Physical fitness predicts adiposity longitudinal changes over childhood and adolescence

Longitudinal Relationships of Physical Activity, Sedentary Time, Cardiorespiratory Fitness, and Muscular Fitness with Body Fatness in Preschoolers

There is still insufficient knowledge about the potential benefits of physical activity and fitness or the adverse impact of sedentary behaviours on body composition at preschool age. Therefore, we aimed to study the relationships of moderate-to-vigorous physical activity (MVPA), sedentary time (ST), cardiorespiratory fitness (CRF), and muscular fitness (MF) with body fat percentage (BF%) in boys and girls. Participants were investigated twice: in the final year of kindergarten, when the boys' median age was 7 years and the girls' median age was 6 years (p = 0.240), and again in the first grade of school. MVPA and ST were measured with an accelerometer, BF% was derived from skinfold thicknesses, CRF was measured with a 20 m shuttle run test, and MF was represented by the mean z-scores from standing long jump and relative upper-limb strength. In girls, higher ST (β = 0.587, p = 0.021) and lower MF (β = -0.231, p = 0.009) at preschool age were related to higher BF% in the first grade of school after adjustment for confounders. MVPA and CRF in preschool children were unrelated to BF% in school among boys and girls. In conclusion, sitting less and having greater muscular fitness at preschool age appear to be beneficial for lower body fatness in the first grade among girls, but not in boys. MVPA and CRF at preschool age are unrelated to body fatness at school age in boys and girls. Our results indicate that girls may especially benefit from decreasing sedentary behaviours and increasing upper- and lower-limb muscular strength at preschool age for a healthy weight profile in the first grade of school.

Physical fitness in Austrian elementary school children prior to and post-COVID-19

BACKGROUND

With the emergence of the COVID-19 pandemic, many countries implemented policies that included movement restrictions, social distancing and school closures in order to control the spread of the virus. Even though these actions may have been necessary to save lives, there have been some unintended consequences that could affect future public health.

METHODS

The present study uses data from more than 24,500 Austrian elementary school children (51.2% male) that participated in a state-wide fitness evaluation program, which was initiated in the 2016/17 school year. In addition to body weight and height, data on cardiorespiratory endurance, muscular power, speed, agility, flexibility and object control were collected from three cohorts prior to the implementation of movement restrictions (school years: 2016/17, 2017/18, 2018/19) and one cohort in 2022, after the majority of COVID-19 policies had been lifted.

RESULTS

Body mass index percentiles were significantly higher in children post-COVID-19 (p < 0.01). Further, cardiorespiratory endurance, agility and flexibility were significantly lower post-COVID-19 compared to the years preceding movement restrictions (p ≤ 0.01), while absolute muscular strength was higher in the year 2022 (p < 0.01).

CONCLUSION

Given the detrimental effects of COVID-19 policies on physical fitness in children, additional efforts are necessary that include versatile opportunities for physical activity and the promotion of physical fitness in order to modify the observed negative health trajectories and ensure future public health.

Analysis of Self-Perceived Physical Fitness of Physical Education Students in Public Schools in Extremadura (Spain)

Adolescence is a stage of crucial physiological and psychological changes within the individual's life cycle, where fitness work is important. With self-perception being crucial in relation to adolescent health and well-being, a positive perception of fitness is directly related to increased practice or higher level of physical activity (PA). Thus, the aims were: (1) to analyze, with the Visual Analogue Fitness Perception Scale for Adolescents (FP VAS A), the self-perceived physical fitness (PF) of high school students, (2) to investigate if there are differences according to sex and school location, and (3) to study the correlations between the items of the FP VAS A with age and body mass index (BMI). For this purpose, a cross-sectional study was designed with a total of 961 participants, 48.8% boys and 51.2% girls in secondary education, where 31.9% studied in rural schools and 68.1% in urban schools. The FP VAS A scale was used to assess self-reported PF. Regarding the results, there were statistically significant differences between sexes (p < 0.001), with boys showing higher scores than girls in all the items of the FP VAS A scale, with the exception of global flexibility. Inverse, mean and significant correlations were established between BMI and self-perceived overall PF (r = -0.202; p < 0.001), cardiorespiratory endurance (r = -0.226; p < 0.001) and movement speed (r = -0.268; p < 0.001). Between age and self-perceived cardiorespiratory endurance (r = -0.138; p < 0.001) an inverse, mean and significant correlation was also observed. In conclusion, boys showed a better self-perception of PF than girls for all physical abilities, with the exception of flexibility. School location was not shown to influence students' self-perceived PF. In addition, most of the self-perceived PF abilities for overall fitness correlated inversely with BMI.

How Do Health, Biological, Behavioral, and Cognitive Variables Interact over Time in Children of Both Sexes? A Complex Systems Approach

The present study examined gender differences in health, physical activity, physical fitness, real and perceived motor competence, and executive function indicators in three time points, and analyzed the dynamic and non-linear association between health, biological, behavioral, and cognitive variables in children followed over time. A total of 67 children (aged between six and 10 years) were followed during two years and split into two cohorts (six to eight years old: C1; eight to 10 years old: C2). Data regarding health, physical activity, real and perceived motor competence, physical fitness, and executive function indicators were obtained according to their respective protocols. Comparison tests and network analysis were estimated. Significant gender differences were found in both cohorts. The emerged networks indicated different topologies in both cohorts. No clusters were observed between the variables in C1, and there was a greater number of interactions at eight years of age. Sparse networks were observed in children aged eight and 10 years in C2, and greater connectivity was observed at nine years of age between health, physical fitness, motor competence, and physical activity indicators. This study showed that there are non-linear dynamic relationships between health, biological, behavioral, and cognitive variables over time during child development.

Effect of Excessive Screen Time on Cardiorespiratory Fitness in Children: A Longitudinal Study

Background: This study investigated the effect of different components of screen time (mobile phone use, TV/video viewing, and video gaming) on cardiorespiratory fitness (CRF) development in children aged 9–12 years. Methods: This was a two-year longitudinal study conducted with 175 children (49.7% girls, mean age = 9.5) in Japan. CRF was assessed using a 20 m shuttle run test conducted at baseline and again at follow-up. Children were categorized as “Good” or “Poor” based on the change in CRF scores for each gender. Screen time was assessed using a self-reported questionnaire at baseline and termed as “high” if children reported ≥ 2 h/day. Univariate and multivariate logistic regression analyses were performed after adjusting for gender, physical activity, and time of data collection. Results: Children scoring “high” on mobile phone use had lower odds of being categorized as “Good” in CRF change (crude odds ratio (OR): 0.34; 95% confidence interval (CI): 0.15–0.90 (adjusted OR: 0.33; 95% CI: 0.12–0.91)). There were no significant effects of TV/video viewing (crude OR: 1.54; 95% CI: 0.84–2.81) and video gaming (crude OR: 0.98; 95% CI: 0.48–1.97) on changes in CRF. Conclusions: Limiting excessive mobile phone usage might be important for ensuring healthy development of CRF in children.

Effects of a physical activity intervention on schoolchildren fitness

The global prevalence of childhood obesity is high. Obesity main causes are linked to sedentary lifestyles. Increasing physical activity (PA) and reducing sedentary activities are recommended to prevent and treat obesity. This study aimed to evaluate the effectiveness of a 6-month school PA intervention on obesity prevention and healthy behaviors in school-aged children. Participating students (10-11 years of age) were randomly divided into an intervention group and a control group. Children in the intervention group (n = 80) participated in a multicomponent PA that included improvement in extracurricular physical activities (with an additional 40 min per day for 5/6 days per week). Children (n = 80) in the control group participated in usual practice. Participants had mean body mass index of 19.7 ± 2.9 kg/m2 , and 33.7% of them were overweight or with obesity at T0. The change in body mass index in intervention group (-2.4 ± 0.6 kg/m2 ) was significantly different from that in control group (3.01 ± 1.8 kg/m2 ). The effects on waist circumference, waist-to-height ratio, and physic fitness were also significant in intervention group compared with control group (all p < 0.05). Furthermore, there is a significant decrease in overweight or children with obesity in the experimental group (to 17.5%, p < 0.05). These findings suggest that a school-based intervention program represents an effective strategy for decreasing the number of overweight and children with obesity.

Physical fitness spurts in childhood: A study in boys

This study aimed to (1) estimate age-at-mid-growth spurt (age-at-MGS) in Portuguese boys from two different regions-the Azores islands and Viana do Castelo, and (2) identify spurts in a variety of physical fitness (PF) components aligned by age-at-MGS in the two samples. A total of 176 (Azores, n = 91; Viana do Castelo, n = 85) boys aged 6 years old were followed annually to 10 years of age. Age-at-MGS and spurts in PF components (speed, explosive muscular strength, abdominal muscular strength, agility, and flexibility) were identified for each sample. The timing and intensities of the spurts were estimated using a non-smooth mathematical procedure. In Azorean boys, age-at-MGS occurred at 7.8 years (6.99 cm y^-1 ), whereas in Viana do Castelo it occurred at 7.9 years (6.20 cm y^-1 ). Spurt in speed was attained 12 months after the MGS in both samples (0.53 and 0.35 cm y^-1 in Azores and Viana do Castelo, respectively), whereas spurts in explosive muscular strength and flexibility occurred 12 months before the MGS and at the MGS (Azores: 21.59 and 5.52 cm y^-1 and Viana do Castelo: 14.12 and 2.5 cm y^-1 , respectively). Agility and abdominal muscular strength peaked between 0 and 12 months after the MGS (Viana do Castelo: 0.37 m s^-1  y^-1 and 6.71 reps y^-1 and Azores: 0.28 m s^-1  y^-1 and 19.36 reps y^-1 , respectively). Results indicate that developmental spurts in explosive strength and flexibility occur before, or are coincident with, the mid-growth spurt in height, whereas spurts in speed, agility, and abdominal muscular strength occur after, or coincident with, the mid-growth spurt in height.

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.

Association of Cardiorespiratory Fitness Levels During Youth With Health Risk Later in Life: A Systematic Review and Meta-analysis

IMPORTANCE

Although the associations between cardiorespiratory fitness (CRF) and health in adults are well understood, to date, no systematic review has quantitatively examined the association between CRF during youth and health parameters later in life.

OBJECTIVES

To examine the prospective association between CRF in childhood and adolescence and future health status and to assess whether changes in CRF are associated with future health status at least 1 year later.

DATA SOURCES

For this systematic review and meta-analysis, MEDLINE, Embase, and SPORTDiscus electronic databases were searched for relevant articles published from database inception to January 30, 2020.

STUDY SELECTION

The following inclusion criteria were used: CRF measured using a validated test and assessed at baseline and/or its change from baseline to the end of follow-up, healthy population with a mean age of 3 to 18 years at baseline, and prospective cohort design with a follow-up period of at least 1 year.

DATA EXTRACTION AND SYNTHESIS

Data were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Random-effects models were used to estimate the pooled effect size.

MAIN OUTCOMES AND MEASURES

Anthropometric and adiposity measurements and cardiometabolic health parameters.

RESULTS

Fifty-five studies were included with a total of 37 563 youths (46% female). Weak-moderate associations were found between CRF at baseline and body mass index (r = -0.11; 95% CI, -0.18 to -0.04; I2 = 59.03), waist circumference (r = -0.29; 95% CI, -0.42 to -0.14; I2 = 69.42), skinfold thickness (r = -0.34; 95% CI, -0.41 to -0.26; I2 = 83.87), obesity (r = -0.15; 95% CI, -0.23 to -0.06; I2 = 86.75), total cholesterol level (r = -0.12; 95% CI, -0.19 to -0.05; I2 = 75.81), high-density lipoprotein cholesterol (HDL-C) level (r = 0.11; 95% CI, 0.05-0.18; I2 = 69.06), total cholesterol to HDL-C ratio (r = -0.19; 95% CI, -0.26 to -0.13; I2 = 67.07), triglyceride levels (r = -0.10; 95% CI, -0.18 to -0.02; I2 = 73.43), homeostasis model assessment for insulin resistance (r = -0.12; 95% CI, -0.18 to -0.06; I2 = 68.26), fasting insulin level (r = -0.07; 95% CI, -0.11 to -0.03; I2 = 0), and cardiometabolic risk (r = -0.18; 95% CI, -0.29 to -0.07; I2 = 90.61) at follow-up. Meta-regression analyses found that early associations in waist circumference (β = 0.014; 95% CI, 0.002-0.026), skinfold thickness (β = 0.006; 95% CI, 0.002-0.011), HDL-C level (β = -0.006; 95% CI, -0.011 to -0.001), triglyceride levels (β = 0.009; 95% CI, 0.004-0.014), and cardiometabolic risk (β = 0.007; 95% CI, 0.003-0.011) from baseline to follow-up dissipated over time. Weak-moderate associations were found between change in CRF and body mass index (r = -0.17; 95% CI, -0.24 to -0.11; I2 = 39.65), skinfold thickness (r = -0.36; 95% CI, -0.58 to -0.09; I2 = 96.84), obesity (r = -0.21; 95% CI, -0.35 to -0.06; I2 = 91.08), HDL-C level (r = 0.05; 95% CI, 0.02-0.08; I2 = 0), low-density lipoprotein cholesterol level (r = -0.06; 95% CI, -0.11 to -0.01; I2 = 58.94), and cardiometabolic risk (r = -0.08; 95% CI, -0.15 to -0.02; I2 = 69.53) later in life.

CONCLUSIONS AND RELEVANCE

This study suggests that early intervention and prevention strategies that target youth CRF may be associated with maintaining health parameters in later life.

Caloric compensation and appetite control in children of different weight status and predisposition to obesity

To prevent childhood obesity it is critical to identify behavioral phenotypes for overeating, especially among children who are predisposed to obesity. We examined caloric compensation and appetite control in 212 normal-weight (NW) and obese (OB) children, ages 7 to 9, who were at high risk (HR) or low risk (LR) for obesity based on maternal obesity. In a within-subjects crossover design, children ate breakfast, lunch, dinner, and snacks in the laboratory once a week for two weeks. Children's percentage compensation index (%COMPX) was computed at breakfast. Twenty-five minutes before breakfast, children received one of two compulsory preloads, which varied in energy density (ED) and caloric content [Low ED (LED): 1.00 kcal/g; 100 kcal; High ED (HED): 1.60 kcal/g; 160 kcal]. Children's appetite was measured hourly using Visual Analog Scales, which were used to compute 3-h post-prandial area under the curve (AUCs) after breakfast and the satiety quotient (SQ), which allows between-group comparisons of a fixed amount of a food's potency to reduce appetite sensations per unit of intake. There were no significant differences in %COMPX, SQ, or AUC among LR-NW, HR-NW, and HR-OB children (P > 0.10). SQs for Hunger and Prospective Consumption were higher and SQ for Fullness lower after consuming the LED compared to the HED preload (P < 0.009). Further, the SQ and AUC for Desire to Eat and AUC for Prospective Consumption significantly predicted energy intake during the remainder of the day (P < 0.03). In this study, HR-NW children did not differ from LR-NW or HR-OB children in their caloric compensation or appetite control. Foods with a high satiating effect may facilitate appetite control and help to moderate daily energy intake in all children, including at-risk children.

Developmental pathways of cardiorespiratory fitness from 6 to 15 years of age

Most of the information gathered about physical fitness of paediatric populations are cross-sectional, resulting in normative perspectives that account for average values relative to age, but not to a comprehensive understanding of developmental individual trajectories. The aim of this study was to model the longitudinal development of cardiorespiratory fitness of boys and girls from 6 to 15 years of age, using an individual centred approach. Two hundred twenty-nine school children (128 boys; 101 girls) were followed on their 20 metres shuttle run test (20mSRT) results from 6 to 15 years of age. Annual measurements were made during the four years of primary school, and again at grade 9th or 10th. Individual trajectories of 20mSRT development were modelled and grouped according to their similarities of change in three different developmental pathways that were included in subsequent hierarchical nested models for testing each sex developmental model of cardiorespiratory fitness. Final models including the developmental pathways showed better deviance statistics (p < .001). Interindividual slope variances were almost zero, and statistically non-significant (0.05 boys 0.01 girls; p > .50), meaning these models capture well the existing variability, in respect to the rate of change. Individual pathways of change in the performance of 20mSRT test can be detected in childhood and adolescence. Additionally, all individual's developmental trajectories in 20mSRT can be described using three significantly different slopes. These pathways are indicative of a high, average, or low rate of change in performance over the years and differ from the normative approach.

Test-Retest Reliability of Student-Administered Health-Related Fitness Tests in School Settings

PURPOSE

To examine the test-retest reliability of student-administered (SA) health-related fitness tests in school settings and to compare indices of reliability with those taken by trained research-assistants.

METHODS

Participants (n = 86; age: 13.43 [0.33] y) were divided into 2 groups, SA (n = 45, girls = 26) or research-assistant administered (RA; n = 41, girls = 21). The SA group had their measures taken by 8 students (age: 15.59 [0.56] y, girls = 4), and the RA group had their measures taken by 8 research-assistants (age: 21.21 [1.38], girls = 5). Tests were administered twice by both groups, 1 week apart. Tests included body mass index, handgrip strength, standing broad jump, isometric plank hold, 90° push-up, 4 × 10-m shuttle run, back-saver sit and reach, and blood pressure.

RESULTS

Intraclass correlation coefficients for SA (≥.797) and RA (≥.866) groups were high, and the observed systematic error (Bland-Altman plot) between test 1 and test 2 was close to 0 for all tests. The coefficient of variation was less than 10% for all tests in the SA group, aside from the 90° push-up (24.3%). The SA group had a marginally lower combined mean coefficient of variation across all tests (6.5%) in comparison with the RA group (6.8%).

CONCLUSION

This study demonstrates that, following familiarization training, SA health-related fitness tests in school-based physical education programs can be considered reliable.

Classes of developmental trajectories of body mass index: Differences in motor competence and cardiorespiratory fitness

The purpose was to identify classes of different developmental trajectories of BMI and testing them for differences in motor competence (MC) and cardiorespiratory fitness (CRF), in children and adolescents (4 to 13 years of age). This was a 5 years' longitudinal study with six cohorts. One hundred and forty-seven children (69 girls) divided into six cohorts participated. At baseline, the youngest and the oldest cohorts had 4 and 11 years of age, respectively. Height and weight were assessed, and BMI was calculated. MC was assessed with KTK and TGMD-2, and CRF was assessed with one-mile run/walk. Developmental trajectories of BMI were identified using latent class linear-mixed modelling. Latent class membership was explained according to covariates of MC and CRF. Two meaningful classes were identified. Class 1 (78.92% of the participants) showed lower initial BMI and a lower slope compared to class 2 (21.08% of the participants) (all ps < 0.001). Class membership only predicted trajectories in motor coordination, with children in class 1 having a better development.In conclusion, this study identified two meaningful trajectories for children based on their BMI development across five time points. In line with previous research, children with slower increasing BMI showed better motor coordination improvements.

Physical Fitness and Somatic Characteristics of the Only Child

The purpose of this study was to examine if only child show differences on somatic growth and physical fitness compared to be a child with siblings. The participants included 542 children (boys: N = 270; girls: N = 270) between 7 and 15 years of age. Somatic growth (height, weight, body mass index) and physical fitness (handgrip strength; flexed harm hang; 60-s sit-ups; standing long jump; 10-m shuttle run and PACER test) were assessed. Variance analysis revealed significant advantages for children with siblings in the flexed arm hang (p = 0.046), 60-s sit-ups (p = 0.002), 10-m shuttle run (p = 0.013) and PACER (p = 0.032). An examination of the possible differential effect of sex on the results revealed no significance for physical fitness variables, but significant interaction were found for weight (p = 0.004) and body mass index (p = 0.005). Despite a lack of interactions between offspring and sex in physical fitness, significant differences between sexes were found in all fitness variables. In conclusion, having siblings showed to be advantageous for general physical fitness in children. This evidence may be used for future analysis and interventions in motor competence, namely considering the growing number of only children in some regions of the world.

Physical fitness in relation to later body composition in pre-school children

OBJECTIVES

Although physical fitness is considered a marker of health in youth, little is known whether physical fitness in pre-school age is related to later body composition. Thus, this study investigated (i) associations of physical fitness at 4.5years of age with body composition 12months later and (ii) whether improvements in physical fitness during the 12-month follow-up were associated with changes in body composition.

DESIGN

This study included 142 children, measured at 4.5 and 5.5years, from the control group of the MINISTOP trial.

METHODS

Physical fitness (cardiorespiratory fitness, lower- and upper-body muscular strength and motor fitness) was measured using the PREFIT test battery. Body composition was assessed using air-displacement plethysmography.

RESULTS

In adjusted regression analyses, greater cardiorespiratory fitness, lower-body muscular strength and motor fitness at 4.5years were associated with a lower fat mass index at 5.5years (standardized β=-0.182 to -0.229, p≤0.028). Conversely, greater cardiorespiratory fitness, lower- and upper-body muscular strength as well as motor fitness at 4.5years of age were associated with a higher fat-free mass index (standardized β=0.255-0.447, p≤0.001). Furthermore, improvements in cardiorespiratory fitness, lower-body muscular strength and motor fitness during the 12-month follow-up period were associated with decreases in fat mass index and/or % fat mass.

CONCLUSIONS

In conclusion, the results of this study provide evidence of the importance of physical fitness early in life. Nevertheless, further studies are needed in order to clarify the influence of physical fitness in the pre-school age with later health outcomes.

Tracking of Physical Fitness of Primary School Children in Trier: A 4-Year Longitudinal Study

Objective

The aim of this study is to measure the motor development and tracking of physical fitness (PF) components of primary school children of Trier in Germany.

Methods

Two longitudinal cohorts, of 1768 children (915 f, 853 m) aged 5–11, were measured. In longitudinal cohort 1, a total of 116 female and 137 male participants aged 6.80 ± 0.42 years at baseline were measured four times from grade 1 to grade 4 (response: 40.4%). Participants of longitudinal cohort 2 (166 f, 149 m; 6.70 ± 0.36 years at baseline, response: 42.6%) were examined three times from grade 1 to grade 3 with the German Motor Test 6–18 (DMT 6–18).

Results

Physical fitness increased significantly over time in all test tasks except flexibility. Gender-specific differences were found in 20 m sprint, 6-minute run, balancing backwards, jumping sideways, and stand and reach. 74.4% of PF stability coefficients were moderate (r = 0.30 to 0.60). Stability of PF declined with increased time frames. Tracking was lower in girls than in boys. Flexibility showed the highest stability among PF variables (r > 0.50). BMI showed the overall highest stability coefficient with r > 0.7.

Conclusions

Gender-specific differences of PF were obvious but cannot always be secured statistically in primary school. Tracking was only moderate. Variability in the timing and speed of the adolescent growth spurt and sexual maturation influence stability of PF. Results from longitudinal cohort 2 largely confirm those from longitudinal cohort 1.

Environmental perceptions and its associations with physical fitness and body composition in adolescents: longitudinal results from the LabMed Physical Activity Study

Background The environmental correlates have been extensively studied in the last years, but most associations with physical fitness (PF) and body composition have been cross-sectional in nature. Objective This study aimed to determine if adolescents' environmental perceptions associated with PF and body composition in a 2-year follow-up. Subjects Participants were 583 adolescents aged 12-18 years (299 girls) from the LabMed Physical Activity Study. Methods PF and body composition were assessed with the protocols of the ALPHA health-related fitness battery and environmental perceptions with the ALPHA environmental questionnaire. Linear regression models were used to determine the associations between environmental perceptions at baseline and PF and anthropometric measures at follow-up. Results Results showed that perceptions of distant facilities at baseline were associated with lower fitness at follow-up in boys. Also, boys' lower study environment perceptions at baseline were associated with higher body composition at follow-up. Positive perceptions of a pleasant environment at baseline were associated with better fitness at follow-up in boys. Additionally, girls' positive bike lanes availability and esthetics perceptions at baseline were associated with better body composition at follow-up. Conclusion Positive environmental perceptions at baseline are associated with better PF and body composition at follow-up.

The role of physical activity in improving physical fitness in children with intellectual and developmental disabilities

BACKGROUND

One in three children in North America are considered overweight or obese. Children with intellectual and developmental disabilities (IDD) are at an increased risk for obesity than their typically developing peers. Decreased physical activity (PA) and low physical fitness may be contributing factors to this rise in obesity.

AIM

Because children with IDD are at an increased risk of diseases related to inactivity, it is important to improve health-related physical fitness to complete activities of daily living and improve health.

METHODS AND PROCEDURES

The focus of this research is on improving the performance of physical fitness components through physical activity programming among a group of children with IDD, ages 7-12 years. The Brockport Physical Fitness Test was used assess levels of physical fitness of 35 children with IDD (25 boys, 10 girls) before and after participation in a 10-week program.

OUTCOMES AND RESULTS

The results of paired sampled t-tests showed participation in 15-h PA program can significantly increase aerobic capacity and muscular strength and endurance in children with IDD.

CONCLUSIONS AND IMPLICATIONS

This study is aimed at understanding the role of PA in helping children with IDD to develop the fitness capacities essential to participation in a wide variety of activities.

A Review of the Promotion of Fitness Measures and Health Outcomes in Youth

The relationship between physical fitness and health in adults is well established, yet until recently, empirical support for the impact of physical fitness levels on health markers in children has not been thoroughly documented. The aim of this review was to provide a summary of current literature that has examined the linkage between measures of health-related physical fitness (ie, cardiorespiratory fitness, musculoskeletal fitness, flexibility, and body composition) and health markers in youth. Specifically, this review focused on the findings from the recent 2012 Institutes of Medicine report on Fitness Measures in Youth as well as other subsequent review articles related to the topic. In addition, recommendations for health-related fitness assessments in youth populations are presented.

International variability in 20 m shuttle run performance in children and youth: who are the fittest from a 50-country comparison? A systematic literature review with pooling of aggregate results

OBJECTIVES

To describe and compare 20 m shuttle run test (20mSRT) performance among children and youth across 50 countries; to explore broad socioeconomic indicators that correlate with 20mSRT performance in children and youth across countries and to evaluate the utility of the 20mSRT as an international population health indicator for children and youth.

METHODS

A systematic review was undertaken to identify papers that explicitly reported descriptive 20mSRT (with 1-min stages) data on apparently healthy 9-17 year-olds. Descriptive data were standardised to running speed (km/h) at the last completed stage. Country-specific 20mSRT performance indices were calculated as population-weighted mean z-scores relative to all children of the same age and sex from all countries. Countries were categorised into developed and developing groups based on the Human Development Index, and a correlational analysis was performed to describe the association between country-specific performance indices and broad socioeconomic indicators using Spearman's rank correlation coefficient.

RESULTS

Performance indices were calculated for 50 countries using collated data on 1 142 026 children and youth aged 9-17 years. The best performing countries were from Africa and Central-Northern Europe. Countries from South America were consistently among the worst performing countries. Country-specific income inequality (Gini index) was a strong negative correlate of the performance index across all 50 countries.

CONCLUSIONS

The pattern of variability in the performance index broadly supports the theory of a physical activity transition and income inequality as the strongest structural determinant of health in children and youth. This simple and cost-effective assessment would be a powerful tool for international population health surveillance.

Motor Competence and its Effect on Positive Developmental Trajectories of Health

In 2008, Stodden and colleagues took a unique developmental approach toward addressing the potential role of motor competence in promoting positive or negative trajectories of physical activity, health-related fitness, and weight status. The conceptual model proposed synergistic relationships among physical activity, motor competence, perceived motor competence, health-related physical fitness, and obesity with associations hypothesized to strengthen over time. At the time the model was proposed, limited evidence was available to support or refute the model hypotheses. Over the past 6 years, the number of investigations exploring these relationships has increased significantly. Thus, it is an appropriate time to examine published data that directly or indirectly relate to specific pathways noted in the conceptual model. Evidence indicates that motor competence is positively associated with perceived competence and multiple aspects of health (i.e., physical activity, cardiorespiratory fitness, muscular strength, muscular endurance, and a healthy weight status). However, questions related to the increased strength of associations across time and antecedent/consequent mechanisms remain. An individual's physical and psychological development is a complex and multifaceted process that synergistically evolves across time. Understanding the most salient factors that influence health and well-being and how relationships among these factors change across time is a critical need for future research in this area. This knowledge could aid in addressing the declining levels of physical activity and fitness along with the increasing rates of obesity across childhood and adolescence.

International normative 20 m shuttle run values from 1 142 026 children and youth representing 50 countries

OBJECTIVE

To develop sex-specific and age-specific international norms for the 20 m shuttle run test (20mSRT) in children and youth (aged 9-17 years), and to estimate the prevalence meeting the FITNESSGRAM criterion-referenced standards for healthy cardiorespiratory endurance (CRE).

METHODS

A systematic review was undertaken to identify papers explicitly reporting descriptive 20mSRT (with 1 min stages) data on children and youth since 1981. Data were included on apparently healthy (free from known disease/injury) 9-17 years old. Following standardisation to a common metric and for protocol differences, pseudo data were generated using Monte Carlo simulation, with population-weighted sex-specific and age-specific normative centiles generated using the Lambda Mu and Sigma (LMS) method. Sex-related and age-related differences were expressed as per cent and standardised differences in means. The prevalence with healthy CRE was estimated using the sex-specific and age-specific FITNESSGRAM criterion-referenced standards for [Formula: see text].

RESULTS

Norms were displayed as tabulated centiles and as smoothed centile curves for the 20mSRT using 4 common metrics (speed at the last completed stage, completed stages/minutes, laps and relative [Formula: see text]). The final data set included 1 142 026 children and youth from 50 countries, extracted from 177 studies. Boys consistently outperformed girls at each age group (mean difference±95% CI: 0.86±0.28 km/h or 0.79±0.20 standardised units), with the magnitude of age-related increase larger for boys than for girls. A higher proportion of boys (mean±95% CI: 67±14%) had healthy CRE than girls (mean±95% CI: 54±17%), with the prevalence of healthy CRE decreasing systematically with age.

CONCLUSIONS

This study provides the most comprehensive and up-to-date set of international sex-specific and age-specific 20mSRT norms for children and youth, which have utility for health and fitness screening, profiling, monitoring and surveillance.

A methodological approach to short-term tracking of youth physical fitness: the Oporto Growth, Health and Performance Study

In this paper, three different statistical approaches were used to investigate short-term tracking of cardiorespiratory and performance-related physical fitness among adolescents. Data were obtained from the Oporto Growth, Health and Performance Study and comprised 1203 adolescents (549 girls) divided into two age cohorts (10-12 and 12-14 years) followed for three consecutive years, with annual assessment. Cardiorespiratory fitness was assessed with 1-mile run/walk test; 50-yard dash, standing long jump, handgrip, and shuttle run test were used to rate performance-related physical fitness. Tracking was expressed in three different ways: auto-correlations, multilevel modelling with crude and adjusted model (for biological maturation, body mass index, and physical activity), and Cohen's Kappa (κ) computed in IBM SPSS 20.0, HLM 7.01 and Longitudinal Data Analysis software, respectively. Tracking of physical fitness components was (1) moderate-to-high when described by auto-correlations; (2) low-to-moderate when crude and adjusted models were used; and (3) low according to Cohen's Kappa (κ). These results demonstrate that when describing tracking, different methods should be considered since they provide distinct and more comprehensive views about physical fitness stability patterns.

THE RELATIONSHIP BETWEEN MOTOR COMPETENCE AND PHYSICAL FITNESS IS WEAKER IN THE 15-16 YR. ADOLESCENT AGE GROUP THAN IN YOUNGER AGE GROUPS (4-5 YR. AND 11-12 YR.)

Developing motor competence and physical fitness can affect the maintenance of a sufficient level of physical activity in children and adolescents. This study assesses the relationship between motor competence and physical fitness from childhood through early adolescence. A cross-sectional sample of 194 participants from 4 to 16 years old were divided into three groups; 4-6 yr. (n=42, M age=5.2, SD 0.6), 11-12 yr. (n=58, M age=12.4, SD=0.3), and 15-16 yr. (n=94, M age=15.9, SD=0.4). To assess motor competence, each child completed the Movement Assessment Battery for Children (MABC). To measure physical fitness, three tasks (strength, speed, and endurance) were selected from the Test of Physical Fitness (TPF). To analyze the significance of the difference between the correlation coefficient in the three age groups (samples) (4-6, 11-12, and 15-16 yr.), Fischer r-to-z transformation was used. The correlation (Pearson's) between motor competence and physical fitness in the age groups was statistically higher for the youngest age groups (4-6 and 11-12 yr.) and the adolescent group (age 15-16). The differences between the two youngest age groups were not statistically significant. The results demonstrate that the correlation between motor competence and physical fitness decreases with age.

Physical Fitness Percentiles of German Children Aged 9-12 Years: Findings from a Longitudinal Study

Background

Generating percentile values is helpful for the identification of children with specific fitness characteristics (i.e., low or high fitness level) to set appropriate fitness goals (i.e., fitness/health promotion and/or long-term youth athlete development). Thus, the aim of this longitudinal study was to assess physical fitness development in healthy children aged 9–12 years and to compute sex- and age-specific percentile values.

Methods

Two-hundred and forty children (88 girls, 152 boys) participated in this study and were tested for their physical fitness. Physical fitness was assessed using the 50-m sprint test (i.e., speed), the 1-kg ball push test, the triple hop test (i.e., upper- and lower- extremity muscular power), the stand-and-reach test (i.e., flexibility), the star run test (i.e., agility), and the 9-min run test (i.e., endurance). Age- and sex-specific percentile values (i.e., P₁₀ to P₉₀) were generated using the Lambda, Mu, and Sigma method. Adjusted (for change in body weight, height, and baseline performance) age- and sex-differences as well as the interactions thereof were expressed by calculating effect sizes (Cohen’s d).

Results

Significant main effects of Age were detected for all physical fitness tests (d = 0.40–1.34), whereas significant main effects of Sex were found for upper-extremity muscular power (d = 0.55), flexibility (d = 0.81), agility (d = 0.44), and endurance (d = 0.32) only. Further, significant Sex by Age interactions were observed for upper-extremity muscular power (d = 0.36), flexibility (d = 0.61), and agility (d = 0.27) in favor of girls. Both, linear and curvilinear shaped curves were found for percentile values across the fitness tests. Accelerated (curvilinear) improvements were observed for upper-extremity muscular power (boys: 10–11 yrs; girls: 9–11 yrs), agility (boys: 9–10 yrs; girls: 9–11 yrs), and endurance (boys: 9–10 yrs; girls: 9–10 yrs). Tabulated percentiles for the 9-min run test indicated that running distances between 1,407–1,507 m, 1,479–1,597 m, 1,423–1,654 m, and 1,433–1,666 m in 9- to 12-year-old boys and 1,262–1,362 m, 1,329–1,434 m, 1,392–1,501 m, and 1,415–1,526 m in 9- to 12-year-old girls correspond to a “medium” fitness level (i.e., P₄₀ to P₆₀) in this population.

Conclusions

The observed differences in physical fitness development between boys and girls illustrate that age- and sex-specific maturational processes might have an impact on the fitness status of healthy children. Our statistical analyses revealed linear (e.g., lower-extremity muscular power) and curvilinear (e.g., agility) models of fitness improvement with age which is indicative of timed and capacity-specific fitness development pattern during childhood. Lastly, the provided age- and sex-specific percentile values can be used by coaches for talent identification and by teachers for rating/grading of children’s motor performance.

The relationship of moderate-to-vigorous physical activity to cognitive processing in adolescents: findings from the ALSPAC birth cohort

The aim of this study was to assess the relations of daily moderate-to-vigorous physical activity (MVPA) to cognitive functions in 15-year-old adolescents from the Avon Longitudinal Study of Parents and Children while controlling for aerobic fitness. A sub-sample of 667 adolescents (M(age) = 15.4 ± 0.16 years; 55% females) who provided valid data on variables of interest, were used in the analyses. MVPA was objectively assessed using an Actigraph GT1M accelerometer and aerobic fitness was expressed as physical work capacity at the heart rate of 170 beats per minute from a cycle ergometer test. A computerized stop-signal task was used to measure mean reaction time (RT) and standard deviation of RT, as indicators of cognitive processing speed and variability during an attention and inhibitory control task. MVPA was not significantly related to cognitive processing speed or variability of cognitive performance in hierarchical linear regression models. In simple regression models, aerobic fitness was negatively related to mean RT on the simple go condition. Our results suggest that aerobic fitness, but not MVPA, was associated with cognitive processing speed under less cognitively demanding task conditions. The results thus indicate a potential global effect of aerobic fitness on cognitive functions in adolescents but this may differ depending on the specific task characteristics.

Evaluation of cardiorespiratory fitness using three field tests in obese adolescents: validity, sensitivity and prediction of peak VO2

OBJECTIVES

Evaluation of cardiorespiratory fitness in obese adolescents is necessary to develop personalised retraining programmes. We aimed to measure cardiorespiratory fitness using 3 field tests, and to evaluate their validity and sensitivity compared to values obtained by laboratory tests.

DESIGN

Longitudinal interventional study in obese adolescents admitted to a rehabilitation centre for a 9-month programme of obesity management.

METHODS

A 12-min walk/run test, an adapted 20 m shuttle walk-run test (starting speed 4 km h(-1), increments of 0.5 km h(-1)min(-1)) and a 4-level submaximal cycle ergometer test were performed to estimate respectively distance covered in 12 min, maximum speed and maximal aerobic power.

RESULTS

Thirty adolescents aged 14.2 ± 1.6 years were included. After 9 months intervention, we observed a significant reduction in body mass index, and an increase in peak VO2 and field test results. We observed significant correlations between pre- and post-intervention values of peak VO2 and distance covered in 12 min (r=0.70 pre; r=0.82 post), maximum speed (r=0.80 pre; r=0.83 post) and maximal aerobic power (r=0.71 pre; r=0.84 post). Multiple linear regression made it possible to estimate peak VO2 based on results from the 3 field tests using prediction equations specific to a population of obese adolescents.

CONCLUSIONS

These field tests, including the adapted 20 m shuttle walk-run test, adequately assess cardiorespiratory fitness in obese adolescents, and are sensitive to changes over time. Predictive equations including BMI are useful in clinical practice to predict peak VO2 in these patients.