Clare Hume

A prospective examination of children's time spent outdoors, objectively measured physical activity and overweight

Objective: This study aimed to determine whether time spent outdoors was associated with objectively measured physical activity, body mass index (BMI) z-score and overweight in elementary-school aged children, cross-sectionally and prospectively over 3 years.Methods: Three-year cohort study with data collected during 2001 and 2004. Nineteen randomly selected state elementary schools across Melbourne, Australia. One hundred and eighty eight 5–6-year-old and 360 10–12-year-old children. Baseline parent reports of childrens time spent outdoors during warmer and cooler months, on weekdays and weekends. At baseline and follow-up, childrens moderate and vigorous physical activity (MVPA) was objectively assessed by accelerometry, and BMI z-score and overweight was calculated from measured height and weight.Results: Cross-sectionally, each additional hour outdoors on weekdays and weekend days during the cooler months was associated with an extra 27 min week−1 MVPA among older girls, and with an extra 20 min week−1 MVPA among older boys. Longitudinally, more time outdoors on weekends predicted higher MVPA on weekends among older girls and boys (5 min week−1). The prevalence of overweight among older children at follow-up was 27–41% lower among those spending more time outdoors at baseline.Conclusion: Encouraging 10–12-year-old children to spend more time outdoors may be an effective strategy for increasing physical activity and preventing increases in overweight and obesity. Intervention research investigating the effect of increasing time outdoors on childrens physical activity and overweight is warranted.

Health Risks, Correlates, and Interventions to Reduce Sedentary Behavior in Young People

CONTEXT Opportunities for young people to be sedentary have increased during leisure time, study time, and transportation time. PURPOSE This review paper focuses on sedentary behaviors among young people aged 2-18 years and includes evidence of the relationship between sedentary behavior and health risk indicators, an overview of public health recommendations, the prevalence of key sedentary behaviors, evidence of correlates of sedentary behavior and the effectiveness of interventions to reduce sedentary behaviors. EVIDENCE ACQUISITION Although this is a narrative style review and not systematic, where possible, findings from relevant review papers were summarized and a search of more recent literature was performed using computer-based databases such as PubMed, Google Scholar, ERIC, PsycINFO, Social Science Index, SportDiscus, and Health Reference Center - Academic. EVIDENCE SYNTHESIS Young people spend 2-4 hours per day in screen-based behaviors and 5-10 hours per day sedentary. Ethnicity, sociodemographic status, having a TV set in the bedroom, and parental behavior appear to be the most consistent correlates of TV viewing time; however, few recent studies aiming to reduce TV viewing or sedentary time among young people have been successful. CONCLUSIONS A growing body of evidence supports the development of public health recommendations to limit the time spent in screen-based behaviors. More research is needed to examine the prospective and experimental evidence of associations between overall sedentary time and health, determinants of sedentary behaviors other than screen-based behaviors, and interventions to reduce overall sedentary time or even alternative sedentary behaviors, such as transport- or education-related sitting time.

Outcomes of a group-randomized trial to prevent excess weight gain, reduce screen behaviours and promote physical activity in 10-year-old children: switch-play.

Objectives:To evaluate the effectiveness of an intervention to prevent excess weight gain, reduce time spent in screen behaviours, promote participation in and enjoyment of physical activity (PA), and improve fundamental movement skills among children.Participants:In 2002, 311 children (78% response; 49% boys), average age 10 years 8 months, were recruited from three government schools in low socioeconomic areas of Melbourne, Australia.Design:Group-randomized controlled trial. Children were randomized by class to one of the four conditions: a behavioural modification group (BM; n=66); a fundamental movement skills group (FMS; n=74); a combined BM/FMS group (BM/FMS; n=93); and a control (usual curriculum) group (n=62). Data were collected at baseline, post intervention, 6- and 12-month follow-up periods.Results:BMI data were available for 295 children at baseline and 268 at 12-month follow-up. After adjusting for food intake and PA, there was a significant intervention effect from baseline to post intervention on age- and sex-adjusted BMI in the BM/FMS group compared with controls (−1.88 kg m−2, P<0.01), which was maintained at 6- and 12-month follow-up periods (−1.53 kg m−2, P<0.05). Children in the BM/FMS group were less likely than controls to be overweight/obese between baseline and post intervention (adjusted odds ratio (AOR)=0.36, P<0.05); also maintained at 12-month follow-up (AOR=0.38, P<0.05). Compared with controls, FMS group children recorded higher levels and greater enjoyment of PA; and BM children recorded higher levels of PA and TV viewing across all four time points. Gender moderated the intervention effects for participation in and enjoyment of PA, and fundamental movement skills.Conclusion:This programme represents a promising approach to preventing excess weight gain and promoting participation in and enjoyment of PA. Examination of the mediators of this intervention and further tailoring of the programme to suit both genders is required.

Is the perception of time pressure a barrier to healthy eating and physical activity among women

OBJECTIVES To describe the proportion of women reporting time is a barrier to healthy eating and physical activity, the characteristics of these women and the perceived causes of time pressure, and to examine associations between perceptions of time as a barrier and consumption of fruit, vegetables and fast food, and physical activity. DESIGN A cross-sectional survey of food intake, physical activity and perceived causes of time pressure. SETTING A randomly selected community sample. SUBJECTS A sample of 1580 women self-reported their food intake and their perceptions of the causes of time pressure in relation to healthy eating. An additional 1521 women self-reported their leisure-time physical activity and their perceptions of the causes of time pressure in relation to physical activity. RESULTS Time pressure was reported as a barrier to healthy eating by 41% of the women and as a barrier to physical activity by 73%. Those who reported time pressure as a barrier to healthy eating were significantly less likely to meet fruit, vegetable and physical activity recommendations, and more likely to eat fast food more frequently. CONCLUSIONS Women reporting time pressure as a barrier to healthy eating and physical activity are less likely to meet recommendations than are women who do not see time pressure as a barrier. Further research is required to understand the perception of time pressure issues among women and devise strategies to improve womens food and physical activity behaviours.

Associations among individual, social, and environmental barriers and children's walking or cycling to school

Purpose. To examine associations among individual, social, and environmental barriers and childrens walking or cycling to school. Design. Exploratory cross-sectional study. Setting. All eight capital cities in Australia. Subjects. Parents (N = 720) of school-aged children (4–13 years; 27% response rate; 49% parents of boys). Measures. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) for parental reporting of barriers to their childrens walking or cycling to school, based on a computer-assisted telephone interview. Results. Forty-one percent of children walked or cycled to school at least once per week. Multivariable analyses found inverse associations with individual (“child prefers to be driven” [OR = 0.4, 95% CI = 0.3–0.6], “no time in the mornings” [OR = 0.5, 95% CI = 0.3–0.8]); social (“worry child will take risks” [OR = 0.6, 95% CI = 0.3–0.9], “no other children to walk with” [OR = 0.7, 95% CI = 0.4–0.99], “no adults to walk with” [OR = 0.6, 95% CI = 0.4–0.9]); and environmental barriers (“too far to walk” [OR = 0.1, 95% CI = 0.0–0.1], “no direct route” [OR = 0.4, 95% CI = 0.2–0.7]) and positive associations with “concern child may be injured in a road accident” (OR = 1.9, 95% CI = 1.1–3.1) and active commuting. Conclusion. Working with parents, schools, and local authorities to improve pedestrian skills and environments may help to overcome barriers.

Does Weight Status Influence Associations Between Children's Fundamental Movement Skills and Physical Activity?

This study sought to determine whether weight status influences the association among childrens fundamental movement skills (FMS) and physical activity (PA). Two hundred forty-eight children ages 9–12 years participated. Proficiency in three object-control skills and two locomotor skills was examined. Accelerometers objectively assessed physical activity. Body mass index was calculated to determine weight status. Correlations between physical activity and FMS proficiency were evident among boys and girls. No significant interaction was apparent when examining FMS proficiency scores, PA variables, and weight status. Future studies should examine a broader range of skills and types of activities to better characterize this relationship and to inform the promotion of movement skill proficiency and PA.

Exercise and calcium combined results in a greater osteogenic effect than either factor alone: a blinded randomized placebo-controlled trial in boys.

We examined the combined effects of exercise and calcium on BMC accrual in pre‐ and early‐pubertal boys. Exercise and calcium together resulted in a 2% greater increase in femur BMC than either factor alone and a 3% greater increase in BMC at the tibia–fibula compared with the placebo group. Increasing dietary calcium seems to be important for optimizing the osteogenic effects of exercise.

Development and reliability of a self-report questionnaire to examine children's perceptions of the physical activity environment at home and in the neighbourhood

BackgroundEnvironmental factors are increasingly being implicated as key influences on childrens physical activity. Few studies have comprehensively examined childrens perceptions of their environment, and there is a paucity of literature on acceptable and reliable scales for measuring these. This study aimed to develop and test the acceptability and reliability of a scale which examined a broad range of environmental perceptions among children.MethodsBased on constructs from ecological models, a survey incorporating items on childrens perceptions of the physical and social environment at home and in the neighbourhood was developed. This was administered on two occasions, nine days apart, to a sample of 39 children aged 11 years (54% boys), attending a metropolitan Australian elementary school. The acceptability of the survey was determined by the proportion of missing responses to each item. The test-retest reliability of individual items, scores and scales were determined using Kappa statistics and percent agreement for categorical variables, and intraclass correlation coefficients (ICC) for continuous variables.ResultsThere were few missing responses to each question, with only 4% of all responses missing. Although some Kappa values were low, all categorical variables showed acceptable reliability when examined for percent agreement between test and retest (range 68%–100% agreement). Continuous variables all showed moderate to good ICC values (range 0.72–0.92).ConclusionFindings suggest this questionnaire is reliable and acceptable to children for assessing environmental perceptions relevant to physical activity among 11-year-old children.

Predictors of time spent outdoors among children: 5-year longitudinal findings

Background Given the importance of physical activity for health and age-related declines in physical activity, understanding influences on related behaviours, such as time outdoors, is crucial. This study aimed to understand individual, social and physical environmental influences on longitudinal changes in urban childrens time outdoors. Methods The time children spent outdoors in 2001, 2004 and 2006 (aged 5–6 and 10–12 years at baseline) was reported by their parents (n=421). In 2001, individual, social and physical environmental factors were self-reported by parents. Generalized estimating equations examined longitudinal relationships between baseline predictors and average change in time outdoors over 5 years. Results Childrens time outdoors significantly declined over time. “Indoor tendencies” inversely predicted time outdoors among younger and older boys, and younger girls. Social opportunities positively predicted time outdoors among younger boys, while “outdoor tendencies” positively predicted time outdoors among older boys. Parental encouragement for activity positively predicted time outdoors among younger and older girls, while lack of adult supervision for active play outdoors after school inversely predicted time outdoors among older girls and older boys. Conclusion Individual (indoor and outdoor tendencies) and social factors (social opportunities, parental encouragement and parental supervision) predicted childrens time outdoors over 5 years. Interventions targeting reduced indoor tendencies, increased outdoor play with others, and increased parental encouragement and supervision are warranted.

Effects of strategies to promote children's physical activity on potential mediators.

The aim of this paper is to review evidence of the effectiveness of interventions that present physical activity outcomes and potential mediators of behavioural change among 4–12-year-old children. A systematic search of electronic databases for original research articles published in peer-review journals between January 1985 and the end of June 2006 was carried out. A total of 19 studies that reported intervention effects on physical activity and mediators of behavioural change were identified. The most common mediators reported included physical activity knowledge or beliefs (11 studies); self-efficacy (8 studies); and enjoyment or preference for physical activity (6 studies). Less frequently reported mediators included attitudes, behavioural capability, intentions, outcome expectancies, social norms, social support and self-concept. Seven of the 11 interventions that reported intervention effects on knowledge/beliefs stated positive changes in this mediator. Four of the eight studies that reported intervention effects on self-efficacy had significant improvements; however, only two out of six interventions reported significant improvements in physical activity enjoyment or preference. None of the studies reviewed reported whether changes in these constructs mediated changes in childrens physical activity behaviours. Although more than half of the studies reviewed reported a positive intervention effect on childrens physical activity, no study carried out a mediating analysis to attempt to identify the mechanisms of change. Future research should more clearly identify the mediators of behavioural change that are being targeted and whether this explains intervention effects.