Results from Estonia's 2022 Report Card on Physical Activity for Children and Youth: Research Gaps and Five Key Messages and Actions to Follow.

The aim of this article is to summarize the results of the 2022 Estonian Physical Activity Report Card across 10 indicators based on available scientific data and national databases, and, additionally, to compare the current results with previous Report Card results. A national expert panel, consisting of research and policy experts, identified the available sources and synthesized as well as graded relevant data related to the physical activity (PA) of Estonian children and youth. Grade B was assigned to Organized Sports and Physical Activity (B-), Community and Environment (B+), and Government (B). Grade C was assigned to Overall Physical Activity (C+), Physical Fitness (C+), Family and Peers (C-), and School (C+). The lowest grade, D, was assigned to Active Play (D), Active Transportation (D+), and Sedentary Behaviors (D-). In Estonia, the participation rate in organized sport is relatively high, and government in addition to community support seem to be at a relatively good level. However, a relatively high number of children and youth did not meet the current PA guidelines, and the levels of sedentary behavior and screen time were very high. The PA of children and youth should be a cross-disciplinary priority, and focus should be put on developing schoolyards and outdoor breaks, varied and easily accessible organized sport, the use of active transportation, and the implementation of physical education that supports leisure time activities.

School Children's Physical Activity and Preferred Activities during Outdoor Recess in Estonia: Using Accelerometers, Recess Observation, and Schoolyard Mapping.

Studies about recess have found that children have higher physical activity (PA) during outdoor recess compared to indoor recess, and well-constructed schoolyards play an important role in stimulating PA in children. This study aimed at investigating the affordances of schoolyards and outdoor recess PA in two urban and two rural primary schools in Estonia. Schoolyards were described with the geographical mapping method, children's activities during outdoor recess were registered by using observations, and PA levels were measured with accelerometers. Students from grades two to six (8-13-year-olds) were included in the study. All observed schoolyards had different spaces including various ball game areas, climbing facilities, and slacklines. The natural environment dominated in the rural schools, and artificial surfaces dominated in the urban schools. Boys in the study tended to enjoy more sport-related activities, whereas girls preferred more social and less active activities. Students participating in outdoor recess spent about twice as much time (20.4%) on moderate-to-vigorous PA (MVPA) compared to indoor recess (9.5%), although boys were more active than girls (22.9% vs. 17.3%). All schoolyards afforded more MVPA during outdoor recess compared to indoor recess, whereas schoolyards with more space per child and natural environment elements generated more varied PA and higher MVPA. These findings confirm the importance of schoolyard design and quality for the variety and intensity of students' PA during outdoor recess.

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.

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

Purpose: This study examined the development of cardiorespiratory fitness (CRF) in children in the transition from kindergarten to basic school according to participation in organized sports and estimated the associations of CRF and body composition indices during the transition from childhood to preadolescence. Methods: Children participated in the three-staged study (kindergarten, 6.6 years, n = 212; 1st grade, 7.6 years, n = 136; and 5th grade, 11.5 years, n = 142) for 5 years and were categorized into three groups according to their participation in organized sports in the study period (whole period, episodically, and never). Cardiorespiratory fitness was assessed by performing a 20-m shuttle run test, while body composition was measured by skinfold thicknesses, and physical activity was registered with an accelerometer. International gender- and age-specific CRF reference normativities were also used to characterize the participants. Results: Children who participated consistently in organized sports had significantly higher CRF levels and lower body fatness (31.3 ± 13.5 laps in 20 m shuttle run; 21.1% ± 6.3% body fat) in 11.5 years than in children who had never participated in sports clubs (20.7 ± 12.0 laps in 20-m shuttle run; 26.1% ± 6.8% body fat). Body composition and CRF did not associate in consistently trained children. The proportion of 5th grade children demonstrating age-appropriate healthy CRF was almost threefold higher in the group of consistent sports training among both boys and girls than among non-members of sports clubs. Conclusion: Consistent attendance in organized sports in childhood and early preadolescence ensures higher CRF and healthier body composition than in children who had no experience of organized sports.

Physical Activity, Fitness, and Cognitive Performance of Estonian First-Grade Schoolchildren According Their MVPA Level in Kindergarten: A Longitudinal Study.

Little is known about the longitudinal trajectories and associations regarding physical activity (PA), physical fitness (PF), and cognitive skills in childhood. Accelerometer-based PA, sedentary behavior (SB), PF, and cognitive skills were measured in Estonian children (n = 147) in kindergarten (6.6 years) and again at school (7.6 years). Children were subgrouped into lower and upper quartiles by their moderate-to-vigorous PA (MVPA) at 6.6 years. Children in the upper quartile had lower SB, higher PA, and greater muscular strength. Attending school, MVPA in the lower quartile improved. In both subgroups, most strength values and cognitive skills improved, while balance deteriorated in first grade. In the upper quartile, a greater MPA at 6.6 years predicted lower perceptual skills at 7.6 years. A greater SB at 6.6 years predicted higher verbal skills, light and moderate PA and MVPA, and lower verbal skills at 7.6 years after taking into account confounding factors such as the child's sex, age, awake wear time (AWT), maternal education, and/or child's sports participation. A vigorous PA at 6.6 years predicted perceptual (in upper quartile) or verbal (in lower quartile) skills at 7.6 years after controlling for similar confounders. No correlation for PF at 6.6 years and cognitive skills at 7.6 years existed; after adjusting for the above-mentioned confounders relative to upper/lower-limb strength, the 4 × 10 m shuttle run results predicted higher perceptual or verbal skills; static balance and cardiorespiratory fitness predicted lower verbal skills. Cardiorespiratory fitness predicted higher perceptual skills after controlling for sex, age, and AWT. Overall, PA and strength were constantly better and SB lower in the upper quartile, yet the lower quartile demonstrated improved MVPA in first grade, and both subgroups increased most components of their strength and cognitive skills in first grade. Higher levels of VPA at kindergarten predicted either better perceptual or verbal skills in first grade after controlling for confounders; the opposite associations were found for other PA levels and cognitive skills in the higher quartile. PF components at kindergarten predicted either superior or inferior cognitive skills in first grade after adjusting for confounders.

Pubertal Physical Activity and Cardiorespiratory Fitness in Relation to Late Adolescent Body Fatness in Boys: A 6-Year Follow-Up Study.

There is a lack of studies investigating whether objectively measured physical activity (PA) and cardiorespiratory fitness (CRF) in puberty is associated with healthier body composition in late adolescence. The study sample included 71 boys, who were measured at puberty (mean age of 12.1 years) and again at late adolescence (mean age of 18.1 years). Physical activity was measured by accelerometry, and total PA, moderate-to-vigorous PA (MVPA), and sedentary time (SED) were calculated, while CRF was assessed by a peak oxygen consumption test. Body composition was measured by dual-energy X-ray absorptiometry, and body fat percentage (%BF), fat mass index (FMI), trunk fat mass index (TFMI), and fat-free mass index (FFMI) were calculated. Body mass index (BMI) and SED time increased, while MVPA, total PA, and CRF decreased from puberty to late adolescence. A relatively high degree of tracking for BMI and CRF, and a low tracking for PA from puberty to late adolescence was observed. Only the CRF value at puberty negatively predicted adolescent BF% (ß = -0.221; p = 0.015), FMI (ß = -0.212; p = 0.006), and TFMI (ß = -0.189; p = 0.015) values. Adolescents whose CRF was above the median at puberty had lower BMI, BF%, FMI, and TFMI in comparison to those whose CRF was below the median at puberty. In conclusion, measured CRF and PA values decreased from puberty to late adolescence. Pubertal CRF predicted body fatness indices six years later in healthy adolescents.

Preschool physical activity and fitness predicts conceptual, verbal and perceptual skills at school.

This study investigated longitudinal relationships between physical activity (PA), fitness and cognitive performance at early years. In total, 147 children at the age of 6.6 and 7.6 years participated in the study. PA and sedentary behaviour (SB) were registered with accelerometer. Skinfold thickness measurements were used to assess body composition. Children's cardiorespiratory fitness (CRF), muscular strength and speed-agility fitness was assessed using PREFIT fitness test battery and static balance by EUROFIT test battery. Cognitive skills were measured with modified Boehm-3 test. Linear regression analyses showed that PA at the age of 6.6 years was positively, while SB was negatively associated with the conceptual skills at the age of 7.6 years after adjusting for confounders. Positive associations were observed between CRF, lower-limbs strength relative to fat-free mass, static balance at the age of 6.6 years with perceptual skills at 7.6 years in unadjusted analysis. PA and fitness were not associated with verbal abilities. Physically active lifestyle and CRF, relative explosive strength of the lower limbs, balance at 6.6 years in kindergarten predict conceptual and perceptual skills, but does not predict verbal abilities 1 year later at first grade in school. SB affects negatively conceptual skills.

Physical fitness in preschool children in relation to later body composition at first grade in school.

BACKGROUND: This study aimed to investigate whether better physical fitness in kindergarten predicts later healthier body composition in first grade at school. METHODS: Body composition was assessed by skinfold thickness measurements. Physical fitness tests included 20 m shuttle run test, handgrip strength test, standing long jump test, 4x10 m shuttle run test as part of PREFIT fitness test battery, and one-leg stance test from EUROFIT test battery. The participants of this study were 147 Estonian children (51% boys) aged 6-8 years, who were measured in the transition from kindergarten to school. RESULTS: After adjusting for maternal body mass index, educational attainment, child's sex, age at the measurements, greater cardiovascular and motor fitness, relative lower body strength, static balance at 6.6 yr were associated with lower fat mass index, fat mass percentage at 12-month follow-up. The relative lower body strength above the median at 6.6 yr were related to lower fat mass index and fat mass percentage at 12-month follow-up, while the static balance test results demonstrated the opposite associations. Improvements in the 4x10 m shuttle run test results during the 12-month follow-up period were associated with the most beneficial changes in body composition status, such as increases in fat-free mass index and decreases in fat mass index, fat mass percentage, waist-to-height ratio after adjusting for maternal body mass index, educational attainment, child's sex, age, at the measurements and baseline values of exposures. CONCLUSION: Better physical fitness tests results at 6.6 yr in kindergarten generally predicted lower body fat parameters in children at 7.6 yr in first grade at school.

Associations between physical activity, body composition, and physical fitness in the transition from preschool to school.

The purpose of the study was to assess the longitudinal associations of physical activity (PA) with body composition and physical fitness (PF) at the 12-month follow-up during the transition from kindergarten to school in Estonian children aged 6 to 8 years (n = 147). PA and sedentary behavior (SB) were assessed using the accelerometer. Body composition was measured from triceps and subscapular skinfold thicknesses and PF using PREFIT test battery. SB at the mean age of 6.6 year had negative relation with upper and lower body strength and motor fitness at the mean age of 7.6 year in adjusted models. Light PA (LPA) and moderate PA(MPA) at 6.6 year were positively and SB was negatively associated with fat-free mass index (FFMI) at 7.6 year after adjustments for confounders [vigorous PA (VPA), total awake wear time, child's sex, age at measurement]. Substituting 5 min/d of SB at 6.6 year with 5 min of VPA was related to higher FFMI at 7.6 year. In adjusted models, VPA at 6.6 year was positively associated with cardiorespiratory fitness at 7.6 year, greater baseline VPA or moderate-to-vigorous PA (MVPA) predicted greater upper body strength a year later and LPA, MPA, VPA, MVPA at 6.6 year were positively related to lower body strength at follow-up. In adjusted analysis greater VPA at 6.6 year was related to better motor fitness at follow-up. Promoting higher-intensity PA and reducing SB at preschool may have long-term effects on body composition and PF in children at the first grade.

Physical fitness and physical activity of 6-7-year-old children according to weight status and sports participation.

BACKGROUND: The aim of this study was to investigate physical fitness and physical activity (PA) of 6-7-year-old children just before entering school according to their sports club (SC) participation and weight status, and to examine possible associations of their body mass index, fat mass and fat-free mass with physical fitness and PA. METHODS: A total of 256 preschoolers aged 6 to 7 years participated in the study. Physical fitness was assessed using PREFIT test battery and objective PA by 7 day accelerometry. Body composition was estimated using two skinfold thickness parameters. SC participation and parental data were assessed by questionnaires. RESULTS: Children participating in SC had higher moderate-to-vigorous PA, vigorous PA and cardiorespiratory fitness than children not participating in SC. Overweight children had lower results in cardiorespiratory fitness and all weight-bearing fitness tests, and better results in handgrip strength test in comparison with normal weight children. Significant associations were found between body composition indices and physical fitness tests. PA level was associated with fat-free mass and physical fitness but not with fatness indices. CONCLUSIONS: Weight-status and body composition together with PA level were associated with physical fitness level. The differences in physical fitness based more upon weight status than SC participation among 6-7-years old children.

Physical activity, sedentary time and sleep duration: associations with body composition in 10-12-year-old Estonian schoolchildren.

BACKGROUND: Physical activity, sedentary time, and sleep duration have been associated with body composition among children. The purpose of the present study was to assess the associations of objectively determined daily physical activity, sedentary time, sleep duration and body composition indices in 10-12-year-old children. METHODS: Two hundred and eleven schoolchildren (96 boys and 115 girls) aged 10.9 ± 0.7 years participated in this study. Objective physical activity intensity and sedentary levels were measured for seven days by accelerometry. Sleep duration was self-reported. Percentage of body fat, waist-to-height ratio and fat free mass were calculated from measured anthropometric parameters. Multiple linear regression models were used to examine the associations between sleep duration, moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA) level and body composition indices. RESULTS: Boys exceeded girls (p < 0.05) in time spent in MVPA and VPA levels. Only 4.3% of the children met the current daily recommendation of at least 60 min MVPA per day. Sleep duration, MVPA and VPA had a negative association with percentage of body fat and waist-to-height ratio. Vigorous physical activity had a positive association with fat-free mass. Sedentary time had a positive association with percentage of body fat and negative association with fat-free mass. CONCLUSIONS: The present study suggests that both sleep duration and MVPA are associated with body composition parameters. Higher levels of MVPA are associated with lower percentage of body fat and waist-to-height ratio regardless of sleep duration. Sedentary time is associated with higher values of percentage of body fat and lower fat-free mass independently of sleep duration.

Perspectives of children and adolescents on the perceived determinants of physical activity during recess.

Promotion of healthy lifestyles in youth focuses on school-based interventions with the aim to increase physical activity (PA) during school days. Drawing on seventeen focus group discussions from three purposively selected Estonian schools, we explored factors that perceivably affect students' recess physical activity (RPA). Both inductive and deductive principles of data analysis were used to extract major and subthemes related to factors that inhibit or enhance RPA. Participants identified barriers and facilitators to recess PA as originating mainly from physical and organizational school environment. Also, unsuitable weather was described as a barrier to being active. Additionally, feelings, behavioral and normative beliefs were described as constraining or facilitating RPA. Results highlighted two culture-specific unique perceived determinants of RPA that need to be addressed during the development of school-based interventions to increase PA.

Physical Education Increases Daily Moderate to Vigorous Physical Activity and Reduces Sedentary Time.

BACKGROUND: Physical activity (PA) is important to mental and physical health. Physical education (PE) lessons have the potential to increase daily moderate to vigorous PA (MVPA) and reduce sedentary time (SED). We measured MVPA and SED in primary school PE, determined the contribution of PE to daily MVPA and SED, and compared PA on days with and without PE. METHODS: PA was measured in 504 first (ages 7-9) and second (ages 10-12) school level children for 1 school week, with inclusion criteria of at least 10 hours of valid data. Linear mixed methods were used for data analysis. RESULTS: In PE, students spent 28.6 ± 16.5% in MVPA and 29.3 ± 19.8% in SED. Each additional MVPA minute in PE was associated with 1.4 more daily MVPA minutes. On days with PE, students had 12.8 (95% CI 10.5; 15.0) minutes more MVPA and 9.7 (95% CI 16.3; 3.1) minutes less SED compared with days without PE. CONCLUSIONS: Although MVPA in PE was relatively low and SED high, PE significantly increased daily MVPA and reduced SED, confirming the important role of PE in supporting the healthy development of children.

Longitudinal Associations Between Sedentary Behavior of Adolescent Girls, Their Mothers, and Best Friends.

PURPOSE: The objective of this study was to examine the prospective relationship and changes in sedentary behavior between adolescent girls, their mothers and best friends over time. METHOD: The results are based on 122 girls aged 11-12 years at baseline measurement, their mothers and best friends who completed ecological momentary assessment diary for the assessment of sedentary behavior. All measurements were taken at 3 time points separated by one year. We used structural equation modeling to examine associations among sedentary behavior of adolescent girls, their mothers and best friends. RESULTS: A linear growth model for adolescent girls' and their best friends' sedentary behavior fit the data well, revealing an overall significant increase in sedentary behavior across time. Initial levels of mothers' and best friends' sedentary behavior were positively related with sedentary behavior of adolescent girls. The changes of adolescent girls' and best friends' sedentary behavior across 3 years were positively related. Cross-lagged panel analysis demonstrated significant reciprocal effects between adolescent girls' and best friends' sedentary behavior. Mothers' sedentary behavior at baseline predicted daughters' sedentary behavior at 1-year follow-up and vice versa. CONCLUSION: From early to midadolescence, changes in adolescent girls' sedentary behavior were associated with changes in best friends' sedentary behavior. These findings suggest reciprocal associations between sedentary behavior of adolescent girls and their best friends.

Longitudinal Association Between Objectively Measured Walking and Depressive Symptoms Among Estonian Older Adults.

Although an inverse correlation between physical activity and depressive symptoms among older adults has been found in research, this relation has seldom been examined prospectively. Accordingly, the current study examined the reciprocal relations between physical activity and depressive symptoms in Estonian older adults over a 2-year period. A three-wave longitudinal model was tested using cross-lagged analysis for 195 individuals aged over 70 years (mean = 72.1, SD = 2.1; 145 females). Results indicated that a cross-lagged model in which depressive symptoms predicted walking at subsequent time points (higher depressive symptoms were related to fewer walking steps), and walking predicted depressive symptoms at subsequent time points (higher walking steps were related to lower depressive symptoms) was most parsimonious and provided acceptable model fit. These results suggest that reduced physical activity may be a long-term consequence of depressive symptoms in older adults.

Objectively measured sedentary behaviour and moderate and vigorous physical activity in different school subjects: a cross-sectional study.

BACKGROUND: Evidence shows the positive influence of moderate and vigorous physical activity (MVPA) and negative influence of sedentary time on health and academic achievement. Although schools can significantly contribute to overall physical activity, little is known about MVPA and sedentary behaviour in different school subjects in different grades. METHODS: Physical activity of 646 students from 18 schools (94 classes) and from three school stages (grades 1-9, aged 7-16) was measured with accelerometry for 5 school days. Time and proportion of MVPA and sedentary time, also average sedentary bout length was calculated for native language (Estonian), mathematics, science, foreign language, music and crafts lessons. RESULTS: A total of 6363 lessons were measured, with lesson duration of 45 min. The average lesson time MVPA remained below 2.2 min in all school stages and in all subjects. Students in grades 4-6 had greatest decline in the proportion of lesson time MVPA in science (ß = -1.9, 95%CI -3.1- -0.6) and music (-1.2, -2.1- -0.4) and in grades 7-9 in music (-1.7, -3.1- -0.3) lessons compared to grades 1-3. In grades 1-3 students spent on average 76% of lesson time (34.0 ± 7.0 min) as sedentary, whereas in grades 7-9 the average proportion of sedentary time was 87% (38.9 ± 5.7 min). An average sedentary bout length increased from 13 min in grades 1-3 to 20 min in grades 7-9. An increase in sedentary bout length from grades 1-3 compared to grades 7-9 was present in most subjects, except crafts, with smallest increase in foreign language (6 min, 3.5-8.9) and greatest in music lessons (16.6 min, 11.9-21.3). Lessons with prolonged sedentary bouts formed a maximum 36% of all lessons in grades 1-3 and 73% in grades 7-9. CONCLUSION: The long sedentary time, bout length and low MVPA in most subjects were unfavourable in respect of both health and academic achievement. Significantly increasing sedentary time and sedentary bout length in older school stages highlights the need for interventions in all subjects and especially in older grades in order to combat the inactivity of children.

Results From Estonia's 2016 Report Card on Physical Activity for Children and Youth.

BACKGROUND: The 2016 Report Card on Physical Activity for Children and Youth, the first of its kind, aims to set baseline physical activity (PA) indicators using the Active Healthy Kids Global Alliance grading system. METHODS: A research work group analyzed and selected data for the grade assignment meeting (GAM). During the GAM, 17 leading researchers and policy experts from Estonia assessed the data and assigned grades for each of the 9 PA indicators. In addition, recommendations were provided for further actions to improve the grades. RESULTS: Grades from A (highest) to F (lowest) were assigned as follows: 1) Overall PA (F); 2) Organized Sport (C); 3) Active Play [incomplete data (INC)]; 4) Active Transportation (INC); 5) Sedentary Behaviors (F); 6) Family and Peers (C); 7) School (C); 8) Community and the Built Environment (B); and 9) Government (C). An indicator was marked as incomplete (INC) when there was a lack of representative quality data. CONCLUSIONS: Evidence suggests that PA levels of Estonian children remain very low, despite moderately supportive social, environmental, and regulatory factors. There are many challenges to overcome in supporting and promoting PA of children and youth (eg, cross-sectional cooperation, implementing interventions, changing social norms, empowerment of parents and educational institutions).

Objectively measured physical activity levels and sedentary time in 7-9-year-old Estonian schoolchildren: independent associations with body composition parameters.

BACKGROUND: Sufficient daily physical activity (PA) is necessary for physical, social and mental health benefits during growth. Most of the available data on children is based on subjective reports, while only limited data on objective PA and sedentary levels is available for primary school children. Increased PA is also an important health indicator of body composition parameters, especially body adiposity indices. The aim of the present study was to determine objectively the amount of daily PA levels at different intensities and sedentary time in normal-weight (NW) and overweight (OW) 7-9-year-old boys and girls, and to find associations between objectively measured PA levels and sedentary time with different body composition values. METHODS: Two hundred and seventy eight (142 boys and 136 girls) primary school children aged 7.9 ± 0.7 years participated in this study. Objective PA intensity and sedentary levels were measured over 7 days by accelerometry. Indices of total fat mass (body fat %, sum of skinfolds), fat distribution (waist-to-height ratio) and muscular component (fat free mass [FFM]) were calculated from measured anthropometric parameters. RESULTS: There were no differences (p > 0.05) in PA intensity levels and sedentary time between boys and girls as well as between NW and OW children. About 11 % of children met the current guidelines of at least 60 min per day of moderate-to-vigorous PA (MVPA). Sedentary time was positively and negatively associated (p < 0.05) with all body fat and FFM values, respectively. Moderate and vigorous PA along with MVPA were negatively and positively associated (p < 0.05) with all body fat and FFM indices, respectively. CONCLUSIONS: The results of present study showed that about 11 % of primary school children were engaged in PA of at least 60 min of MVPA daily. While MVPA is negatively associated with fat mass indices and positively associated with FFM regardless of different confounders, sedentary time is negatively related to FFM and positively with fat mass values after adjusting for several confounders. These results suggest that higher MVPA level and lower sedentary time level are important in maintaining and developing healthy body composition in primary school children during growth.

Different Methods Yielded Two-Fold Difference in Compliance with Physical Activity Guidelines on School Days.

INTRODUCTION: The aim was to compare the average and the days method in exploring the compliance of children with physical activity guidelines and describe their physical activity patterns in different school day segments. METHODS: Physical activity was objectively measured in 472 children aged 6-13 for one school week. Children were compliant when fulfilling PA recommendations 1) on average over all measured days (average method) or 2) on at least four measured days (days method). To explore the difference in moderate to vigorous physical activity (MVPA) minutes between compliant and non-complaint children (using both the average and days method) in various day segments, linear mixed models was used. RESULTS: Compliance with physical activity guidelines was significantly higher with the average compared to the days method (51.7% and 23.7%, respectively). In segmented-day analysis, compliant children accrued more MVPA minutes in all day segments, especially during after-school. Gender differences appeared only during the in-school segments, where girls spent less time in MVPA (average method: -4.39 min, 95% CI = -5.36,-3.42, days method: -4.45 min, 95%CI = -5.46,-3.44). Older children accrued more MVPA minutes during physical education classes, but less during breaks, compared to younger children. CONCLUSIONS: The used methods yielded remarkably different prevalence estimates for compliance to physical activity recommendations. To ensure comparability between studies, interventions and reports, there is a need for internationally agreed operationalization and assessment methods of physical activity guidelines. As non-compliant children had lower MVPA during all day segments, greater efforts should be made to provide physical activity opportunities both during and after school.

Review on aging, unloading and reloading: changes in skeletal muscle quantity and quality.

Aging and muscle unloading are associated with a decline in muscle mass, structure, force and changes in the mechanical properties of skeletal muscle. There is a perception that reloading restores muscle architecture and function but differences in the regeneration capacity of intra- and extra-cellular compartments, age dependent susceptibility to muscle damage, particularly in the contractile machinery, make it difficult to attribute the main role of the above mentioned components. This review briefly summarizes studies that examine aging skeletal muscle during unloading and reloading. The article highlights changes in muscle mass, structure, extra-cellular matrix (ECM) components, strength, locomotion, adaptability to exercise, peculiarities of protein metabolism, susceptibility to glucocorticoids and recovery of muscle from injury.