Is public transport a promising strategy for increasing physical activity? Evidence from a study of objectively measured public transport use and physical activity.

BACKGROUND: Greater public transport use has been linked to higher physical activity levels. However, neither the amount of physical activity associated with each daily public transport trip performed, nor the potential total physical activity gain associated with an increase in trips/day, has been determined. Using objective measures, we aimed to quantify the association between public transport use, physical activity and sedentary time. METHODS: A longitudinal study of Australian adults living in Hobart, Tasmania, who were infrequent bus users (≥ 18 years; used bus ≤ 2 times/week). The number of bus trips performed each day was determined from objective smartcard data provided by the public transportation (bus) provider across a 36-week study timeframe. Accelerometer measured steps/day (primary outcome), moderate-to-vigorous physical activity (min/day), and sedentary time (min/day) were assessed across four separate one-week periods. RESULTS: Among 73 participants across 1483 day-level observations, on days that public transport was used, participants achieved significantly more steps (ß = 2147.48; 95%CI = 1465.94, 2829.03), moderate to vigorous physical activity (ß = 22.79; 95% CI = 14.33, 31.26), and sedentary time (ß = 37.00; 95% CI = 19.80, 54.21) compared to days where no public transport trips were made. The largest increase in steps per day associated with a one-trip increase was observed when the number of trips performed each day increased from zero to one (ß = 1761.63; 95%CI = 821.38, 2701.87). The increase in the number of steps per day was smaller and non-significant when the number of trips performed increased from one to two (ß = 596.93; 95%CI=-585.16, 1779.01), and two to three or more (ß = 632.39; 95%CI=-1331.45, 2596.24) trips per day. Significant increases in sedentary time were observed when the number of trips performed increased from zero to one (ß = 39.38; 95%CI = 14.38, 64.39) and one to two (ß = 48.76; 95%CI = 25.39, 72.12); but not when bus trips increased from two to three or more (ß=-27.81; 95%CI=-76.00, 20.37). CONCLUSIONS: Greater public transport use was associated with higher physical activity and sedentary behaviour. Bus use may yield cumulative increases in steps that amount to 15-30% of the daily recommended physical activity target. A policy and public health focus on intersectoral action to promote public transport may yield meaningful increases in physical activity and subsequent health benefits.

The association between device-measured sitting time and cardiometabolic health risk factors in children.

BACKGROUND: There is limited evidence of the associations between postural-derived sitting time, waist-worn derived sedentary time and children's health and the moderation effect of physical activity (PA). This study examined associations of children's device-measured sitting time with cardiometabolic health risk factors, including moderation by physical activity. METHODS: Cross-sectional baseline data from children (mean-age 8.2 ± 0.5 years) in Melbourne, Australia (2010) participating in the TransformUs program were used. Children simultaneously wore an activPAL to assess sitting time and an ActiGraph GT3X to assess sedentary time and physical activity intensity. Cardiometabolic health risk factors included: adiposity (body mass index [BMI], waist circumference [WC]), systolic and diastolic blood pressure (SBP, DBP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), cholesterol, triglycerides, fasting plasma glucose (FPG), serum insulin, and 25-hydroxyvitaminD (25[OH]D). Linear regression models (n = 71-113) assessed associations between sitting time with each health risk factor, adjusted for different PA intensities (i.e. light [LIPA], moderate-vigorous intensities [MVPA], separately on each model), age, sex, adiposity, and clustering by school. Interaction terms examined moderation. The analyses were repeated using device-measured sedentary time (i.e. ActiGraph GT3X) for comparison. RESULTS: Sitting time was positively associated with SBP (b = 0.015; 95%CI: 0.004, 0.026), DBP (b = 0.012; 95%CI:0.004, 0.020), and FPG (b = 0.001; 95%CI: 0.000, 0.000), after adjusting for higher PA intensities. The association between sitting time and insulin (b = 0.003; 95%CI: 0.000, 0.006) was attenuated after adjusting for higher PA intensities. When the models were adjusted for LIPA and MVPA, there was a negative association with LDL (b=-0.001; 95%CI: -0.002, -0.000 and b=-0.001; 95%CI: -0.003, -0.000, respectively). There was a negative association of sedentary time with WCz (b=-0.003; 95%CI: -0.005, 0.000) and BMIz (b=-0.003; 95%CI: -0.006, -0.000) when the models were adjusted by MVPA. Sedentary time was positively associated with triglycerides (b = 0.001; 95%CI: 0.000, 0.001) but attenuated after adjusting for MVPA. No evidence of moderation effects was found. CONCLUSIONS: Higher volumes of sitting and sedentary time were associated with some adverse associations on some cardiometabolic health risk factors in children. These associations were more evident when sitting time was the predictor. This suggests that reducing time spent sitting may benefit some cardiometabolic health outcomes, but future experimental research is needed to confirm causal relationships and identify the biological mechanisms that might be involved. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12609000715279.

Influence of park visitation on physical activity, well-being and social connectedness among Australians during COVID-19.

This cross-sectional study examined associations of park visitation with physical activity (PA), well-being, and social connectedness among 1089 participants during the coronavirus disease 2019 pandemic. In August 2020, adolescents and adults in Australia self-reported demographics, usual park visitation, frequency and duration of park visits, PA, well-being and social connectedness. Multilevel linear regression models examined associations of park visitation with well-being and social connectedness. Multilevel mixed-effects negative binomial regression models examined associations between visitation and PA. Compared to not visiting a park, visitation was positively associated with well-being (B = 3.92, 95% confidence interval [CI] = 1.24, 6.60) and days/week performing PA for 30 min (B = 1.24, 95% CI = 1.11, 1.39) per day and negatively associated with social connectedness (B = -3.75, 95% CI = -7.11, -0.39). Compared to visiting a park less than once/week, visiting once/week was positively associated with well-being (B = 3.90, 95% CI = 0.53, 7.21). Visiting more than once/week was positively associated with days/week performing PA for 30 min (B = 1.37, 95% CI = 1.21, 1.58) and 60 min (B = 1.34, 95% CI = 1.09, 1.64) per day and with well-being (B = 4.19, 95% CI = 0.90, 7.49). Duration of park visits was positively associated with days/week performing PA for 30 min (B = 1.09, 95% CI = 1.04, 1.13) and 60 min (B = 1.09, 95% CI = 1.02, 1.17) per day. Our findings highlight the role of parks in positively influencing health-related outcomes and the 'dosage' of park use needed to attain health benefits.

Do food-related capabilities, opportunities and motivations of adolescents mediate the association between socioeconomic position in adolescence and diet quality in early adulthood?

BACKGROUND: Socio-economic position (SEP) in adolescence may influence diet quality over the life course. However, knowledge of whether individual and environmental determinants of diet quality mediate the longitudinal association between SEP and diet quality is limited. This study examined whether and to what extent food-related capabilities, opportunities and motivations of adolescents mediated the longitudinal association between SEP in adolescence and diet quality in early adulthood overall and by sex. METHODS: Longitudinal data (annual surveys) from 774 adolescents (16.9 years at baseline; 76% female) from ProjectADAPT (T1 (baseline), T2, T3) were used. SEP in adolescence (T1) was operationalized as highest level of parental education and area-level disadvantage (based on postcode). The Capabilities, Opportunities and Motivations for Behaviour (COM-B) model was used as a framework to inform the analysis. Determinants in adolescence (T2) included food-related activities and skills (Capability), home availability of fruit and vegetables (Opportunity) and self-efficacy (Motivation). Diet quality in early adulthood (T3) was calculated using a modified version of the Australian Dietary Guidelines Index based on brief dietary questions on intake of foods from eight food groups. Structural equation modelling was used to estimate the mediating effects of adolescents' COM-B in associations between adolescent SEP and diet quality in early adulthood overall and by sex. Standardized beta coefficients (ß) and robust 95% confidence intervals (CI) were generated, adjusted for confounders (T1 age, sex, diet quality, whether still at school, and living at home) and clustering by school. RESULTS: There was evidence of an indirect effect of area-level disadvantage on diet quality via Opportunity (ß: 0.021; 95% CI: 0.003 to 0.038), but limited evidence for parental education (ß: 0.018; 95% CI: -0.003 to 0.039). Opportunity mediated 60.9% of the association between area-level disadvantage and diet quality. There was no evidence of an indirect effect via Capability or Motivation for either area-level disadvantage or parental education, or in males and females separately. CONCLUSIONS: Using the COM-B model, the home availability of fruit and vegetables (Opportunity) of adolescents explained a large proportion of the association between area-level disadvantage in adolescence and diet quality in early adulthood. Interventions to address poor diet quality among adolescents with a lower SEP should prioritize environmental determinants of diet quality.

Do 20-minute neighbourhoods moderate associations between work and commute hours with food consumption?

OBJECTIVE: To examine associations between work and commute hours with food consumption and test whether neighbourhood type (20-minute neighbourhood (20MN)/non-20MN) moderate associations. DESIGN: Cross-sectional analysis of the Places and Locations for Activity and Nutrition study (ProjectPLAN). Exposures were work hours (not working (0 h), working up to full-time (1-38 h/week), working overtime (> 38 h/week)), and among those employed, combined weekly work and commute hours (continuous). Outcomes were usual consumption of fruit, vegetables, takeaway food, snacks and soft drinks, and number of discretionary food types (takeaway, snacks and soft drinks) consumed weekly. Generalised linear models were fitted to examine associations between each exposure and outcome. The moderating role of neighbourhood type was examined through interaction terms between each exposure and neighbourhood type (20MN/non-20MN). SETTING: Melbourne and Adelaide, Australia, 2018-2019. PARTICIPANTS: Adults ≥ 18 years old (n 769). RESULTS: Although all confidence intervals contained the null, overall, patterns suggested non-workers and overtime workers have less healthy food behaviours than up-to-full-time workers. Among those employed, analysis of continuous work and commute hours data suggested longer work and commute hours were positively associated with takeaway consumption (OR = 1·014, 95 % CI 0·999, 1·030, P-value = 0·066). Patterns of better behaviours were observed across most outcomes for those in 20MN than non-20MN. However, differences in associations between work and commute hours with food consumption across neighbourhood type were negligible. CONCLUSIONS: Longer work and commute hours may induce poorer food behaviours. There was weak evidence to suggest 20MN moderate associations between work and commute hours with food consumption, although behaviours appeared healthier for those in 20MN.

A latent transition analysis of physical activity and screen-based sedentary behavior from adolescence to young adulthood.

BACKGROUND: Distinct typologies of physical activity and screen-based sedentary behaviors are common during adolescence, but it is unknown how these change over time. This longitudinal study examined the stability of activity-related behavioral typologies over the transition out of secondary school. METHODS: Year 11 students (penultimate school year) completed a self-report survey (baseline), which was repeated 2 years later (follow-up) (75% female, mean baseline age: 16.9 ± 0.4 years). Latent transition analysis identified typologies of physical activity and screen time behaviors and explored changes in typology membership between baseline and follow-up among those with complete data and who were not attending secondary school at follow-up (n = 803). RESULTS: Three unique typologies were identified and labelled as: 1) Sedentary gamers (baseline: 17%; follow-up: 15%: high levels of screen behaviors, particularly video gaming); 2) Inactives (baseline: 46%; follow-up: 48%: low physical activities, average levels of screen behaviors); and 3) Actives (baseline: 37%; follow-up: 37%: high physical activities, low screen behaviors). Most participants remained in the same typology (83.2%), 8.5% transitioned to a typology with a more health-enhancing profile and 8.3% transitioned to a typology with a more detrimental behavioral profile. CONCLUSIONS: The high proportion within the 'inactive' typology and the stability of typologies over the transition period suggests that public health interventions are required to improve activity-related behavior typologies before adolescents leave secondary school.

Is level of implementation linked with intervention outcomes? Process evaluation of the TransformUs intervention to increase children's physical activity and reduce sedentary behaviour.

BACKGROUND: TransformUs was a four-arm school-based intervention to increase physical activity and reduce sedentary behaviour among primary school children. Pedagogical and environmental strategies targeted the classroom, school grounds and family setting. The aims of this study were to evaluate program fidelity, dose, appropriateness, satisfaction and sustainability, and associations between implementation level and outcomes among the three intervention arms. METHODS: At baseline, 18-months (mid-intervention) and 30-months (post-intervention), teachers, parents and children completed surveys, and children wore GT3X ActiGraph accelerometers for 8 days at each time point to determine physical activity and sedentary time. Implementation data were pooled across the three intervention groups and teachers were categorised by level of implementation: (i) 'Low' (< 33% delivered); (ii) 'Moderate' (33-67% delivered); and (iii) 'High' (> 67% delivered). Linear and logistic mixed models examined between group differences in implementation, and the association with children's physical activity and sedentary time outcomes. Qualitative survey data were analysed thematically. RESULTS: Among intervention recipients, 52% (n = 85) of teachers, 29% (n = 331) of parents and 92% (n = 407) of children completed baseline evaluation surveys. At 18-months, teachers delivered on average 70% of the key messages, 65% set active/standing homework, 30% reported delivering > 1 standing lesson/day, and 56% delivered active breaks per day. The majority of teachers (96%) made activity/sports equipment available during recess and lunch, and also used this equipment in class (81%). Fidelity and dose of key messages and active homework reduced over time, whilst fidelity of standing lessons, active breaks and equipment use increased. TransformUs was deemed appropriate for the school setting and positively received. Implementation level and child behavioural outcomes were not associated. Integration of TransformUs into existing practices, children's enjoyment, and teachers' awareness of program benefits all facilitated delivery and sustainability. CONCLUSIONS: This study demonstrated that intervention dose and fidelity increased over time, and that children's enjoyment, senior school leadership and effective integration of interventions into school practices facilitated improved intervention delivery and sustainability. Teacher implementation level and child behavioural outcomes were unrelated, suggesting intervention efficacy was achieved irrespective of implementation variability. The potential translatability of TransformUs into practice contexts may therefore be increased. Findings have informed scale-up of TransformUs across Victoria, Australia. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number ISRCTN83725066; Australian New Zealand Clinical Trials Registry Number ACTRN12609000715279. Registered 19 August 2009. Available at: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=308387&isReview=true.

Associations of accelerometer measured school- and non-school based physical activity and sedentary time with body mass index: IPEN Adolescent study.

BACKGROUND: This study examined the strength, shape and direction of associations of accelerometer-assessed overall, school- and non-school-based moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) with BMI among adolescents across the world. Second, we examined whether these associations differed by study site and sex. METHODS: Cross-sectional data from the IPEN Adolescent study, an observational multi-country study, were used. Participants wore an accelerometer for seven days, reported height and weight, and completed a socio-demographic survey. In total, 4852 adolescents (46.6% boys), aged 11-19 years (mean age = 14.6, SD = 1.7 years) were included in the analyses, using generalized additive mixed models. RESULTS: Adolescents accumulated on average 41.3 (SD = 22.6) min/day of MVPA and 531.8 (SD = 81.1) min/day of ST, and the prevalence of overweight and obesity was 17.2% (IOTF), but these mean values differed by country. Linear negative associations of accelerometer-based MVPA and ST with standardized BMI scores and the likelihood of being overweight/obese were found. School-based ST and non-school-based MVPA were more strongly negatively associated to the outcomes than non-school based ST and school-based MVPA. Study site moderated the associations; adolescent sex did not. No curvilinear associations were found. CONCLUSIONS: This multi-country study confirmed the importance of MVPA as a potential protective factor against overweight/obesity in adolescents. Non-school-based MVPA seemed to be the main driver of these associations. Unexpected results were found for ST, calling for further examination in methodologically sound international studies but using inclinometers or pressure sensors to provide more precise ST measures.

Neighbourhood food typologies, fast food outlet visitation and snack food purchasing among adolescents in Melbourne, Australia.

OBJECTIVE: Despite the increased attention on neighbourhood food environments and dietary behaviours, studies focusing on adolescents are limited. This study aims to characterise typologies of food environments surrounding adolescents and their associations with fast food outlet visitation and snack food purchasing to/from school. DESIGN: The number of food outlets (supermarket; green grocers; butcher/seafood/deli; bakeries; convenience stores; fast food/takeaways; café and restaurants) within a 1 km buffer from home was determined using a Geographic Information System. Adolescents' self-reported frequency of fast food outlet visitation and snack food purchasing to/from school. Latent Profile Analysis was conducted to identify typologies of the food environment. Cross-sectional multilevel logistic regression analyses were conducted to examine the relationships between food typologies, fast food outlet visitations and snack food purchasing to/from school. SETTING: Melbourne, Australia. PARTICIPANTS: Totally, 410 adolescents (mean age= 15·5 (sd = 1·5) years). RESULTS: Four distinct typologies of food outlets were identified: (1) limited variety/low number; (2) some variety/low number; (3) high variety/medium number and (4) high variety/high number. Adolescents living in Typologies 1 and 2 had three times higher odds of visiting fast food outlets ≥1 per week (Typology 1: OR = 3·71, 95 % CI 1·23, 11·19; Typology 2: OR = 3·65, 95 % CI 1·21, 10·99) than those living in Typology 4. No evidence of association was found between typologies of the food environments and snack food purchasing behaviour to/from school among adolescents. CONCLUSION: Local government could emphasise an overall balance of food outlets when designing neighbourhoods to reduce propensity for fast food outlet visitation among adolescents.

What do adults want in parks? A qualitative study using walk-along interviews.

BACKGROUND: Parks provide opportunities for physical activity and social interaction and are critical for enhancing public health. It is therefore important to better understand the needs and preferences of park features among adults to help park designers to create parks that optimise use. This qualitative study provided an in-depth examination of factors and characteristics that influence visitation, park-based physical activity, and social interaction among adults (19-64 years). We also explored perceptions of parks and park use and impacts of COVID on park usage and needs. METHODS: Participants (n = 27, 40.4 years [+ 11.9], 70% female) were interviewed from 2017 to 2020 while walking through one of eight diverse parks located in varying socioeconomic areas of metropolitan Melbourne, Australia. Participants were prompted to discuss their experiences, opinions and preferences regarding park features. All interviews were transcribed verbatim and analysed using NVivo 12 software. RESULTS: Park features and characteristics highly valued for visitation related to aesthetics and atmosphere, including trees, gardens, spaciousness, and water features. Features most valued for physical activity included walking and bike tracks, basketball rings, nice aesthetics, and sports walls. Features most valued for social interaction included seating and tables, and picnic/barbecue areas. CONCLUSIONS: This study highlights features and characteristics that may be important to prioritise, to encourage active and social park visits among adults. This evidence will help policy and decision makers, urban planners, landscape architects, and local, state, and national government organisations to create parks that support adults to lead healthy and active lives. Future research should examine the relative importance of the features identified in this study to inform future park design/redesign.

From motorised to active travel: using GPS data to explore potential physical activity gains among adolescents.

BACKGROUND: A high proportion of adolescents worldwide are not doing enough physical activity for health benefits. Replacing short motorised trips with walking or cycling has the potential to increase physical activity at the population level. This study aimed to estimate the proportion of short distance motorised trips that could be replaced with walking or cycling, and the potential physical activity gains by sociodemographic and trip characteristics. METHODS: Data were from a subsample of the NEighbourhood Activity in Youth (NEArbY) study conducted among adolescents in Melbourne. A total of 217 adolescents with at least one motorised trip completed a survey and wore a Global Positioning Systems (GPS) device for eight consecutive days. Classification of travel modes were based on speed. GPS data points were geocoded in ArcGIS. Motorised trips within walkable (1.3 km) and cyclable (4.2 km) distances were identified (threshold based on 80th percentile of walking and cycling trip distances among Victorian adolescents), and the additional physical activity minutes that could be accrued by replacing walkable or cyclable motorised trip to active trips were quantified. Multilevel linear regression was used to assess differences in physical activity minutes gain by sociodemographic and trip characteristics. RESULTS: A total of 4,116 motorised trips were made. Of these, 17% were walkable and 61% were cyclable. Replacing motorised trips by walking and cycling resulted in estimated gains of six minutes and 15 min of physical activity per day, respectively. CONCLUSION: The sizable proportion of replaceable trips and potential physical activity gains from this shift calls for attention to improve safe and connected infrastructure to support active travel.

Outdoor public recreation spaces and social connectedness among adolescents.

BACKGROUND: Outdoor public recreation spaces are important settings for leisure and physical activity. Adolescents' use of these spaces may contribute to social connectedness via social interaction with peers and the community in these settings. However, research on this topic is limited. This exploratory study examined associations of frequency of visitation and physical activity in outdoor public recreation spaces with social connectedness among adolescents in Melbourne, Australia. METHODS: Adolescents self-reported their frequency of visitation to parks, trails, beach/lake, and sports facilities; frequency of physical activity in a park, local street or path, and their street; and social connectedness. Separate analyses were conducted for visitation (n = 349, 15.4 ± 1.6 years, 58% female) and physical activity (n = 441, 15.4 ± 1.6 years, 59% female) using multilevel linear regression models. RESULTS: No significant associations were observed for frequency of visitation to a park (B = 0.86, 95% CI = - 0.26, 1.99), trails (B = 0.41, 95% CI = - 0.61, 1.44), beach/lake (B = - 0.44, 95% CI = - 1.46, 0.57), or sports facilities (B = 0.64, 95% CI = - 0.43, 1.70), nor for frequency of physical activity in their street (B = - 0.07, 95% CI = - 0.46, 0.31), local street/path (B = - 0.05, 95% CI = - 0.43, 0.33) or in a park (B = 0.23, 95% CI = - 0.14, 0.60) with adolescents' social connectedness. CONCLUSIONS: The findings did not support the hypothesis that visiting and being active in outdoor public recreation spaces are associated with adolescents' social connectedness. Future research should consider the duration and context of outdoor public recreation space use (e.g., sports, socialising, relaxing alone) and whether different types and/or a combination of public spaces are more/less conducive to social connectedness.

"Everything kind of revolves around technology": a qualitative exploration of families' screen use experiences, and intervention suggestions.

BACKGROUND: Managing children's screen time is challenging for most families. Interventions have had limited success in reducing screen time, potentially due to a lack of understanding of the experiences, needs and recommendations of families. This study aimed to 1) understand the screen time experiences of families, particularly during COVID-19 lockdowns; and 2) explore parent and child suggestions for the design, components, and content of a screen time management program. METHODS: Parents and children from 30 families living in Victoria, Australia completed a semi-structured interview (63 interviews) via Zoom in October-November 2021. Parents were maged 40.8 (± 8.9) years and predominantly female (90%). Children were maged 11.4 (± 2.4) years and 47% female. The interviews were audio recorded, transcribed verbatim and analysed using inductive thematic analysis combined with a summative content analysis approach. RESULTS: Three themes under Aim 1 emerged. Theme 1) 'Screen time management experiences and practices', including rules and strategies, challenges, and the impact of COVID-19 lockdowns. Theme 2) 'Impact of screens on family interaction and communication' including conflicts within the family, reduced face-to-face interactions, and negative impact on child's behaviour and wellbeing. Theme 3) 'Benefits of increased screen time due to COVID-19 lockdowns' including continuation of social interactions, extracurricular activities, improved technology skills and using screens as a 'babysitter'. Findings from Aim 2 suggest that families want a screen time management program delivered online to parents and children, which includes static and interactive content that incorporates health information, alternative activities, cyber-safety information, tips for goal setting and rewards, screen monitoring tools, links to reputable information, and parent social connections. Reminders via text message or through the online platform would help maintain engagement in the program. CONCLUSIONS: Families are experiencing challenges in managing the complex balance between the increased need for screens and the impact it has on the family. These findings provide valuable parent and child insights to assist in developing screen time management programs that are created with an understanding of the needs and challenges of families.

Test-retest reliability of a measure of perceived activity compensation in primary school children and their parents: a mixed methods study.

There is a lack of specific tools for assessing children's activity compensatory responses. This study 1) determined test-retest reliability and internal consistency of survey items assessing children's self-reported and parents' proxy-reported perceived compensatory responses; and 2) described children's and parents' views of potential compensatory mechanisms. Children (n = 55; mean age 10.2 ± 0.9) and their parents (n = 60) completed a survey twice, seven days apart. A sub-sample (17 parents; 13 children) participated in a short, semi-structured interview. Intraclass Correlation Coefficients (ICCs) and Cronbach's alpha assessed absolute agreement and internal consistency. Interviews were analysed via thematic analysis. Seven self- and proxy-reported survey sub-scales had excellent test-retest reliability (ICC ≥ 0.75), three had good (ICC ≥ 0.56) and one fair (ICC = 0.44). All survey items and sub-scales had acceptable internal consistency (alpha >0.67). Thematic analysis identified two overarching themes: awareness of compensation and mechanisms of compensation. After an active day at school, most participants perceived that compensation occurred later that day. Mechanisms of compensation included psychological, physiological, environmental, and interpersonal mechanisms. This reliable survey provides a new tool for assessing children's and their parents' perceptions of activity compensation and may inform future intervention designs. Future research is needed to establish concordance between perceived and device-assessed compensation.

Socioecological correlates associated with muscle-strengthening exercise at home during COVID-19 among adolescents: The our life at home study.

This study examined adolescent muscle-strengthening exercise (MSE) participation at home and associated socioecological correlates during Australia's initial COVID-19 lockdown restrictions. Adolescents (N = 731, Mage = 16.3, SD = 1.2 years, 73% female) self-reported their MSE participation in February 2020 (pre-lockdown; at a gym or at home) and April/May (during lockdown; at home only as gyms were closed). They also reported a range of potential individual, family, and home environment correlates. Remoteness and area-level socioeconomic disadvantage were also considered. Logistic regression models examined potential correlates of participation in any MSE and MSE engagement ≥3 times/week during April/May. Fewer adolescents participated in MSE during April/May (48%) than February (54%), however, the proportions that engaged in MSE ≥3 times/week were the same (30%). Prioritising being active every day (OR = 2.43, 95% CI = 1.52, 3.90), being active with sibling/s ≥ 5 days/week (OR = 2.24, 95% CI = 1.00, 5.00) and access to weights at home (OR = 2.98, 95% CI = 1.94, 4.57) were associated with higher odds of any MSE participation at home during April/May. These variables were also positively associated with MSE participation at home ≥3 times/week. Understanding how to support adolescents to prioritise being active, engage in MSE with siblings, and provide equipment may assist adolescents to engage in home-based MSE.

Plastic and Placenta: Identification of Polyethylene Glycol (PEG) Compounds in the Human Placenta by HPLC-MS/MS System.

The placenta is a crucial interface between the fetus and the maternal environment. It allows for nutrient absorption, thermal regulation, waste elimination, and gas exchange through the mother's blood supply. Furthermore, the placenta determines important adjustments and epigenetic modifications that can change the phenotypic expression of the individual even long after birth. Polyethylene glycol (PEG) is a polyether compound derived from petroleum with many applications, from medicine to industrial manufacturing. In this study, for the first time, an integration of ultra-high-performance liquid chromatography (UHPLC) coupled with mass spectrometry (MS) was used to detect suites of PEG compounds in human placenta samples, collected from 12 placentas, originating from physiological pregnancy. In 10 placentas, we identified fragments of PEG in both chorioamniotic membranes and placental cotyledons, for a total of 36 samples.

Understanding children's preference for park features that encourage physical activity: an adaptive choice based conjoint analysis.

BACKGROUND: Parks are a key setting for physical activity for children. However, little is known about which park features children prefer and which features are most likely to encourage them to be active in parks. This study examined the relative importance of park features among children for influencing their choice of park for engaging in park-based physical activity. METHODS: Children (n = 252; 8-12 years, 42% male) attending three primary schools in Melbourne, Australia completed a survey at school. They were required to complete a series of Adaptive Choice-Based Conjoint analysis tasks, with responses used to identify the part-worth utilities and relative importance scores of selected park features using Hierarchical Bayes analyses within Sawtooth Software. RESULTS: For the overall sample and both boys and girls, the most important driver of choice for a park that would encourage them to be active was presence of a flying fox (overall conjoint analysis relative importance score: 15.8%; 95%CI = 14.5, 17.1), followed by a playground (13.5%; 95%CI = 11.9, 15.2). For the overall sample, trees for climbing had the third highest importance score (10.2%; 95%CI = 8.9, 11.6); however, swings had 3rd highest importance for girls (11.1, 95%CI = 9.3, 12.9) and an obstacle course/parkour area had the 3rd highest importance score for boys (10.7, 95%CI = 9.0, 12.4). For features with two levels, part-worth utility scores showed that the presence of a feature was always preferred over the absence of a feature. For features with multiple levels, long flying foxes, large adventure playgrounds, lots of trees for climbing, large round swings, large climbing equipment, and large grassy open space were the preferred levels. CONCLUSION: To ensure parks appeal as a setting that encourages children to engage in physical activity, park planners and local authorities and organisations involved in park design should prioritise the inclusion of a long flying fox, large adventure playgrounds, lots of trees for climbing, large round swings and obstacle courses/parkour areas.

Characterizing children's eating patterns: does the choice of eating occasion definition matter?

BACKGROUND: Recommendations to define eating occasions (EO) currently exist for research in adults, but not for children or adolescents. We examined how varying EO definitions affect the characterization of eating patterns in children and adolescents. METHODS: Cross-sectional dietary data collected using a 24-h recall data during the 2011-12 Australian National Nutrition and Physical Activity Survey (1364 boys and 1337 girls aged 2-18 years) were analyzed. Eight definitions were applied: participant-identified, time-of-day, and 6 neutral definitions (EO separated by 15- or 60-min and/or an additional energy criterion of 21 or 210 kJ). Frequency of and total energy intake from meals, snacks, and all EO were estimated. F tests stratified by gender and age-group, were used to assess differences between definitions. Agreement between definitions of meal and snack frequencies was assessed using intraclass correlation coefficients (ICC). Linear regression was used to estimate the proportion of variance in total energy intake (kJ) and BMI z-score predicted by each definition. RESULTS: Mean frequencies of meals and snacks differed between the participant-identified and time-of-day definitions, in boys and girls and for all age groups (P < 0.01). Across the six neutral definitions, there were differences between mean frequencies of EO with the largest mean difference observed for children aged 2-3 y (boys: 2.3, girls: 2.5; P < 0.003). Between the participant-identified and time-of-day definitions, there was good agreement for frequencies of snacks (ICC for both genders: 0.93) but not meals (boys: 0.36; girls: 0.38). The 15-min time interval plus 210 kJ definition of an EO consistently predicted the most variance in total energy intake (R2 range = 8.1-34.8). Definitions that delineated meals and snacks better predicted variance in BMI z-score, when compared to the neutral definitions. CONCLUSIONS: How eating patterns are characterized vary depending on the EO definitions employed, particularly in young children. Variance in total energy intake was best predicted by a variation of the neutral definition whereas definitions that delineated meals and snacks performed better in relation to predicting BMI variance. Further international research that compares EO definitions in children will help inform a standard approach.

Effect of commercial wearables and digital behaviour change resources on the physical activity of adolescents attending schools in socio-economically disadvantaged areas: the RAW-PA cluster-randomised controlled trial.

BACKGROUND: There has been increasing interest in using wearable activity trackers to promote physical activity in youth. This study examined the short- and longer-term effects of a wearable activity tracker combined with digital behaviour change resources on the physical activity of adolescents attending schools in socio-economically disadvantaged areas. METHODS: The Raising Awareness of Physical Activity (RAW-PA) Study was a 12-week, multicomponent intervention that combined a Fitbit Flex (and accompanying app), and online digital behaviour change resources and weekly challenges delivered via Facebook. RAW-PA was evaluated using a cluster-randomised controlled trial with 275 adolescents (50.2% female; 13.7 ± 0.4 years) from 18 Melbourne secondary schools (intervention n = 9; wait-list control group n = 9). The primary outcome was moderate- to vigorous-intensity physical activity (MVPA), measured using hip-worn ActiGraph accelerometers. The secondary outcome was self-reported physical activity. Data were collected at baseline, 12-weeks (immediately post-intervention), and 6-months post-intervention (follow-up). Multilevel models were used to determine the effects of the intervention on daily MVPA over time, adjusting for covariates. RESULTS: No significant differences were observed between intervention and wait-list control adolescents' device-assessed MVPA immediately post-intervention. At 6-months post-intervention, adolescents in the intervention group engaged in 5 min (95% CI: - 9.1 to - 1.0) less MVPA per day than those in the wait-list control group. Males in the intervention group engaged in 11 min (95% CI: - 17.6 to - 4.5) less MVPA than males in the wait-list control group at 6-months post-intervention. No significant differences were observed for females at either time point. For self-reported physical activity, no significant effects were found at 12-weeks and 6-months post-intervention. CONCLUSIONS: Combining a wearable activity tracker with digital behaviour change resources and weekly challenges did not increase inactive adolescents' accelerometer-derived and self-reported physical activity levels immediately post-intervention. This contrasts previous research that has suggested wearable activity tracker may increase youth physical activity levels in the short-term. Lower engagement in MVPA 6-months post-intervention was observed for males but not for females, though it is unclear why this finding was observed. The results suggest wearable activity trackers, in combination with supporting materials, may not be effective for increasing physical activity levels in adolescents. TRIAL REGISTRATION: ACTRN12616000899448 . Australian and New Zealand Clinical Trials Registry. Registered 7 July 2016.

Volume and accumulation patterns of physical activity and sedentary time: longitudinal changes and tracking from early to late childhood.

BACKGROUND: Physical activity (PA) decreases and sedentary time (SED) increases across childhood, with both behaviours tracking. However, no studies have examined how accumulation patterns of PA and SED (i.e., prolonged bouts, frequency of breaks in sedentary time) change and track over time. The aim of this study was to investigate longitudinal changes in and tracking of total volume and accumulation patterns of SED, light-intensity PA (LPA), moderate-intensity PA (MPA), vigorous-intensity PA (VPA) among boys and girls. METHODS: In 2008/09 (T1), children in HAPPY (3-5y; n = 758) in Melbourne, Australia wore ActiGraph GT1M accelerometers to objectively assess SED, LPA, MPA and VPA. This was repeated at age 6-8y (T2; n = 473) and 9-11y (T3; n = 478). Ten pattern variables were computed: bouts of ≥ 5-, ≥ 10-, ≥ 15- and ≥ 20-min for SED, ≥ 1- and ≥ 5-min for LPA, ≥ 1-min for MPA, ≥ 1- and ≥ 5-min for VPA, and breaks in SED (interruptions of > 25 counts 15 s- 1). Longitudinal mixed models examined changes from T1-3, controlling for T1 age. Generalized estimating equations assessed tracking over the three time points, controlling for T1 age and time between measurements. Analyses were stratified by sex. RESULTS: Total volume and bouts of SED and SED breaks increased, while total volume and bouts of LPA decreased for both sexes. There was a small decrease in total volume of MPA for girls, but time spent in ≥ 1-min bouts increased for both sexes. Total volume of VPA increased for both sexes, with time spent in ≥ 1-min bouts increasing for boys only. All volume and pattern variables tracked moderately for boys, except for all SED bouts ≥ 15-min, LPA bouts ≥ 5-min and MPA bouts ≥ 1-min (which tracked weakly). For girls, total SED and SED bouts ≥ 1-min tracked strongly, total volume of LPA, MPA and VPA, ≥ 5- and ≥ 10-min SED bouts, and ≥ 1-min LPA and MPA bouts tracked moderately, and SED breaks, all SED bouts ≥ 15 min, LPA bouts ≥ 5 min and all VPA bouts tracked weakly. CONCLUSIONS: Patterns of SED and PA change from early to late childhood; with the exception of SED breaks and VPA, changes were detrimental. Total volumes and short bouts tended to track more strongly than longer bouts. Interventions to prevent declines in PA and increases in SED are important from early in life.