Understanding variations in the built environment over time to inform longitudinal studies of young children's physical activity behaviour - The BEACHES project.

We know relatively little about the role the neighbourhood built environment plays in promoting young children's physical activity, particularly its longitudinal effect either through repeated exposure to the same environment or through change in exposure by moving from one neighbourhood to another. This study characterised the neighbourhood environment of young children in the PLAYCE cohort study over three timepoints from 2015 to 2023. There were statistically significant differences in built environment attributes between timepoints and across socio-economic status, however they did not represent practically significant differences. These findings inform the analysis approach of subsequent research in the BEACHES Project, an international study examining the role of the built environment on child physical activity and obesity using multiple cohorts.

Long-term exposure to green and blue space and incidence of cardiovascular disease: A Danish Nurse Cohort study.

BACKGROUND: Few cohort studies have examined the associations of natural surroundings (green and blue space) with cardiovascular disease (CVD) and show mixed findings. We aimed to investigate the associations between long-term exposure to green and blue space and incidence of CVD in the Danish Nurse Cohort. METHODS: We followed 19,070 female nurses living in Denmark from 1993/1999 to 2018. The shortest Euclidian distance from a residence to three types of green space (park, woodland, and heathland) and four types of blue space (lake, river, coast, and wetland), along with total count of all types of natural surroundings within a 500 meter (m), 1000 m, and 5000 m radius from a residence, were calculated using GeoDanmark data from 2005. Distance was log-transformed to correct for a right-skewed data distribution. Residential air pollution and road traffic noise data for 2005 were estimated by the Danish air pollution modeling system ('DEHM/UBM/AirGIS') and Nord2000 model, respectively. Cox proportional hazards models were used to estimate associations between green and blue space and the first-ever incidence of total CVD and certain CVD subtypes after adjusting for individual factors, air pollution, and noise. We examined effect modification by age, smoking status, occupational status, household income, and urbanicity level. Hazard ratio (HR) and 95% confidence interval (95% CI) were presented per e unit (equivalent to ∼2.72 fold) increase in distance. RESULTS: 8179 new cases of CVD were observed over 344,084 person-years. Living further from woodland was associated with higher stroke incidence (HR: 1.153; 95% CI: 1.029-1.293), while living further from heathland was associated with reduced total CVD incidence (HR: 0.975; 95% CI: 0.955-0.996). No associations were found between distance to park, woodland, lake, river, coast, or wetland and total CVD incidence. Total count of all types of green and blue spaces within a 5000 m radius was linked to a reduced risk of CVD incidence. Adjusting for air pollution or road traffic noise did not alter observed associations. Younger individuals (<50 years old) were observed to have lower HRs when living closer to all types of natural surroundings. CONCLUSION: We found that proximity to woodland was associated with a reduced risk of stroke, whilst no significant or even inverse associations were observed between proximity to other types of natural surroundings and CVD incidence. Total count of all types of natural surroundings within a 5000 m radius was negatively associated with CVD incidence, suggesting cumulative benefits of these areas.

Developmental trends in young children's device-measured physical activity and sedentary behaviour.

BACKGROUND: Knowledge of developmental trends in meeting age-specific 24-hour movement behaviour guidelines is lacking. This study describes developmental trends in device-measured physical activity and sedentary time over a three-year period among Western Australian children aged two to seven years, including differences between boys and girls. The proportion of children meeting age-specific physical activity guidelines before and after they transition to full-time school was also examined. METHODS: Data from waves 1 and 2 of the Play Spaces and Environments for Children's Physical Activity (PLAYCE) cohort study were used (analysis n = 1217). Physical activity and sedentary time were measured by accelerometry at ages two to five (preschool, wave 1) and ages five to seven (commenced full-time school, wave 2). Accelerometer data were processed using a validated machine-learning physical activity classification model. Daily time spent in sedentary behaviour, energetic play (moderate-to-vigorous physical activity (MVPA)), total physical activity, and meeting physical activity guidelines were analysed using linear and generalised linear mixed-effects models with age by sex interaction terms. RESULTS: All movement behaviours changed significantly with increasing age, and trends were similar in boys and girls. Total daily physical activity increased from age two to five then declined to age seven. Mean daily total physical activity exceeded 180 min/day from ages two to five. Daily energetic play increased significantly from age two to seven, however, was below 60 min/day at all ages except for seven-year-old boys. Daily sedentary time decreased to age five then increased to age seven but remained lower than at age two. All two-year-olds met their age-specific physical activity guideline, decreasing to 5% of girls and 6% of boys at age four. At age seven, 46% of boys and 35% of girls met their age-specific physical activity guideline. CONCLUSIONS: Young children's energetic play and total physical activity increased with age, but few children aged three to seven met the energetic play (MVPA) guideline. Interventions should focus on increasing children's energetic play in early childhood. Clearer guidance and strategies are needed to support young children as they change developmentally and as they transition from one age-specific movement guideline to the next.

Population-referenced percentiles for total movement and energetic play at early childhood education and care.

OBJECTIVES: Childcare services such as preschools and long day care centres have been identified as a key setting to promote physical activity in early childhood as they provide access to large numbers of children for prolonged periods. Yet, specific standards for the type and amount of physical activity (PA) children accumulate whilst attending childcare are lacking. The purpose of this study was to derive population-referenced percentile values for children's total movement and energetic play whilst attending early childhood education and care services. DESIGN: We analysed accelerometer data collected in four Australian studies involving over 150 long day care services and 3893 accelerometer records from 1945 children to derive population-referenced percentile values for total movement and energetic play whilst attending formal early childhood education and care. METHODS: Accelerometer data were processed into time spent in total movement and energetic play using a random forest physical activity classification model. Total movement and energetic play estimates were transformed to a standard normal distribution and percentiles were calculated for a 4-, 6-, 8-, and 10-hour early childhood education and care day. RESULTS: On an average 8-hour early childhood education and care day (50th percentile), Australian pre-schoolers spend between 269 and 292 min, or 60 % of their day in movement. In contrast, Australian pre-schoolers only accumulate between 15 and 29 min of energetic play. CONCLUSIONS: The percentile reference values can be used to monitor young children's physical activity and energetic play levels whilst attending childcare. Educators can use the percentiles to assign norm-referenced ratings to identify children who could benefit from additional support for physical activity.

Preschool children's physical activity in the home, childcare and neighbourhood environment: A latent profile analysis using device-based measures.

Based on the socioecological conceptual model, the physical environment within the home, childcare and neighbourhood domains are key factors that influence preschool children's physical activity; however, the relative importance of each of these domains for preschool children's physical activity is unclear. We explored the physical environment characteristics within three latent profiles of 115 preschool children aged 2-5 years based on where they accumulated moderate-to-vigorous physical activity (MVPA) across five GPS-derived environmental domains. The three profiles were "Active at home" (n = 41), "Active except close to home" (n = 61), and "Active except in local neighbourhood" (n = 13). Compared to other profiles, "Active at home" had fewer parks and playgrounds within their 500-1600 m neighbourhood. Findings suggest preschool children's MVPA profiles are reflections of their physical environmental opportunities.

The role of playgrounds in promoting children's health - a scoping review.

BACKGROUND: Active outdoor play is important for children's health and development, and playgrounds provide good places for play. However, the importance of playground use for health and well-being is unclear. Our scoping review aims to create an overview of all research on playground use and health benefits for children. METHODS: Scopus, Web of Science, SportDiscus, and PsycInfo were searched using two search blocks, focusing on 'playground' and 'children' respectively, for publications from 2000 to November 2023. The primary inclusion criterion was examining the relationship between playground use and positive physical, mental, or social health outcomes. Only papers published in English were reviewed. For each publication, we synthesized and condensed the results, categorizing them by playground setting, reported health outcome, participant age group, study design, methodologies, publication's country, year, and 'stage of evidence'. RESULTS: Data from 247 studies were extracted and nearly 80% of these publications were descriptive or exploratory studies. Fifty-two were intervention studies. Adding playground markings to schoolyards led to increased physical activity. Greening schoolyards had mainly positive effects on social and mental health. In Early Childhood Education and Care, renewing play structures had a positive effect on physical activity in three publications. All Public Open Space interventions we found were different, with mixed effects on health outcomes. CONCLUSIONS: The existing evidence provides good arguments for policy makers, city planners and school-leaders to invest in adding playground markings in schoolyards as this will likely result in more physical activity. The evidence for the health benefits of investing in new play structures indicated that tailoring the playground to local needs is important as 'one size does not fit all' and playgrounds need to be designed as engaging and interesting places for children's play if they are to generate health benefits. Investing in 'greening' playgrounds is likely to result in social and mental health benefits for children, but does not always result in more physical activity. The research field needs more efficacy and effectiveness studies, and in particular replication and scale-up studies to demonstrate which type of playground interventions are successful. PROTOCOL: The review protocol was registered at Open Science Framework ( https://doi.org/10.17605/OSF.IO/UYN2V ).

A systematic review on the associations between the built environment and adult's physical activity in global tropical and subtropical climate regions.

BACKGROUND: Physical inactivity is a major public health concern, exacerbated in countries with a (sub)tropical climate. The built environment can facilitate physical activity; however, current evidence is mainly from North American and European countries with activity-friendly climate conditions. This study explored associations between built environment features and physical activity in global tropical or subtropical dry or desert climate regions. METHODS: A systematic review of four major databases (Web of Science, Scopus, PubMed, and SportDISCUS) was performed. To be included, studies had to investigate associations between perceived or objective built environment characteristics and adult's physical activity and had to be conducted in a location with (sub)tropical climate. Each investigated association was reported as one case and results were synthesized based upon perceived and objectively assessed environment characteristics as well as Western and non-Western countries. Study quality was evaluated using a tool designed for assessing studies on built environment and physical activity. RESULTS: Eighty-four articles from 50 studies in 13 countries with a total of 2546 built environment-physical activity associations were included. Design (connectivity, walking/cycling infrastructure), desirability (aesthetics, safety), and destination accessibility were the built environment characteristics most frequently associated with physical activity across the domains active transport, recreational physical activity, total walking and cycling, and moderate-to-vigorous physical activity, particularly if multiple attributes were present at the same time. Very few studies assessed built environment attributes specifically relevant to physical activity in (sub)tropical climates. Most studies were conducted in Western countries, with results being largely comparable with non-Western countries. Findings were largely generalizable across gender and age groups. Results from natural experiments indicated that relocating to an activity-friendly neighborhood impacted sub-groups differently. CONCLUSIONS: Built environment attributes, including destination accessibility, connectivity, walking and cycling infrastructure, safety, and aesthetics, are positively associated with physical activity in locations with (sub)tropical climate. However, few studies focus on built environment attributes specifically relevant in a hot climate, such as shade or indoor recreation options. Further, there is limited evidence from non-Western countries, where most of the urban population lives in (sub)tropical climates. Policy makers should focus on implementing activity-friendly environment attributes to create sustainable and climate-resilient cities.

Physical Activity-Related Practices and Psychosocial Factors of Childcare Educators: A Latent Profile Analysis.

Limited research investigates early childhood education and care (ECEC) educators' involvement in promoting physical activity. The aim was to identify distinct profiles based on physical activity-related practices and psychosocial factors in ECEC educators and examine how they relate to the amount of time allocated to children's physical activity. A secondary analysis of educator-reported survey data from the Play Active study was undertaken. Educators (n = 532) reported on four practices and four psychosocial subscales adapted from the Environment and Policy Evaluation and Observation relating to the provision of physical activity in childcare. Latent profile analysis was used to identify distinct groups of educators based on their practices and psychosocial factors. Logistic regression analysed associations between latent profiles and educator-reported time provided for children's physical activity. Five profiles of educators' physical activity-related practices and psychosocial factors were identified. Profiles with higher practice scores also had higher psychosocial scores. Educators in profiles characterised by higher scores had greater odds of meeting the best practice guidelines for daily time allocated to children for total physical activity and energetic play. This study highlights interventions which address multiple educator behaviour change determinants to improve children's physical activity in childcare.

Identifying multilevel predictors of behavioral outcomes like park use: A comparison of conditional and marginal modeling approaches.

This study compared marginal and conditional modeling approaches for identifying individual, park and neighborhood park use predictors. Data were derived from the ParkIndex study, which occurred in 128 block groups in Brooklyn (New York), Seattle (Washington), Raleigh (North Carolina), and Greenville (South Carolina). Survey respondents (n = 320) indicated parks within one half-mile of their block group used within the past month. Parks (n = 263) were audited using the Community Park Audit Tool. Measures were collected at the individual (park visitation, physical activity, sociodemographic characteristics), park (distance, quality, size), and block group (park count, population density, age structure, racial composition, walkability) levels. Generalized linear mixed models and generalized estimating equations were used. Ten-fold cross validation compared predictive performance of models. Conditional and marginal models identified common park use predictors: participant race, participant education, distance to parks, park quality, and population >65yrs. Additionally, the conditional mode identified park size as a park use predictor. The conditional model exhibited superior predictive value compared to the marginal model, and they exhibited similar generalizability. Future research should consider conditional and marginal approaches for analyzing health behavior data and employ cross-validation techniques to identify instances where marginal models display superior or comparable performance.

Individual and day-to-day differences in domain-specific physical activity of 10- to 11-year-old children in Denmark-Measured using GPS and accelerometry.

OBJECTIVE: Physical activity (PA) and the achievement of 60 min of moderate-to-physical-activity daily is declining in school-aged-children, and effective strategies to increase PA is needed. We aimed to examine the individual and day-to-day distribution of PA on schooldays among children aged 10-11 in 4 domains-school, home, transport, and other. METHODS: Data were collected from August to September 2020 using accelerometer and GPS data to measure daily PA-levels and to locate in which domain PA occurs. Daily PA-levels were assessed in each domain, and analyses of the individual and day-to-day differences in PA-levels were calculated. RESULTS: The school domain contributed the most to children's daily MVPA with 47% of average MVPA, followed by the home domain with 26% of daily average MVPA, the other domain with 19% of daily average MVPA and the transport domain with 8% of daily average MVPA. Our results showed individual differences in where PA occurs, day-to-day differences in total MVPA and day-to-day differences in the MVPA-levels across domains. CONCLUSIONS: The school domain contributed the most to children's MVPA-levels followed by the domains of home, other, and transport. Our study indicated that PA-levels and the distribution of PA across domains differ from day-to-day. Future interventions should target more than one domain to accommodate these individual- and day-to-day differences in the goal of increasing PA-levels and to reduce the decline in PA seen from childhood to adolescence.

Where Are Czech Adolescents Active? The Patterns of Movement and Transport Behavior in Different Active Living Domains.

To understand the environmental determinants of physical activity (PA), precise spatial localization is crucial. This cross-sectional study focuses on the spatiotemporal distribution of PA among Czech adolescents (n = 171) using Global Positioning System loggers and accelerometers. The results showed that adolescents spent most of their time in sedentary behavior, with 57.2% and 58.5% of monitored time at home and school, respectively. The park and playground had the lowest proportion of sedentary behavior but also the lowest amount of moderate to vigorous PA (MVPA). However, when considering the time spent in each domain, the highest proportion of MVPA was seen in publicly accessible playgrounds (13.3% of the time). Chi-square analysis showed that the relative distribution of different PA intensities did not differ across spatial domains. Based on these results, the authors propose 2 key strategies for increasing MVPA in adolescents: Increase the time spent in activity-supportive environments, such as parks and playgrounds, and design techniques to increase MVPA at home and school settings.

Youth-centred participatory action approach towards co-created implementation of socially and physically activating environmental interventions in Africa and Europe: the YoPA project study protocol.

INTRODUCTION: The majority of adolescents do not meet guidelines for healthy behaviours, posing major risks for developing multiple non-communicable diseases. Unhealthy lifestyles seem more prevalent in urban than rural areas, with the neighbourhood environment as a mediating pathway. How to develop and implement sustainable and effective interventions focused on adolescent health and well-being in urban vulnerable life situations is a key challenge. This paper describes the protocol of a Youth-centred Participatory Action (YoPA) project aiming to tailor, implement, and evaluate social and physical environmental interventions. METHODS AND ANALYSIS: In diverse urban environments in Denmark, the Netherlands, Nigeria and South Africa, we will engage a dynamic group of 15-20 adolescents (12-19 years) growing up in vulnerable life situations and other key stakeholders (eg, policy makers, urban planners, community leaders) in local co-creation communities. Together with academic researchers and local stakeholders, adolescents will take a leading role in mapping the local system; tailoring; implementing and evaluating interventions during participatory meetings over the course of 3 years. YoPA applies a participatory mixed methods design guided by a novel Systems, User perspectives, Participatory co-creation process, Effects, Reach, Adoption, Implementation and Maintenance framework assessing: (i) the local systems, (ii) user perspectives, (iii) the participatory co-creation process, (iv) effects, (v) reach, (vi) adoption, (vii) implementation and (viii) maintenance of interventions. Through a realist evaluation, YoPA will explore why and how specific outcomes were reached (or not) in each setting (n=800-1000 adolescents in total). ETHICS AND DISSEMINATION: This study received approval from the ethics committees in Denmark, the Netherlands, Nigeria and South Africa and will be disseminated via various collaborative dissemination activities targeting multiple audiences. We will obtain informed consent from all participants. We envision that our YoPA co-creation approach will serve as a guide for participation of adolescents in vulnerable life situations in implementation of health promotion and urban planning in Europe, Africa and globally. TRIAL REGISTRATION NUMBER: NCT06181162.

Association between preschooler outdoor play and home yard vegetation as measured by high resolution imagery: Findings from the PLAYCE study.

Outdoor play in the home yard is an important source of physical activity for many preschoolers. This study investigated if home yard size and vegetation are related to preschooler outdoor play time. High-resolution remotely sensed data were used to distinguish between types of vegetation coverage in the home yard. Shrub and tree cover, and yard size, were positively associated with outdoor play. Following stratification by socio-economic status (SES - parent education), only tree cover was positively associated with preschooler outdoor play in low SES households. All types of vegetation cover were positively associated with preschooler outdoor play in higher SES households. This study highlights the importance of larger yard sizes and higher levels of vegetation for facilitating outdoor play in preschoolers.

The built environment and child obesity: A review of Australian policies.

Child obesity is a serious public health challenge affected by both individual choice and societal and environmental factors. The main modifiable risk factors for child obesity are unhealthy eating and low levels of physical activity, both influenced by aspects of the built environment. Coordinated government policy across jurisdictions, developed using strong research evidence, can enable built environments that better support healthy lifestyles. This study reviewed current Australian and Western Australian government policies to understand if and how they address the impact of the built environment on child obesity, physical activity, sedentary behavior, and diet. Current government policy documents related to the built environment and child health were analyzed using the Comprehensive Analysis of Policy on Physical Activity framework. Ten Australian and 31 Western Australian government policy documents were identified. Most referred to the role of the built environment in supporting physical activity. Very few policies mentioned the built environment's role in reducing sedentary behaviors, supporting healthy eating, and addressing obesity. Few recognized the needs of children, and none mentioned children in policy development. Future government policy development should include the voices of children and child-specific built environment features. Inter-organizational policies with transparent implementation and evaluation plans are recommended.

The role of playgrounds in the development of children's fundamental movement skills: A scoping review.

Fundamental movement skills (FMS) are the basic skills children should develop but are low in children from high-income countries. Literature indicates that playgrounds can play an important role challenging children's balance, agility, and coordination. However, knowledge on the influence of playgrounds on children's FMS development is fragmented. The aim of the present scoping review was to create an overview of all research that is relevant when studying the influence of unstructured playground play on children's FMS. Four electronic databases (Scopus, Web of Science, SportDiscus, and PsycInfo) were searched systematically in May 2022 and October 2023 following the PRISMA guidelines, leading to a final set of 14 publications meeting the inclusion criteria. The results of these publications indicate that it is important to design playgrounds with various features targeting balance, climbing, throwing, and catching to provide opportunities for children to enhance each FMS (i.e., stability, locomotor skills, and object control skills). Also, spreading features over a large area of the playground seems to ensure ample space per child, stimulate children to use locomotor skills by moving to and from features, and to play active games without equipment. Possibly, also natural play settings develop children's FMS. These findings, however, should be read with caution. More experimental studies using objective and standardized FMS tests are needed in this research field for a more robust conclusion.

Prioritizing a research agenda on built environments and physical activity: a twin panel Delphi consensus process with researchers and knowledge users.

BACKGROUND: The growth of urban dwelling populations globally has led to rapid increases of research and policy initiatives addressing associations between the built environment and physical activity (PA). Given this rapid proliferation, it is important to identify priority areas and research questions for moving the field forward. The objective of this study was to identify and compare research priorities on the built environment and PA among researchers and knowledge users (e.g., policy makers, practitioners). METHODS: Between September 2022 and April 2023, a three-round, modified Delphi survey was conducted among two independent panels of international researchers (n = 38) and knowledge users (n = 23) to identify similarities and differences in perceived research priorities on the built environment and PA and generate twin 'top 10' lists of the most important research needs. RESULTS: From a broad range of self-identified issues, both panels ranked in common the most pressing research priorities including stronger study designs such as natural experiments, research that examines inequalities and inequities, establishing the cost effectiveness of interventions, safety and injuries related to engagement in active transportation (AT), and considerations for climate change and climate adaptation. Additional priorities identified by researchers included: implementation science, research that incorporates Indigenous perspectives, land-use policies, built environments that support active aging, and participatory research. Additional priorities identified by knowledge users included: built environments and PA among people living with disabilities and a need for national data on trip chaining, multi-modal travel, and non-work or school-related AT. CONCLUSIONS: Five common research priorities between the two groups emerged, including (1) to better understand causality, (2) interactions with the natural environment, (3) economic evaluations, (4) social disparities, and (5) preventable AT-related injuries. The findings may help set directions for future research, interdisciplinary and intersectoral collaborations, and funding opportunities.

Recreational walking and perceived environmental qualities: a national map-based survey in Denmark.

BACKGROUND: The aim of the study is to explore the diversity in recreational walking motives across groups with different sociodemographic characteristics, and to use a dynamic and person-centered approach to geographically assess recreational walking behavior, and preferences for place quality related to recreational walking. METHODS: A total of 1838 adult respondents (age 15-90 years), who engage in recreational walking, participated in the map-based survey. We used the online platform Maptionnaire to collect georeferenced information on the respondents' home location, other start locations for walking trips, and point of interest on their trips. Distance between home location and other start locations as well as point of interest were computed using a Geographic Information System (GIS). Additional information on recreational walking behavior and motives were collected using the traditional questionnaire function in Maptionnaire. RESULTS: The most prevalent motives for walking were mental well-being and physical health, together with enjoyment and experiences related to walking. Having a tertiary education was positively associated with mental well-being motive, experiences, and taking the dog and the children outside. Income was also positively associated with experiences and walking the dog together with enjoyment of walking and spending time with others. Using the map-based approach, we found that recreational walking often starts at a location away from home and is not limited to the nearest neighborhood. A total of 4598 points of interest were mapped, and the most frequently reported place qualities were greenery, water, wildlife, good views, and tranquility. CONCLUSION: We used a dynamic and person-centered approach and thereby giving the respondents the opportunity to point to relevant locations for their walking behavior independently of their residential neighborhood. Recreational walking often starts away from home or is not limit to the nearest neighborhod. The median distance from home to the mapped points of interests was between 1.0 and 1.6 km for home-based trips and between 9.4 and 30.6 km for trips with other start locations. The most popular place quality related to the mapped points were greenery, water, wildlife, good views, and tranquility.

Association of composite park quality with park use in four diverse cities.

Park use has numerous health benefits. However, little research has investigated how the combination of park facilities, amenities, and conditions are related to park visitation. This study examined the association between a novel composite park quality metric and the use of specific parks, including variations by demographics. Data were collected in 128 census block groups across four diverse cities in the USA. Adults (n = 262) used an online, map-based survey to indicate which parks within one half-mile they had used within the past 30 days. All parks (n = 263) were audited using the Community Park Audit Tool, and a composite quality metric was calculated by standardizing and averaging six key components: access, facilities, amenities, aesthetic features, quality concerns, and neighborhood concerns. A total of 2429 participant-park pairs were analyzed. The average park quality score was 40.4/100 (s.d. = 30.2). For the full sample, a greater park quality score was significantly related to park use (OR = 1.02, 95% CI = 1.01-1.03) such that for each one unit increase in a park's quality score, there was a 2% increase in the likelihood of the park being used. There was also a significant interaction by gender, with park quality associated with park use among females (OR = 1.03, 95% CI = 1.02-1.05) but not males (OR = 1.00, 95% CI = 0.99-1.02). Enhancing overall park quality may increase the likelihood of a park being used. Future research can explore the utility of this comprehensive quality metric for predicting other health behaviors and outcomes and how interventions to enhance park quality augment park use and health over time.

Device-based physical activity measures for population surveillance-issues of selection bias and reactivity.

Background: Device-based measurement in physical activity surveillance is increasing, but research design choices could increase the risk of self-selection bias and reactive behaviour. The aim of this study is to compare the self-reported physical activity profiles of four different samples: participants in a large national survey, participants in a telephone-based survey of non-responders, participants in the large national survey who accepted the invitation to device-based measuring, and the same sample during the week of monitoring. Methods: In October 2020, 163,133 Danish adults participated in a national survey and of those 39,480 signed up for device-based measurements. A balanced random sample (n = 3,750) was invited to wear an accelerometer of whom 1,525 accepted the invitation. Additionally, a short telephone-based survey on 829 non-responders to the national survey was conducted. Sociodemographic characteristics and self-reported weekly frequencies of physical activity across four domains are compared. Results: The participants in the national survey were older, more often female, and more often not working. Participants in the telephone-based survey were younger, more often doing unskilled work, and were more often active at home and at work. The participants in the device-based sample were more often active during transport and leisure in the national survey, and participants categorized in the most active category increased during the week of monitoring from 29.0% to 60.7% and from 58.5% to 81.7% for active transport and leisure activities, respectively. Conclusion: Recruiting a population representative sample for device-based measurement of physical activity is challenging, and there is a substantial risk of sample selection bias and measurement reactivity. Further research in this area is needed if device-based measures should be considered for population physical activity surveillance.

Neighborhood Places for Preschool Children's Physical Activity: A Mixed-Methods Study Using Global Positioning System, Geographic Information Systems, and Accelerometry Data.

BACKGROUND: This study adds to the current literature by using a novel device-based method to explore where preschool children are physically active outside of home and childcare settings. This study combined accelerometry with geospatial data to explore the influence of the environment on preschool children's physical activity by objectively identifying the locations where preschool children engage in moderate to vigorous physical activity (MVPA) within and outside of their neighborhood. METHODS: Accelerometry, Global Positioning System, and Geographic Information Systems data from 168 preschool children aged 2-5 years were processed in ArcGIS Pro to identify locations (per 25 × 25-m fishnet cell) with high MVPA counts. Locations with high MVPA counts were defined as those with the top 20% of MVPA counts per fishnet cell. The land use for high MVPA count location was determined for 3 domains: <500 m from home, 500 to 1600 m from home, and >1600 m from home. RESULTS: Locations with high MVPA counts <500 m from home were playgrounds (66.6%), schools (16.7%), and parks (16.7%). Locations with high MVPA counts 500 to 1600 m from home included playgrounds (33.3%), nonhome residential (29.6%), childcare centers (11.1%), and parks (3.7%). Locations with high MVPA counts >1600 m from home included nonhome residential (54.7%), sports and recreation centers (11.1%), playgrounds (6.8%), and parks (5.3%). CONCLUSIONS: Our findings highlight that local parks and playgrounds provide physical activity opportunities for preschool children, yet beyond the local neighborhood, the homes of others are important locations for preschool children to accumulate MVPA. These findings can be used to inform the design of current and future neighborhood places to better accommodate preschool children's MVPA.