Sedentary patterns, physical activity and health-related physical fitness in youth: a cross-sectional study

Association between daily movement behaviors and optimal physical fitness of university students: a compositional data analysis

OBJECTIVE

This study investigates the relationship between movement behaviors and physical fitness (PF) in university students, and based on the top 5% of model-predicted outcomes for PF to determine the optimal movement behaviors balance.

METHODS

A total of 463 university students aged 15-24 years from Jinhua City wore accelerometers to measure moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LPA), and sedentary behavior (SB). Sleep (SLP) was self-reported. The body mass index (BMI), forced vital capacity (FVC), 50-meter dash, standing long jump, sit-and-reach, sit-ups (female), pull-ups (male), 800-meter run (female), and 1000-meter run (male) were used as indicators to assess the physical fitness of university students. Regression analysis was used to examine the relationship between movement behaviors and PF. All possible movement component combinations were investigated to determine the best correlation (top 5%) with each outcome.

RESULTS

For males, SB (β = 5.05, p < 0.05) was significantly correlated with an increase in BMI. MVPA was significantly correlated with improvements in BMI (β = -1.75, p < 0.05), FVC (β = 494.21, p < 0.05), and endurance qualities (β = -25.77, p < 0.05). For females, MVPA was significantly correlated with improvements in BMI (β = -1.03, p < 0.05), FVC (β = 176.05, p < 0.05), speed capability (β = -0.26, p < 0.05), and endurance qualities (β = -16.38, p < 0.05). LPA was associated with improvements in endurance qualities (β = -24.10, p < 0.05). SB was significantly correlated with a decline in endurance qualities (β = 24.25, p < 0.05). The average (range) optimal combination of time use was as follows: For males, MVPA = 142 min/day, SB = 534 min/day, LPA = 295 min/day, and SLP = 469 min/day. For females, MVPA = 115 min/day, SB = 536 min/day, LPA = 306 min/day, and SLP = 482 min/day.

CONCLUSION

For both males and females, increased MVPA and reduced sedentary time were associated with improved endurance and strength, while optimal sleep duration contributed to overall fitness. These findings highlight the importance of a balanced daily movement schedule for university students.

Associations between sedentary types, sedentary patterns and cognitive ability in preschool children

The preschool years are a critical period for developing cognitive abilities such as reasoning, memorization, comprehension, quick thinking, and problem-solving. Sedentary behavior (SB) is known to be associated with cognitive development in preschool children. However, limited research has focused on how different types of SB (active, passive) and sedentary patterns (bouts, breaks) affect preschool children's cognitive abilities. This cross-sectional study aimed to investigate: (1) the relationship between sedentary types and preschoolers' cognitive abilities; and (2) the relationship between sedentary patterns and preschoolers' cognitive abilities. Preschoolers aged 3 to 6 years (n = 353) were recruited from 5 kindergartens in Changsha, Hunan, China. Sedentary types were reported by parents, sedentary patterns were measured by preschoolers wearing an ActiGraph wGT3X-BT for seven consecutive days, and cognitive abilities were assessed using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV). The relationships between variables were analyzed using multiple linear regression models. Non-screen-based active SB was associated with higher full-scale IQ and fluid reasoning index in boys and higher visual spatial index in girls. Screen-based active SB was negatively associated with overall cognitive ability. Passive SB potentially had a negative effect on overall cognitive ability, but screen-based passive SB was positively associated with higher fluid reasoning indices in girls. Preschoolers' cognitive ability was positively associated with sedentary breaks, but not with sedentary bouts.

CONCLUSIONS

Not all types of SB are equal when examining optimal cognitive development in preschoolers. Frequent breaks from sedentary time were associated with better cognitive development. Encouraging more frequent breaks to interrupt prolonged SB may be a viable strategy for reducing sedentary time to promote optimal cognitive development. These findings should be further validated in larger prospective studies.

WHAT IS KNOWN

• Sedentary behavior is not advantageous for cognitive development.

WHAT IS NEW

• Not all types of sedentary behavior are harmful. • Active sedentary behaviors are beneficial to overall cognitive development, but screen-based active sedentary behaviors may negatively impact some areas of cognitive performance. • Cognitive abilities in preschoolers are associated with sedentary breaks, but not with sedentary bouts.

Getting up for brain health: Association of sedentary behavior breaks with cognition and mental health in children

Children spend most of their waking hours sedentary and reducing this behavior has been challenging. Interrupting prolonged episodes of sedentary behavior with active breaks can provide mental and cognitive health benefits. Considering the multifactorial nature of these health aspects, this study aimed to verify the role of body mass index (BMI), cardiorespiratory fitness (CRF), and moderate to vigorous physical activity (MVPA) in the relationship between the break in sedentary time with cognitive and mental health in children. This is a cross-sectional study with 129 children (62 boys), aged between 6 and 11 years (mean 8.73 ± 1.53) from a public school in southern Brazil. For the assessment of fluid intelligence, psychologists applied Raven's Colored Progressive Matrices test. Mental health was measured using the Strengths and Difficulties Questionnaire. Sedentary breaks were measured using accelerometers, and CRF was determined using the 6-min walk test. Generalized linear regression analyses were used to verify associations of sedentary breaks with fluid intelligence and mental health, according to children's BMI, CRF, and MVPA. All models were adjusted for sex, age, somatic maturation, and total time of accelerometer use. Our results indicated that sedentary breaks were associated with fluid intelligence in overweight/obese (β = 0.108; p = 0.021) and physically inactive children (β = 0.083; p = 0.010). Regarding mental health, no association was identified with sedentary breaks. In conclusion, sedentary breaks should be encouraged for the benefits of fluid intelligence, especially in children who do not meet physical activity recommendations and are overweight.

Are there associations between sedentary time inside and outside preschools with preschoolers' executive function?

Preschool children spend a large part of their day at school, and a large part of that time they spend in sedentary time. Although sedentary time negatively affects regions of the brain responsible for cognition, it is believed that the type of sedentary time performed can favor executive functions' performance. The present study explored the associations between sedentary time inside and outside preschools with executive function (EF) tasks in preschoolers. Seventy-three preschool children (60% girls; 55.0 ± 9.1 months of age) were objectively assessed for sedentary time and physical activity (PA) using accelerometers (wGT3X). EF was evaluated using the Go/No-Go paradigm through the Early Years Toolbox - YET. Go's inverse efficiency (IE) and the No-Go accuracy were analyzed. To establish possible associations between EF and sedentary time, a structural equation model was conducted after adjustments for sex, age, body mass index, and moderate-to-vigorous PA. A significant and positive association between sedentary time on weekend days and IE (b = 0.61; p < .001) was observed. The general model explained 52% of the variation in IE and 2.1% in the accuracy of No-Go. The sedentary time on weekend days seems to be related to worse EI. This result emphasizes a context-dependent association between time being sedentary and preschoolers' EF. Further investigations should focus on exploring the type of sedentary behavior children are engaged in different contexts.

Effects of Swimming Exercise on Early Adolescents' Physical Conditioning and Physical Health: A Systematic Review

BACKGROUND/OBJECTIVES

Swimming is a popular and cost-effective way to prevent sedentary behavior and improve physical conditioning and health during early adolescence. However, information on its impact and benefits on daily life activities is lacking. This systematic review aims to summarize the chronic effects of swimming on physical conditioning and physical health outcomes in early adolescents.

METHODS

The PRISMA 2020 guidelines were followed and PubMed, Scopus, Web of Science, and International Symposium of Biomechanics and Medicine in Swimming proceedings databases were searched. Eligibility criteria were defined on the PICOS framework (healthy adolescents in early puberty, swimming programmes or training, passive or active control groups, general effects on physical conditioning or health, longitudinal) and risk of bias was assessed using RoBANS 2.

RESULTS

From 2365 records, 20 non-randomized studies met the defined criteria. High heterogeneity in sample size and intervention was observed. While studies related to physical conditioning (n = 5) focused on physiological variables and muscular function, the evidence regarding physical health outcomes (n = 15) explored bone accrual, haemodynamics, body composition, musculoskeletal system, and lung growth. High overall risk of bias (70%) was observed due to strict criteria.

CONCLUSIONS

Swimming exercise seems to improve cardiorespiratory fitness, cardiac output, haemodynamics, heart growth, motor performance, and body composition of early adolescents. Despite clear evidence that exists on these chronic effects, research on bone health, postural deficit, motor skills, and sleep quality is still missing.

Associations between accelerometer-measured physical activity and sedentary behaviour with physical function among older women: a cross-sectional study

BACKGROUND

This study aimed to investigate the relationships between accelerometer-measured physical activity (PA) and sedentary behaviour (SB) with physical function (PF) among older Chinese women in the community.

METHODS

The present study comprised 1,113 community-dwelling older females, with an average age of 65 ± 2 years. We employed a linear regression analysis to investigate the relationship between patterns of PA and SB with PF. PA variables consisted of total PA time, bouted PA time (a continuous PA that lasts equal to or more than 10 min), and sporadic PA time (a continuous PA that lasts less than 10 min). SB variables included total SB time, 30-min bout of SB (a continuous SB that lasts equal to or more than 30 min), and 60-min bout of SB (a continuous SB that lasts equal to or more than 60 min). PF variables comprised handgrip strength (HGS), one-legged stance test with eyes closed (OLSTEC), usual walking speed (UWS), maximum walking speed (MWS) and chair-stand time (CT). To explore the joint effects of moderate-to-vigorous-intensity PA (MVPA) and SB on PF, we divided the duration of SB and MVPA participation in older women into different combinations: low MVPA & high SB, low MVPA & low SB, high MVPA & high SB, high MVPA & low SB.

RESULTS

The study revealed a significant association between 30-min bout of SB and CT, which remained after adjusting for total MVPA time (P = 0.021). Both total MVPA and bouted MVPA were found to be positively associated with better UWS, MWS, CT, and PF Z-score. When the combination of low MVPA & high SB was used as a reference, the regression coefficients for PF ascended by 1.32 (P < 0.001) in the high MVPA & high SB group and by 1.13 (P < 0.001) in the high MVPA & low SB group.

CONCLUSIONS

A significant association was observed between poorer lower limb function and prolonged, uninterrupted SB in older women, rather than with the total SB time. Concurrently, the insufficient engagement in MVPA may also be a crucial factor contributing to poorer PF in older women. Engaging in longer durations and higher intensity of PA, such as bouts of MVPA lasting a minimum of 10 min or longer, may contribute to better PF.

The effects of kettlebell training versus resistance training using the own body mass on physical fitness and physiological adaptations in obese adults: a randomized controlled trial

AIM OF STUDY

This study aimed to explore the effects of different types of resistance training using kettlebells versus the own body mass, in comparison to a passive control, on key physical fitness and physiological parameters in young, obese adults.

METHODS

Data from 60 sedentary, obese male college students, aged 17-26, were used for final analyses. Participants were randomly assigned to one of three groups: a control group (CG, n = 20, no training), a kettlebell resistance training group (KRTG, n = 20), or a bodyweight resistance training group (BWRTG, n = 20). Selected measures of physical fitness were tested using the 12-minutes run test, the push-up test, the sit-up test, and the sit-and-reach test. Physiological measures included vital capacity, resting and maximum heart rate (HRmax), mean arterial blood pressure, breath holding time, and respiratory rate. Biochemical variables were measured in the morning, in a fasted state, and comprised high and low density lipoprotein, total cholesterol, and triglycerides. The 12-weeks progressive KRTG and BWRTG were specifically tailored using sets, repetitions, and intensity levels.

RESULTS

Notable findings include significant body fat reductions in BWRTG (p < 0.001; d = 1.53) and KRTG (p < 0.001; d = 1.43), and a substantial increase in VO2max for BWRTG (p < 0.001; d = 1.32) and KRTG (p < 0.001; d = 1.34) compared to CG. KRTG also showed significant improvements in vital capacity (p < 0.001; d = 1.61) and reductions in resting heart rate (p = 0.024, d = 1.05) and respiratory rate (p = 0.001, d = 1.55), with BWRTG showing similar trends (resting heart rate: p = 0.041, d = 1.35; respiratory rate: p = 0.001, d = 1.98). Both intervention groups significantly improved breath holding time (KRTG: p = 0.001, d = 1.58; BWRTG: p < 0.001, d = 1.98) and reduced total cholesterol and low-density lipoprotein levels compared to CG.

CONCLUSIONS

This study demonstrates that both KRTG and BWRTG are effective in improving body composition and selected fitness and physiological measures. Thus, resistance training using kettlebells or bodyweight training are recommended if the goal is to improve body composition and fitness in obese male adults.

TRIAL REGISTRATION

OSF, September, 28th 2023. https://doi.org/10.17605/OSF.IO/Z6Y9Gosf.io/2mb98.

Effectiveness of mHealth App-Based Interventions for Increasing Physical Activity and Improving Physical Fitness in Children and Adolescents: Systematic Review and Meta-Analysis

BACKGROUND

The COVID-19 pandemic has significantly reduced physical activity (PA) levels and increased sedentary behavior (SB), which can lead to worsening physical fitness (PF). Children and adolescents may benefit from mobile health (mHealth) apps to increase PA and improve PF. However, the effectiveness of mHealth app-based interventions and potential moderators in this population are not yet fully understood.

OBJECTIVE

This study aims to review and analyze the effectiveness of mHealth app-based interventions in promoting PA and improving PF and identify potential moderators of the efficacy of mHealth app-based interventions in children and adolescents.

METHODS

We searched for randomized controlled trials (RCTs) published in the PubMed, Web of Science, EBSCO, and Cochrane Library databases until December 25, 2023, to conduct this meta-analysis. We included articles with intervention groups that investigated the effects of mHealth-based apps on PA and PF among children and adolescents. Due to high heterogeneity, a meta-analysis was conducted using a random effects model. The Cochrane Risk of Bias Assessment Tool was used to evaluate the risk of bias. Subgroup analysis and meta-regression analyses were performed to identify potential influences impacting effect sizes.

RESULTS

We included 28 RCTs with a total of 5643 participants. In general, the risk of bias of included studies was low. Our findings showed that mHealth app-based interventions significantly increased total PA (TPA; standardized mean difference [SMD] 0.29, 95% CI 0.13-0.45; P<.001), reduced SB (SMD -0.97, 95% CI -1.67 to -0.28; P=.006) and BMI (weighted mean difference -0.31 kg/m2, 95% CI -0.60 to -0.01 kg/m2; P=.12), and improved muscle strength (SMD 1.97, 95% CI 0.09-3.86; P=.04) and agility (SMD -0.35, 95% CI -0.61 to -0.10; P=.006). However, mHealth app-based interventions insignificantly affected moderate to vigorous PA (MVPA; SMD 0.11, 95% CI -0.04 to 0.25; P<.001), waist circumference (weighted mean difference 0.38 cm, 95% CI -1.28 to 2.04 cm; P=.65), muscular power (SMD 0.01, 95% CI -0.08 to 0.10; P=.81), cardiorespiratory fitness (SMD -0.20, 95% CI -0.45 to 0.05; P=.11), muscular endurance (SMD 0.47, 95% CI -0.08 to 1.02; P=.10), and flexibility (SMD 0.09, 95% CI -0.23 to 0.41; P=.58). Subgroup analyses and meta-regression showed that intervention duration was associated with TPA and MVPA, and age and types of intervention was associated with BMI.

CONCLUSIONS

Our meta-analysis suggests that mHealth app-based interventions may yield small-to-large beneficial effects on TPA, SB, BMI, agility, and muscle strength in children and adolescents. Furthermore, age and intervention duration may correlate with the higher effectiveness of mHealth app-based interventions. However, due to the limited number and quality of included studies, the aforementioned conclusions require validation through additional high-quality research.

TRIAL REGISTRATION

PROSPERO CRD42023426532; https://tinyurl.com/25jm4kmf.

Associations of habitual sedentary time with executive functioning and short-term memory in 7th and 8th grade adolescents

BACKGROUND

While there is increasing evidence for negative physical health consequences of high volumes of sedentary time and prolonged sedentary time in adolescents, the association with cognition is less clear. This study investigated the association of volumes of habitual sedentary time and prolonged sedentary time with executive functions and short-term memory in adolescents.

METHODS

This study has a cross-sectional observational study design. Volumes of sedentary time and prolonged sedentary time (accumulated sedentary time spent in bouts of  ≥ 30 min) were measured using the Axivity AX3 accelerometer. Six cognitive functions (spatial and verbal short-term memory; and working memory, visuospatial working memory, response inhibition and planning as executive functions) were measured using six validated cognitive assessments. Data were analysed using generalised linear models.

RESULTS

Data of 119 adolescents were analysed (49% boys, 13.4 ± 0.6 year). No evidence for an association of volumes of sedentary time and prolonged sedentary time with spatial and verbal short-term memory, working memory, and visuospatial working memory was found. Volumes of sedentary time and prolonged sedentary time were significantly related to planning. One hour more sedentary time or prolonged sedentary time per day was associated with respectively on average 17.7% (95% C.I.: 3.5-29.7%) and 12.1% (95% C.I.: 3.9-19.6%) lower scores on the planning task.

CONCLUSIONS

No evidence was found for an association of volumes of habitual sedentary time and prolonged sedentary time with short-term memory and executive functions, except for planning. Furthermore, the context of sedentary activities could be an important confounder in the association of sedentary time and prolonged sedentary time with cognition among adolescents. Future research should therefore collect data on the context of sedentary activities.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov in January 2020 (NCT04327414; released on March 11, 2020).

Steps per day and health-related quality of life in schoolchildren: the mediator role of cardiorespiratory fitness

To analyse the relationship between steps per day and health-related quality of life (HRQoL) and cardiorespiratory fitness (CRF) and to examine whether the relationship between steps per day and HRQoL is mediated by CRF in schoolchildren. This was a cross-sectional study including 501 schoolchildren (aged 9-12 years, 47% girls), from Cuenca, Spain. Steps per day were measured using the Xiaomi Mi Band 3 Smart Bracelet, HRQoL was estimated by the KIDSCREEN-27 questionnaire, and CRF was assessed using the 20-m shuttle run test. Analysis of covariance and multivariate analysis of covariance models showed that children with a higher mean number of steps per day (> 9000 steps/day) had better HRQoL (global score, and physical and psychological well-being) and higher CRF levels than their peers with a lower number of steps per day (p < 0.05); however, these differences were no longer significant when controlling for sex, age, mother's education level, and CRF (p > 0.05). Linear regression models estimated that each 1000-step increment was associated with better CRF (β = 0.350; 95% CI, 0.192 to 0.508). In addition, the relationship between steps per day and HRQoL was mediated by CRF (p < 0.05).    Conclusion: Steps per day are a good metric to estimate daily physical activity because of its positive relationship with CRF. Moreover, those children taking more than 9000 steps per day are associated with higher levels of physical and psychological well-being. Finally, a substantial part of the improvement in HRQoL achieved through the increase in physical activity (steps per day) is mediated by CRF. What is Known: • Physical activity is known to have a positive impact on health-related quality of life in children. Steps per day are commonly used as a measure of physical activity. • Cardiorespiratory fitness is a recognized indicator of overall health in youth. What is New: • Increments of steps per day were associated with better CRF, with a nonlinear association after approximately 9000 steps/day. • Schoolchildren with > 9000 steps/ day showed better HRQoL.

Longitudinal pathways of associations between motor proficiency and physical fitness during earlier and later childhood: The NW-CHILD study

Understanding the relationships between motor proficiency (MP) and physical fitness (PF) is important for the future health of children, although longitudinal findings of this nature are limited. This study explored the association between MP and PF during earlier childhood (6 and 9 years old) and later childhood (12 years old) in boys and girls. A stratified and randomized research design including a baseline and two follow-up time-point measures (2010, 2013, and 2016) were used. Primary school children (N = 374, boys = 178; girls = 196) were tested with the Bruininks-Oseretsky Test of Motor-Proficiency-2, Short Form, and the Test of Gross Motor Development- 2, at ages 6 and 9 years, and with the Progressive Aerobic Cardiovascular Endurance Run test at age 12. Spearman Rank Order Correlations and stepwise regression analyses were used to analyze the data. Although of a low magnitude, proof of a dynamic longitudinal, but a stable relationship between MP and PF were found and with different gender-specific relationships in this pathway of association. A small but significant percentage of variation in PF at 12 years could be explained by overall motor competence (MC) and object control skills (OCS) at the ages of 6 and 9 years. Among girls, the association with PF at 12 years was influenced by both OCS, and MC, although only MC contributed to the variation found in boys. Socio-economic status made an insignificant contribution at 6 years to later PF in boys, but not in girls. MC, including OCS during early and middle childhood can be considered as possible triggers of physical activity which again, can increase PF during later childhood. Obtaining early competence in these developmental areas is therefore important to promote positive and sustainable trajectories of health with long-term health outcomes.

The promoting effect of exercise motivation on physical fitness in college students: a mediation effect model

BACKGROUND

In recent years, the physical fitness situation of college students is worrying in China. Exercise motivation is of great importance for the physical activity and physical fitness. However, existing studies have paid limited attention to the specific effect between exercise motivation, physical activity and physical fitness, and even less to the different genders and exercise motivation dimensions. This study aimed to investigate the promoting effect of sport motivation on physical fitness with different gender and dimension in college students.

METHODS

Physical fitness levels of 2544 college students in Wuhan and Jingzhou city were measured. Exercise motivation and physical activity was assessed using the Chinese version of the motives for physical activities measure-revised scale and the physical activity survey scale, respectively. Correlation analysis and structural equation model were used to explore the relationship between exercise motivation, physical activity and physical fitness. Bootstrap method was used to test the mediating effect. Multilevel regression analysis was used to examine the effects of different dimensions of exercise motivation on PF.

RESULTS

The exercise motivation of college students was directly related to physical fitness (effect value: 0.307) or indirectly related through the mediating effect of physical activity (effect value: 0.092). The mediation effect percentage of physical activity on exercise motivation and physical fitness in male (51.20%) was greater than female (27.18%), and the standardized regression coefficient of the health dimension to PF was β = 0.151, P < 0.001, and the competence dimension to PF was β = 0.189, P < 0.001.

CONCLUSIONS

The exercise motivation of college students can directly influence PF or indirectly influence PF through the mediating effect of PA. The promoting effect of exercise motivation and PA on PF in college students is related to gender and dimensions of exercise motivation. Therefore, we can improve physical fitness levels of college students by promoting their exercise motivation (especially for health motivation and competence motivation) and increasing their participation in physical activity. This study provides new strategies for improving physical fitness in college students.

Sedentary behavior patterns and the risk of non-communicable diseases and all-cause mortality: A systematic review and meta-analysis

BACKGROUND

The association between sedentary behavior and health-related outcomes has been well established, whereas it is inconclusive whether a sedentary behavior pattern is an additional risk factor for health-related outcomes independent of total sedentary time and physical activity.

OBJECTIVES

To determine sedentary behavior patterns and their association with risks of noncommunicable diseases and all-cause mortality and to assess whether this association is independent of total sedentary time and physical activity.

DESIGN

This was a systematic review and meta-analysis.

METHODS

Studies were obtained by searching the Web of Science Core Collection, PubMed/Medline, the Cochrane Library, Embase, CINAHL, and SPORTDiscus up to April 2023. All observational studies published in English or Chinese were included if they explored sedentary behavior patterns and their association with risks of abdominal obesity, metabolic syndrome, diabetes, cardiovascular disease, cancer, and all-cause mortality among individuals who had never experienced the outcome event before the baseline assessment. Data extraction using a standardized form and quality appraisal using two authoritative tools were then performed. All these steps were completed by two independent reviewers from December 2022 to May 2023. If data were sufficiently homogenous, meta-analyses were performed; otherwise, narrative syntheses were employed. Harvest plots were also used to visually represent the distribution of evidence.

RESULTS

Eighteen studies comprising 11 prospective cohort studies and seven cross-sectional studies were included. The findings suggested that prolonged sedentary time and usual sedentary bout duration were two metrics that reflected the nonlinear dose-response effect of prolonged sedentary behavior patterns. Only extremely high levels of prolonged sedentary behavior patterns significantly increased the risk of adverse health outcomes, independent of physical activity. Whether prolonged sitting was an additional risk factor for adverse health outcomes, independent of total sedentary time, was inconclusive due to an insufficient number of primary studies that included total sedentary time as one of the potential covariates. There was some evidence that supported a sedentary bout that significantly increased the risk of adverse health outcomes was 30-60 min. The threshold of prolonged sedentary time differed with outcomes, and future studies are needed to make this threshold more precise.

CONCLUSION

A prolonged sedentary behavior pattern was associated with increased risks of several major noncommunicable diseases and all-cause mortality. People, especially those who do not reach the recommended level of moderate-to-vigorous physical activity, are encouraged to interrupt sedentary bouts every 30 to 60 min and limit prolonged sedentary time per day as much as possible.

TWEETABLE ABSTRACT

Breaking up consecutive sedentary bouts >30 to 60 min and substituting them with brief bouts of physical activity.

Mediating Effects of the COVID-19 Pandemic on the Associations between Physical Activity and Physical Fitness; Cross-Sectional Study among High School Adolescents

The COVID-19 pandemic and the imposed social distancing measures caused negative changes in physical activity levels (PALs) and physical fitness (PF) among adolescents, but the potential mediating effect of the pandemic on the association between PAL and PF is unknown. This study aimed to evaluate gender-specific associations between objectively measured PAL and indices of PF among high school adolescents during the period of the COVID-19 pandemic. The participants were 150 adolescents (101 females) aged 14-18 years; their anthropometrics were evaluated, and they were tested on PF (cardiorespiratory fitness (CRF; beep test), power (broad jump), flexibility (sit-and-reach test), and abdominal strength (sit-ups)) and PAL (using a pedometer for 7 days) during the pandemic period. A T-test was calculated to determine differences between genders. Associations between variables were evaluated using Pearson correlations. Additionally, multivariate taxonomic classification was used to sort participants into homogenous groups (clusters) according to their PF, and then analysis of variance (ANOVA) was performed to differentiate them according to PAL. For the total sample, PAL was correlated with CRF only (R = 0.25, p < 0.05), while gender-stratified correlations showed that PAL was significantly associated with CRF among girls only (R = 0.29, p < 0.05), which was additionally confirmed with multivariate cluster analysis and subsequent ANOVA. No association between PAL and PF was found for boys. The relatively low association between PAL and PF is most likely related to the mediating effect of the change in life circumstances during the COVID-19 pandemic, and limited applicability of pedometers in evaluating high-intensity PAL. Further studies in other age groups and environments are warranted.

Associations between combinations of 24-h movement behaviors and physical fitness among Chinese adolescents: Sex and age disparities

OBJECTIVE

To analyze the relationship between 24-h movement behaviors and adolescents' physical fitness, with sex difference and age disparity explored specifically.

METHODS

A total of 135 852 Chinese adolescents aged 13-22 years were included in this cross-sectional study. Self-reported 24-h movement behavioral times, including moderate to vigorous physical activity (MVPA), recreational screen, and sleep, were identified as meeting guidelines based on Canadian recommendations. Physical fitness indicator (PFI) was calculated through sex- and age-specific z scores of body mass index, forced vital capacity, 50 m dash, sit-and-reach, standing long jump, body muscle strength, and endurance running, and then classified as: low level (<20th), middle level (20th-80th), and high level (>80th). Mixed effect logistic regression was applied to analyze the association, and interaction terms were constructed to prove the sex and age disparities.

RESULTS

Only 12.4% of adolescents aged 13-22 years met all three recommendations. The number of meeting guidelines exhibited a typical dose-response relationship with high level PFI (OR = 1.22 [95% CI: 1.19-1.25]), and in detail, meeting MVPA + recreational screen (OR = 2.29 [95% CI: 2.09-2.51]) or MVPA-only (OR = 2.16 [95% CI: 1.93-2.41]) guidelines were better associated with high-level PFI. Besides, meeting MVPA-only guideline was proved with stronger association with high-level PFI for boys (p-interaction = 0.005). The dose-response relationship in boys of the number of guidelines met with PFI was stronger in 19- to 22-year-olds (p-interaction <0.001) and 16- to 18-year-olds (p-interaction = 0.001) than that in 13- to 15-year-olds.

CONCLUSION

The prevalence of meeting 24-h movement behaviors guidelines among Chinese adolescents aged 13-22 years was relatively low. It was associated with adolescents' physical fitness, with meeting MVPA + recreational screen or MVPA-only guidelines bringing greater benefits, and sex difference and age disparity existing.

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.

Assessment of physical activity among adolescents: a guide to the literature

Purpose

The aim of this article is to systematically review articles and annual reports concerning young peoples' physical activity (PA) and linking this to considerations of the state and national defense.

Method

A systematic search of the literature included an analysis of publications accessible in global databases and other available books, student papers, and projects. The articles and reports were categorized based on year of publication, methods used, age of respondents, sample size, country, and digital object identifier (DOI).

Results

The result of this search is an overview of the extent and manner in which the worldwide scientific community is addressing the current situation and the long-term development of the physical fitness of adolescents. This publication also maps to what extent professional publications and articles are addressing PA from the perspective of the needs of armies and armed forces of various countries around the world.

Conclusions

The article provides a systematic overview of methods used to measure PA, and an overview of articles dealing with assessing PA. The examined articles indicate that from the perspective of not only national defense, but also health and overall quality of life, in particular, we need initiatives to encourage and motivate young people to increase their everyday PA. The research therefore also includes an overview of factors that may considerably influence PA. The results ascertained in this publication will be used, i.a. for investigating a longitudinal defense research project of the Ministry of Defense of the Czech Republic in which the authors are participating.

Perceived Physical Literacy Is Associated with Cardiorespiratory Fitness, Body Composition and Physical Activity Levels in Secondary School Students

BACKGROUND

Overweight and obese adolescents are often associated with lower Physical Activity (PA) levels and low Cardiorespiratory Fitness (CRF). Recently, the concept of Physical Literacy (PL), has been suggested to be associated with higher levels of active behavior and better health in adolescents. The purpose of this study is to investigate the relationships between PL, body composition, cardiorespiratory fitness and physical activity levels in French secondary school students.

METHODS

The level of PL was assessed in 85 French adolescents using a French version of the Perceived Physical Literacy Instrument (F-PPLI). Cardiorespiratory fitness was measured by the "20 m adapted walk/shuttle run test". The PA level was assessed by the Youth Risk Behavior Surveillance System questionnaire. Weight status was measured by the Body Mass Index (BMI) and the body composition data.

RESULTS

We find a significant association between the PL and the percentage Fat Mass (%FM) (r = -0.43; p ≤ 0.01), between the PL and moderate to vigorous PA (MVPA) per week (r = 0.38; p ≤ 0.01). The PL was associated (r = 0.36; p ≤ 0.01) with the percentage of Skeletal Muscle Mass (%SMM) and cardiorespiratory fitness (r = 0.40; p ≤ 0.05).

CONCLUSIONS

Developing the PL for the most disadvantaged secondary school students in a PA program could be a suitable strategy to increase their PA level, reduce their adiposity, and promote better long-term health.

Evaluation of the relationship between nutritional status, levels of physical activity and physical strength in adolescents

BACKGROUND & AIMS

The study aimed at evaluating the relationship among anthropometric measurements, levels of physical activity and physical fitness in schoolchildren.

METHODS

A cross-sectional study was carried out in public schools, with 173 adolescents from 10 to 17 years of age. Socioeconomic data were obtained by a structured questionnaire. Anthropometric measures were assessed and classified according to Body Mass Index (BMI)/age and Waist Circumference (WC). The long version of the International Physical Activity Questionnaire (IPAQ) was used to assess the level of physical activity, while the physical fitness level was assessed using the Projeto Esporte Brasil (PROESP) test protocol.

RESULTS

72,3% of the adolescents were eutrophic and 24.3% were overweight and 22.6% were at high risk for cardiovascular disease, with no statistical difference between the sexes (p > 0.05). 53.8% were physically inactive, regardless of sex and nutritional status. 86.1% of the adolescents showed low physical fitness, more significantly for sit-and-reach andsquare tests of females. BMI was directly correlated with physical fitness in the assessment ofupper limb power and agility (medicine ball throw and square test) and indirectly with aerobic capacity and lower limb power (abdominal resistance, horizontal jump and general resistance). The opposite was observed in the correlation of endurance (abdominal and general) and medicine ball throw with WC. Also, there was a likely visceral obesity and consequent cardiovascular risk in females more than in males.

CONCLUSIONS

These findings reinforce the connection between physical activity and the presence of overweight and obesity in adolescents and also the need to effectively intervene in this groupin order to ensure the prevention of chronic non-communicable diseases in adulthood.

Adolescents' Flexibility Can Affect Motor Competence: The Pathway from Health Related Physical Fitness to Motor Competence

Motor competence has been shown to predict health-related physical fitness (HRPF) components in youth, but there is indeterminate evidence for the reverse path. Even less is known about the specific relationship between motor competence and flexibility. Our aims in this study were to analyze the relationship between flexibility and motor competence among adolescents; and, secondarily, to examine the relationships between motor competence and other HRPF components (body composition and musculoskeletal fitness). We conducted a longitudinal study (14-months follow-up) with two measurement points of 128 participants (55.5% girls; 45% boys) aged 12-13 years at baseline. We assessed HRPF components at the first time point and determined motor competence at the second time point. We assessed HRPF in terms of body composition (body fat percentage), musculoskeletal fitness (sit-up test), and flexibility (sit and reach). We determined motor competence using the Körperkoordinationstest für Kinder (KTK). We employed multivariate analyses of variance (MANOVA) to examine the effect of HRPF on motor competence through three models, in which each HRPF component was considered an independent variable. Sex, age, physical activity, and body mass index (BMI) z-scores were considered confounders. In our crude models all HRPF components significantly affected motor competence. In adjusted models, flexibility (p = .002) and body composition (p < .001) significantly affected motor competence. Overall, these results supported the assumptions that HRPF components are related to motor competence in adolescence, and that flexibility can affect motor competence in young people.

Trend in health-related physical fitness for Chinese male first-year college students: 2013-2019

Introduction

Physical fitness is a health indicator contributing to the prevention of non-communicable diseases that threaten public health. Studies across a number of global populations indicate that physical fitness is generally declining. This study investigated the trend in physical fitness of Chinese male first-year college students from 2013 to 2019 to offer critical information for fostering individual and public health.

Methods

This study used archival data and a natural experiment design capturing 4 years of data prior to implementation of the Healthy China 2030 initiative and 3 years following. Physical fitness tests were based on the Chinese national student physical fitness standards for males including body mass index, vital capacity, standing-long-jump, sit-and-reach, pull-ups, 50 m sprint, and 1,000 m run. Because the physical fitness tests set different standards for males and females, female data will be reported separately. Data from a total of 3,185 Chinese male first-year college students from a private university in Hebei Province of China were included in the study. A one-way multivariate analysis of variance was used for analyzing the research data.

Results

The results indicated an overall significant difference in health-related physical fitness of Chinese male first-year college students, with scores on health indicators generally declining from 2013 to 2019. Despite improvement on some fitness variables in some years, performance on virtually all indicators was diminished compared to baseline years.

Discussion

These findings can contribute to the existing global literature in the field of public health showing general declines in physical fitness. Chinese universities have the opportunity to support Healthy China 2030 goals and cultivate individuals' physical fitness by offering physical education course that encourage college students to participate in moderate-to-vigorous-intensity physical activities in order to support physical fitness development.

Assessment of Motor Abilities and Physical Fitness in Youth in the Context of Talent Identification-OSF Test

(1) Background: Physical fitness during childhood is an important indicator of current and future health status. Defining physical fitness levels is a key element of talent identification in the training of children and adolescents. It is also crucial in developing a sports career path. This study sought to validate a physical fitness test (OSF test) and to determine fitness norms for children and adolescents with a special focus on talent identification within its particular sub-tests of endurance, speed, strength and power. (2) Methods: A total of 27,187 athletes who participated in the 'Athletics for all' (AFA) programme were included in the analysis. Physical fitness was assessed using a validated OSF test (3 × 10 shuttle run, standing broad jump, 1 kg medicine ball overhead throw, 4-min run). (3) Results: Four key motor abilities (speed, power, strength and endurance) were assessed in children and adolescents. The OSF test was normalised, i.e., a reference frame in the form of centile charts was developed. (4) Conclusions: The centile charts developed for particular parts of the OSF test make it possible to interpret scores in particular motor sub-tests and, first and foremost, enable users to compare a given score with results obtained by their peers.

An empirical study of physical activity and sports affecting mental health of university students

Physical activity (PA) and sports are extremely essential elements for physical and mental health among adolescents. Around 30% of 16 years old and above in Malaysia have mental health issues. For this purpose, 512 university students from Malaysia were surveyed through social media, with 74% response rate. Structural equation model partial least square (SEM-PLS) was used to examine the effect of PA and sports on mental health. The results revealed that both PA (b = 0.402, p < 0.001) and sports (b = 0.330, p < 0.001) significantly predict mental health among university students. The model explained 35.8% variance in mental health. The study suggests that PA and sports activity need to be promoted among university students to control prevailing mental health issues in adolescents.

Associations between Sedentary Time and Sedentary Patterns and Cardiorespiratory Fitness in Chinese Children and Adolescents

The increase in sedentary behavior in children and adolescents has become a worldwide public health problem. This study aimed to explore the associations between sedentary time (ST) and sedentary patterns (SP) and the cardiorespiratory fitness (CRF) of Chinese children and adolescents. The CRF of 535 participants was determined using a 20-m shuttle run test. ST and SP were measured with accelerometers. Questionnaires were used to investigate the different types of ST. Multiple linear regression models were used to test the associations between ST and SP and CRF. In this study, only some ST and SP indicators were found to be significantly associated with CRF in girls. With each additional 10 min of screen time or passive traffic time, VO2max decreases by 0.06 mL/kg/min (B = −0.006, 95% CI: −0.010~−0.001) and 0.31 mL/kg/min (B = −0.031, 95% CI: −0.061~−0.002), respectively, with MVPA control. With each additional 10 min of breaks in ST or duration of breaks in ST, VO2max increases by 0.41 mL/kg/min (B = 0.041, 95% CI: 0.007~0.076) and 0.21 mL/kg/min (B = 0.021, 95% CI: 0.007~0.035), respectively, with control total ST. Breaks in ST (B = 0.075, 95% CI: 0.027~0.123) and the duration of breaks in ST (B = 0.021, 95% CI: 0.012~0.146) were positively correlated with CRF when controlling for LPA, but these associations were not significant when controlling for MVPA (B = 0.003, 95% CI: −0.042~0.048; B = 0.001, 95% CI: −0.024~0.025). The total ST of children and adolescents was found to not be correlated with CRF, but when ST was divided into different types, the screen time and passive traffic time of girls were negatively correlated with CRF. More breaks in ST and the duration of breaks in ST were positively associated with higher CRF in girls. MVPA performed during breaks in ST may be the key factor affecting CRF. Schools and public health departments should take all feasible means to actively intervene with CRF in children and adolescents.

Patterns of Objectively Measured Sedentary Time and Emotional Disorder Symptoms Among Youth

OBJECTIVE

We examined the within-person longitudinal and bidirectional associations between patterns of sedentary time accumulation [alpha (sedentary bout duration/length), sedentary breaks (number of breaks in sedentary bouts)], and symptoms of major depressive disorder and generalized anxiety disorder.

METHODS

Children [N = 167, 10.1(0.9) years old, 54.5% female, 59.3% Hispanic, 35.9% overweight/obese at baseline] participated in a 3-year longitudinal study that consisted of assessments of sedentary time, and depressive and anxiety symptoms. At each assessment, participants wore accelerometers and completed the Revised Child Anxiety and Depression Scale. Separate random intercept cross-lagged panel models estimated the within-person longitudinal and bidirectional associations between alpha, sedentary breaks, and symptoms of major depressive disorder and generalized anxiety disorder across chronological age intervals.

RESULTS

Having greater than one's own usual depressive symptoms at age 11 was associated with fewer sedentary breaks 1 year later. Having greater than one's own usual generalized anxiety symptoms at age 11 was associated with longer sedentary bouts and fewer sedentary breaks 1 year later. In contrast, having greater than one's own usual sedentary breaks at age 10 was associated with fewer generalized anxiety symptoms 1 year later. All other associations, including at younger ages, were null.

CONCLUSION

Deviations from one's usual levels of depressive or anxiety symptoms may be important for how sedentary time is subsequently accumulated. Intraindividual processes appear to be at play, therefore more within-person research is needed. Intervention strategies for promoting a healthier accumulation of sedentary time may consider targeting occasions when depressive and anxiety symptoms are greater than usual.

Influence of Sport Practice and Body Weight on Physical Fitness in Schoolchildren Living in the Campania Region

Background: Physical fitness (PF) levels correlate with health hallmarks at all ages. In this study, w aimed to determine the PF level of schoolchildren from the Campania Region (Italy) through health-related PF (HRPF) components, taking into account body weight and sport practice (SP). Methods: PF level was determined in 565 schoolchildren aged 10−13 (11.7 ± 1.0 yrs; m: 353, f: 212) using some of the Eurofit battery tests. Results: 77% children practiced sport, boys more than girls (86% vs. 63%, respectively; p < 0.05). Boys performed better than girls (p < 0.05) in the Plate Tapping, Standing Broad Jump, Bent-Arm Hang, and 10 × 5 m Shuttle Run tests; girls performed better in the Sit-and-Reach Test (p < 0.05). Conclusion: Overweight/obese status negatively affects the muscular strength of lower limbs, even if it progressively improves during growth. SP was revealed to be a determinant in performance only in some PF tests, likely due to the heterogeneous training level among boys and girls who practice sport.

Accelerometer-Measured Physical Activity Levels and Patterns Vary in an Age- and Sex-Dependent Fashion among Finnish Children and Adolescents

Background: The purpose of this study was to measure physical activity (PA), sedentary behavior (SB), and hour-by-hour PA patterns with an accelerometer in a population-based sample of Finnish children and adolescents. Methods: A total of 3274 participants (3rd, 5th, 7th, 9th graders) from 176 schools wore a hip-worn triaxial accelerometer for seven days during waking hours. Mean amplitude deviation of the acceleration data was used to assess PA intensity that was converted to metabolic equivalents and categorized into light, moderate, and vigorous PA. Angle for posture estimation was used to measure SB and standing. Results: The majority of participants’ PA consisted of light PA, and they were sedentary for more than half of their waking hours. Children were more active than adolescents, and boys were more active than girls. Participants took, on average, 9890 steps daily, and one third met the PA recommendation. The participants were divided into tertiles based on daily steps to investigate the variation in PA patterns. Compared to the least active tertile, the most active tertile took twice as many steps on weekdays and nearly three times as many steps on the weekend. Conclusions: The majority of the participants were not active enough, and there was a great variation in PA levels and patterns, especially among the adolescents and on weekends.

A Longitudinal Examination of Withholding All or Part of School Recess on Children's Physical Activity and Sedentary Behavior: Evidence from a Natural Experiment

School recess is a daily opportunity for school-age students to be physically active. However, in some territories teachers often use recess for other purposes (e.g., children's poor classroom behavior might be punished with reduced time for recess). This study aimed to examine the impact of such practices on children's physical activity (PA) and the relationships between PA, gender, body mass index (BMI), and academic achievement. Forty-six first-grade students from two natural classrooms wore an accelerometer over the course of 6 weeks to measure their metabolic equivalent of task (METs) and sedentary behavior during school recess. Gender, age, BMI, the classroom to which students belonged, and academic achievement were also analyzed in two Generalized Estimating Equations models. Results revealed that boys achieved more METs and spent less time participating in sedentary behavior than girls during recess. Children within a healthy weight range of BMI yielded more METs than underweight and overweight/obese children. Academic achievement was positively associated with the METS and negatively with the sedentary behavior. Finally, withholding all or part of school recess significantly reduced children's PA and extended their sedentary behavior. The literature indicates that school recess plays an important role in promoting numerous children's health outcomes. Therefore, students should not be excluded from participation in all or part of recess.

Association of modifiable factors with the development of physical fitness of Austrian primary school children: A 4-year longitudinal study

Physical fitness (PF) shows favourable associations with several health indicators in children. Children's PF depends on a variety of non-modifiable (e.g., sex and age) and modifiable factors (e.g., weight status and sports participation). The aim of this study was to evaluate the impact of modifiable and non-modifiable factors on the development of PF during the 4 years of primary school. A longitudinal study was carried out with 265 children. PF was assessed using the German Motor Performance Test 6-18, whereas modifiable and non-modifiable factors with parent's and children's questionnaires. Total PF z-score increased by 1.4 standard deviations from 1^st to 4^th year and raw values of subtests improved by an average of about 40%. The variables "parents' physical activity", "never being overweight", "sports club participation", and "playing outside" were positively associated with PF development. The present study highlights that a variety of modifiable factors, both from children and their parents, are significantly associated with the development of children's PF during primary education. Interventions should not only focus on direct actions, such as proposing specific exercise programs, but also aim at increasing parents' awareness of their role model function in endorsing their children's healthy active lifestyle, especially at early ages.

Do Fitter Children Better Assess Their Physical Activity with Questionnaire Than Less Fit Children?

Most physical activity (PA) questionnaires assess moderate to vigorous PA (MVPA) describing the physical exertion of individuals that might be influenced by their physical fitness. Therefore, the aim of this study was to determine whether fitter children could better assess their PA with the questionnaire than less fit children. The cross-sectional validation study was conducted with 108 children (60 girls) aged 11 to 14 years, who were divided into three fitness groups based on the results of the 600 m running test. To answer the research question, the agreement between their assessment of PA using the SHAPES questionnaire and the UKK RM42 accelerometer data was analysed. One quarter of the participants achieved at least 60 min of MVPA each day, measured by accelerometer. The average MVPA obtained was 97.8 ± 35.6 min per day, with the high fitness group having a significantly higher value compared with the other groups. Moderate to high validity coefficients were found in the high fitness group (Spearman’s ρ range 0.34–0.70). In contrast, the lower fitness groups had poor to moderate validity for all variables (Spearman’s ρ range 0.03–0.42). These results suggest that the fittest children self-assess their PA with the questionnaire better than less fit children, which may advance new directions for the development and evaluation of PA questionnaires and their usability.

Sex Moderated Mediation of the Musculoskeletal Fitness in Relationship between High-Intensive Interval Training Performing during Physical Education Classes and Cardiorespiratory Fitness in Healthy Boys and Girls

High-intensive interval training (HIIT) is indicated as a means of improving cardiorespiratory fitness (CRF) and musculoskeletal fitness (MSF). The relationship between CRF and MSF was examined too. Little is known about gaining CRF from HIIT independence of MSF in adolescents. Therefore, this study is aimed at investigating whether MSF mediated the relationship between HIIT and CRF and whether sex moderate this relation. The study sample included 122 individuals (45 boys, 77 girls) 16.12 ± 0.38 years of secondary school age. Participants were assigned to the HIIT intervention or control groups. The intervention lasted 14 minutes during one physical education lesson per week for ten weeks. Outcome and potential mediator were residual changes calculated from pre- and postintervention results of MSF components: handgrip (HG), sit-ups (ABS), sit-and-reach (FL), vertical jump (VJ), and Harvard step-test representing cardiorespiratory fitness (CRF). MSF index (MSFI) was calculated as a construct, agglomerating all MSF, and tested its usefulness. HIIT significantly impacted CRF in boys and girls (B = 2.32, p = 0.032; B = 2.28, p = 0.005, respectively). The impact of the HIIT program on the ABS and FL was observed only in girls. The moderation effect of sex was confirmed. Significant effect of HIIT on CRF decreased (B_direct < B_total) and was no significant after including FL (B = 1.46, p = 0.62)—complete mediation, but no ABS (B = 2.97, p = 0.001)—partial mediation. CRF was mediated by changes in ABS (B = 2.28, p < 0.001) and FL (4.18, p < 0.001). MSFI was not mediating; its usefulness was limited. HIIT is an effective tool in the development of CRF in both sexes. MSF played a limited role in the relationship between HIIT and CRF. It suggested different mechanisms in both sexes: girls who performed better to the HIIT had better values of FL and ABS, but not boys. HIIT intervention involved modifications in ABS or FL, which also influenced the increase of CRF.

Health-Related Motor Testing of Children in Primary School: A Systematic Review of Criterion-Referenced Standards

Being physically fit in younger years prevents several diseases in the presence as well as in the life course. Therefore, monitoring physical fitness and motor competence through motor testing is essential for determining developmental status and identifying health-related risks. The main objectives of this systematic review were (1) to identify currently available health-related criterion-referenced standards and cut-off points for physical fitness and motor competence test items, (2) to frame the methodological background on setting health-related criterion-referenced standards and (3) to give implications for a health-related evaluation system for physical fitness and motor competence tests. The electronic data base search (PubMed, Web of Science and SURF) yielded 2062 records in total and identified six empirical studies reporting cut-off points of motor test items for children (7-10 years), as well as 30 methodological papers discussing determination approaches to health-related criterion-referenced standards. Data collection, selection and analyses followed the PRISMA guidelines. Health-related motor test standards need to be gender- and age-specific but should refer to an absolute cut-off point rather than to relative performance in the reference group. Due to the lack of data on health-related criterion referenced standards, receiver-operating-characteristic (ROC) curves provide a tool for the determination of cut-off points and criterion referenced standards for physical fitness and motor competence tests. A standardized approach forms the fundamental base for a globally applicable evaluation of health-related fitness tests.

Effects of Active Video Games on Health-Related Physical Fitness and Motor Competence in Children and Adolescents With Overweight or Obesity: Systematic Review and Meta-Analysis

Background

Childhood obesity is one of the most important public health problems. Active video games (AVGs) have been proposed as an attractive alternative to increase energy expenditure and are being investigated to determine their effectiveness against childhood obesity.

Objective

The aim of this study is to summarize the existing research and draw conclusions about the effects of AVGs on health-related physical fitness and motor competence in children and adolescents with overweight and obesity.

Methods

The search strategy was applied to PubMed, MEDLINE, Web of Science, and SPORTDiscus, including randomized and nonrandomized controlled trials investigating the effects of AVG programs on health-related physical fitness and motor competence in children and adolescents with overweight and obesity. To measure the risk of bias in randomized and nonrandomized controlled trials, 2 different quality assessment tools were used. In total, 15 articles met the inclusion criteria, and the variables of interest were BMI, body fat percentage, cardiorespiratory fitness (CRF), waist circumference, fat-free mass, muscular fitness, and motor competence. A meta-analysis was performed.

Results

Positive effects were found for BMI and body fat percentage, favoring the AVG group compared with a control group with no intervention (mean difference −0.209; 95% CI −0.388 to −0.031 vs mean difference −0.879; 95% CI −1.138 to −0.602). Positive effects seem to be observed for CRF. The effects of AVG interventions on muscular fitness, fat-free mass, waist circumference, and motor competence are unclear.

Conclusions

AVG programs showed positive effects on BMI, body fat percentage, and CRF. AVG could be a good strategy to combat childhood obesity.

Breaks in Sedentary Time and Cardiometabolic Markers in Adolescents

BACKGROUND

The interruption of the time spent in sedentary behavior (breaks) has been associated with better levels of cardiometabolic indicators in the adult population, but in adolescents, further investigations are still needed to confirm these findings.

OBJECTIVES

To analyze the association of the number of breaks per day in sedentary behaviors with cardiometabolic markers and whether it was moderated by nutritional status and excessive time on sedentary behavior in adolescents.

METHODS

This is a cross-sectional study of 537 adolescents (52.3% girls), aged between 10 and 14 years, enrolled in public schools in the city of João Pessoa, Paraíba state, Brazil. The number of daily breaks (>100 counts/minutes) in sedentary time was measured by Actigraph GT3X+ accelerometers. The following cardiometabolic markers were analyzed: systolic and diastolic blood pressure (mmHg), fasting blood glucose levels, total cholesterol, triglycerides, HDL-c, LDL-c (all in mg/dL) and body mass index (BMI) (kg/m2). Linear regression was used to analyze the association between the number of breaks and cardiometabolic markers and whether this association was moderated by nutritional status and excessive time in sedentary behavior. The significance level of p<0.05 was adopted for all analyses.

RESULTS

The number of daily breaks was negatively associated with BMI (boys - ß = -0.083; 95%CI: -0.132; -0.034 and girls - ß = -0.115; 95%CI: -0.169; -0.061), but not with the remaining cardiometabolic markers. The number of breaks per day was negatively associated with BMI (ß = -0.069; 95% CI: -0.102; -0.035), but not with the other cardiometabolic markers and this association was not moderated by the adolescents' nutritional status (p=0.221), or by excessive time in sedentary behavior (p=0.176).

CONCLUSIONS

Including breaks in sedentary time seems to contribute to lower BMI values in adolescents.

Association of sedentary patterns with body fat distribution among US children and adolescents: a population-based study

BACKGROUND/OBJECTIVES

Children and adolescents spend a substantial amount of time being sedentary. The impact of prolonged sedentary patterns on fat distribution has not been elucidated especially in the context of physical activity level. Our objective is to examine the independent and joint associations of prolonged sedentary patterns and physical activity level with fat distribution among children and adolescents.

SUBJECTS/METHODS

This included US children (8-11 years) and adolescents (12-19 years) from the National Health and Nutrition Examination Survey 2003-2006. Sedentary patterns comprise accelerometer-measured average sedentary bout duration and self-reported time of sitting watching TV/videos. Fat distribution (trunk and total fat percentage) was determined via dual X-ray absorptiometry.

RESULTS

Among 810 children and 2062 adolescents, average sedentary bout duration was associated with greater total and trunk fat percentages only among male children, after adjusting for moderate-to-vigorous physical activity (MVPA) level by accelerometer. Prolonged sitting watching TV/videos was associated with higher total and trunk fat percentages in male children and all adolescents, independent of levels of MVPA (all P for trend <0.05). Compared with ≤1 h/day, male children who spent ≥4 h/day sitting watching TV/videos had 4.43% higher trunk fat (95% CI, 1.69-7.17%), with similar associations for female (3.53%; 95% CI, 1.03-6.03%) and male adolescents (4.78%; 95% CI, 2.97-6.60%). About 13-17% children and adolescents spent <1 h on MVPA and ≥4 h sitting watching TV/videos per day. Compared with the most active group (MVPA ≥ 1 h/day and sitting watching TV/videos ≤1 h/day), trunk fat in this least active group was 6.21% higher in female children, 9.90% higher in male children, 6.84% higher in female adolescents, and 5.36% higher in male adolescents.

CONCLUSIONS

Prolonged time spent on sitting watching TV/videos was associated with fat accumulation among children and adolescents, independent of physical activity level.

Moderate-to-Vigorous Physical Activity Is Associated With Cardiorespiratory Fitness Among Primary Schoolchildren Living in Côte d'Ivoire, South Africa, and Tanzania

Background: Physical inactivity and low cardiorespiratory fitness (CRF) are independent cardiovascular risk factors among children, but have rarely been investigated concurrently in sub-Saharan Africa. The purpose of this study was to compare physical activity (PA) and CRF of primary schoolchildren living in Côte d'Ivoire (CI), South Africa (ZA), and Tanzania (TZ), to test sex- and age-related differences, and to examine whether PA and CRF are associated with each other. Methods: Baseline data from an ongoing cluster-randomized controlled trial were used, including 499 children from CI (Taabo, 49% girls, M = 8.0 ± 1.6 years), 1,074 children from ZA (Gqeberha, 49% girls, M = 8.3 ± 1.4 years), and 593 children from TZ (Ifakara, 51% girls, M = 9.4 ± 1.7 years). PA was assessed by accelerometry and CRF by a 20 m shuttle-run test. The data were analyzed using multi-/univariate analyses of variance and mixed linear models. Results: Most children met recommendations put forward by the World Health Organization for moderate-to-vigorous PA (MVPA) and achieved high CRF scores. In CI, 89.6% of the children met MVPA recommendations (boys: 91.7%, girls: 87.4%), whereas this rate was 76.9% in ZA (boys: 91.0%, girls: 62.4%), and 93.8% in TZ (boys: 95.5%, girls: 92.0%). Children from TZ had the highest CRF and MVPA levels, followed by children from CI and ZA. Boys had higher MVPA levels than girls, whereas girls engaged in more sedentary behavior. Sex differences were strongest in ZA. Sedentary behavior and MVPA were higher among older schoolchildren compared to their younger peers. Higher MVPA, but not sedentary behavior, was associated with better CRF. Conclusions: In all three settings, higher levels of MVPA were associated with higher CRF scores. Nevertheless, children living in the most urbanized setting (such as observed in ZA) were physically less active and had lower CRF than peers living in more rural areas (such as observed in CI and TZ). Particularly for girls, urbanization might increase the risk for insufficient MVPA, which may have negative effects on their CRF, thus negatively influencing health and well-being at later age.

Association between Health-Related Physical Fitness and Respiratory Diseases in Adolescents: An Age- and Gender-Matched Study

The current study examined the differences in health-related physical fitness (HRPF), physical activity (PA), and sedentary behavior (SB) between adolescents with and without ongoing respiratory diseases (RD). This study's participants were from 12 to 15 years old (7th-10th grade) in South Korea. Adolescents with RD were selected through RD-related questions (i.e., asthma, rhinitis, sinusitis, and bronchitis) (n = 139); in contrast, adolescents without RD, randomly selected from the general group, responded to any health problem-related questions as "No" (n = 139). HRPF was measured based on the FITNESSGRAM and EURO FIT test batteries and the measurements of HRPF included cardiovascular endurance, muscular strength, muscular endurance, flexibility, and body composition. All statistical analyses were conducted by SPSS 25.0, and the independent t-test was used to compare the HRPF and PA between the two groups. Moreover, the measured HRPF was compared with a series of analyses of three-way ANOVAs (age × gender × group). Adolescents with RD had a positive association with less participation in PA (p < 0.05; RD: 3081.81 ± 4793.37; general: 2073.64 ± 3123.47) and with more time spent on SB (above 12 h per week: RD group (38.85%) and general group (33.09%)). Furthermore, adolescents in the RD group showed significant effects on all components of HRPF (p < 0.05). Our study confirmed that HRPF is an essential predictor of adolescents' health outcomes, especially for those with RD. We suggest that increased HRPF can be an effective treatment for respiratory diseases in adolescents, and health practitioners should pay more attention to helping adolescents with RD to gain or maintain high HRPF.

Evidencing the Influence of the COVID-19 Pandemic and Imposed Lockdown Measures on Fitness Status in Adolescents: A Preliminary Report

It was established that the COVID-19 pandemic resulted in decreased physical activity levels, potentially leading to reduced physical fitness. The aim of this research was to investigate the impact of the COVID-19 lockdown on fitness indices in adolescents. We observed high school adolescents (33% girls; aged 15–17 years) divided into two cohorts. The first cohort (control; n = 48) included adolescents who were in school during the 2018/2019 year, while the second cohort (lockdown; n = 66) was observed during the school year 2019/2020 when COVID-19 lockdown measures were imposed. Variables included body height, body mass, BMI, sit-ups, and the 600 m dash. Both cohorts were tested at the beginning and at the end of the observed school years. A factorial analysis of variance for repeated measurements evidenced an improvement in sit-ups and the 600 m dash in the control, and a decrease of the same capacities in the lockdown cohort. In the lockdown cohort, a decrease in muscular fitness was more evident in boys than in girls. No differential changes between cohorts were evidenced in anthropometrics. Results suggest that the COVID-19 lockdown negatively influenced muscular fitness status in adolescents, especially in boys.

Physical Fitness and Motor Competence in Chinese and German Elementary School Children in Relation to Different Physical Activity Settings

(1) Background: Children with greater physical activity (PA) may show a higher physical fitness (PF) and motor competence (MC) compared to peers with less PA. The purpose of this study was to examine the relationship between moderate-to-vigorous physical activity (MVPA), PF, and MC in 8- to 9-year old children in Germany and China. MVPA was differentiated into five PA settings: family sport, club training, school sport, leisure sport, and outside play. (2) Methods: This longitudinal study comprised N = 577 children (n = 311 girls, n = 266 boys) who were studied over a one-year period. Each child's PF and MC was determined using sports motor tests. The children's PAs were measured using a questionnaire. (3) Results: The children's PA was positively associated with PF and MC. The MVPA-settings: family sport, leisure sport, outside play, school, and club sport, explained between 18 and 23 percent of the variance in selected PF and MC characteristics in a multivariate linear regression analysis. (4) Conclusions: An increase in the children's MVPA might be an appropriate aim in the school sport in Germany as well as in the club sport system in China. Furthermore, family sport should be enhanced in Germany and outside play activities in China, respectively.

Physical Activity and Sedentary Behavior Patterns Across Weekdays and Weekend Days in Youth With Multiple Sclerosis and Controls

Background:

This study quantified and compared weekday and weekend patterns of device-measured physical activity (PA) and sedentary behavior between youth with pediatric multiple sclerosis (MS) and controls for the purpose of informing future PA behavior change interventions.

Methods:

Participant data were obtained from 3 ongoing observational studies, and the sample included 40 participants with pediatric MS and 41 controls. Light PA (LPA), moderate to vigorous PA (MVPA), and sedentary behavior data were collected using activity monitors (ActiGraph LLC) over 1 week. The main analysis involved a 2-way mixed factor analysis of variance with group as a between-subjects factor (pediatric MS vs control) and day as a within-subjects factor (weekday vs weekend day).

Results:

There was no group by day interaction from the analysis of variance for percentage of activity monitor wear time spent in LPA, MVPA, or sedentary behavior. There was no effect of group for LPA, MVPA, or sedentary behavior. There was an effect of day of week on percentage of day spent in LPA, MVPA, and sedentary behavior.

Conclusions:

These results suggest that youth with pediatric MS and controls were less physically active and more sedentary on weekends than on weekdays, but there were no differences between groups in PA and sedentary behavior overall or by day of the week. Physical activity interventions may be more successful by initially targeting weekend day activity.

Body mass index, physical activity, and physical fitness of adolescence

Background: Adolescents experience growth and significant changes in body composition which influence physical activity and response to sport or exercise. The level of physical fitness in adolescent girls is usually lower than that of boys, due to differences in body composition and levels of physical activity. The aim of this study was to examine the relationship between fat mass percentage, body composition, physical activity, and physical fitness.

Design and Methods: This study used an analytical observational, and cross-sectional design with total samples consisting of 70 male and female students aged 14-15 years. They were selected through simple random sampling, and the data collected were anthropometric measurements, body composition, physical activity and physical fitness. In addition, the Pearson correlation test was used for data analysis.

Results: The results showed that 68.57% of participants had a normal body mass index, 74.3% had moderate physical activity, and 44.28% had fat mass percentage including an obesity category and, 54.29% had low physical fitness. Furthermore, the Pearson test showed a significant relationship between physical activity, body mass index and fat mass percentage with physical fitness.

Conclusions: An increased fat mass percentage is associated with decreased levels of physical fitness. Furthermore, a good determinant of low physical fitness in obese conditions is the percentage of fat mass rather than BMI.

Physical Activity, Screen-Based Sedentary Behavior and Physical Fitness in Chinese Adolescents: A Cross-Sectional Study

Purpose: The aim of this study is to explore the relationship between screen-based sedentary behavior, physical activity and physical fitness among Chinese adolescents. Methods: This study randomly selected adolescents from 10 administrative districts in Shandong, China. The data gathering tools for demographic and other characteristics (gender, age, body mass index and socioeconomic status), PA (PAQ-A) and screen-based sedentary behavior (YRBSS) and physical fitness (NSPFH 2014) were utilized in this study. Statistical analysis was performed by T-test, chi-square test and multiple linear regression. Results: 10,002 adolescents (14.39 years ± 1.79) participated in the study. The results demonstrated that BMI and high TV viewing time had a significant negative correlation with physical fitness, but there was no association between the amount of time spent playing computer/video games and physical fitness among adolescents. High SES and physical activity in leisure time five or more times per week were significantly associated with most dimensions of physical fitness. Conclusions: the results suggest that we not only need to focus on adolescent risk behavior associated with low socioeconomic status and obesity, but also enforce physical activity and reduce sedentary television-watching behavior, which will be crucial pathways and strategies to improve the physical fitness of Chinese adolescents.

Fitness, physical activity, or sedentary patterns? Integrated analysis with obesity surrogates in a large youth sample

OBJECTIVE

Physical fitness (PF) and physical activity (PA) are inversely associated with body mass index and waist circumference (WC), whereas sedentary time (ST) seems to boost obesity in youth. The aim was to examine the associations of each selected PF test, PA-related exposures, and specific ST patterns with obesity and determine the most relevant ones, in a large sample of a school-aged adolescent.

METHODS

The sample consisted of 2696 Portuguese youth aged 10 to 18 years. Height, weight, and WC were measured. PA and ST components were measured using accelerometry. PF was evaluated using a battery of tests.

RESULTS

The Progressive Aerobic Cardiovascular Endurance Run (PACER) and push-up tests seemed to be the exposures that presented the strongest and more consistent associations with obesity, independent of PA/ST profiles (P < .05). The second exposure of relevance for adolescent obesity level was the breaks in ST with a negative relationship regardless of PA/PF profiles (P < .05). Finally, ST accumulated in periods of <30 minutes, and moderate-to-vigorous PA were favorably associated with obesity, independent of ST/PF.

CONCLUSIONS

Independent of PA and ST, cardiorespiratory fitness (CRF), measured by PACER, was associated with obesity markers. This may be in part due to the dependence of PACER performance on adiposity. Also, limiting prolonged ST and promoting interruptions in this behavior were associated with obesity. These associations suggest that future research should examine other strategies beyond PA promotion for tackling obesity that consider CRF and breaking ST.

One-year surveillance of body mass index and cardiorespiratory fitness in UK primary school children in North West England and the impact of school deprivation level

OBJECTIVES

Cardiorespiratory fitness (CRF) is independently associated with health and academic attainment in childhood and adolescence. Yet overweight/obesity remains the focus in public health policy. Surveillance of body mass index (BMI) and CRF considering school deprivation levels is limited. Therefore, we examined this in English primary schools.

METHODS

Participants (n=409) were students (9-10 years) from 13 schools. BMI and CRF (20 m shuttle run) were measured at three time points across the academic year and a fourth after summer recess.

RESULTS

BMI z-scores significantly decreased (p=0.015) from autumn (z=0.336 (95% CI 0.212 to 0.460)) to spring (z=0.252 (95% CI 0.132 to 0.371)), and then significantly increased (p=0.010) to summer (z=0.327 (95% CI 0.207 to 0.447)). CRF significantly increased (p<0.001) from autumn (z=0.091 (95% CI -0.014 to 0.196)) to spring (z=0.492 (95% CI 0.367 to 0.616)), no change (p=0.308) into summer (z=0.411 (95% CI 0.294 to 0.528)) and a significant decrease (p<0.001) into the following autumn term (z=0.125 (95% CI 0.021 to 0.230)). BMI was unaffected by deprivation; however, pupils from the most deprived areas saw significantly greater reductions in CRF compared with pupils from affluent areas. No time, or deprivation level, by sex interactions were found.

CONCLUSION

Significant reductions in children's CRF occurred over the summer recess and were greater among children from schools in the most deprived areas. This may help inform future research into interventions targeting physical activity of schoolchildren, particularly over the summer recess.

Differences in adolescent activity and dietary behaviors across home, school, and other locations warrant location-specific intervention approaches

BACKGROUND

Investigation of physical activity and dietary behaviors across locations can inform "setting-specific" health behavior interventions and improve understanding of contextual vulnerabilities to poor health. This study examined how physical activity, sedentary time, and dietary behaviors differed across home, school, and other locations in young adolescents.

METHODS

Participants were adolescents aged 12-16 years from the Baltimore-Washington, DC and the Seattle areas from a larger cross-sectional study. Participants (n = 472) wore an accelerometer and Global Positioning Systems (GPS) tracker (Mean days = 5.12, SD = 1.62) to collect location-based physical activity and sedentary data. Participants (n = 789) completed 24-h dietary recalls to assess dietary behaviors and eating locations. Spatial analyses were performed to classify daily physical activity, sedentary time patterns, and dietary behaviors by location, categorized as home, school, and "other" locations.

RESULTS

Adolescents were least physically active at home (2.5 min/hour of wear time) and school (2.9 min/hour of wear time) compared to "other" locations (5.9 min/hour of wear time). Participants spent a slightly greater proportion of wear time in sedentary time when at school (41 min/hour of wear time) than at home (39 min/hour of wear time), and time in bouts lasting ≥30 min (10 min/hour of wear time) and mean sedentary bout duration (5 min) were highest at school. About 61% of daily energy intake occurred at home, 25% at school, and 14% at "other" locations. Proportionately to energy intake, daily added sugar intake (5 g/100 kcal), fruits and vegetables (0.16 servings/100 kcal), high calorie beverages (0.09 beverages/100 kcal), whole grains (0.04 servings/100 kcal), grams of fiber (0.65 g/100 kcal), and calories of fat (33 kcal/100 kcal) and saturated fat (12 kcal/100 kcal) consumed were nutritionally least favorable at "other" locations. Daily sweet and savory snacks consumed was highest at school (0.14 snacks/100 kcal).

CONCLUSIONS

Adolescents' health behaviors differed based on the location/environment they were in. Although dietary behaviors were generally more favorable in the home and school locations, physical activity was generally low and sedentary time was higher in these locations. Health behavior interventions that address the multiple locations in which adolescents spend time and use location-specific behavior change strategies should be explored to optimize health behaviors in each location.

Correlates of children's physical activity during the COVID-19 confinement in Portugal

OBJECTIVES

The aim of the study was to understand the role of household variables on the percentage of physical activity (%PA) during the coronavirus disease 2019 (COVID-19) confinement in Portugal.

STUDY DESIGN

A cross-sectional study design using an anonymous online survey was launched to assess how Portuguese families with children aged younger than 13 years adjusted their daily routines to the confinement.

METHODS

Separate analyses of variance were performed to investigate how factors such as the number of children, age, sex, the housing characteristics, and the adults' job situation can affect the percentage of time for PA (%PA).

RESULTS

Findings, based on data from 2159 children, indicate that (1) boys and girls did not differ in the %PA on any of the age-groups; (2) children with an outdoor space and who had other children in the household were significantly more active (P < .001); (3) children from families with all adults working from home showed lower levels of %PA; and (4) being younger, having a big outdoor space, having other children in the household, and having at least one adult free from working from home were significant positive predictors of children's %PA, explaining 21% of the overall variance.

CONCLUSION

Time allocated for PA during this period is reduced compared with what is usually reported on normal days. It is necessary to find strategies to increase children's PA, especially in families in which both parents are working and have no outdoor space.

Promoting Health-Related Cardiorespiratory Fitness in Physical Education: The Role of Class Intensity and Habitual Physical Activity

Physical education (PE) has the potential to promote health-related fitness, however, its contribution is still not clear. The aim of this study was to assess whether students’ health-related cardiorespiratory fitness (CRF) improved from the beginning to the end of the school year, and to examine the role of PE class intensity and habitual physical activity (PA) in promoting students’ CRF. This observational study employed a longitudinal design. Participants were 212 7th and 8th grade students (105 boys), mean age 12.9 years old, followed during one school year, from September 2017 to June 2018. The Progressive Aerobic Cardiovascular Endurance Run (PACER) was used to assess CRF at baseline and follow-up. PA was measured using accelerometers. PE class intensity was assessed using the System for Observing Fitness Instruction Time. Findings indicated that from the beginning to the end of the school year, a greater percentage of participants were in the CRF healthy fitness zone (73.1% to 79.7%, p = 0.022). Among boys, participating in organized sports (B = 4.61, 95% confidence interval [CI]: 0.33, 8.88) and the percentage of PE time being very active (B = 0.90, 95% CI: 0.44, 1.35) were positively associated with the change in PACER laps. Among girls, daily vigorous PA (B = 0.38, 95% CI: 0.15, 0.60) and participating in organized sports (B = 4.10, 95% CI: 0.93, 7.27) were also positively associated with PACER change, while being overweight or obese (B = −5.11, 95% CI: −8.28, −1.93) was negatively associated. In conclusion, PE was demonstrated to have a positive role in the promotion of CRF, especially among boys, while for girls, habitual PA seems to have a greater contribution. Nevertheless, results and conclusions should be considered carefully, taking into account study limitations, such as the non-direct measures of PE class intensity, CRF, and school setting.

Validity of Items Assessing Self-Reported Number of Breaks in Sitting Time among Children and Adolescents

Background: Sedentary behaviour guidelines recommend that individuals should regularly break up sitting time. Accurately monitoring such breaks is needed to inform guidelines concerning how regularly to break up sitting time and to evaluate intervention effects. We investigated the concurrent validity of three “UP4FUN child questionnaire” items assessing the number of breaks in sitting time among children and adolescents. Methods: Fifty-seven children and adolescents self-reported number of breaks from sitting taken at school, while watching TV, and during other screen time activities. Participants also wore an activPAL monitor (PAL Technologies, Glasgow, UK) to objectively assess the number of sitting time breaks (frequency/hour) during the school period and the school-free period (which was divided in the periods “after school” and “during the evening”). Concurrent validity was assessed using Spearman rank correlations. Results: Self-reported number of breaks/hour at school showed good concurrent validity (ρ = 0.676). Results were moderate to good for self-reported number of breaks/hour while watching TV (ρ range for different periods: 0.482 to 0.536) and moderate for self-reported number of breaks/hour in total screen time (ρ range for different periods: 0.377 to 0.468). Poor concurrent validity was found for self-reported number of breaks/hour during other screen time activities (ρ range for different periods: 0.157 to 0.274). Conclusions: Only the questionnaire items about number of breaks at school and while watching TV appear to be acceptable for further use in research focussing on breaks in prolonged sitting among children and adolescents.

Physical Activity, Physical Fitness and the Sense of Coherence-Their Role in Body Acceptance among Polish Adolescents

The aim of the study was to investigate the protective role of physical activity (PA) and other health-related bio-psycho components (physical fitness, body composition, body perception and the sense of coherence (SOC)) in body acceptance. We searched for gender differences in those relationships. We investigated 231 adolescents aged 13-16 years from an urban area in Poland. We conducted objective measurements of height, weight, fat% and relative value of minute oxygen consumption. Questionnaires for PA, SOC Body Figure Perception and body acceptance were applied. Linear regression was used for analyzing determinants of body acceptance. We found that more physically active girls reported a less slim ideal vision of their figure (p < 0.05). Physical fitness is a better predictor of body acceptance than physical activity. In the final model, the sense of coherence, body mass index (BMI), and gender (being a boy) were also predictors of body acceptance (F(6,92) = 13.084, p < 0.0001). Gender differences were discussed in the present study. Fitness enhancing physical activity should be recommended for adolescents to achieve the protective psychosocial effect especially among girls. Physical activity on a daily basis brings positive results in a more adequate and reasonable body assessment and it can play a protective role in terms of mental wellbeing. Body satisfaction varies between genders and it is a more sensitive issue among girls than boys during adolescence.

The Motor and Leisure Time Conditioning of Young Table Tennis Players' Physical Fitness

The purpose of the study was to assess the association between physical fitness and the lifestyle determinants of elite junior table tennis players. The basic anthropometric characteristics (body height and body weight) were collected of 87 Polish table tennis players (girls, n = 38 and boys, n = 49, at different stages of sport training, targeted and specialized) aged 11–17 years. The level of special fitness tests from the Table Tennis Specific Battery Test were used, assessing reaction speed and displacement speed. All eight International Physical Fitness Test trials were also used to determine the level of general fitness of the participants. Selected questions from the Health Behaviour in School-Aged Children questionnaire were asked to measure factors associated with leisure time. The findings confirm a relationship between sedentary forms of leisure time activity and the training of young players at the targeted stage (Z = −2.93, p = 0.003 school days and Z = −2.12, p = 0.034 days off). Moreover, competitors with longer training experience more often chose active forms of spending free time. Knowledge of the global physical activity undertaken by young athletes during their leisure time provides a better understanding of their individual needs and may help young table tennis players to succeed at a world-class level in the future.