How to design and establish a national school-based physical fitness monitoring and surveillance system for children and adolescents: A 10-step approach recommended by the FitBack network.

BACKGROUND: Providing individual- and population-level data on children's physical fitness (PF) is a crucial public health and education priority. However, few national fitness monitoring or surveillance systems are currently in practice internationally. We aim to summarize the current European PF monitoring and surveillance systems for school-aged children and to provide experience-based guidelines on how to design such systems. METHODS: The FitBack network consists of experts from diverse backgrounds with the common interest to improve the accessibility of PF monitoring for young people globally. Through FitBack network, we identified and compared the national or regional PF monitoring and surveillance systems currently in operation across Europe. We formulated a 10-step approach for designing and establishing one's own system, based on analysis of experienced strengths, weaknesses, opportunities, and threats to monitoring childhood fitness. RESULTS: We identified a total of eight PF monitoring systems in Finland, France, Galicia of Spain, Hungary, Lithuania, Portugal, Serbia, and Slovenia. The FitBack network recommends the following steps for designing and establishing one's own system: (1) set up mission statements and aims, (2) involve stakeholders, (3) utilize scientific background, (4) governance structure, (5) ensure sufficient funding, (6) data management planning, (7) provide meaningful feedback, (8) conduct pilot testing, (9) plan implementation process, and (10) invest in communication with stakeholders. CONCLUSIONS: This study provides an updated overview of the best practices for school-aged children's fitness monitoring and surveillance in Europe. Additionally, it offers a 10-step approach to assist in the creation of similar systems in Europe or globally.

Associations of polygenic inheritance of physical activity with aerobic fitness, cardiometabolic risk factors and diseases: the HUNT study.

Physical activity (PA), aerobic fitness, and cardiometabolic diseases (CMD) are highly heritable multifactorial phenotypes. Shared genetic factors may underlie the associations between higher levels of PA and better aerobic fitness and a lower risk for CMDs. We aimed to study how PA genotype associates with self-reported PA, aerobic fitness, cardiometabolic risk factors and diseases. PA genotype, which combined variation in over one million of gene variants, was composed using the SBayesR polygenic scoring methodology. First, we constructed a polygenic risk score for PA in the Trøndelag Health Study (N = 47,148) using UK Biobank single nucleotide polymorphism-specific weights (N = 400,124). The associations of the PA PRS and continuous variables were analysed using linear regression models and with CMD incidences using Cox proportional hazard models. The results showed that genotypes predisposing to higher amount of PA were associated with greater self-reported PA (Beta [B] = 0.282 MET-h/wk per SD of PRS for PA, 95% confidence interval [CI] = 0.211, 0.354) but not with aerobic fitness. These genotypes were also associated with healthier cardiometabolic profile (waist circumference [B = -0.003 cm, 95% CI = -0.004, -0.002], body mass index [B = -0.002 kg/m2, 95% CI = -0.004, -0.001], high-density lipoprotein cholesterol [B = 0.004 mmol/L, 95% CI = 0.002, 0.006]) and lower incidence of hypertensive diseases (Hazard Ratio [HR] = 0.97, 95% CI = 0.951, 0.990), stroke (HR = 0.94, 95% CI = 0.903, 0.978) and type 2 diabetes (HR = 0.94, 95 % CI = 0.902, 0.970). Observed associations were independent of self-reported PA. These results support earlier findings suggesting small pleiotropic effects between PA and CMDs and provide new evidence about associations of polygenic inheritance of PA and intermediate cardiometabolic risk factors.

How physical activity, fitness, and motor skills contribute to math performance: Working memory as a mediating factor.

PURPOSE: The purpose of this study was to examine whether physical activity, fitness, and motor skills have an indirect association with math performance via cognitive outcomes and if so, through which aspects of cognition? METHODS: This study comprised 311 6th-9th grade adolescents (12-17 years [M age = 14.0 years], 59% girls) from seven schools throughout Finland in 2015. Math performance was measured via a teacher-rated math achievement and the Basic Arithmetic test. Cognitive functions were measured by broad cognitive test battery. Physical activity was assessed with a self-reported questionnaire and a hip-worn accelerometer. Aerobic fitness was estimated using a maximal 20-m shuttle run test, muscular fitness with curl-up and push-up tests, and motor skills with a 5-leaps test and a throwing-catching combination test. Structural equation modeling was applied to examine the associations. RESULTS: In both boys and girls, motor skills had a positive indirect association with math outcomes through visuospatial working memory. Among girls, muscular fitness had a positive indirect association with math outcomes through visuospatial working memory. Aerobic fitness was positively associated with math achievement, but the indirect path via cognition was not observed. Self-reported physical activity had a borderline indirect positive association with math outcomes through visuospatial working memory. Accelerometer-based physical activity did not correlate with math performance. CONCLUSION: Motor skills and muscular fitness had indirect positive associations with math performance, mediated by visuospatial working memory. The results give support to the viewpoints that the connections between motor skills, fitness, and physical activity to academic skills are mediated via specific cognitive skills.

Physical fitness development in relation to changes in body composition and physical activity in adolescence.

The decline in adolescents' physical fitness (PF) in recent decades has raised concerns about current population's possible future challenges with health and physical functional capacity. This study explored the associations between body composition, physical activity, maturation, and PF development in adolescents. Furthermore, PF development of adolescents with low initial PF was assessed. A 2-year observational study was conducted between spring 2013 and 2015. Nine comprehensive schools and their 10- to 13-year-old students were invited to participate in the study (1778), and a total of 971 students (54.6%) agreed. Cardiorespiratory fitness (20-meter shuttle run), muscular fitness (push-ups), fundamental movement skills (5-leaps test), body composition (bioelectrical impedance analysis), moderate-to-vigorous physical activity (accelerometer), and pubertal status (self-assessment questionnaire) were measured at 1-year intervals. Latent growth curve modeling (LGM) was used to study PF development over time. Change in fat mass had the strongest and most coherent associations with PF development during adolescence. Fat-free mass, moderate-to-vigorous physical activity, and pubertal status were associated with PF development, although not systematically. Subgroup analyses showed that PF development in the low fitness group followed a similar pattern as the whole population. However, their PF remained significantly lower throughout the 2-year period. The findings suggest that fat accumulation is an essential detrimental factor for PF development during adolescence. Actions to prevent excessive fat accumulation might help to prevent future declines in functional capacity. Indications that low fitness levels sustain during adolescence highlight the relevance of detecting these individuals and providing interventions already before adolescence.

Genetic Liability to Cardiovascular Disease, Physical Activity, and Mortality: Findings from the Finnish Twin Cohort.

PURPOSE: We investigated whether longitudinally assessed physical activity (PA) and adherence specifically to World Health Organization PA guidelines mitigate or moderate mortality risk regardless of genetic liability to cardiovascular disease (CVD). We also estimated the causality of the PA-mortality association. METHODS: The study used the older Finnish Twin Cohort with 4897 participants aged 33 to 60 yr (54.3% women). Genetic liability to coronary heart disease and systolic and diastolic blood pressure was estimated with polygenic risk scores (PRS) derived from the Pan-UK Biobank ( N ≈ 400,000; >1,000,000 genetic variants). Leisure-time PA was assessed with validated and structured questionnaires three times during 1975 to 1990. The main effects of adherence to PA guidelines and the PRS × PA interactions were evaluated with Cox proportional hazards models against all-cause and CVD mortality. A cotwin control design with 180 monozygotic twin pairs discordant for meeting the guidelines was used for causal inference. RESULTS: During the 17.4-yr (mean) follow-up (85,136 person-years), 1195 participants died, with 389 CVD deaths. PRS (per 1 SD increase) were associated with a 17% to 24% higher CVD mortality risk but not with all-cause mortality except for the PRS for diastolic blood pressure. Adherence to PA guidelines did not show significant independent main effects or interactions with all-cause or CVD mortality. Twins whose activity levels adhered to PA guidelines over a 15-yr period did not have statistically significantly reduced mortality risk compared with their less active identical twin sibling. The findings were similar among high, intermediate, and low genetic risk levels for CVD. CONCLUSIONS: The genetically informed Finnish Twin Cohort data could not confirm that adherence to PA guidelines either mitigates or moderates genetic CVD risk or causally reduces mortality risk.

Physical activity, physical fitness and self-rated health: cross-sectional and longitudinal associations in adolescents.

Objectives: To evaluate the independent associations of physical activity and physical fitness with self-rated health in adolescents. Methods: Data from a 2-year observational study (2013-2015) were used (n=256, 58% girls, 13.7±0.3 years at baseline). Self-rated health was assessed with a questionnaire, physical activity by an accelerometer and a questionnaire, and physical fitness via the measurements included in the Finnish national Move! monitoring system for physical functional capacity and their z-score average (fitness index). Results: Self-reported physical activity had cross-sectional associations with self-rated health (girls ß 0.213, p=0.006, ß 0.221 boys p=0.021) while accelerometer-based moderate-to-vigorous physical activity did not. Higher self-reported physical activity at baseline was associated with higher self-rated health at follow-up in boys (ß 0.289, p<0.001), but not in girls (ß -0.056, p=0.430). Accelerometer-based moderate-to-vigorous physical activity had positive longitudinal associations with future self-rated health in boys, but some of these similar associations were negative in girls. Fitness index had a positive cross-sectional association with self-rated health in boys (ß 0.282 or ß 0.283, p=0.002), but not in girls (ß 0.162 or ß 0.161, p=0.051). Physical fitness was not longitudinally associated with self-rated health. Conclusions: Self-reported physical activity showed potential to explain current and future self-rated health better than accelerometer-based physical activity or physical fitness. We recommended to consider self-reported physical activity as an adequate metric of adolescent health in the population-level surveillance systems.

The associations of long-term physical activity in adulthood with later biological ageing and all-cause mortality - a prospective twin study.

Objectives: The association between leisure-time physical activity (LTPA) and a lower risk of mortality is susceptible to bias from multiple sources. We investigated the potential of biological ageing to mediate the association between long-term LTPA and mortality and whether the methods used to account for reverse causality affect the interpretation of this association. Methods: Study participants were twins from the older Finnish Twin Cohort (n=22,750; 18-50 years at baseline). LTPA was assessed using questionnaires in 1975, 1981 and 1990. The mortality follow-up lasted until 2020 and biological ageing was assessed using epigenetic clocks in a subsample (n=1,153) with blood samples taken during the follow-up. Using latent profile analysis, we identified classes with distinct longitudinal LTPA patterns and studied differences in biological ageing between these classes. We employed survival models to examine differences in total, short-term and long-term all-cause mortality, and multilevel models for twin data to control for familial factors. Results: We identified four classes of long-term LTPA: sedentary, moderately active, active and highly active. Although biological ageing was accelerated in sedentary and highly active classes, after adjusting for other lifestyle-related factors, the associations mainly attenuated. Physically active classes had a maximum 7% lower risk of total mortality over the sedentary class, but this association was consistent only in the short term and could largely be accounted for by familial factors. LTPA exhibited less favourable associations when prevalent diseases were exclusion criteria rather than covariate. Conclusion: Being active may reflect a healthy phenotype instead of causally reducing mortality.

Physical fitness characteristics and neck and shoulder pain incidence in school-aged children-A 2-year follow-up.

Background and Aims: Neck and shoulder pain (NSP) is common in school age, but preventative factors have not been identified. The purpose was to study whether a fitness test could be used to predict the incidence of NSP and determine whether good physical fitness characters would be associated with lower NSP incidence in school-aged children at 2-year follow-up. Methods: After the invitation to nine schools, 970 children (10-15 years old) agreed to participate. Flexibility, fundamental movement skills, musculoskeletal fitness, and cardiorespiratory fitness measurements included in Finnish Schools on the Move! monitoring system for physical functional capacity were measured at baseline in 2013. The NSP incidence was assessed by an online survey during school hours after 1 and 2 years. Logistic regression was used to analyze associations between physical fitness characteristics and NSP incidence. Results: The mean prevalence of NSP was 26% at baseline. The NSP incidence was 15% in the first and 18% in the second follow-up year. Good physical fitness was not associated with lower NSP incidence in the 2-year follow-up. Successful lower back extension (odds ratio [OR] = 2.83) and good scores in curl-up (OR = 1.80) adjusted with age, gender, and body mass index, were associated with higher NSP incidence between T0 and T2. Throwing-catching combination (OR = 0.55) was associated with a lower NSP incidence in unadjusted analysis, but the association did not remain after adjustments. Conclusion: Good physical fitness characteristics were not consistently associated with a lower NSP incidence in school-aged children in a 2-year follow-up. The role of general field-based physical fitness test as a screening tool for NSP incidence remains unconfirmed. More longitudinal studies are needed to detect the factors underlying NSP incidence in school-aged children.

Precision exercise medicine: predicting unfavourable status and development in the 20-m shuttle run test performance in adolescence with machine learning.

OBJECTIVES: To assess the ability to predict individual unfavourable future status and development in the 20m shuttle run test (20MSRT) during adolescence with machine learning (random forest (RF) classifier). METHODS: Data from a 2-year observational study (2013‒2015, 12.4±1.3 years, n=633, 50% girls), with 48 baseline characteristics (questionnaires (demographics, physical, psychological, social and lifestyle factors), objective measurements (anthropometrics, fitness characteristics, physical activity, body composition and academic scores)) were used to predict: (Task 1) unfavourable future 20MSRT status (identification of individuals in the lowest 20MSRT tertile after 2 years), and (Task 2) unfavourable 20MSRT development (identification of individuals with 20MSRT development in the lowest tertile among adolescents with baseline 20MSRT below median level). RESULTS: Prediction performance for future 20MSRT status (Task 1) was (area under the receiver operating characteristic curve, AUC) 83% and 76%, sensitivity 80% and 60%, and specificity 78% and 79% in girls and boys, respectively. Twenty variables showed predictive power in boys, 14 in girls, including fitness characteristics, physical activity, academic scores, adiposity, life enjoyment, parental support, social status in school and perceived fitness.Prediction performance for future development (Task 2) was lower and differed statistically from random level only in girls (AUC 68% and 40% in girls and boys). CONCLUSION: RF classifier predicted future unfavourable status in 20MSRT and identified potential individuals for interventions based on a holistic profile (14‒20 baseline characteristics). The MATLAB script and functions employing the RF classifier of this study are available for future precision exercise medicine research.

Longitudinal associations of fundamental movement skills with objectively measured physical activity and sedentariness during school transition from primary to lower secondary school.

OBJECTIVES: This study aimed to investigate cross-lagged associations of leaping skill and throwing-catching skills with objectively measured moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) during school transition from upper primary (Grade 6) to lower secondary school (Grade 7). DESIGN: This study is a one-year prospective follow-up study within Finnish school settings. Students' MVPA, ST, leaping skill and throwing-catching skills were measured at Grade 6 and subsequently at Grade 7. METHODS: A sample of 336 students (163 girls, 173 boys; M age=12.0 years, SD=0.4 at Grade 6 participated in the study. Students' MVPA and ST were measured objectively by hip-worn accelerometers. Leaping skill was measured by 5-leaps test. Throwing and catching skills were measured by throwing-catching combination test. Cross-lagged structural equation modeling was conducted to evaluate the associations between MVPA, ST, leaping skill, and throwing-catching skills at Grade 6 and Grade 7. RESULTS: Results demonstrated three significant cross-lagged associations among girls: (1) leaping skill measured at Grade 6 was negatively associated with ST at Grade 7; (2) objectively measured MVPA at Grade 6 associated positively with leaping skill at Grade 7; and (3) throwing-catching skills measured at Grade 6 associated positively with leaping skill measured at Grade 7. There were no statistically significant cross-lagged associations between the study variables for the sample of boys. CONCLUSIONS: The results of this study indicated that supporting opportunities for girls' engagement in both MVPA and leaping skill development activities during their primary school education is strongly recommended.

The Longitudinal Associations of Fitness and Motor Skills with Academic Achievement.

PURPOSE: This study aimed to examine both independent and dependent longitudinal associations of physical fitness (PF) components with academic achievement. METHODS: A total of 954 fourth to seventh graders (9-15 yr [Mage = 12.5 yr], 52% girls) from nine schools throughout Finland participated in a 2-yr follow-up study. Register-based academic achievement scores (grade point average [GPA]) and PF were assessed in the spring of 2013-2015. Aerobic fitness was measured with a maximal 20-m shuttle run test, muscular fitness with curl-up and push-up tests, and motor skills with a 5-leaps test and a throwing-catching combination test. Structural equation modeling was applied to examine the longitudinal associations adjusting for age, gender, pubertal stage, body fat percentage, learning difficulties, and mother's education. RESULTS: The changes in aerobic and muscular fitness were positively associated with the changes in GPA (B = 0.27, 99% confidence interval [CI] = 0.06-0.48; B = 0.36, 99% CI = 0.11-0.63, respectively), whereas the changes in motor skills were not associated with the changes in GPA. Better motor skills in year 2 predicted better GPA a year later (B = 0.06, 99% CI = 0.00-0.11; B = 0.06, 99% CI = 0.01-0.11), whereas aerobic and muscular fitness did not predict GPA. GPA in year 1 predicted both aerobic (B = 0.08, 99% CI = 0.01-0.15) and muscular (B = 0.08, 99% CI = 0.02-0.15) fitness, and motor skills (B = 0.08, 99% CI = 0.02-0.15) a year later. CONCLUSION: The changes in both aerobic and muscular fitness were positively associated with the changes in academic achievement during adolescence, whereas the changes in motor skills had only borderline significant association. However, better motor skills, although not systematically, independently predicted better academic achievement 1 yr later, whereas aerobic or muscular fitness did not. Better academic achievement predicted better motor skills, aerobic fitness, and muscular fitness. Developmental changes in adolescence may induce parallel and simultaneous changes in academic achievement and PF.

Objectively measured physical activity, body composition and physical fitness: Cross-sectional associations in 9- to 15-year-old children.

The aim of this study was to examine and quantify the cross-sectional associations of body composition (BC), physical activity (PA) and sedentary time (ST) with physical fitness (PF) in children and adolescents. A sample of 594 Finnish students (56% girls), aged 9-15 (12.4 ± 1.3 years) were selected for a study performed in 2013. The measurements of the Move! monitoring system for physical functional capacity were used to measure cardiorespiratory and musculoskeletal fitness and fundamental movement skills. Moderate-to-vigorous PA (MVPA) and ST were measured objectively with an accelerometer and BC by a bioelectrical impedance analysis. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated to represent height-adjusted BC. Associations were explored with a linear regression model. In general, FMI had statistically significant negative associations, while FFMI and MVPA had positive associations with PF. No statistically significant associations were observed between ST and PF. In general, FMI had the strongest association with PF, although some variation occurred with sex and PF component. However, associations were practically relevant only in 20-m shuttle run, push-up, curl-up and 5-leaps test. For example, approximately 5 kg increase in fat mass in 155 cm tall children was estimated to correspond to  8 laps in 20-m shuttle run. Similar increase in fat-free mass corresponded to +4 and +6 laps, and 10 min increase in daily MVPA +3 and +2 laps in 20-m shuttle run, in boys and girls, respectively. Understanding these associations is necessary when interpreting children's PF and designing interventions.