Summary: Positive activity behaviours (i.e. higher physical activity [PA]/lower sedentary behaviour [SB]) are beneficial from infancy, yet evidence suggests that young children (0‐ to 6‐year‐olds) are relatively inactive. To better understand the perceived influences on these behaviours and to aid intervention development, this paper systematically synthesizes the extensive qualitative literature regarding perceived barriers and facilitators to PA and SB in young children (0–6 years old). A search of eight electronic databases (July 2016) identified 43 papers for inclusion. Data extraction and evidence synthesis were conducted using thematic content analysis, underpinned by the socio‐ecological model (i.e. individual, interpersonal, community, organizational and policy levels). Parents, childcare providers and children perceived seven broad themes to be important for PA and SB, including the child; the home; out‐of‐home childcare; parent–childcare provider interactions; environmental factors; safety; and weather. Each theme mapped onto between one and five levels of the socio‐ecological model; barriers and facilitators at the interpersonal level (e.g. parents, care providers and family) were most frequently cited, reflecting the important (perceived) role adults/peers play in shaping young children's behaviours. We provide an overarching framework to explain PA and SB in early childhood. We also highlight where gaps in the current literature exist (e.g. from male carers; in developing countries; and barriers and facilitators in the environmental and policy domains) and where future quantitative work may focus to provide novel insights about children's activity behaviours (e.g. safety and weather).

Physical activity (PA) and sedentary behaviour (SB) of pre-school aged children are associated with important health and developmental outcomes. Accurate measurement of these behaviours in young children is critical for research and practice in this area. The aim of this review was to examine the validity, reliability, and feasibility of measurement tools used to assess PA and SB of pre-school aged children.Searches of electronic databases, and manual searching, were conducted to identify articles that examined the measurement properties (validity, reliability or feasibility) of measurement tools used to examine PA and/or SB of pre-school aged children (3–7 years old). Following screening, data were extracted and risk of bias assessment completed on all included articles.A total of 69 articles, describing 75 individual studies were included. Studies assessed measurement tools for PA (n = 27), SB (n = 5), and both PA and SB (n = 43). Outcome measures of PA and SB differed between studies (e.g. moderate to vigorous activity, step count, posture allocation). Most studies examined the measurement properties of one measurement tool only (n = 65). Measurement tools examined included: calorimetry, direct observation, combined heart rate and accelerometry, heart rate monitors, accelerometers, pedometers, and proxy report (parent, carer or teacher reported) measures (questionnaires or diaries). Studies most frequently assessed the validity (criterion and convergent) (n = 65), face and content validity (n = 2), test-retest reliability (n = 10) and intra-instrument reliability (n = 1) of the measurement tools. Feasibility data was abstracted from 41 studies.Multiple measurement tools used to measure PA and SB in pre-school aged children showed some degree of validity, reliability and feasibility, but often for different purposes. Accelerometers, including the Actigraph (in particular GT3X versions), Actical, ActivPAL and Fitbit (Flex and Zip), and proxy reported measurement tools used in combination may be useful for a range of outcome measures, to measure intensity alongside contextual information.

Background Understanding the determinants of children’s health behaviours is important to develop successful behaviour-change interventions. Objective We aimed to synthesise the evidence around determinants (‘preceding predictors’) of change in physical activity (PA) in young children (0–6 years of age). Methods As part of a suite of reviews, prospective quantitative studies investigating change in physical activity in children aged 0–6 years were identified from eight databases (to October 2015): MEDLINE, Embase, CINAHL, PsycINFO, Web of Knowledge, British Nursing Index, Applied Social Sciences Index and Abstracts, and Sociological Abstracts. Determinants and direction of association were extracted, described and synthesised according to the socio-ecological model (individual, interpersonal, organisational, community, policy). Results Forty-four determinants, predominantly in the interpersonal and organisational domains, were reported across 44 papers (six prospective cohort, 38 interventional); 14 determinants were assessed in four or more papers. Parental monitoring showed a consistent positive association with change in PA; provider training was positively associated with change in children’s moderate-to-vigorous PA only. Five (sex, parental goal setting, social support, motor skill training and increased time for PA) showed no clear association. A further seven (child knowledge, parental knowledge, parental motivation, parenting skills, parental self-efficacy, curriculum materials and portable equipment) were consistently not associated with change in children’s PA. Maternal role-modelling was positively associated with change in PA in all three studies in which it was examined. Conclusions A range of studied determinants of change in young children’s PA were identified, but only parental monitoring was found to be consistently positively associated. More evidence dealing with community and policy domains from low-/middle-income countries and about lesser-explored modifiable family- and childcare-related determinants is required. International Prospective Register for Systematic Reviews (PROSPERO) Registration Number CRD42012002881.

Young children are thought to be inactive in childcare, but little is known about location-specific activity levels. This observational study sought to describe the in-care and out-of-care activity patterns of preschool-aged children and explore differences in physical activity level by childcare attendance. Three to four-year-old children were recruited from 30 preschool and nursery ‘settings’ in Cambridgeshire, UK. Average minutes per hour (min/h) spent sedentary (SED), in light physical activity (LPA) and in moderate-to-vigorous PA (MVPA) were measured by accelerometry for up to 7 days (mean: 6.7 ± 1.1). Weekly childcare attendance patterns were reported by parents. The within-child association between childcare attendance and outcomes was assessed using two- and three-level hierarchical regression; sex by care (in/out) interactions were considered. Two hundred and two children (51 % female) had valid activity data for ≥2 days. Children, and particularly boys, were less sedentary and more active when in care compared to at home (SED: Boys: β (SE): −6.4 (0.5) min/h, Girls: −4.8 (0.5); LPA: Boys: 0.6 (0.4), Girls: 1.8 (0.4); MVPA: Boys: 5.7 (0.5); Girls: 3.0 (0.4)). Differences between in-care and at-home activity were largest in the (early) mornings and early evenings for boys; no compensation in at-home activity occurred later in the day. On days when children were in care part-time (1–5 h) or full-time (>5 h), they were significantly less sedentary and more active compared with non-care days. Young children, and particularly boys, accumulate more MVPA in care compared to at home. Future research should identify factors accounting for this difference and consider targeting non-care time in intervention efforts to increase higher-intensity activity and decrease sedentary time in preschoolers.

Physical activity in pregnancy and postpartum is beneficial to mothers and infants. To advance knowledge of objective physical activity measurement during these periods, this study compares hip to wrist accelerometer compliance; assesses convergent validity (correlation) between hip- and wrist-worn accelerometry; and assesses change in physical activity from pregnancy to postpartum. We recruited women during pregnancy (n = 100; 2014-2015), asking them to wear hip and wrist accelerometers for 7 days during Trimester 2 (T2), Trimester 3 (T3), and 3-, 6-, 9- and 12-months postpartum. We assessed average wear-time and correlations (axis-specific counts/minute, vector magnitude counts/day and step counts/day) at T2, T3, and postpartum. Compliance was higher for wrist-worn accelerometers. Hip and wrist accelerometers showed moderate to high correlations (Pearson's r 0.59 to 0.84). Hip-measured sedentary and active time differed little between T2 and T3. Moderate-to-vigorous physical activity decreased at T3 and remained low postpartum. Light physical activity increased and sedentary time decreased throughout the postpartum period. Wrist accelerometers may be preferable during pregnancy and appear comparable to hip accelerometers. As physical activity declines during later pregnancy and may not rebound post birth, support for re-engaging in physical activity earlier in the postpartum period may benefit women.