Associations of accelerometer-measured sedentary time,sedentary bouts,and physical activity with adiposity and fitness in children

ABSTRACT

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO₂max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO₂max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO₂max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO₂max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.     

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.     

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· day -1 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 carryover 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 carryover 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.     

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.     

Health locus of control predicts free-living, but not supervised, physical activity: a test of exercise-specific control and outcome-expectancy hypotheses

We statistically controlled fitness (1.5-mile run), outcome-expectancy values, and perceived barriers for physical activity and then compared internal health locus of control (IHLOC) with internal exercise locus of control (IEXLOC) for predicting the physical activity of college students (N = 84). Prospective observations of self-reported free-living physical activity (seven-day recall) and supervised running (time x distance) were made at 2-, 5-, and 9-week intervals. IHLOC predicted seven-day recall at Week 2 (beta = .19) and Week 5 (beta = .36) (increase in adjusted R2 ranged from .05 to .12, p less than .05). Consistent with theory, the prediction was not reproducible when generalized outcome-expectancy value rather than outcome-expectancy value for health was assessed. IHLOC was unrelated to supervised running. IEXLOC was unrelated to activity in all analyses, even though exercise-specific measures of outcome-expectancy values (beta s = .20) and perceived barriers (beta s = .27-.32) predicted both seven-day recall and supervised running (p less than .05). IHLOC also discriminated (p less than .05) high active and low active subjects when criterion groups were formed from population norms on seven-day recall (greater than or less than 280 kcal.kg-1.week-1). Results indicate that tests of decision theories that include locus of control measures specific to health or exercise must adjust for fitness, perceived barriers to physical activity, and behaviorally relevant outcome-expectancy values of physical activity when studying college students. The construct validity of exercise locus of control remains uncertain for college students.     

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.     

The European sectoral social dialogue committee in professional football: power relations,legitimacy and control

By analysing the political arena of the European Sectoral Social Dialogue Committee in the Professional Football Sector, the aim of this paper is to offer a better understanding of the Committee and its opportunities and prospects. First and foremost, the normative, legal context of the Committee precludes the conclusion of agreements that deviate from the Fédération Internationale de Football Association transfer rules or are contrary to European Union (EU) law. Furthermore, while EU involvement in the matter of social dialogue in professional football is democratically legitimate, the lack of solid support from the European Parliament and the Council is problematic. Most importantly, the power relations between the actors are a decisive element for the prospects of the Committee. After analysing the added value of the Committee for the respective actors, it is clear that currently, hopes for a wider bargaining agreement in professional football are not realistic.     

Goal conflict and the moderating effects of intention stability in intention-behavior relations: physical activity among Hong Kong chinese

This study examined how goal conflict influences the pattern of the moderating effects of intention stability on the intention-behavior relations in the context of physical activity participation. A longitudinal study of 136 young adult students with three waves of data collection (a 2-week interval between waves) was conducted. Results showed a significant three-way interaction among intention, goal conflict,& intention stability in explaining vigorous-intensity physical activity (Beta = -.25, p < .05). Consistent with our expectation, the pattern of the three-way interaction revealed that when the level of goal conflict was low, the intention-behavior relations were stronger with stable intentions and weaker with unstable intentions. However, when the level of goal conflict was high, the intention-behavior relations were weaker with stable intentions and stronger with unstable intentions. Possible underlying processes of goal conflict and intention stability on the intention-behavior relations are discussed.     

Associations of physical activity,sedentary time,and physical fitness with mental health during pregnancy: The GESTAFIT project

PurposeThis study was aimed to analyze the associations of objectively measured physical activity (PA), sedentary time, and physical fitness with mental health in the early second trimester (16 ± 2 gestational weeks) of pregnancy.MethodsFrom 229 women initially contacted, 124 pregnant women participated in the present cross-sectional study. Data were collected between November 2015 and March 2017. The participants wore Actigraph GT3X+ Triaxial accelerometers for 9 consecutive days to objectively measure their PA levels and sedentary time. A performance-based test battery was used to measure physical fitness. Self-report questionnaires assessed psychological ill-being (i.e., negative affect, anxiety, and depression), and psychological well-being (i.e., emotional intelligence, resilience, and positive affect). Linear regression analyses were adjusted for age, educational level, accelerometer wear time, miscarriages, and low back pain.ResultsModerate-to-vigorous PA was negatively associated with depression (β = –0.222, adjusted R² = 0.050, p = 0.041). Higher levels of sedentary time were negatively associated with positive affect (β = –0.260, adjusted R² = 0.085, p = 0.017). Greater upper-body flexibility was positively associated with better emotional regulation (β = 0.195, adjusted R²= 0.030, p = 0.047). The remaining associations were not significant (all p > 0.05).ConclusionAn active lifestyle characterized by higher levels of moderate-to-vigorous PA and lower levels of sedentary time during pregnancy might modestly improve the mental health of pregnant women. Although previous research has focused on the benefits of cardiorespiratory exercise, the present study shows that only upper-body flexibility is related to emotional regulation in early pregnant women. If the present findings are corroborated in further experimental research, physical exercise programs should focus on enhancing flexibility to promote improvements in emotional regulation during early second-trimester of pregnancy.     

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

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

中学生分层能力信念与心肺功能、身体活动水平和毅力/努力的关系

本研究旨在考察体育教学中中学生的具体情境能力(自我效能感)、环境能力(能力信念)和整体能力(认知体能),对心肺功能、课堂身体活动水平和毅力/努力的预测效应。研究对象为217名中学生,每隔一天进行一堂40分钟的体育课。研究通过沿用已久的调查问卷评价学生在体育课中的自我效能感、能力信念、认知能力信念和毅力/努力,使用计步器测量课堂身体活动水平,以及采用递增速度有氧耐力跑测试其心肺功能。通过相关分析,得出能力信念与三项指标显著相关:首先,运用回归分析得出自我效能感对中学生心肺功能影响显著,此结果也反映出中学生课堂的身体活动水平。其次能力信念与中学生的毅力/努力呈显著相关。因此自我效能感是中学生心肺功能和身体活动水平的主要影响因素,而能力信念对中学生毅力/努力的作用最为显著。     

Accelerometry to measure physical activity in toddlers: Determination of wear time requirements for a reliable estimate of physical activity

Accelerometry is widely used to evaluate physical activity in toddlers however recommendations regarding wear time are needed to understand physical activity behaviours in this age group. This study aimed to determine the minimum wear time to reliably evaluate physical activity in toddlers. Children from the 3D Birth Cohort (n = 255, 49.8% boys, 2.1 ± 0.2 years) were asked to wear an accelerometer (GT3X+, ActiGraph) for 7 days. Physical activity was expressed in active time (min/day) and counts per minute (CPM). Single day intraclass correlation coefficients (ICCs) were calculated to assess the effect of varying minimal wear time on reliability estimates. The Spearman-Brown formula was used to determine wear time required to achieve reliability levels of 70%, 80% and 90%. For active time, a reliability of 72.1% was achieved with wearing the accelerometer for ≥ 4 days of ≥ 6 h, which comprised 85.9% of the sample. For CPM, ≥ 4 days of ≥ 6 h provided a reliability of 74.7% and comprised 85.9% of the children. Results differed slightly when girls and boys were analysed separately, but restricting analyses to children with a weekend day did not. In summary, a minimum of 4 days with ≥ 6 h of accelerometry data provides a reliable estimate of physical activity in 2-year toddlers.     

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.     

Centralising space: the physical education and physical activity experiences of South Asian,Muslim girls

This paper explores the physical education (PE) and physical activity experiences of a group of South Asian, Muslim girls, a group typically marginalised in PE and physical activity research. The study responds to ongoing calls for research to explore across different spaces in young people's lives. Specifically, I draw on a ‘middle-ground’ approach, using Hill Collins' matrix of domination and the notion of intersectionality. These concepts offer the possibility to explore the kinds of settings (physical, social and cultural) in which girls undertake PE and physical activity, how these spaces influence experience and how the girls navigate these spaces. The study is based in a large, urban, co-educational, secondary school in Yorkshire, England (95% of the students are from minority ethnic communities, 91% are Muslim and 63% live in the top 10% most deprived neighbourhoods in the country). Data generation involved three phases: observations, creating research artefacts in focus groups and in-depth interviews. The findings reveal the diverse ways the girls are physically active. They also demonstrate a complexity to their involvement which is contingent upon space, discourses and people. For example, discourses of competition, ability and peers are more significant within PE; whilst family, religion and culture feature beyond this context. The paper concludes by acknowledging the girls' heterogeneity and agency in the ways they strategically navigate spaces in their quest to be physically active on their terms.     

The effects of physical activity and physical fitness on children's achievement and cognitive outcomes: a meta-analysis

It is common knowledge that physical activity leads to numerous health and psychological benefits. However; the relationship between children's physical activity and academic achievement has been debated in the literature. Some studies have found strong, positive relationships between physical activity and cognitive outcomes, while other studies have reported small, negative associations. This study was a comprehensive, quantitative synthesis of the literature, using a total of 59 studies from 1947 to 2009 for analysis. Results indicated a significant and positive effect of physical activity on children's achievement and cognitive outcomes, with aerobic exercise having the greatest effect. A number of moderator variables were also found to play a significant role in this relationship. Findings are discussed in light of improving children's academic performance and changing school-based policy.     

A systematic review and meta-analysis of implicit theory research in sport,physical activity,and physical education

The purpose of this systematic review and meta-analysis was to gather, catalogue, assess, and evaluate the available evidence examining implicit beliefs about ability in the sport, physical activity, and physical education contexts. A total of 43 studies were found, of which 39 were subjected to meta analyses. With only 7 experimental studies, the strength of evidence is moderate, and the field would benefit from greater experimental work. Overall, incremental beliefs were moderately associated with a small group of theoretically derived correlates, while entity beliefs were only weakly associated. The field would benefit from expanding these outcomes to include a wider range of pertinent outcomes. Researchers should focus their efforts on systematically exploring the most powerful ways of inducing adaptive implicit beliefs with the aim of providing solutions to significant problems such as preventing dropout from organised sports, improving academic grades in and beyond physical education, and increasing levels of physical activity.     

The effects of an enhanced quality Physical Education programme on the physical activity levels of Grade 7 learners in Potchefstroom,South Africa

Background: The absence of Physical Education (PE) from the South African school curriculum before its reintroduction in recent years contributed to health concerns regarding the low physical activity (PA) levels of children and adolescents in South Africa.

Purpose: This study evaluated the effects of a once-a-week enhanced quality PE programme on the PA levels of South African Grade 7 learners.

Methods: Using a pre-test and post-test control-group design, 110 Grade 7 learners aged 12–13 years (experimental school, n?=?40; control schools, n?=?70) from two primary schools in Potchefstroom, South Africa, were studied. They participated in a 12-week PE intervention programme based on the guidelines of the South African Curriculum and Assessment Policy Statement, which allocates one hour per week to PE teaching. The intervention included five quality-enhancing components, namely well-trained teachers, homework activities, a reward system, hand-made apparatus and the monitoring of activity intensity. In the experimental school, 40 learners were randomly assigned from the total Grade 7 class (n?=?124) to the experimental group, while two control groups (n?=?37 and n?=?33) were used, one from the same school as the experimental school and the other from a different school. Additionally, to control for PE teacher interaction effect, the experimental group was divided into 4 experimental sub-groups of 10 learners each, which were taught by 4 different PE teachers, and the pre-test and post-test data of these experimental sub-groups were also analysed. Children's PA levels were measured before and after the intervention using a validated Children's Leisure Activities Study Survey questionnaire. The Kruskal–Wallis and Wilcoxon signed-rank tests were used to evaluate the effects of the intervention programme.

Results: No significant differences were found within the experimental group between the 4 experimental sub-groups and between the 2 control groups at pre- and post-test measurements (p?>?.05). There was a significant effect for the experimental group as a whole, as results of the total experimental group showed statistically significant increases in moderate PA (ES?=?0.47; p?=?.014), vigorous PA (ES?=?0.48; p?=?.012) and total PA (ES?=?0.51; p?=?.008) as well as decreases in sedentary behaviours (ES?=?0.39; p?=?.041) after the 12-week intervention programme, whereas no significant changes were found in the control group. Statistically significant improvements were also found in all 4 experimental sub-groups between pre- and post-tests for the time spent in moderate PA (p?=?.028–.05; ES?=?0.23–0.64), vigorous PA (p?=?.018–.036; ES?=?0.23–0.63), total PA (p?=?.017–.05; ES?=?0.30–0.68) and sedentary time (p?=?.014–.049; ES?=?0.26–0.66), whereas no marked changes were observed among the two control groups, indicating no PE teacher interaction effect on the results.

Conclusions: The enhanced quality PE programme can be used as a valuable framework for PE implementation targeted at promoting learners’ PA levels, even in the presence of restricted time allocation, and limited teaching and learning resources.     

Conducting research with young Chinese-Australian students in health and physical education and physical activity: epistemology,positionality and methodologies

Research that delves into the sociocultural perspectives of health and physical education and physical activity (HPEPA) in the lives of ethnic minority students in Westernised countries is often conducted by investigators who are Westerners, native English speakers and racially different from the study participants. Limited research is conducted by researchers who have racial and/or linguistic identities similar to those of study participants, and even fewer reports include the reflexivity data of the research process. This paper draws upon my own experience, as a young Hong Kong-Chinese female Australian, of conducting research with Chinese students and their White HPE teachers in Australia. I discuss a number of aspects of the epistemological dilemmas of being an insider and outsider as a researcher, and the practical and methodological issues in recruiting participants and conducting research with them. In addition, reversing the ethnic gaze by focusing on the teachers (i.e. a young Chinese female conducting research with White teachers) can help to illuminate new perspectives on the construction of otherness and positionalities within research. The reflections add to current discourse on problematising HPEPA research in general, particularly when researching the Other. This paper concludes that an intersection of racial, ethnic, class, gender and age identity can and does have some effect on the research process, as the Chinese students raised particular questions to a young, female Chinese researcher, and they were more willing to talk about racial and cultural issues they felt I could relate to.     

The Beijing 2022 Winter Olympics:An opportunity to promote physical activity and winter sports in Chinese youth

TagedPIn February and March 2022,China will host the Beijing 2022 Olympic and Paralympic Winter Games.The vision for this landmark event promises a“joyful rendezvous upon pure ice and snow uniting the passion of hundreds of millions for winter sports”.1 Themes have been developed to create a positive environmental impact with new development for the northern region of the country and to promote winter sports and improve the health and well-being of the Chinese people.The key messages for the winter games include inspiring youth with the Olympic spirit and encouraging millions to embrace winter sports.Notably,the Chinese government aims to mobilize at least 300 million of its citizens to engage in winter sports as an outcome of hosting the Winter Olympic Games.