Publications

Children who engage in active school transportation (AST) have higher levels of physical activity (PA). Climate and weather were shown to influence adults’ daily travel behaviours, but their influence on children’s AST and PA has been less examined. This study examined the influence of weather conditions on children’s AST and overall PA. Children in grades 4 to 6 (N = 1699; age, 10.2 ± 1.0 years) were recruited in schools located in urban, suburban and rural areas, stratified by area-level socioeconomic status, in 3 different regions of Canada (Trois-Rivières, Québec; Ottawa, Ontario; Vancouver, British Columbia). Mode of school travel was self-reported and physical activity was measured using a pedometer. We used publicly available data on total precipitation and early morning temperature. AST increased with temperature only among girls. Daily precipitation was negatively associated with boys’ and girls’ PA while warmer temperature was associated with increased PA on weekend days. We also observed that season and region moderated the relationship between weather conditions and children’s physical activity behaviours. Our results suggest that daily weather variations influence children’s AST and PA to a greater extent than seasonal variations. Interventions designed to help children and families adapt to weather-related barriers to AST and PA are needed. Novelty: In Canada, weather conditions may influence children’s active behaviours daily. Associations between weather conditions, choice of travel mode and physical activity vary by sex, season, and region. Weather affects children's PA differently during the week than on weekends.

Based on a representative sample of the Canadian population, this article quantifies the bias resulting from the use of selfreported rather than directly measured height, weight and body mass index (BMI). Associations between BMI categories and selected health conditions are compared to see if the misclassification resulting from the use of self-reported data alters associations between obesity and obesity-related health conditions. The analysis is based on 4,567 respondents to the 2005 Canadian Community Health Survey (CCHS) who, during a face-to-face interview, provided self-reported values for height and weight and were then measured by trained interviewers. Based on self-reported data, a substantial proportion of individuals with excess body weight were erroneously placed in lower BMI categories. This misclassification resulted in elevated associations between overweight/obesity and morbidity.

This study examined the feasibility of developing correction factors to adjust self-reported measures of Body Mass Index to more closely approximate measured values. Data are from the 2005 Canadian Community Health Survey where respondents were asked to report their height and weight and were subsequently measured. Regression analyses were used to determine which socio-demographic and health characteristics were associated with the discrepancies between reported and measured values. The sample was then split into two groups. In the first, the self-reported BMI and the predictors of the discrepancies were regressed on the measured BMI. Correction equations were generated using all predictor variables that were significant at the p<0.05 level. These correction equations were then tested in the second group to derive estimates of sensitivity, specificity and of obesity prevalence. Logistic regression was used to examine the relationship between measured, reported and corrected BMI and obesity-related health conditions. Corrected estimates provided more accurate measures of obesity prevalence, mean BMI and sensitivity levels. Self-reported data exaggerated the relationship between BMI and health conditions, while in most cases the corrected estimates provided odds ratios that were more similar to those generated with the measured BMI.

Introduction To examine the association between participation frequency per week in physical education (PE) classes and physical activity (PA) and sitting time levels in adolescents according to the economic development level of the region of residence. Methods A cross-sectional study with a sample representative of Brazil was carried out with 12,220 students aged 11–19 years. Participation frequency per week in PE classes, moderate-to-vigorous PA (MVPA), PA during PE classes, active commuting, PA outside of school hours, total accumulated PA, time sitting in front of the TV and total sitting time were assessed by using a self-administered questionnaire. Results Adolescents who reported having PE classes were more likely to meet MVPA recommendations (1–2 PE class/week–OR: 1.3, 95%CI: 1.1–1.5; ≥3 PE class/week–OR: 2.0, 95%CI: 1.7–2.5), spent more time in PA outside of school hours (1–2 PE class/week–OR: 1.6, 95%CI: 1.4–1.9; ≥3 PE class/week–OR: 2.0, 95%CI: 1.5–2.6), and accumulated more PA (1–2 PE class/week–OR: 1.9, 95%CI: 1.6–2.2; ≥3 PE class/week–OR: 6.0, 95%CI: 4.0–8.9) than students who reported not taking PE classes. Boys from regions with higher Human Development Index (HDI) who took ≥3 PE classes/week were more likely to have higher levels of active commuting (OR: 1.4, 95%CI: 1.1–1.9) and less likely of getting in front of TV (OR: 0.7, 95%CI: 0.5–0.9). Adolescents from regions with higher HDI were more likely to have more time spent in PA during PE classes (Male–OR: 2.7, 95%CI: 2.4–3.1; Female–OR = 3.2, 95%CI: 2.8–3.7). Conclusions Having PE classes is associated with a higher level of PA in both sexes and in both regions and lower level of sitting time in boys from regions with higher HDI.

The importance of hormones in regulating physiological functions and processes has intrigued scientists since they were first characterized by Baylis and Starling in 1904 (1). Research advances in endocrinology have led to an improved understanding of the intricate and diverse functions of the endocrine system. In addition, advances in technology and analytical procedures have facilitated the convenience and accuracy of hormone measurements. These advancements have facilitated the proliferation of endocrine research in exercise and sport science over the past 30 years (Fig. 1). This relative explosion in research related to exercise endocrinology has contributed greatly to the understanding of the physiological consequences of exercise and physical training. Nevertheless, the emerging research is often inconsistent, contradictory, and difficult to interpret. In some cases, research discrepancies may be explained by methodological or analytical inconsistencies.

Leaders from the Canadian Society for Exercise Physiology convened representatives of national organizations, content experts, methodologists, stakeholders, and end-users who followed rigorous and transparent guideline development procedures to create the Canadian 24-Hour Movement Guidelines for Children and Youth: An Integration of Physical Activity, Sedentary Behaviour, and Sleep. These novel guidelines for children and youth aged 5–17 years respect the natural and intuitive integration of movement behaviours across the whole day (24-h period). The development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument and systematic reviews of evidence informing the guidelines were assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Four systematic reviews (physical activity, sedentary behaviour, sleep, integrated behaviours) examining the relationships between and among movement behaviours and several health indicators were completed and interpreted by expert consensus. Complementary compositional analyses were performed using Canadian Health Measures Survey data to examine the relationships between movement behaviours and health indicators. A stakeholder survey was employed (n = 590) and 28 focus groups/stakeholder interviews (n = 104) were completed to gather feedback on draft guidelines. Following an introductory preamble, the guidelines provide evidence-informed recommendations for a healthy day (24 h), comprising a combination of sleep, sedentary behaviours, light-, moderate-, and vigorous-intensity physical activity. Proactive dissemination, promotion, implementation, and evaluation plans have been prepared in an effort to optimize uptake and activation of the new guidelines. Future research should consider the integrated relationships among movement behaviours, and similar integrated guidelines for other age groups should be developed.

Healthy movement behaviours of Canadian children and youth have been found to be suboptimal; this is associated with declines in physical fitness, increases in obesity, and elevated chronic disease risk. Physical literacy is an evolving construct representing foundational domains upon which physically active lifestyles are based. Many sectors and organizations in Canada are embracing physical literacy in their programs, practices, policies, and research; however, the use of inconsistent definitions and conceptualizations of physical literacy had been identified by stakeholders as hindering promotion and advancement efforts.With leadership from ParticipACTION, organizations from the physical activity, public health, sport, physical education, and recreation sectors collaborated to create a physical literacy consensus definition and position statement for use by all Canadian organizations and individuals. The process involved an environmental scan, survey of related evidence, stakeholder consultations, and creation of a Steering Committee. From this background work a consensus statement was drafted, shared with stakeholders, revised, and ratified.Canada's Physical Literacy Consensus Statement was launched in June 2015 at the International Physical Literacy Conference in Vancouver, British Columbia. To further promote the Consensus Statement, the Sport for Life Society developed and simultaneously released the "Vancouver Declaration", which contained additional guidance on physical literacy. Both the Consensus Statement and the Declaration endorsed the International Physical Literacy Association's definition of physical literacy, namely "the motivation, confidence, physical competence, knowledge and understanding to value and take responsibility for engagement in physical activities for life".Sector partners hope that the Consensus Statement, with its standardized definition, brings greater harmony, synergy, and consistency to physical literacy efforts in Canada and internationally. Going forward, the impact of this initiative on the sector, and the more distal goal of increasing habitual physical activity levels, should be assessed.

Introduction Compositional data analysis is one appropriate method for co-dependent data, even when data are collected for a subdivision of the 24-hour period, such as the waking day. Objectives were to use compositional analyses to examine the combined and relative associations of sedentary time (ST), light-intensity physical activity (LPA), moderate-intensity physical activity (MPA), and vigorous-intensity physical activity (VPA) with cardiometabolic biomarkers in a representative sample of children and youth. Methods This cross-sectional study included 2544 participants aged 6–17 years from the 2003–2006 United States National Health and Nutrition Examination Survey. ST (<100 counts per minute), LPA (100 counts per minute to <4 METs; Freedson age-specific equation), MPA (4 to <7 METs), and VPA (≥7 METs) were accelerometer-derived. Cardiometabolic biomarkers included waist circumference, body mass index (BMI) z-score, HDL-cholesterol, C-reactive protein, and blood pressure. Triglycerides, glucose, insulin, and LDL-cholesterol were measured in a fasting sub-sample of adolescents (n = 670). Compositional linear regression models were conducted. Results The composition of ST, LPA, MPA, and VPA was significantly associated with BMI z-score, log waist circumference, systolic and diastolic blood pressure, HDL-cholesterol, and log plasma glucose (variance explained: 1–29%). Relative to the other three behaviors, VPA was negatively associated with BMI z-score (γVPA = -0.206, p = 0.005) and waist circumference (γVPA = -0.03, p = 0.001). Conversely, ST was positively associated with waist circumference (γST = 0.029, p = 0.013). ST and VPA were also positively associated with diastolic blood pressure (γST = 2.700, p = 0.018; γVPA = 1.246, p = 0.038), relative to the other behaviors, whereas negative associations were observed for LPA (γLPA = -2.892, p = 0.026). Finally, VPA was positively associated with HDL-cholesterol, relative to other behaviors (γVPA = 0.058, p<0.001). Conclusions The ST and physical activity composition appears important for many aspects of cardiometabolic health in children and youth. Compositions with more time in higher-intensity activities may be better for some aspects of cardiometabolic health.

The relationships among sedentary time, television viewing time, and dietary patterns in children are not fully understood. The aim of this paper was to determine which of self-reported television viewing time or objectively measured sedentary time is a better correlate of the frequency of consumption of healthy and unhealthy foods. A cross-sectional study was conducted of 9- to 11-year-old children (n = 523; 57.1% female) from Ottawa, Ontario, Canada. Accelerometers were used to determine total sedentary time, and questionnaires were used to determine the number of hours of television watching and the frequency of consumption of foods per week. Television viewing was negatively associated with the frequency of consumption of fruits, vegetables, and green vegetables, and positively associated with the frequency of consumption of sweets, soft drinks, diet soft drinks, pastries, potato chips, French fries, fruit juices, ice cream, fried foods, and fast food. Except for diet soft drinks and fruit juices, these associations were independent of covariates, including sedentary time. Total sedentary time was negatively associated with the frequency of consumption of sports drinks, independent of covariates, including television viewing. In combined sedentary time and television viewing analyses, children watching >2 h of television per day consumed several unhealthy food items more frequently than did children watching ≤2 h of television, regardless of sedentary time. In conclusion, this paper provides evidence to suggest that television viewing time is more strongly associated with unhealthy dietary patterns than is total sedentary time. Future research should focus on reducing television viewing time, as a means of improving dietary patterns and potentially reducing childhood obesity.