Children's physical activity and physical self-perceptions

The aim of this study was to determine the relationship between physical self-perceptions and physical activity in Canadian school children aged 10-14 years. The sample consisted of 220 boys and 246 girls in grades 5-8. Physical activity was assessed by 7-day recall using the Physical Activity Questionnaire for Older Children. Self-perceptions of physical conditioning, sports competence, strength, body appearance and general physical self-worth were measured by the Physical Self-Perception Profile (PSPP). We found that boys were more physically active than girls and had higher perceptions of sport competence and strength. All PSPP scales were significantly correlated with physical activity in both boys and girls. Structural equation modelling procedures found the hierarchical PSPP model provided a good fit to the observed data, with little evidence of differences between the sexes. Analysis of five alternative structural models of the relationship between the PSPP and physical activity found the most parsimonious model to have significant pathways from both physical conditioning and sport skills to physical activity. Models for the sample as a whole, for boys and for girls were similar, accounting for an R2 of 0.27-0.29 for physical activity. Our results demonstrate that physical self-perceptions, especially physical conditioning and sport skills, are significant correlates of activity in this population.     

Children's physical activity and physical self-perceptions

The aim of this study was to determine the relationship between physical self-perceptions and physical activity in Canadian school children aged 10–14 years. The sample consisted of 220 boys and 246 girls in grades 5–8. Physical activity was assessed by 7-day recall using the Physical Activity Questionnaire for Older Children. Selfperceptions of physical conditioning, sports competence, strength, body appearance and general physical selfworth were measured by the Physical Self-Perception Profile (PSPP). We found that boys were more physically active than girls and had higher perceptions of sport competence and strength. All PSPP scales were significantly correlated with physical activity in both boys and girls. Structural equation modelling procedures found the hierarchical PSPP model provided a good fit to the observed data, with little evidence of diff erences between the sexes. Analysis of five alternative structural models of the relationship between the PSPP and physical activity found the most parsimonious model to have significant pathways from both physical conditioning and sport skills to physical activity. Models for the sample as a whole, for boys and for girls were similar, accounting for an R 2 of 0.27–0.29 for physical activity. Our results demonstrate that physical self-perceptions, especially physical conditioning and sport skills, are significant correlates of activity in this population.     

Reliability of pedometer-determined free-living physical activity data in college women

This study examined stability and reliability of free-living physical activity assessed by pedometer in 69 young female college students (M age = 18.7 years, SD = 1.2, range: 18-25 years; body mass index = 23.2 kg/m2, SD = 0.6) for two complete weeks (Week 1 and Week 2) separated by 12 weeks. During Week 1, participants took an average of 8880 steps/day, SD = 3219, range: 1858-19480; during Week 2 9088 steps/day, SD = 3299, range 1736-16837; t (68) = -.568, p = .572. In both weeks, only Sunday differed significantly (repeated measures analysis of variance; Week 1: p < .0001; Week 2: p < .01) from all other days of the week. The computed intraclass correlation between weeks was moderate (.72). Group mean pedometer-determined physical activity was stable across 2 weeks separated by 12 weeks in this young, healthy sample of women. Individuals within these groups held their rank order to a moderate extent over time. These findings provide important evidence of the reliability of pedometer-determined physical activity data and are of practical importance to study design.     

Exploring self-perceptions and social influences as correlates of adolescent leisure-time physical activity

This study examined adolescent leisure-time physical activity correlates using the expectancy-value (EV) model. Adolescents (N = 857) completed questionnaires to assess competence and value self-perceptions, social influences, and physical activity. Direct and indirect effects of self-perceptions and parent and best friend influences on physical activity were explored using structural equation modeling. Measurement models were a good fit to the data and gender invariance was supported. The structural mediation model was a reasonable fit to the data, whereby the indirect effects of parents and peers and the direct effects of competence beliefs and values together accounted for 49% of the variance in physical activity. In this model, the pattern of relationships was similar for adolescent males and females. Findings supporting the EV model provide theoretical and practical implications for understanding adolescent physical activity.     

The influence of maturation,body size and physical self-perceptions on longitudinal changes in physical activity in adolescent girls

Abstract

The aim of this study was to adopt a longitudinal design to explore the direct effects of both absolute and relative maturation and changes in body size on physical activity, and explore if, and how, physical self-perceptions might mediate this effect. We recruited 208 girls (11.8 ± 0.4 years) at baseline. Data were collected at three subsequent time points, each 6 months apart. At 18 months, 119 girls remained in the study. At each time point, girls completed the Physical Activity Questionnaire for Children, the Pubertal Development Scale (from which, both a measure of relative and absolute maturation were defined) and the Physical Self-Perception Profile, and had physical size characteristics assessed. Multilevel modelling for physical activity indicated a significant negative effect of age, positive effect for physical condition and sport competence and positive association for relatively early maturers. Absolute maturation, body mass, waist circumference and sum of skinfolds did not significantly contribute to the model. Contrary to common hypotheses, relatively more mature girls may, in fact, be more active than their less mature peers. However, neither changes in absolute maturation nor physical size appear to directly influence changes in physical activity in adolescent girls.     

Screen time and moderate-to-vigorous physical activity changes and displacement in adolescence: A prospective cohort study

Background: This paper determines longitudinal changes in the time Spanish adolescents devote to moderate-to-vigorous physical activity (MVPA) and screen media activity (SMA). Moreover, it examines the displacement hypothesis between time spent on SMA and MVPA.

Methods: A cohort of 755 adolescents participated in a prospective cohort study over a three-year period. Repeated measures ANOVA to highlight interaction effects among all variables and Structural Equation Modeling (SEM) techniques were employed.

Results: Age and gender-related variations in longitudinal changes in time spent on MVPA and SMA evolved in the inverse direction (decreased on MVPA/increased on SMA) according to the ANOVA. The potential displacement between time spent on SMA and MVPA from Wave I to Wave II was analysed via SEM. The first model, estimated in the overall sample, showed no evidence for the displacement hypothesis. Subsequently, a multigroup sequence of panel models was performed and a partial displacement was observed only in boys. Hence, boys who spent more time on SMA were more likely to devote less time to MVPA three years later.

Conclusion: This study confirms the opposite trend on the time spent on MVPA and SMA over a three-year period, being clearly higher in SMA. Further SEM analyses reveal a deferred displacement hypothesis between SMA and MVPA only in boys. This partial gendered displacement may be linked to the different uses adolescents make of screen media. The incursion of new technological devices (smartphones or tablets) and their wide range of possibilities for social networking or gaming could explain this displacement     

A prospective study on changes of cognitions, interpersonal influences, and physical activity in Taiwanese youth

The decline of physical activity during adolescence is not well understood. This prospective study followed 969 Taiwanese students from eighth to ninth grade and examined their physical activity-related cognitions, interpersonal influences, and behavior of physical activity across the grade transition. Gender differences were found in the effects of the grade transition on physical activity and its related cognitions. The correlation coefficients showed moderate tracking for physical activity, cognitions, and interpersonal influences for both genders. The results also indicated that cognitions are more stable than behavior. The present study provides evidence of the decline in physical activity in Taiwanese youth across the grade transition as well as gender differences in the variables cognitions and interpersonal influences.     

Playing outdoor and practising sport: A study of physical activity levels in Portuguese children

In outdoor activities, it seems reasonable that the longer children spend in spontaneous physical activity (PA), the higher the probability of being active. Indeed, the time spent outdoor has been identified as a variable consistently associated with the children’s PA. Outdoor playing, such as the organized sports practice, appears associated with healthier lifestyle standards. All the recommendations mention the importance of increasing daily PA practice in children and teenagers, but few studies highlight the relationship between outdoor play and the recommended PA levels. The purpose of this study is to investigate the relationships between the frequency of outdoor play, the frequency of the organized sports practice, and the compliance of the recommendations for PA practice in children in the inner city area of Porto. The sample of this study is composed of 422 individuals (mean age of 11.6 years). Two hundred and twenty-five of them were girls and 197 were boys from the sixth grade (elementary schools located in the inner city area of Porto). PA was objectively evaluated using accelerometers. Participants reported frequency of participation in different PA contexts, such as sports practice and outdoor play. The results show a predictor effect of participating in sports three or more times per week on compliance of PA guidelines.

In conclusion, organized sports practice seems more effective than outdoor play to reach the recommended levels of PA in children.     

Environmental correlates of sedentary behaviors and physical activity in Chinese preschool children: A cross-sectional study

ObjectiveThis cross-sectional study examined environmental correlates of sedentary behavior (SB) and physical activity (PA) in preschool children in the urban area of Tianjin, China.MethodsData were collected from the Physical Activity and Health in Tianjin Chinese Children study, involving healthy children 3–6 years old and their families. In all children (n = 980), leisure-time SB (LTSB) and leisure-time PA (LTPA) were reported in min/day by parents. In a subgroup (n = 134), overall sedentary time, light PA, and moderate-to-vigorous PA (MVPA) were objectively measured using ActiGraph accelerometry (≥3 days, ≥10 h/day). Environmental correlates were collected using a questionnaire that included home and neighborhood characteristics (e.g., traffic safety, presence of physical activity facilities) and children's behaviors. Potential correlates were identified using linear regression analysis.ResultsMultiple linear regression analysis showed that “having grandparents as primary caregivers” (βs and 95% confidence intervals (95%CIs) for overall sedentary time: 29.7 (2.1–57.2); LTSB (ln): 0.19 (0.11–0.28)) and “having a television (for LTSB (ln): 0.13 (0.00–0.25)) or computer (for LTSB (ln): 0.13 (0.03–0.23)) in the child's bedroom” were both associated with higher SB. Furthermore, “having grandparents as primary caregivers” was associated with less MVPA (β (95%CI): ?7.6 (?14.1 to ?1.2)), and “active commuting to school by walking” correlated with more MVPA (β (95%CI): 9.8 (2.2–17.4)). The path model showed that “more neighborhood PA facilities close to home” was indirectly related to higher LTPA (ln), which was partly mediated by “outdoor play” (path coefficients (95%CI): 0.005 (0.002–0.008)) and “going to these facilities more often” (path coefficients (95%CI): 0.013 (0.008–0.018)). Traffic safety was not a correlate.ConclusionFamily structure and media exposure in the home maybe important factors in shaping preschoolers’ PA patterns. Built environmental correlates could indirectly influence preschoolers’ LTPA through parental help with engaging in active behaviors.     

BMI-referenced cut-points for recommended daily pedometer-determined steps in Australian children and adolescents

The purpose of this study was to establish sex-specific criterion-referenced standards for pedometer-determined physical activity related to body mass index (BMI)-defined weight status among youth. We analyzed data from 7-16-year-old boys (n = 338) and girls (n = 337) and used pedometer-assessed physical activity and anthropometric data to derive average steps/day and BMI. Sex-specific criterion-referenced standards for steps/day relating to healthy weight and overweight/obese were determined using the contrasting groups method. Healthy weight children took more steps/day than overweight or obese (boys: 14,413 vs. 12,088, and girls: 12,562 vs. 10,114, respectively; p < .001). The optimal BMI-referenced cut-point emerging flom our sample was 16,000 steps/day for both boys and girls. Our results and those reported elsewhere suggest that youth take insufficient pedometer-determined steps/day to avoid becoming overweight.     

Bidirectional cross-sectional and prospective associations between physical activity and body composition in adolescence: birth cohort study

The aim of this study was to investigate the cross-sectional and prospective associations between physical activity and body composition in adolescence. This is a prospective study, including 4,103 adolescents belonging to the Pelotas (Brazil) 1993 birth cohort, who were followed up at the mean ages of 11.3 and 14.7 years. Subsample analyses included 511 individuals with accelerometry and deuterium dilution data at 13.3 years. Sum of skinfolds at age 11.3 years was highly correlated with skinfolds at age 14.7 years (rho = 0.74, P < 0.001). More than 85% of participants remained in the same quintile or changed by not more than one quintile during the 3.4 year period. Tracking of physical activity was considerably lower, although still significant; the correlation was 0.24 (P < 0.001) and 61.4% of the adolescents moved one or less quintiles. In fully-adjusted models, no significant cross-sectional or longitudinal associations were found between physical activity and body composition, neither in boys nor in girls. These null results were confirmed in the 511 individuals with accelerometry and deuterium data. We provide evidence of tracking of physical activity and particularly body composition during adolescence. Our results do not support the hypothesis that physical activity and fatness are strongly related in adolescents.     

Moderate-to-vigorous physical activity,executive functions and prefrontal brain oxygenation in children: A functional near-infrared spectroscopy study

Despite accumulating evidence that regular exercise improves executive functioning, the underlying neurophysiological mechanisms have rarely been investigated. The present study aimed to compare cognitive performance as well as task-specific concentration changes in oxygenated haemoglobin in the prefrontal cortex between children with higher and lower moderate-to-vigorous physical activity (MVPA). Physical activity was measured over 7 consecutive days using actigraphy. Afterwards, participants (N = 50) completed verbal fluency tests (VFTs) and mental arithmetic (MA) for the assessment of cognitive flexibility and working memory capacity. During the tasks, changes of oxygenated haemoglobin were measured with functional near-infrared spectroscopy. Using average MVPA of 11-year-old children as cut-point, the sample was divided into children with lower and higher MVPA. Analyses of variance revealed no significant differences in correct and false responses on the cognitive tests between groups. With regard to oxygenated haemoglobin, no group differences were found for concentration changes in response to the cognitive tasks. In conclusion, VFTs and MA increased children’s activation in prefrontal regions associated with cognitive flexibility and working memory, respectively. However, these executive functions and cortical activation were not different between children with lower and higher MVPA.     

The measurement of physical activity in young children

Two studies were conducted to determine the validity of various measures of physical activity in young children. In Study 1, 21 preschool children were utilized to explore how well measures of children's activity obtained from parents, teachers, and the children predicted observed behavior at school and in the home. Study 2 (n = 51 preschool children) focused on the predictive validity of the Caltrac motion sensor. In both studies, detailed minute-by-minute ratings of children's activity in Study 1 were generally ineffective in predicting observed physical activity. Children's activity preferences, however, were significantly related to the proportion of high intensity physical activity performed. In Study 2, there was a significant relationship (r = .86, p less than .0001) between Caltrac readings and observed physical activity. This correlation was similar for boys and girls, normal and overweight children, and younger and older children. These findings suggest that the Caltrac monitor may provide a valid index of individual differences in physical activity in young children.     

Adiposity,physical activity and neuromuscular performance in children

We investigated the associations of body fat percentage (BF%), objectively assessed moderate-to-vigorous physical activity (MVPA) and different types of physical activity assessed by a questionnaire with neuromuscular performance. The participants were 404 children aged 6–8 years. BF% was assessed using dual-energy x-ray absorptiometry and physical activity by combined heart rate and movement sensing and a questionnaire. The results of 50-m shuttle run, 15-m sprint run, hand grip strength, standing long jump, sit-up, modified flamingo balance, box-and-block and sit-and-reach tests were used as measures of neuromuscular performance. Children who had a combination of higher BF% and lower levels of physical activity had the poorest performance in 50-m shuttle run, 15-m sprint run and standing long jump tests. Higher BF% was associated with slower 50-m shuttle run and 15-m sprint times, shorter distance jumped in standing long jump test, fewer sit-ups, more errors in balance test and less cubes moved in box-and-block test. Higher levels of physical activity and particularly MVPA assessed objectively by combined accelerometer and heart rate monitor were related to shorter 50-m shuttle run and 15-m sprint times. In conclusion, higher BF% and lower levels of physical activity and particularly the combination of these two factors were associated with worse neuromuscular performance.     

A cross-cultural study of adolescents' physical activity levels in France and Spain

Abstract

The goals of this study were (1) to describe and compare levels of physical activity (PA), assessed by accelerometry, of adolescents in two close Spanish and French cities according to gender and period of the week and (2) to assess, with reference to country and gender, the extent to which international PA guidelines were fulfilled. The PA of 401 adolescents (53.37% females) from France and Spain (55.72% French) aged 14.45±0.67 years was assessed with GT3X accelerometers for seven consecutive days to evaluate their habitual levels of moderate to vigorous physical activity (MVPA). Data collection took place from September to December 2010 in six public and state schools in France and Spain. There were significant differences in MVPA in terms of country, gender and period of the week. Spanish adolescents were more active than French adolescents, boys were more active than girls and MVPA was higher on weekdays than at weekends. French girls showed the lowest level of PA. Only 35.9% of the whole sample met the guidelines for PA in both countries. Governments of relevant countries, especially France, should adopt PA promotion policies targeted at adolescents in order to enhance their compliance with PA guidelines.     

情绪调节体育教学模式对初中女生身体自我概念、状态焦虑的影响

探讨基于情绪调节基本理论的体育课程教学干预对初中女生身体自我概念及状态焦虑的影响.采用重复测量的实验设计,以淮安市清河中学初三学生为实验对象,其中对照组20人,实验组20人.实验组参加为期10周,每周3次,每次60 min的情绪调节体育教学;对照组不参加任何与身体活动有关的体育训练.采用状态焦虑量表(SAI)和身体自我描述问卷(PSDQ)分别在实验前、实验中、实验后对初中女生进行测量.结果:1)实验组在身体活动、身体协调、运动能力以及身体灵活性方面显著优于对照组;2)实验组学生状态焦虑水平显著低于对照组,说明10周的情绪调节体育教学干预,能有效提高初中女生身体自我概念,降低状态焦虑水平.     

Health-enhancing physical activity and sedentary behaviour in children and adolescents

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.     

Health-enhancing physical activity and sedentary behaviour in children and adolescents

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.     

The physical activity, fitness and health of children

It is clear that, despite their natural tendencies, children have become less physically active in recent decades, with children today expending approximately 600 kcal days' less than their counterparts 50 years ago. Although the health consequences of a reduced energy expenditure in adults is well documented, there is little direct evidence linking sedentariness with health in children. However, three main benefits arising from adequate childhood physical activity have been postulated. The first is direct improvements in childhood health status; evidence is accumulating that more active children generally display healthier cardiovascular profiles, are leaner and develop higher peak bone masses than their less active counterparts. Secondly, there is a biological carry-over effect into adulthood, whereby improved adult health status results from childhood physical activity. In particular, childhood obesity may be a precursor for a range of adverse health effects in adulthood, while higher bone masses in young people reduce the risk of osteoporosis in old age. Finally, there may be a behavioural carry-over into adulthood, whereby active children are more likely to become more active (healthy) adults. However, supporting evidence for this assertion is weak. Given this background, recent health guidelines suggesting that children should accumulate 60 min of moderate-intensity physical activity every day--supplemented by regular activities that promote strength flexibility and bone strength--appear to be justified. Future developments should include the implementation of large-scale, longitudinal studies spanning childhood and young adulthood, the further refinement of tools for measuring physical activity accurately in young people, and research into the relative strength of association between fitness--as well as activity--and health in children.