Michelle R. Stone

Maintaining recommended sleep throughout the week is associated with increased physical activity in children.

OBJECTIVE Given evidence of weekday-weekend variability in childrens sleep and associations with obesity there is rationale for exploring sleep in relation to weekday and weekend physical activity (PA) and examining whether weekday-weekend variations in sleep impact physical activity. METHODS Childrens (n=856) physical activity was measured using accelerometry (Toronto; 2010-2011). Sleep was assessed via parental report and collapsed into three categories (<9h; 9-10h; ≥ 10 h) and differences in anthropometric and physical activity characteristics were assessed. Data were compared to determine whether sleep increased, decreased or was maintained across the week and relationships with activity and overweight/obesity were explored (cross-sectional analysis) after controlling for confounders. RESULTS On weekdays, children who slept the least (<9h) were less active in terms of overall intensity than those attaining ≥ 10 h, and more were overweight/obese (p<0.05). On weekends, differences in light physical activity occurred at lower sleep levels. Weekday-weekend sleep regularity mattered; overall intensity was higher among those maintaining recommended sleep (>9h) compared to those engaging in weekend-catch-up-sleep. CONCLUSION While sleep is associated with obesity and activity in children, relationships vary by day. Recommended weekday-weekend sleep (regularity) supports healthy activity and should be an important health-promoting strategy. Future studies using longitudinal designs (to establish causality) are recommended.

Patterns of Sedentary Behavior and Weight Status Among Children

To make robust conclusions regarding the association between accelerometer-measured sedentary time and overweight and obesity among children, several gaps in the literature must be addressed. The purpose of this study was to examine associations between sedentary time, weekday sedentary time, weekend sedentary time, sedentary bouts, sedentary breaks, and BMI z-score among children and by low (bottom 50%) and high (top 50%) moderate- to vigorous-intensity physical activity (MVPA) participation. Results are based on 787 children aged 11 years living in Toronto, Canada. Childrens physical activity and sedentary time were objectively assessed using ActiGraph accelerometers in 2010/11. Height and weight were measured and BMI z-scores were calculated based on the World Health Organization growth standards. When participants were stratified into low and high MVPA groups, sedentary bouts of 5-9 (β = 0.22 [95% CI: 0.01, 0.43]) and 10-19 (0.30 [-0.05, 0.55]) minutes for total days were associated with BMI z-score in the low MVPA group only. Similar trends were observed with the weekday but not the weekend variables. Therefore, in addition to increasing MVPA, reducing time spent in 5- to 19-min sedentary bouts may have important implications for weight status particularly for children with lower MVPA participation during the week.

The freedom to explore: examining the influence of independent mobility on weekday, weekend and after-school physical activity behaviour in children living in urban and inner-suburban neighbourhoods of varying socioeconomic status

BackgroundChildren’s independent mobility (CIM) is critical to healthy development in childhood. The physical layout and social characteristics of neighbourhoods can impact opportunities for CIM. While global evidence is mounting on CIM, to the authors’ knowledge, Canadian data on CIM and related health outcomes (i.e., physical activity (PA) behaviour) are missing. The purpose of this study was to examine if CIM is related to multiple characteristics of accelerometry-measured PA behaviour (total PA, light PA, moderate-to-vigorous PA, time spent sedentary) and whether associations between CIM and PA behaviour systematically vary by place of residence, stratifying by gender and type of day/period (weekdays, after-school, weekend).MethodsParticipants were recruited through Project BEAT (Built Environment and Active Transport; http://www.beat.utoronto.ca). Children (n = 856) were stratified into four neighbourhood classifications based on the period of neighbourhood development (urban built environment (BE) (old BE) versus inner-suburban BE (new BE)) and socioeconomic status (SES; low SES and high SES). Physical activity was measured via accelerometry (ActiGraph GT1M). CIM was assessed via parental report and two categories were created (low CIM, n = 332; high CIM, n = 524). A series of two-factor ANOVAs were used to determine gender-specific differences in PA for weekdays, weekend days and the after-school period, according to level of CIM, across four neighbourhood classifications.ResultsChildren who were granted at least some independent mobility (high CIM) had more positive PA profiles across the school week, during the after-school period, and over the weekend; they were also less sedentary. The influence of CIM on PA behaviour was particularly salient during the after-school period. Associations of CIM with PA varied by gender, and also by neighbourhood classification. CIM seemed to matter more in urban neighbourhoods for boys and suburban neighbourhoods for girls.ConclusionOur findings highlight the importance of independent mobility to multiple characteristics of children’s PA behaviour across the week. Furthermore, they emphasize that independent mobility-activity relationships need to be considered by gender and the type of neighbourhood independent mobility is offered in. Future work will focus on developing a predictive model of CIM that could be used to inform decision-making around alleviating barriers to CIM.

Do parental perceptions of the neighbourhood environment influence children’s independent mobility? Evidence from Toronto, Canada:

Children’s independent mobility (CIM), or a child’s freedom to explore their neighbourhood unsupervised, is important for their psychological development and potentially enables daily physical activity. However, the correlates of CIM remain under-studied particularly in terms of the influence of the neighbourhood environment. Within this context, children’s independent mobility in Toronto, Canada, was examined using linear regression and ordered logit models. Findings demonstrate that a higher level of CIM was correlated with more physical activity. Parental perceptions related to neighbourhood safety, stranger danger and sociability were associated with CIM. A child’s independent mobility was also correlated with age, sex, language spoken at home and parental travel attitudes. Interventions to increase CIM should focus on enhancing the neighbourhood social environment. Increasing the independent mobility of girls and of children with diverse ethno-cultural backgrounds are also worthy of particular research and policy attention.

Active school travel: an evaluation of the Canadian school travel planning intervention.

OBJECTIVE Active school travel (AST) may provide a significant source of physical activity for children although rates of AST are declining in many countries. The objective of this study was to evaluate the Canadian School Travel Planning (STP) intervention by examining changes in school travel mode and predictors of mode change. METHODS Schools (n=106) across Canada participated between January 2010 and March 2012. STP committees implemented school-specific strategies to increase active school transport (AST) which included educational strategies, activities and events, capital improvement projects and enforcement initiatives. Travel mode at each school was assessed by a hands-up survey and school travel plans were reviewed for content. RESULTS Complete data were available for 53 schools. There was no increase in AST at follow-up after one year. There was variation in mode change between schools. Only season of data collection predicted a decrease in AST in the morning (B=-5.36, p<.05). CONCLUSION This Canadian STP evaluation showed no change in AST after one year. There was evidence of some localized success at nearly half of the participating schools. More robust monitoring and evaluation are needed to examine STP effectiveness.

The “Path” Not Taken: Exploring Structural Differences in Mapped- Versus Shortest-Network-Path School Travel Routes

OBJECTIVES School route measurement often involves estimating the shortest network path. We challenged the relatively uncritical adoption of this method in school travel research and tested the route discordance hypothesis that several types of difference exist between shortest network paths and reported school routes. METHODS We constructed the mapped and shortest path through network routes for a sample of 759 children aged 9 to 13 years in grades 5 and 6 (boys = 45%, girls = 54%, unreported gender = 1%), in Toronto, Ontario, Canada. We used Wilcoxon signed-rank tests to compare reported with shortest-path route measures including distance, route directness, intersection crossings, and route overlap. Measurement difference was explored by mode and location. RESULTS We found statistical evidence of route discordance for walkers and children who were driven and detected it more often for inner suburban cases. Evidence of route discordance varied by mode and school location. CONCLUSIONS We found statistically significant differences for route structure and built environment variables measured along reported and geographic information systems-based shortest-path school routes. Uncertainty produced by the shortest-path approach challenges its conceptual and empirical validity in school travel research.

The relationship between school physical activity policy and objectively measured physical activity of elementary school students: a multilevel model analysis

BackgroundThere is evidence of school level variability in the physical activity of children and youth. Less is known about factors that may contribute to this variation. The purpose of this study was to examine if the school health environment (Healthy Physical Environment, Instruction and Programs, Supportive Social Environment, and Community Partnerships) is associated with objectively measured time spent in light to vigorous physical activity among a sample of Toronto children.MethodsThe sample comprised 856 grade 5 and 6 students from 18 elementary schools in Toronto, Ontario. Multilevel linear regression analyses were used to examine the impact of school physical activity policy on students’ time spent in light-to-vigorous physical activity.ResultsSignificant between-school random variation in objectively measured time spent in light-to-vigorous physical activity was identified [σ2μ0 = 0.067; p < 0.001]; school-level differences accounted for 6.7% of the variability in the time individual students spent in light-to-vigorous physical activity. Of the 22 school-level variables, students attending schools with support for active transportation to/from school and written policies/practices for physical activity, accumulated significantly more minutes of physical activity per school week than students who attended schools that did not.ConclusionsSchool physical activity policy and support for active school travel is associated with objectively measured time spent in light to vigorous physical activity. School physical activity policy might be a critical mechanism through which schools can impact the physical activity levels of their students.

Measures of outdoor play and independent mobility in children and youth: A methodological review

OBJECTIVES Declines in childrens outdoor play have been documented globally, which are partly due to heightened restrictions around childrens independent mobility. Literature on outdoor play and childrens independent mobility is increasing, yet no paper has summarized the various methodological approaches used. A methodological review could highlight most commonly used measures and comprehensive research designs that could result in more standardized methodological approaches. DESIGN Methodological review. METHODS A standardized protocol guided a methodological review of published research on measures of outdoor play and childrens independent mobility in children and youth (0-18 years). Online searches of 8 electronic databases were conducted and studies included if they contained a subjective/objective measure of outdoor play or childrens independent mobility. References of included articles were scanned to identify additional articles. RESULTS Twenty-four studies were included on outdoor play, and twenty-three on childrens independent mobility. Study designs were diverse. Common objective measures included accelerometry, global positioning systems and direct observation; questionnaires, surveys and interviews were common subjective measures. Focus groups, activity logs, monitoring sheets, travel/activity diaries, behavioral maps and guided tours were also utilized. Questionnaires were used most frequently, yet few studies used the same questionnaire. Five studies employed comprehensive, mixed-methods designs. CONCLUSIONS Outdoor play and childrens independent mobility have been measured using a wide variety of techniques, with only a few studies using similar methodologies. A standardized methodological approach does not exist. Future researchers should consider including both objective measures (accelerometry and global positioning systems) and subjective measures (questionnaires, activity logs, interviews), as more comprehensive designs will enhance understanding of each multidimensional construct. Creating a standardized methodological approach would improve study comparisons.

Children's outdoor playtime, physical activity, and parental perceptions of the neighbourhood environment

The purpose of this study was to examine the association between the hours of outdoor play and objective measures of physical activity and identify the correlates of outdoor playing time in terms of parental perceptions of the neighbourhood environment. Time spent in outdoor play, both on a typical weekday and a typical weekend day, and neighbourhood perceptions, was assessed by parental self-report for 889 students attending grades 5 and 6 in Toronto, Canada (mean age: 10.50 ± 0.72 years). Physical activity was assessed by accelerometry. Ordered logit models were estimated to explore the influence of neighbourhood perceptions on the time spent playing outdoors. Regardless of a childs age and sex, duration of play was significantly correlated with minutes of moderate-to-vigorous physical activity. Parental concerns about strangers and fast drivers were inversely associated with duration of play on a typical weekday. Parental safety concerns continue to present a formidable barrier to greater outdoor play.

Food access and children’s BMI in Toronto, Ontario: assessing how the food environment relates to overweight and obesity

ObjectivesThe objective was to examine how access to fast food restaurants, less healthy/healthier food outlets and supermarkets relate to measured levels of overweight and obesity among grade 5 and 6 students.MethodsMeasured height and weight data were obtained to measure BMI. The location and type of food outlet were derived from Toronto Public Health. The density of fast food, less healthy/healthy food outlets and supermarkets within a 1-km walk of the child’s home was calculated along with the distance to the closest. Logistic regression models examined the relationship between food access and overweight/obesity.ResultsLower income residents were more likely to be overweight or obese, as were boys. Living in an area with a higher density of healthy food outlets and in close proximity to a supermarket decreased the odds of being overweight or obese.ConclusionsAddressing several limitations in the literature, the findings confirm an association between the food retail environment and body weight. Density of healthy food outlets and distance to the nearest supermarket are important factors to be considered in addressing the childhood obesity pandemic.