Accurate assessment is required to assess current and changing physical activity levels, and to evaluate the effectiveness of interventions designed to increase activity levels. This study systematically reviewed the literature to determine the extent of agreement between subjectively (self-report e.g. questionnaire, diary) and objectively (directly measured; e.g. accelerometry, doubly labeled water) assessed physical activity in adults.

Given the rapid development during the early years (0-4 years), an understanding of the health implications of physical activity is needed. The purpose of this systematic review was to examine the relationships between objectively and subjectively measured physical activity and health indicators in the early years. Electronic databases were originally searched in April, 2016. Included studies needed to be peer-reviewed, written in English or French, and meet a priori study criteria. The population was apparently healthy children aged 1 month to 59.99 months/4.99 years. The intervention/exposure was objectively and subjectively measured physical activity. The comparator was various volumes, durations, frequencies, patterns, types, and intensities of physical activity. The outcomes were health indicators ranked as critical (adiposity, motor development, psychosocial health, cognitive development, fitness) and important (bone and skeletal health, cardiometabolic health, and risks/harm). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework was used to assess the quality of evidence for each health indicator by each study design. Ninety-six studies representing 71,291 unique participants from 36 countries were included. Physical activity interventions were consistently (>60% of studies) associated with improved motor and cognitive development, and psychosocial and cardiometabolic health. Across observational studies, physical activity was consistently associated with favourable motor development, fitness, and bone and skeletal health. For intensity, light- and moderate-intensity physical activity were not consistently associated with any health indicators, whereas moderate- to vigorous-intensity, vigorous-intensity, and total physical activity were consistently favourably associated with multiple health indicators. Across study designs, consistent favourable associations with health indicators were observed for a variety of types of physical activity, including active play, aerobic, dance, prone position (infants; ≤1 year), and structured/organized. Apart from ≥30 min/day of the prone position for infants, the most favourable frequency and duration of physical activity was unclear. However, more physical activity appeared better for health. Evidence ranged from “very low” to “high” quality. Specific types of physical activity, total physical activity, and physical activity of at least moderate- to vigorous-intensity were consistently favourably associated with multiple health indicators. The majority of evidence was in preschool-aged children (3-4 years). Findings will inform evidence-based guidelines.

The Canadian Society for Exercise Physiology convened representatives of national organizations, research experts, methodologists, stakeholders, and end-users who followed rigorous and transparent guideline development procedures to create the Canadian 24-Hour Movement Guidelines for the Early Years (0–4 years): An Integration of Physical Activity, Sedentary Behaviour, and Sleep. These novel guidelines for children of the early years embrace 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 and Evaluation (AGREE) II instrument. Four systematic reviews (physical activity, sedentary behaviour, sleep, combined behaviours) examining the relationships within and among movement behaviours and several health indicators were completed and interpreted by a Guideline Development Panel. The systematic reviews that were conducted to inform the development of the guidelines, and the framework that was applied to develop the recommendations, followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. Complementary compositional analyses were performed using data from the Canadian Health Measures Survey to examine the relationships between movement behaviours and indicators of adiposity. A review of the evidence on the cost effectiveness and resource use associated with the implementation of the proposed guidelines was also undertaken. A stakeholder survey (n = 546), 10 key informant interviews, and 14 focus groups (n = 92 participants) were completed to gather feedback on draft guidelines and their dissemination. The guidelines provide evidence-informed recommendations as to the combinations of light-, moderate- and vigorous-intensity physical activity, sedentary behaviours, and sleep that infants (<1 year), toddlers (1–2 years) and preschoolers (3–4 years) should achieve for a healthy day (24 h). Proactive dissemination, promotion, implementation, and evaluation plans were prepared to optimize uptake and activation of the new guidelines. These guidelines represent a sensible evolution of public health guidelines whereby optimal health is framed within the balance of movement behaviours across the whole day, while respecting preferences of end-users. Future research should consider the integrated relationships among movement behaviours, and similar integrated guidelines for other age groups should be developed.

Appropriate in utero growth is essential for offspring development and is a critical contributor to long-term health. Fetal growth is largely dictated by the availability of nutrients in maternal circulation and the ability of these nutrients to be transported into fetal circulation via the placenta. Substrate flux across placental gradients is dependent on the accessibility and activity of nutrient-specific transporters. Changes in the expression and activity of these transporters is implicated in cases of restricted and excessive fetal growth, and may represent a control mechanism by which fetal growth rate attempts to match availability of nutrients in maternal circulation. This review provides an overview of placenta nutrient transport with an emphasis on macro-nutrient transporters. It highlights the changes in expression and activity of these transporters associated with common pregnancy pathologies, including intrauterine growth restriction, macrosomia, diabetes and obesity, as well as the potential impact of maternal diet. Molecular signaling pathways linking maternal nutrient availability and placenta nutrient transport are discussed. How sexual dimorphism affects fetal growth strategies and the placenta’s response to an altered intrauterine environment is considered. Further knowledge in this area may be the first step in the development of targeted interventions to help optimize fetal growth.

Background. Accurate assessment of physical activity (PA) in children and adolescents is required to establish PA levels, monitor changes and inform public healthy policy. This study systematically reviews the literature to determine the extent of agreement between indirect (e.g., questionnaire) and direct (e.g., accelerometry) assessments of PA in pediatric populations (≤19 years). Methods. Literature was identified through searching electronic databases (e.g., MEDLINE, EMBASE), websites of relevant organizations and conference abstracts until April 2007. Studies were included if they collected indirect and direct measures of PA in pediatric populations and were reported in English. Quality of included studies was appraised using a modified Downs and Black tool. Results. A total of 83 studies were included; 24 describing comparable data and 59 including a correlation analysis. The majority of correlations reported between indirect and direct measures were low-to-moderate (range: −0.56–0.89). Overall, 72% of the indirect measures overestimated the directly measured values. Combined gender, as well as male- and female-only data comparing indirect measures to accelerometery, heart rate monitoring or direct observation, all reported an overestimation by indirect method. A similar trend was observed in combined gender data comparing indirect measures with doubly labelled water; however, the opposite trend was observed in the male- and female-only data with a slight underestimation by indirect measure. Conclusions. Substantial discrepancies and moderate correlations between indirect methods and direct measures of assessing PA in pediatric populations are of concern, especially when trying to establish relationships with health outcomes.

The primary aim of this paper is to provide a rationale for the necessity of intervening with a physical activity intervention in the preschool years and why the daycare environment is amenable to such intervention. We also review the prevalence of physical activity, sedentary behaviour and obesity in the preschool population and the impact that these lifestyle behaviours and conditions have on the health of preschool aged children, as secondary objectives. Moreover we discuss implications for intervention and research using a “lessons learned” model based on our research team’s experience of conducting a randomized controlled trial aimed at increasing physical activity, reducing sedentary behaviour and improving motor skill development and body composition in preschoolers. Lastly, we make conclusions based on the literature and highlight issues and directions that need to be addressed in future research in order to maximize health promotion and chronic disease prevention in the pediatric population.