aerobic and anaerobic thresholds did not show significant tracking. CONCLUSIONS: The results of this study indicate that preventive efforts aiming to increase cardiorespiratory fitness should include all adolescents, irrespective of their cardiorespiratory fitness status. Conversely, strategies aiming at obesity prevention should focus on high-risk groups of adolescents.

Physical fitness among children with diverse weight status during and after the COVID-19 pandemic: a population-wide, cohort study based on the Slovenian physical fitness surveillance system (SLOfit).

Background: COVID-19 public health crisis has exerted immediate negative impacts on children's physical fitness, but the longer-term effects are not clear, and the impact on children with excess weight is yet unknown. We examined changes in multiple components of physical fitness in response to COVID-19 imposed restrictions, but also a year after the restrictions were terminated, and compared these trends in groups of boys and girls with normal weight, overweight, or obesity before the pandemic. Methods: Information was gathered through Slovenia's national fitness surveillance system, and included 41,330 children (19,890 girls), aged 5-17, who had their fitness levels measured yearly from 2019 to 2022. Multilevel linear mixed models, fitted separately for boys and girls, were used to model the individual-level trends over time in centile score for each fitness test across 3 weight groups. Findings: Overall fitness levels decreased markedly across all weight categories between 2019 and 2020, with the largest decreases in Total Fitness Index observed in children with normal weight and overweight (-8.4 and -7.7 centiles for boys and -8.3 and -8.8 for girls, respectively, p < 0.001). While there was some recovery in the overall fitness level between 2020 and 2022, it remained much lower in 2022 compared to 2019 across most groups, apart from boys with obesity. Fitness components that had the largest impact on general fitness trends were cardiorespiratory fitness, lower body power, body core, and upper body strength. Interpretation: A severe decline in fitness that has not come close to returning to pre-pandemic levels in most population groups of youth begs for urgent population-wide initiatives that will provide additional opportunities for physical activity to youth. Among vulnerable groups, girls with overweight and obesity deserve a special focus of these policies. Funding: Horizon 2020 (Grant no. 774548), Slovenian National Research Agency (Grant no. P5-0142), Croatian Science Foundation (Grant no. DOK-2020-01-3728).

Correction: Radman et al. Prevalence of Key Modifiable Cardiovascular Risk Factors among Urban Adolescents: The CRO-PALS Study. Int. J. Environ. Res. Public Health 2020, 17, 3162.

The authors regret to acknowledge that a mistake has been made in the original article [...].

Effectiveness of a population-scaled, school-based physical activity intervention for the prevention of childhood obesity.

OBJECTIVE: The aim of this study was to examine the effectiveness of a real-world, population-scaled, school-based physical activity (PA) intervention that provided two to three additional physical education lessons per week to children aged 6 to 14 years in Slovenia. METHODS: More than 34,000 participants from over 200 schools were compared with a similar number of nonparticipants from the same schools. Generalized estimating equations were used to estimate the effects of differing levels of exposure to the intervention (i.e., from 1-5 years) on BMI in children with normal weight, overweight, or obesity at baseline. RESULTS: BMI was lower in the intervention group, irrespective of participation duration or baseline weight status. The difference in BMI increased with the program duration, with maximal effects being seen after 3 to 4 years of participation, and was consistently larger for children with obesity (peaking at 1.4 kg/m2 [95% CI: 1.0-1.9] for girls with obesity and peaking at 0.9 kg/m2 [95% CI: 0.6-1.3] for boys with obesity). The program started to become effective at reversing obesity after 3 years, whereas the lowest numbers needed to treat (NNTs) were observed after 5 years (NNTs = 17 for girls and 12 for boys). CONCLUSIONS: The population-scaled, school-based PA intervention was effective in preventing and treating obesity. The effects were the greatest in children initially presenting with obesity, such that the program was able to benefit children needing support the most.

Adult height prediction using the growth curve comparison method.

Understanding the growth pattern is important in view of child and adolescent development. Due to different tempo of growth and timing of adolescent growth spurt, individuals reach their adult height at different ages. Accurate models to assess the growth involve intrusive radiological methods whereas the predictive models based solely on height data are typically limited to percentiles and therefore rather inaccurate, especially during the onset of puberty. There is a need for more accurate non-invasive methods for height prediction that are easily applicable in the fields of sports and physical education, as well as in endocrinology. We developed a novel method, called Growth Curve Comparison (GCC), for height prediction, based on a large cohort of > 16,000 Slovenian schoolchildren followed yearly from ages 8 to 18. We compared the GCC method to the percentile method, linear regressor, decision tree regressor, and extreme gradient boosting. The GCC method outperformed the predictions of other methods over the entire age span both in boys and girls. The method was incorporated into a publicly available web application. We anticipate our method to be applicable also to other models predicting developmental outcomes of children and adolescents, such as for comparison of any developmental curves of anthropometric as well as fitness data. It can serve as a useful tool for assessment, planning, implementation, and monitoring of somatic and motor development of children and youth.

The dilemma of physical activity questionnaires: Fitter people are less prone to over reporting.

Physical activity questionnaires (PAQs) are a popular method of monitoring physical activity, although their validity is usually low. Descriptions of physical activity levels in questionnaires usually rely on physical responses to physical activity. Therefore, we hypothesised that the validity of PAQs would be higher in the more physically fit group of participants. To test this, we conducted a validation study with 179 adults whom we divided into three fitness groups based on their cardiovascular fitness and age. Participants were measured for one week using the UKK RM42 accelerometer and self-reported their physical activity using IPAQ-SF, GPAQ, and EHIS-PAQ. We analysed the differences between fitness groups in terms of validity for each PAQ using ANOVA. We also performed an equivalence testing to compare the data obtained with the PAQs and the accelerometers. The results showed a significant trend toward higher validity for moderate to vigorous physical activity from the low to high fitness group as assessed by GPAQ and IPAQ-SF (low, intermediate and high fitness group: 0.06-0.21; 0.26-0.29; 0.40, respectively). The equivalence testing showed that all fitness groups overestimated their physical activity and underestimated their sedentary behaviour, with the high fitness group overestimating their physical activity the least. However, EHIS-PAQ was found to agree best with accelerometer data in assessing moderate to vigorous physical activity, regardless of fitness group, and had a validity greater than 0.4 for all fitness groups. In conclusion, we confirmed that when using PAQs describing physical responses to physical activity, participants' fitness should be considered in the interpretation, especially when comparing results internationally.

Assessment of Nutrient Intake and Diet Quality in Adolescent Dietary Supplement Users vs. Non-Users: The CRO-PALS Longitudinal Study.

Dietary supplement users tend to have a better diet quality and overall prudent lifestyle. The main goals of this research were to report the prevalence and type of dietary supplements among Croatian adolescents and to examine the differences in the diet quality among dietary supplement users vs. non-users at the beginning (15/16 y) and at the end of high school education (18/19 y). This research is based on results of the longitudinal CRO-PALS study in which 607 adolescents participated, who had complete dietary, anthropometric, and physical activity data at the beginning (15/16 y) and at the end of their high school education (18/19 y). The dietary assessment method used was a single multi-pass 24 h recall. Dietary supplement users were divided into two groups for the purposes of statistical analysis-users of vitamin and multivitamin preparations (VMV) and users of mineral and multivitamin preparations (MMV). As they aged, there was an increase in the consumption of dietary supplements, and the most frequently used preparation in both age groups was vitamin C (23.7% of users). Dietary supplement users had a higher intake of non-carbonated sweetened drinks and a lower intake of fruits and vegetables in both genders and both age groups. Fast food intake was higher among dietary supplement girl users and boys who were not dietary supplements users in both age groups. Dietary supplement users had a higher achieved average intake of most micronutrients (values obtained only from food) in both genders and both age groups (with exceptions for certain vitamins and minerals). By observing other parameters for assessing the diet quality in this research, we can conclude that girls who do not use dietary supplements have a better diet quality in both age groups.

Physical Activity of Children and Adolescents in Croatia: A Global Matrix 4.0 Systematic Review of Its Prevalence and Associated Personal, Social, Environmental, and Policy Factors.

BACKGROUND: The previous review of physical activity (PA) among Croatian children and adolescents was conducted a decade ago. Therefore, the aim of this study was to summarize recent evidence on PA of Croatian children and adolescents and associated personal, social, environmental, and policy factors. METHODS: Eighteen experts reviewed the available evidence and provided ratings (from the lowest grade "F" to the highest grade "A+") for the 10 Global Matrix indicators. A systematic search with 100 keywords was conducted in Hrcak, PubMed/MEDLINE, Scopus, SPORTDiscus, and Web of Science for documents published from January 01, 2012, to April 15, 2022. We also conducted internet searches and secondary analyses of data (relative frequencies) from 6 studies. RESULTS: After assessing 7562 references, we included 90 publications in the review and 18 studies (83.3% of medium-to-good quality) in evidence synthesis. We found a high prevalence of insufficient PA (especially among girls) and excessive screen time (especially among boys). PA participation of children and adolescents in Croatia has declined over time. The following grades were assigned to the indicators for Croatia: B- for overall PA, C- for organized sport and PA, C for active play, C- for active transportation, D+ for sedentary behavior, inconclusive for physical fitness, D+ for family and peers, B- for school, B- for community and environment, and D+ for government. CONCLUSIONS: Coordinated actions are needed across sectors to improve PA promotion, with a focus on increasing PA among girls, reducing sedentary screen time among boys, improving parental support for PA, and further development of national PA policies.

Validation of the Sensewear Armband during recreational in-line skating.

Multi-sensor body monitors that combine accelerometry with other physiological data are designed to overcome drawbacks of accelerometers in assessing activities with little or no vertical movement. One of such devices is the Sensewear Armband (SWA) which has been extensively validated during various activities. However, very few of the validation studies included activities other than walking and running. The aim of this investigation was to assess the validity of the SWA during recreational in-line skating. Nineteen participants (11 females and 8 males), 28 (±6) years of age, performed in-line skating exercise on a circular track at a self-selected pace. Energy expenditure was measured with the SWA and the Cosmed K4b(2) breath-by-breath portable metabolic unit. The mean (SD) energy expenditure during in-line skating estimated by the SWA [25.5 (5.8) kJ/min] was significantly lower compared with indirect calorimetry [44.2 (9.7) kJ/min, P < 0.001]. Similarly, the mean (SD) MET values recorded by the SWA were also lower compared with IC [5.3 (1.0) METs vs. 9.1 (1.6) METs, P < 0.001]. The ratio limits of agreement suggest that in 95% of cases the SWA will underestimate the energy expenditure and MET values during in-line skating by as much as 24-56% compared with indirect calorimetry. In conclusion, the results of the present study indicate that the SWA is not able to overcome the drawbacks of accelerometry in assessing activities with limited vertical movement.

Does time of the day matter? Temporal associations between physical activity and quality and quantity of subsequent sleep in adolescents.

Temporal associations between moderate-to-vigorous physical activity (MVPA) at four different multi-hour intervals during the day and the following indicators of sleep quality and sleep quantity in adolescents were examined. This research is a part of the CRO-PALS study, including 129 adolescents (48 boys, 81 girls; mean age ± SD = 15.6 ± 0.4 years) having complete data on sleep and MVPA measured by the SenseWear Pro3 Armband monitor. As data had a hierarchical structure, repeated measures multilevel modelling was used to assess the associations between PA and sleep. During school nights, in girls, morning MVPA was not related to following indicators of sleep quality and sleep quantity. At the same time, evening MVPA was linked with longer sleep onset latency (ß = 0.064; 95%CI = 0.025 to 0.103) and higher wake after sleep onset (ß = 0.156; 95%CI = 0.0482 to 0.2638). Moreover, during weekend nights, morning MVPA was not associated with sleep, while evening MVPA was accompanied by longer sleep onset latency (ß = 0.058; 95%CI = 0.023 to 0.093), higher wake after sleep onset (ß = 0.104; 95%CI = 0.012 to 0.20), and negatively with sleep efficiency (ß = -0.019; 95%CI = -0.037 to -0.001). In boys the specific multi-hour interval of performing physical activity was not associated with any of indicators of sleep quality. In conclusion, while no strong relations between MVPA and sleep were seen among boys, in girls morning hours MVPA resulted in better sleep patterns over school nights, while afternoon MVPA was followed with slight worsening of some indicators of sleep quality across the whole week.