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Objective: This study aimed to explore sleep duration in young Australians on different types of days across weight classes. Methods: Use of time and anthropometric data were collected on 8,866 nights from 3,884 9–18 year old Australians. The association between sleep duration and weight status was examined using factorial ANOVA for four day types: S-S (to bed and waking on school days); S-NS (to bed on school day and waking on non-school day); NS-NS (to bed and waking on non-school days); NS-S (to bed on non-school day and waking on school day). Results: Sleep duration varied with weight status when all day types were considered together (p=0.0012). Obese adolescents slept less than normal and underweight adolescents. However, the relationship varied for different day types; with the strongest relationship for NS-S days (on which obese children slept 65 min less than very underweight children, p

Background: The after-school period is potentially a "critical window" for promoting physical activity in children. The purpose of this study was to qualitatively explore children's perceptions of the factors influencing their engagement in physical activity during the after-school period as the first phase in the development of a questionnaire. Conclusions: In this study, hearing children's voices allowed the emergence of factors which may not be exposed using existing surveys. These findings are grounded in children's perceptions and therefore serve as a valuable contribution to the existing literature, potentially leading to improved intervention and questionnaire design. Methods: Fifty-four South Australian children age 10-13 years participated in same gender focus groups. Transcripts, field notes, and activity documents were analyzed using content analysis. Through an inductive thematic approach, data were coded and categorized into perceived barriers and facilitators according to a social ecological model. Results: Children identified a number of factors, including safety in the neighborhood and home settings, distance to and from places, weather, availability of time, perceived competence, enjoyment of physical activity, peer influence, and parent influence. New insights into bullying and teasing by peers and fear of dangerous animals and objects were revealed by the children. Refereed/Peer-reviewed

Objectives: The eat well be active Community Programs (ewba) aimed to prevent obesity among children aged 0–18 years in two Australian communities from 2006 to 2010. Methods: ewba was a multi-strategy intervention in children's settings. The evaluation was quasi-experimental, including a before and after survey with intervention (INT) and non-randomised comparison (COMP) communities. Outcome measures included BMI-z score (zBMI) and overweight/obesity prevalence in children aged 4-5 years; and zBMI, waist circumference (WC) z-score and overweight/ obesity prevalence in children aged 10-12 years. Results: After 3 years, among the 4–5 years old, mean zBMI was significantly lower in both INT (−0.20, p < 0.05) and COMP (−0.15, p < 0.05), however, changes were not significantly different between INT and COMP. There was a larger reduction in overweight/obesity prevalence in INT (−6.3 %) compared to COMP (−3.7 %) (p < 0.05, χ 2 test). In the 10–12 years old, mean zBMI did not change significantly in INT or COMP. There was a significant reduction in WC z-score in INT (−0.17, p < 0.05) but not in COMP (−0.10, p = NS), although not significantly different between INT and COMP (p = 0.092). Conclusions: These findings suggest that the ewba community intervention had a moderate impact, showing modest improvements in weight status at 3-year follow-up. Refereed/Peer-reviewed

ObjectiveIn the early years of life, influential attributes are formed and may be difficult to change later in life. Early childhood is now recognised as a key target in the prevention of overweight and obesity, and the knowledge that children gain at this time about food and its health benefits may have an important influence on their dietary choices and preferences in later life. Therefore, an activity was designed using age-appropriate methods to assess nutrition knowledge of young children.DesignThe Healthy Food Knowledge Activity was developed using a list of thirty healthy and unhealthy foods and drinks generated from the Australian Guide to Healthy Eating.SettingThe activity was conducted with individual children from reception classes of South Australian schools.SubjectsChildren aged 5–6 years undertook the activity in a pilot study (n 13) and in the main study (n 192).ResultsPilot data indicated good test–retest reliability of the activity (r = 0·84, P < 0·01). In the main study, there was a good distribution of scores with acceptable skewness and kurtosis statistics. A breakdown of responses indicated good face validity, with more obvious foods being more correctly classified.ConclusionsChildren as young as 5–6 years of age can correctly identify healthy foods, and this can be measured objectively. This activity also provides interesting insights regarding misconceptions about foods that could be attributed to influences such as media advertising and that can be addressed by educators of this age group.

Objectives: While there is consistent evidence that rural adults in Australia are less active than their urban counterparts, studies relating geographical remoteness to activity patterns in Australian adolescents have yielded inconsistent results. The aim of this study was to describe objectively and subjectively measured patterns of physical activity and sedentary behaviours across remoteness categories in a representative sample of 9-16 year old Australians. Conclusions: Activity levels among Australian adolescents show contrasting patterns of geographical differences to those found in Australian adults. Higher levels of free play among rural Australian adolescents may be due to more available space and less fear of traffic and stranger risks. Design: Cross-sectional observational study. Methods: 2071 Australian adolescents provided self-report use of time data on four days and wore a pedometer for at least 6 days within the 2007 Australian National Children's Nutrition and Physical Activity Survey. Comparisons of activity patterns were made across four objectively-determined remoteness categories (Major City, Inner Regional, Outer Regional and Remote), adjusting for household income, parental education and age. Results: Adolescents living in major cities self-reported 11-29 min less moderate to vigorous physical activity each day than their counterparts living in geographically more remote areas, and took 150-850 fewer steps each day. While there were no differences in time spent in sport or active transport, differences in free play participation were significant. Males in major cities also reported higher levels of screen time. Differences were somewhat more marked among males than among females. Refereed/Peer-reviewed

Objectives: To explore children's perceptions of the factors influencing their engagement in physical activity during the "critical" lunchtime period, using a social-ecological framework. Design: This study was an in-depth descriptive qualitative design. Methods: Fifty-four South Australian children aged 10-13 years participated in same-gender focus groups. Transcripts, field notes and activity documents were analysed using content analysis. Using an inductive thematic approach, data were coded and categorised into perceived barriers and facilitators according to a social-ecological model. Results: Children identified a range of environmental, social and intrapersonal barriers and facilitators. Bullying/teasing, the school uniform and school rules were exposed as explicit barriers to lunchtime play. Other important barriers included lack of access to, and poor suitability of, space, lack of access to programs/facilities and equipment, and lack of peer and teacher support. Perceived facilitators of lunchtime physical activity centred on access to equipment, enjoyment, motivation to improve skills, and peer support and acceptance. The freedom to make up or modify rules for games was also perceived to be a facilitator of lunchtime play. Conclusions: Communicating with children has been an effective approach in uncovering perceived barriers and facilitators to lunchtime play that may not have been previously considered in the quantitative correlate literature. Lunchtime interventions targeting children's physical activity should focus on addressing the barriers perceived to be important to lunchtime play. Language: en

There is a growing number and diversity of students in Australian universities. A disturbingly high proportion of students adopt passive roles in structured classes, thereby forfeiting the opportunity to engage actively in the learning process. A clearer understanding of factors influencing active participation is likely to encourage re-evaluation of how the classroom setting is structured. In 2008, a questionnaire was administered on-line across the Division of Health Sciences in an Australian university. Survey items represented: self-reported participation in classes; fear of teacher and peer criticisms; peer support; family and school background; confidence; informal contact with teachers; and expectations of students’ roles at university. Path analysis assessed independence and interdependence of pathways linking participation with hypothesised predictors. 764 respondents (559 females) provided complete responses (29% response rate). Among males and females there was a relatively strong pathway linking fear of teachers, confidence and participation, with higher levels of fear predicting lower confidence and participation. In turn, students’ perceptions of their role in the learning process was strongly associated with fear of teachers, indicating that undergraduate students’ belief that it is inappropriate to ask questions indirectly reduces their confidence to participate through fear of teacher criticisms. A direct association was seen between students’ perceptions of their role in the learning process and fear of peer criticism, suggesting that the pressure to play a passive role is reinforced by peer pressure. Students’ perceptions of their role was associated with school and family background, suggesting that earlier encouragement to communicate influences students’ perceived role and status at university. These findings underscore the importance of teaching strategies that diminish students’ concerns related to the perceived consequences of participation. With expanding classes and shrinking contact time, the challenge before the tertiary learning community is to foster a sense of connectedness among its members. Refereed/Peer-reviewed

The aim of this study was to determine the accuracy of dual-energy X-ray absorptiometry (DXA)-derived percentage fat estimates in obese adults by using four-compartment (4C) values as criterion measures. Differences between methods were also investigated in relation to the influence of fat-free mass (FFM) hydration and various anthropometric measurements. Six women and eight men (age 22-54 years, BMI 28.7-39.9 kg/m2, 4C percent body fat (%BF) 31.3-52.6%) had relative body fat (%BF) determined via DXA and a 4C method that incorporated measures of body density (BD), total body water (TBW), and bone mineral mass (BMM) via underwater weighing, deuterium dilution, and DXA, respectively. Anthropometric measurements were also undertaken: height, waist and gluteal girth, and anterior-posterior (A-P) chest depth. Values for both methods were significantly correlated (r2 = 0.894) and no significant difference (P = 0.57) was detected between the means (DXA = 41.1%BF, 4C = 41.5%BF). The slope and intercept for the regression line were not significantly different (P > 0.05) from 1 and 0, respectively. Although both methods were significantly correlated, intraindividual differences between the methods were sizable (4C-DXA, range = -3.04 to 4.01%BF) and significantly correlated with tissue thickness (chest depth) or most surrogates of tissue thickness (body mass, BMI, waist girth) but not FFM hydration and gluteal girth. DXA provided cross-sectional %BF data for obese adults without bias. However, individual data are associated with large prediction errors (4.2%BF). This error appears to be associated with tissue thickness indicating that the DXA device used may not be able to accurately account for beam hardening in obese cohorts. Refereed/Peer-reviewed

Background Evidence for psychosocial and environmental correlates on children's physical activity is scattered and somewhat unconvincing. Further, the moderating influences of socioeconomic position (SEP) on these influences are largely unexplored. The aim of this study was to examine the interactions of SEP, operationalised by mother education, and predictors of children's physical activity based on the Youth Physical Activity Promotion Model. Methods In 2005, a sample of South Australians (10–15 y) was surveyed on psychosocial and environmental correlates of physical activity using the Children's Physical Activity Correlates Questionnaire (n = 3300) and a parent survey (n = 1720). The following constructs were derived: 'is it worth it?' (perceived outcomes); 'am I able?' (perceived competency); 'reinforcing' (parental support); and 'enabling' (parent-perceived barriers). Self-reported physical activity was represented by a global score derived from the Physical Activity Questionnaire for Adolescents. Associations among physical activity and hypothesised correlates were tested among children with mothers of high (university educated) and low (left school at or before 15 y) SEP. Results Among high SEP children, 'is it worth it?' emerged as a significant predictor of physical activity for boys and girls. Among low SEP children, 'is it worth it?' predicted boys' physical activity, while among girls, 'reinforcing' was the only significant predictor, explaining ~35% of the total explained variance in physical activity. Conclusion While perceived outcomes emerged as a consistent predictor of physical activity in this sample, parental support was a powerful limiting factor among low SEP girls. Interventions among this high risk group should focus on supporting parents to provide both emotional and instrumental support for their daughters to engage in physical activity.

Organised sport among youth makes a substantial contribution to daily energy expenditure. This study investigated socioeconomic gradients in sport participation and predictors of participation. A representative sample of young South Australians (10–15 y; n = 1737) was surveyed on organised sport participation in the previous 12 months, and predictors derived from the Children's Physical Activity Correlates scale and a parent survey. Four constructs were derived: ‘is it worth it?’ (perceived outcomes); ‘am I able?’ (perceived competency); ‘reinforcing’ (parental support); and ‘enabling’ (perceived barriers, from the parent survey). Socioeconomic position (SEP) was operationalised by an area-level indicator, the Socioeconomic Indicator for Advantage (SEIFA), split into tertiles. Sport participation was higher among high (highest SEIFA tertile) compared with low (lowest SEIFA tertile) SEP children. All predictors except ‘am I able?’ were positively associated with sport participation among boys and girls. Of these predictors, the ‘enabling’ construct varied by SEP among both boys and girls, with high SEP children reporting fewer barriers to participation. High SEP girls reported higher scores on ‘reinforcing’ and ‘is it worth it?’ than their low SEP counterparts. Low SEP girls reported lower levels of both instrumental and affective support from parents to play sport. There are distinct SEP gradients in sport participation, as well as its psychosocial and environmental predictors among South Australian youth. Low SEP girls are the most disadvantaged in terms of parental support to participate in sport. Interventions targeting this vulnerable group are urgently required. Refereed/Peer-reviewed

Researchers and practitioners interested in assessing physical activity in children are often faced with the dilemma of what instrument to use. While there is a plethora of physical activity instruments to choose from, there is currently no guide regarding the suitability of common assessment instruments. The purpose of this paper is to provide a user’s guide for selecting physical activity assessment instruments appropriate for use with children and adolescents. While recommendations regarding specific instruments are not provided, the guide offers information about key attributes and considerations for the use of eight physical activity assessment approaches: heart rate monitoring; accelerometry; pedometry; direct observation; self-report; parent report; teacher report; and diaries/logs. Attributes of instruments and other factors to be considered in the selection of assessment instruments include: population (age); sample size; respondent burden; method/delivery mode; assessment time frame; physical activity information required (data output); data management; measurement error; cost (instrument and administration) and other limitations. A decision flow chart has been developed to assist researchers and practitioners to select an appropriate method of assessing physical activity. Five real-life scenarios are presented to illustrate this process in light of key instrument attributes. It is important that researchers, practitioners and policy makers understand the strengths and limitations of different methods of assessing physical activity, and are guided on selection of the most appropriate instrument/s to suit their needs. © 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Refereed/Peer-reviewed

Refereed/Peer-reviewed

Approaches to weight management have traditionally focussed on caloric intake versus caloric expenditure. Despite a range of interventions based on these approaches, the proportion of overweight children and adolescents continues to rise. There are increasing indications that other factors, such as sleet) duration, may be at play. This commentary on current research related to the impact of sleep duration provides an insight into the mounting evidence of its possible link to overweight in children and adolescents. Here we focus on children and adolescents as typical age cohorts in schools experiencing health and physical education programs. Children and adolescents are sleeping less than ever before, and there is now emerging evidence that sleep duration has a profound effect on weight regulating hormones leading to weight gain. It is proposed that a 24-hour view of children and adolescents be taken into account. Moreover, a reassessment of the impact of sleep deprivation may lead to extra considerations in the information and practices embodied in the HPE curricula for the growing battle against obesity. Refereed/Peer-reviewed

1.Discipline of Paediatrics, University of Adelaide, Adelaide, 5000, Australia2.Child and Adolescent Respiratory and Sleep Health Centre (CARSHC), Women’s and Children’s Hospital, North Adelaide, 5006, Australia3.Nutritional Physiology Research Centre, University of South Australia, Adelaide, 5000, Australia

Objective: To describe trends in health attitudes and self-perceptions among school-age South Australians between 1985 and 2004. Methods: The questionnaire from the 1985 Australian Schools Health and Fitness Survey was administered during 2004 in those South Australian schools that participated in the 1985 survey. Using chi square, responses were compared for 10–15 year-olds (1985, n=398; 2004, n=467) on attitudes to: visiting the doctor and dentist, smoking, sleep, diet, exercise, stress, having friends, and knowledge about fitness and health. Additionally, self-perceptions of health and fitness were compared. Results: Among boys and girls between 1985 and 2004, there were significant declines in the perceived importance of regularly visiting the dentist and doctor, but improved attitudes to being a non-smoker. Among boys, the perceived importance of sleep and diet declined between surveys. A smaller percentage of boys and girls in the latter survey perceived their current health status as ‘good’. In the lower SES sample, the percentage of girls rating healthy diet as ‘very important’ was lower in 2004. Conclusions: There have been general declines in perceived importance of many health-related behaviours among South Australian youth between 1985–2004. In contrast, the perceived importance of not smoking was higher in 2004 than 1985. Implications: The relative success of anti-smoking campaigns targeting youth suggests that health education must be accompanied by broader environmental support in order to effect positive behavioural change.

This study examined whether active commuting to and from school was associated with more frequent walking and cycling to other neighborhood destinations. Parents reported on free-time physical activity and frequency of active commuting among 1,643 South Australians (9–15 years), as well as their perceptions of risk associated with active commuting in the neighborhood. Groups were formed on the basis of active and motorized transport to and from school and compared on the frequency of walking and cycling to other neighborhood destinations. Those who actively commuted between home and school were approximately 30% more likely to actively commute to other neighborhood destinations, independent of age, free-time physical activity, and neighborhood risk. Active commuting to and from school is part of a broader habit of walking and cycling in the neighborhood among school age South Australians. The advantages of promoting active transport between home and school might extend beyond the energy expenditure of that journey alone.

Understanding factors that influence physical activity levels of adolescents can assist the design of more effective interventions. Social support is a consistent correlate of youth physical activity but few studies have examined this in different cultural settings. Male adolescents (n=180, age=13.58+/-0.97 years) from a metropolitan single sex private school participated in this study. Habitual physical activity was estimated using the 3-day physical activity recall (3dPAR), and aspects of social support to be physically active using a specifically designed questionnaire. Comparisons were made between Anglo-Australians (n=118), whose parents were both born in Australia, and Vietnamese-Australians (n=62), whose parents were both born in Vietnam. There was a trend towards higher physical activity among Anglo-Australians, particularly on weekends. Anglo-Australians reported significantly more parental and peer support across most items pertaining to these constructs. Among the whole sample, social support variables explained 5-12% of the total explained variance in physical activity, with items pertaining to father and best friend support emerging as the strongest and most consistent predictors in multiple regression models. Among Anglo-Australians, the prediction models were relatively weak, explaining 0-9% of the total explained variance in physical activity. Prediction models for physical activity among Vietnamese-Australians were much stronger, explaining 11-32% of the total explained variance, with father's support variables contributing consistently to these models. The strong paternal influence on physical activity among Vietnamese-Australians needs to be confirmed in more diverse population groups, but results from this study suggest that interventions promoting physical activity among adolescent boys need to take into account cultural background as a moderator of widely reported social influences.

It is not clear whether the global increase in weight problems in children is the result of excessive energy intake or decreasing energy expenditure. Methodological limitations have made it difficult to analyse. There is evidence that at least part of the problem may lie with increasing energy consumption, but it is important to examine the other side of the energy equation also. However, it is not possible to conclusively describe physical activity trends because of the absence of suitable baseline data. One solution is to summate all available evidence in as many areas of daily activities as possible and then draw tentative conclusions. This review summarises available trend data on direct representations of physical activity in a range of contexts, together with indirect measures such as sedentariness, fitness, and attitudes. The conclusions drawn are: physical activity in clearly defined contexts such as active transport, school physical education, and organised sports is declining in many countries; young people would like to be active but are often constrained by external factors such as school policy or curricula, parental rules in relation to safety and convenience, and physical environmental factors.

2005

BackgroundThe lunchtime and after-school contexts are critical windows in a school day for children to be physically active. While numerous studies have investigated correlates of children's habitual physical activity, few have explored correlates of physical activity occurring at lunchtime and after-school from a social-ecological perspective. Exploring correlates that influence physical activity occurring in specific contexts can potentially improve the prediction and understanding of physical activity. Using a context-specific approach, this study investigated correlates of children's lunchtime and after-school physical activity.MethodsCross-sectional data were collected from 423 South Australian children aged 10.0-13.9 years (200 boys; 223 girls) attending 10 different schools. Lunchtime and after-school physical activity was assessed using accelerometers. Correlates were assessed using purposely developed context-specific questionnaires. Correlated Component Regression analysis was conducted to derive correlates of context-specific physical activity and determine the variance explained by prediction equations.ResultsThe model of boys' lunchtime physical activity contained 6 correlates and explained 25% of the variance. For girls, the model explained 17% variance from 9 correlates. Enjoyment of walking during lunchtime was the strongest correlate for both boys and girls. Boys' and girls' after-school physical activity models explained 20% variance from 14 correlates and 7% variance from the single item correlate, "I do an organised sport or activity after-school because it gets you fit", respectively.ConclusionsIncreasing specificity of correlate research has enabled the identification of unique features of, and a more in-depth interpretation of, lunchtime and after-school physical activity behaviour and is a potential strategy for advancing the physical activity correlate research field. The findings of this study could be used to inform and tailor gender-specific public health messages and interventions for promoting lunchtime and after-school physical activity in children.

Several studies have reported values for projected frontal area in cycling. Even when similar systems (i.e. riders and bicycles) have been measured, the results have diverged widely. It seems likely that this variability is due to methodological differences. The aims of the present study were to compare three methods of determining the frontal area in cyclists, and to determine the effects on the measured frontal area of variables which contribute to distortion and perspective in photographs. Theoretical models were developed to describe the expected effects of changing the relative position of the cyclist and the reference dimension, the position of the camera relative to the cyclist, and the focal length of the camera. Photographs were then taken of cyclists using different camera positions and settings, and analysed using three different methods: photographic weighing and manual and computerized planimetry. All three methods showed high precision and reliability, and yielded results that were substantially similar (mean values differed by3.3%). Of possible sources of error, frontal deviation of the reference dimension had the most dramatic effect. Displacing the reference board forward by 0.4 m decreased the measured frontal area by 25%. As the distance between the camera and the cyclist increased, the frontal area decreased by about 5% for each metre. As the focal length of the camera became shorter, the frontal area became smaller, varying by8% for focal lengths ranging from 28 to 70 mm. These results showed close agreement with the theoretical models, and can be explained in terms of the perspective and distortion effects which occur in photography. The results demonstrate the importance of standardization in measuring the frontal area of cyclists.

Assessment of correlates of physical activity occurring at different times of the day, locations and contexts, is imperative to understanding children’s physical activity behaviour. The purpose of this review was to identify the correlates of children’s physical activity (aged 8–14 years) occurring during the school break time and after-school periods. A review was conducted of the peer-reviewed literature, published between 1990 and January 2011. A total of 22 studies (12 school break time studies, 10 after-school studies) were included in the review. Across the 22 studies, 17 studies were cross-sectional and five studies were interventions. In the school break time studies, 39 potential correlates were identified, of which gender and age were consistently associated with school break time physical activity in two or more studies, and family affluence, access to a gym, access to four or more physical activity programs and the condition of a playing field were all associated with school break time physical activity in only one study. Access to loose and fixed equipment, playground markings, size of and access to play space and the length of school break time were all positively associated with changes in school break time physical activity in intervention studies. Thirty-six potential correlates of after-school physical activity were identified. Gender (with boys more active), younger age, lower body mass index (for females), lower TV viewing/playing video games, and greater access to facilities were associated with higher levels of after-school physical activity in two or more studies. Parent supervision was negatively associated with females’ after-school physical activity in one study. This review has revealed a relatively small number of studies investigating the school break time and after-school periods in the specified age range and only a few correlates have demonstrated a consistent association with physical activity. This highlights the infancy of this area and a need for further investigation into time-specific physical activity behaviour so that interventions designed for these specific periods can target the important correlates. Refereed/Peer-reviewed