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.

Cost-effectiveness of reducing children's sedentary time and increasing physical activity at school: the Transform-Us! intervention.

BACKGROUND: Improving physical activity and reducing sedentary behavior represent important areas for intervention in childhood in order to reduce the burden of chronic disease related to obesity and physical inactivity in later life. This paper aims to determine the cost-effectiveness of a multi-arm primary school-based intervention to increase physical activity and/or reduce sedentary time in 8-9 year old children (Transform-Us!). METHODS: Modelled cost-utility analysis, using costs and effects from a cluster randomized controlled trial of a 30-month intervention that used pedagogical and environmental strategies to reduce and break up sedentary behaviour (SB-I), promote physical activity (PA-I), or a combined approach (PA + SB-I), compared to current practice. A validated multiple-cohort lifetable model (ACE-Obesity Policy model) estimated the obesity and physical activity-related health outcomes (measured as change in body mass index and change in metabolic equivalent task minutes respectively) and healthcare cost-savings over the cohort's lifetime from the public-payer perspective, assuming the intervention was delivered to all 8-9 year old children attending Australian Government primary schools. Sensitivity analyses tested the impact on cost-effectiveness of varying key input parameters, including maintenance of intervention effect assumptions. RESULTS: Cost-effectiveness results demonstrated that, when compared to control schools, the PA-I and SB-I intervention arms were "dominant", meaning that they resulted in net health benefits and healthcare cost-savings if the intervention effects were maintained. When the costs and effects of these intervention arms were extrapolated to the Australian population, results suggested significant potential as obesity prevention measures (PA-I: 60,780 HALYs saved (95% UI 15,007-109,413), healthcare cost-savings AUD641M (95% UI AUD165M-$1.1B); SB-I: 61,126 HALYs saved (95% UI 11,770 - 111,249), healthcare cost-savings AUD654M (95% UI AUD126M-1.2B)). The PA-I and SB-I interventions remained cost-effective in sensitivity analysis, assuming the full decay of intervention effect after 10 years. CONCLUSIONS: The PA-I and SB-I Transform-Us! intervention arms represent good value for money and could lead to health benefits and healthcare cost-savings arising from the prevention of chronic disease in later life if intervention effects are sustained. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number (ISRCTN83725066). Australia and New Zealand Clinical Trials Registry Number (ACTRN12609000715279).

Scaling up a school-based intervention to increase physical activity and reduce sedentary behaviour in children: protocol for the TransformUs hybrid effectiveness-implementation trial.

INTRODUCTION: Efficacious programmes require implementation at scale to maximise their public health impact. TransformUs is an efficacious behavioural and environmental intervention for increasing primary (elementary) school children's (5-12 years) physical activity and reducing their sedentary behaviour within school and home settings. This paper describes the study protocol of a 5-year effectiveness-implementation trial to assess the scalability and effectiveness of the TransformUs programme. METHODS AND ANALYSIS: A type II hybrid implementation-effectiveness trial, TransformUs is being disseminated to all primary schools in the state of Victoria, Australia (n=1786). Data are being collected using mixed methods at the system (state government, partner organisations), organisation (school) and individual (teacher, parent and child) levels. Evaluation is based on programme Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework. RE-AIM domains are being measured using a quasi-experimental, pre/post, non-equivalent group design, at baseline, 12 and 24 months. Effectiveness will be determined in a subsample of 20 intervention schools (in Victoria) and 20 control schools (in New South Wales (NSW), Australia), at baseline, 12 and 24 months. Primary outcomes include TransformUs Reach, Adoption, Implementation and organisational Maintenance (implementation trial), and children's physical activity and sedentary time assessed using accelerometers (effectiveness trial). Secondary outcomes include average sedentary time and moderate to vigorous-intensity physical activity on weekdays and during school hours, body mass index z-scores and waist circumference (effectiveness trial). Linear mixed-effects models will be fitted to compare outcomes between intervention and control participants accounting for clustering of children within schools, confounding and random effects. ETHICS AND DISSEMINATION: The trial was approved by the Deakin University Human Research Ethics Committee (HEAG-H 28_2017), Victorian Department of Education, the NSW Department of Education, Australian Catholic University (2017-145R), Melbourne Archdiocese Catholic Schools and Catholic Schools NSW. Partners, schools/teachers and parents will provide an informed signed consent form prior to participating. Parents will provide consent for their child to participate in the effectiveness trial. Findings will be disseminated via peer-reviewed publications, scientific conferences, summary reports to schools and our partner organisations, and will inform education policy and practice on effective and sustainable ways to promote physical activity and reduce sedentary behaviours population-wide. TRIAL REGISTRATION NUMBER: Australian Clinical Trials Registration Registry (ACTRN12617000204347).

Cross-Sectional Associations of Screen Time Activities With Alcohol and Tobacco Consumption Among Brazilian Adolescents.

Objectives: Little is known about the association between specific types of screen time and adolescents' substance use. Thus, this study aimed to investigate the associations between screen time for studying, working, watching movies, playing games, and using social media and frequency of alcohol and tobacco use. Methods: In this cross-sectional study, Brazilian adolescents answered survey questions related to frequency of tobacco and alcohol consumption, and reported their daily volume of five types of screen time. Multilevel ordered logistic regression models were performed. Results: Each 1-hour increase in ST for studying was associated with 26% lower odds of smoking (OR = 0.74; 95% CI: 0.61-0.90) and 17% lower odds of drinking alcohol (OR = 0.83; 95% CI: 0.76-0.91) in the past 30 days. The increase of 1 hour of social media use was associated with 10% greater odds of smoking (OR = 1.10; 95% CI: 1.02-1.18) and a 13% greater chance of consuming alcohol (OR = 1.13; 95% CI: 1.08-1.18) in the past 30 days. Conclusion: The association between screen time and substance use appears to be type-specific. Future longitudinal research is needed to explore causal relationships.

Validity, Reliability, and Feasibility of Physical Literacy Assessments Designed for School Children: A Systematic Review.

BACKGROUND: While the burgeoning researcher and practitioner interest in physical literacy has stimulated new assessment approaches, the optimal tool for assessment among school-aged children remains unclear. OBJECTIVE: The purpose of this review was to: (i) identify assessment instruments designed to measure physical literacy in school-aged children; (ii) map instruments to a holistic construct of physical literacy (as specified by the Australian Physical Literacy Framework); (iii) document the validity and reliability for these instruments; and (iv) assess the feasibility of these instruments for use in school environments. DESIGN: This systematic review (registered with PROSPERO on 21 August, 2022) was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. DATA SOURCES: Reviews of physical literacy assessments in the past 5 years (2017 +) were initially used to identify relevant assessments. Following that, a search (20 July, 2022) in six databases (CINAHL, ERIC, GlobalHealth, MEDLINE, PsycINFO, SPORTDiscus) was conducted for assessments that were missed/or published since publication of the reviews. Each step of screening involved evaluation from two authors, with any issues resolved through discussion with a third author. Nine instruments were identified from eight reviews. The database search identified 375 potential papers of which 67 full text papers were screened, resulting in 39 papers relevant to a physical literacy assessment. INCLUSION AND EXCLUSION CRITERIA: Instruments were classified against the Australian Physical Literacy Framework and needed to have assessed at least three of the Australian Physical Literacy Framework domains (i.e., psychological, social, cognitive, and/or physical). ANALYSES: Instruments were assessed for five aspects of validity (test content, response processes, internal structure, relations with other variables, and the consequences of testing). Feasibility in schools was documented according to time, space, equipment, training, and qualifications. RESULTS: Assessments with more validity/reliability evidence, according to age, were as follows: for children, the Physical Literacy in Children Questionnaire (PL-C Quest) and Passport for Life (PFL). For older children and adolescents, the Canadian Assessment for Physical Literacy (CAPL version 2). For adolescents, the Adolescent Physical Literacy Questionnaire (APLQ) and Portuguese Physical Literacy Assessment Questionnaire (PPLA-Q). Survey-based instruments were appraised to be the most feasible to administer in schools. CONCLUSIONS: This review identified optimal physical literacy assessments for children and adolescents based on current validity and reliability data. Instrument validity for specific populations was a clear gap, particularly for children with disability. While survey-based instruments were deemed the most feasible for use in schools, a comprehensive assessment may arguably require objective measures for elements in the physical domain. If a physical literacy assessment in schools is to be performed by teachers, this may require linking physical literacy to the curriculum and developing teachers' skills to develop and assess children's physical literacy.

Exploring Children's Self-Reported Activity Compensation: The REACT Study.

PURPOSE: Previous research has focused on device-based measures of activity compensation, with little understanding of how children perceive potential compensatory responses to activity or inactivity, or whether these change after periods of activity or inactivity. The aim of this study was (a) to explore the alignment between children's self-reported usual compensation and compensation recall after experimental conditions and (b) to examine sex differences. METHODS: In total, 360 children (47% boys) participated in at least one of three experimental conditions over 6 wk: (a) restricted physical activity (PA; indoor play), (b) imposed moderate- to vigorous-intensity PA (MVPA; sports class), and (c) imposed light-intensity PA (LPA; standing lesson). Before the first condition, children reported their "usual compensation" behavior to examples of restricted/imposed PA, and 2-3 d after each experimental condition, they completed a recall measure of their compensation after the condition. Multilevel regression models were conducted to determine whether children's perceptions of "usual compensation" score were associated with recalled compensation score after imposed or restricted PA. Additional models were fitted for sex-specific associations. RESULTS: Overall and among girls, the usual compensation score was positively associated with the compensatory recall score for the additional MVPA and LPA conditions ( P < 0.0005; e.g., they thought they would usually compensate for additional MVPA and then perceived that they compensated after additional MVPA). A negative association was seen in the restricted activity condition among girls ( P = 0.03). All associations in the boys' analyses were statistically nonsignificant. CONCLUSIONS: These findings suggest some alignment between children's self-reported usual compensation and compensation recall after imposed changes to routine activity. Future research should consider device-measured comparisons and identify characteristics of children at risk of activity compensation in future interventions.

The impact of height-adjustable desks and classroom prompts on classroom sitting time, social, and motivational factors among adolescents.

PURPOSE: This quasi-experimental study examined the impact of height-adjustable desks in combination with prompts to break up prolonged sitting time during class time and identified social and motivational factors associated with breaking up sitting time among adolescents. Teachers' perceptions of strategies were also examined. METHODS: Over 17 weeks, 1 classroom in a government secondary school in Melbourne, Australia, was equipped with 27 height-adjustable desks and prompts (posters and desk stickers) to break up classroom sitting time. Teachers received professional development in the use of the desks and prompts. One group of adolescents (n = 55) had 2-5 lessons/week using the height-adjustable desks in an intervention classroom, and a comparison group matched by year level and subject (n = 50) was taught in traditional "seated" classrooms. Adolescents wore an activPAL monitor at baseline (T0), 4 weeks (T1), and 17 weeks (T2) and completed a survey at T0 and T2. Six teachers participated in interviews at T2. Effect sizes were calculated (d). RESULTS: Linear mixed models found that, compared to the traditional "seated" classrooms, the adolescents in the intervention classroom had significantly lower sitting time (T1: -9.7 min/lesson, d = -0.96; T2: -6.7 min/lesson, d = -0.70) and time spent in sitting bouts >15 min (T2: -11.2 min/lesson, d = -0.62), and had significantly higher standing time (T1: 7.3 min/lesson, d = 0.84; T2: 5.8 min/lesson, d = 0.91), number of breaks from sitting (T1: 1.3 breaks/lesson, d = 0.49; T2: 1.8 breaks/lesson, d = 0.67), and stepping time (T1: 2.5 min/lesson, d = 0.66). Intervention classroom adolescents reported greater habit strength (d = 0.58), self-efficacy for breaking up sitting time (d = 0.75), and indicated that having a teacher/classmate remind them to stand as helpful (d = 0.50). CONCLUSION: This intervention shows promise for targeting sitting behaviors in the classroom and indicates that incorporating social and motivational strategies may further enhance outcomes.

Transform-Us! cluster RCT: 18-month and 30-month effects on children's physical activity, sedentary time and cardiometabolic risk markers.

OBJECTIVE: To test the efficacy of the Transform-Us! school- and home-based intervention on children's physical activity (PA), sedentary behaviour (SB) and cardiometabolic risk factor profiles. METHODS: A 30-month 2×2 factorial design cluster randomised controlled trial delivered in 20 primary schools (148 Year 3 classes) in Melbourne, Australia (2010-2012), that used pedagogical and environmental strategies to reduce and break up SB, promote PA or a combined approach, compared with usual practice. Primary outcomes (accelerometry data; n=348) were assessed at baseline, 18 and 30 months. Secondary outcomes included body mass index (BMI) and waist circumference (WC) (n=564), blood pressure (BP) (n=537) and biomarkers (minimum n=206). Generalised linear mixed models estimated the interactive effects of the PA and SB interventions on the outcomes. If there was no interaction, the main effects were assessed. RESULTS: At 18 months, there were intervention effects on children's weekday SB (-27 min, 95% CI: -47.3 to -5.3) for the PA intervention, and on children's average day PA (5.5 min, 95% CI: 0.1 to 10.8) for the SB intervention. At 30 months, there was an intervention effect for children's average day SB (-33.3 min, 95% CI: -50.6 and -16.0) for the SB intervention. Children's BMI (PA and SB groups) and systolic BP (combined group) were lower, and diastolic BP (PA group) was higher. There were positive effects on WC at both time points (SB intervention) and mixed effects on blood parameters. CONCLUSIONS: The Transform-Us! PA and SB interventions show promise as a pragmatic approach for reducing children's SB and adiposity indicators; but achieving substantial increases in PA remains challenging. TRIAL REGISTRATION: ISRCTN83725066; ACTRN12609000715279.

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.

"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.

Intervention effects on children's movement behaviour accumulation as a result of the Transform-Us! school- and home-based cluster randomised controlled trial.

BACKGROUND: It is unknown if and how children's movement behaviour accumulation patterns change as a result of physical activity and/or sedentary behaviour interventions. It is important to establish the effectiveness of interventions targeting changes in such accumulation patterns. This study aimed to investigate the effect of the Transform-Us! school- and home-based intervention program on children's movement behaviour accumulation patterns, focusing on sporadic accumulation versus time in bouts. METHODS: Baseline and post-intervention (18 months) accelerometer data from the Transform-Us! 2 × 2 factorial design cluster randomised controlled trial was used (Melbourne, 2010-2012; analytical sample n = 267; aged 8-9 years). Linear mixed models were fitted to examine effects of three different interventions (targeting increases in physical activity [PA-I], reductions in sedentary time [SB-I], or both [PA + SB-I]) compared to a usual practice (control) group on post-intervention movement behaviour accumulation compositions with eight components, including sporadic time and bouts of sedentary time, and light-, moderate- and vigorous-intensity physical activity. RESULTS: Intervention effects on distribution of time in the post-intervention waking movement behaviour accumulation composition (adjusted for baseline composition) were small and not significant. However, visual inspection of the change in compositions over time revealed that only groups with a sedentary behaviour intervention component (SB-I and PA + SB-I) reduced time in sedentary bouts, compared to the overall sample compositional mean. In addition, the SB-I group was the only group with an increase in vigorous-intensity physical activity. The combined intervention group (PA + SB-I) was characterized by the largest proportional increase in MPA bouts. The usual practice group was characterized by the largest proportional increases in both sporadic and bouts of sedentary time. CONCLUSIONS: This study showed some early evidence to suggest that the "break up your sitting" message may result in greater impact than the "move more" message. Future research, including larger sample sizes, should investigate if this type of messaging is indeed more effective in changing movement behaviours and ultimately child health. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number ISRCTN83725066 ; Australian New Zealand Clinical Trials Registry Number ACTRN12609000715279 .

Associations between the neighbourhood social environment and preschool children's physical activity and screen time.

BACKGROUND: The neighbourhood social environment (NSE) has been associated with physical activity and screen time behaviours in adults and youth however less is known about this relationship in preschool-aged children (2-5 years). This study seeks to explore associations between the NSE and the physical activity and screen time behaviours of preschool-aged children. METHOD: Cross-sectional data was collected in 2019. Parents (n = 214) of preschool-aged children (m = 3.8 ± 0.8 years), from 187 different Australian postcodes representing all states and territories were invited to complete an online survey where they answered questions about their NSE (perceived social cohesion, social interaction, sense of community, social norms and neighbourhood crime) and proxy-reported their child's usual physical activity and screen time (minutes/day). Two hierarchical linear regressions were run separately to assess relationships between NSE predictor variables and physical activity and screen time. Three logistic regressions were run to determine associations between NSE constructs and the likelihood of meeting: 1) physical activity (≥ 180 min/day including ≥ 60 min of moderate-to-vigorous-intensity), 2) screen time (≤ 60 min/day) and 3) both physical activity and screen time guidelines. Child age, gender, childcare attendance, and neighbourhood level socioeconomic status (SES) were controlled for in all analyses. RESULTS: Social interaction was associated with increased daily physical activity (b = 17.76, 95%CI = 0.81, 34.71), decreased daily screen time (b = -12.77, 95%CI = -23.23, -2.23) and improved the likelihood of meeting physical activity (OR = 1.81, 95%CI = 1.20, 2.75) and combined physical activity and screen time guidelines (OR = 1.51, 95%CI = 1.03, 2.21). Higher neighbourhood crime was associated with a lower likelihood of meeting screen time guidelines (OR = 0.47, 95%CI = 0.47, 0.99). Social cohesion, sense of community and social norms were not statistically significant predictors of daily physical activity, screen time or meeting guidelines. CONCLUSION: Social interaction showed the most consistent associations with physical activity and screen time. Future research should consider potential mediators of this relationship, including parental facilitation of children's outdoor time. Improving understanding of the relationship between the NSE and physical activity and screen time in young children can help to guide community-based initiatives striving to optimise behavioural, health and social outcomes.

Exploring activity compensation amongst youth and adults: a systematic review.

BACKGROUND: Globally, significant efforts have focused on increasing physical activity and reducing sedentary behaviour in youth and adults across a range of settings (e.g., schools, workplaces, community, and home). Despite this, interventions have had varied efficacy and typically have failed to sustain changes in behaviours over time. One explanation that has been put forth to explain the mixed success of interventions is activity compensation. However, little is known about activity compensation, including whether compensation occurs, and perceptions and potential mechanisms of activity compensation. Understanding activity compensation would assist in tailoring and targeting of potential intervention strategies. The primary aim of this review was to synthesise research that has investigated activity compensation in youth and adults. The secondary aim was to identify potential reasons for and/or awareness of compensatory changes that may have occurred. METHODS: An electronic search of the EBSCOhost (via Academic Search Complete, CINAHL Complete, Education Source, Health Source: Nursing/Academic Edition, PsycINFO, SPORTdiscus with Full Text), MEDLINE Complete, Global Health, EMBASE, Scopus and Web of Science databases up to May 2021 was conducted. Quality assessment of included quantitative studies used a modified compensation-specific McMaster Quality Assessment Tool. RESULTS: A total of 44 studies met the inclusion criteria (22 = adult populations; 22 = youth populations) and were classified as (1) quantitative (n = 31); (2) combination of quantitative and behavioural (n = 11); (3) behavioural only (n = 1); and (4) qualitative (n = 1). Of the 42 studies that included a quantitative component, 11 (26%) reported compensation occurred. Within the 13 studies examining specific behaviours, 35 behaviours were assessed, and evidence of compensation was inconsistent. Compensation mechanisms included fatigue, time constraints, lack of motivation, drive to be inactive, fear of overexertion, and autonomous motivation. CONCLUSION: Little evidence of compensation was reported in the included quantitative studies; however, inconsistencies between studies makes comparisons difficult. There was considerable variability in the types of behaviours assessed in quantitative studies, and few studies examined potential compensatory mechanisms. Future research, using compensation specific study designs, methods, and analytic techniques, within different population sub-groups, should address these evidence gaps.

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.

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.

Physical activity and active recreation before and during COVID-19: The Our Life at Home study.

OBJECTIVES: To examine the effects of COVID-19 related 'lockdown restrictions' on Australian's (5-75 years) physical activity recommendation achievement and active recreation participation. DESIGN: Cross-sectional online survey with self and proxy-report items (where the participant was a parent). METHODS: Adults (n = 1360) and adolescents (n = 1292) reported the frequency they performed 30- or 60-min of moderate-to-vigorous physical activity (MVPA), muscle-strengthening exercises, and participation in 11 active recreation behaviours in February 2020 (pre-COVID-19) and in April/May (during lockdown restrictions). Parents also proxy-reported activity for their child (n = 147, 5-12 years). Mixed effects logistic regressions or a logistic regression (with robust sandwich estimation for variance) assessed recall differences pre- and during lockdown, and interaction by sex. RESULTS: Compared to February, in April/May children were less likely to meet MVPA recommendations (OR = 0.27, 95%CI = 0.12-0.64); adolescents males, but not females, were less likely to meet MVPA (OR = 0.71, 95%CI 0.43, 1.17) and both recommendations (OR = 0.12, 95%CI = 0.02, 0.79); and adults were more likely to meet MVPA (OR = 1.26, 95%CI = 1.01, 1.57) but less likely to meet muscle-strengthening exercise recommendations (OR = 0.76, 9%CI = 0.65, 0.89). Across age groups more participants reported walking, muscle strengthening exercises at home, and yoga/Pilates/stretching at home, and fewer performed informal sport practice and play, and recreational activities. CONCLUSIONS: Lockdown restrictions had different effects on physical activity and active recreation among age groups and by sex. Physical activity promotion strategies that target children and adolescents, at home physical activity options, active neighbourhoods, and (re)engagement in informal sport and recreational activities post-COVID-19 are critical for (re)engaging Australians in health-enhancing behaviours.

Does light-intensity physical activity moderate the relationship between sitting time and adiposity markers in adolescents?

BACKGROUND: While the relationship between sedentary time and adiposity markers may be independent of moderate-to-vigorous intensity physical activity (MVPA) among adolescents, little is known about the role of light-intensity physical activity (LIPA) in this relationship. The aim of this cross-sectional study was to examine whether device-measured LIPA and MVPA moderate the associations between objectively measured sitting time and adiposity markers (body mass index (BMI)) and waist circumference (WC)) among adolescents. METHODS: This study included accelerometer and inclinometer data obtained from 219 adolescents (age = 14.9 ± 1.6 years, mean ± SD), collected during 2014 and 2015 in Melbourne, Australia. ActiGraph GT3X accelerometers were used to determine time spent in total-LIPA (101 counts/min to 3.99 metabolic equivalents (METs)) was dichotomized into low-LIPA (101-799 counts/min) and high LIPA (800 counts/min to 3.99 METs), and MVPA (≥ 4 METs). The average time spent sitting was obtained from activPAL inclinometers. Anthropometric measures were assessed by trained staff. Interactions between sitting and total-LIPA, low-LIPA, high-LIPA, and MVPA on BMI z-score (zBMI) and WC z-score (zWC), respectively, were examined using linear regression, adjusting for age and sex; and moderation by total-LIPA, low-LIPA, high-LIPA, and MVPA were examined by adding interaction terms. Significant interaction effects were probed by comparing associations at the mean and at 1 SD below and above the mean. RESULTS: Total-LIPA significantly moderated the association between sitting time and zBMI, and low-LIPA significantly moderated the association between sitting time and zBMI and zWC. No other associations were found for total-LIPA, high-LIPA, or MVPA. Specifically, at high levels of total-LIPA (+1 SD), there is a negative association between sitting time and zBMI. In addition, at high levels of low-LIPA (+1 SD), there is a negative association between sitting time and zBMI and zWC. CONCLUSION: Associations between sitting and adiposity depended on time spent in total-LIPA and low-LIPA, but not high-LIPA or MVPA. Results suggest that increasing time spent in LIPA may provide protection from the deleterious effects of sitting on adiposity markers among adolescents. Experimental evidence is needed to support these conclusions.

Changes in Families' Leisure, Educational/Work and Social Screen Time Behaviours before and during COVID-19 in Australia: Findings from the Our Life at Home Study.

This study aimed to understand differences in leisure, educational/work and social screen time behaviours experienced by parents and children due to COVID-19 lockdown restrictions, which may inform behaviour change strategies and policy in the transition to a COVID-normal life. Participants in the "Our Life at Home" study (n = 218 parents from Australia, 43.4 ± 6.8 years, 88% female) completed a cross-sectional online survey in April/May 2020. Parents recalled their own and their child (8.7 ± 2.0 years, 42% female) or adolescents (15.0 ± 1.5 years, 50% female) participation in nine screen time behaviours in the past month (during lockdown) and retrospectively for February 2020 (pre-lockdown), providing data on 436 individuals. Screen time behaviours included leisure (computer/laptop and tablet/smartphone for leisure, TV/videos/DVDs and game consoles); education/work (computer/laptop and tablet/smartphone for work/education); and social screen time (computer/tablet/smartphone for social communication with friends, family and work (parents only)). Wilcoxon signed-rank tests and effect sizes (r) compared the time spent in each behaviour pre-lockdown and during lockdown. Large differences were observed in social (parents: r = 0.41-0.57; children: r = 0.55-0.65; adolescents: r = 0.28-0.43) and education (children: r = 0.50-0.65 and adolescents: r = 0.25-0.37) behaviours. There were small or no differences in leisure time screen use. COVID-19 lockdown restrictions have impacted parent's and children's screen time, and future research and policy should consider strategies to support families to manage screen time.

Effectiveness and moderators of a multicomponent school-based intervention on screen time devices: the Movimente cluster-randomized controlled trial.

BACKGROUND: Interventions targeting reduce screen time in adolescents are urgently needed, mainly in low and middle-income countries because of the lack of evidence. Thus, the aims of the study were to examine the effect of a cluster-randomized controlled trial on screen time (ST) devices among Brazilian adolescents and to identify possible moderators. METHODS: Movimente was a multicomponent school-based intervention that was performed in 2017 and consisted of teacher training, education curriculum, and environmental improvements. Baseline and post-intervention assessments (over one academic year) were conducted with students aged 10-16 years at baseline (baseline n = 921, [n = 538 intervention group; n = 383 control group]). A self-report questionnaire was used to measure daily minutes of device specific screen time (TV, computer, video games and smartphone) and demographic variables. Linear mixed models were used to examine intervention effects and an exploratory moderation analysis (sex, grade and socioeconomic status) was performed. RESULTS: The intervention had no significant effects on TV time (ß = - 6.4, 95% CI: - 6.1;13.4), game time (ß = - 8.2, 95% CI: - 7.2;10.8), computer time (ß = 1.1, 95% CI: - 6.3;18.5), smartphone time (ß = - 10.2, 95% CI: - 32.5;12.1), screen time (ß = - 12.8, 95% CI: - 50.5;24.8), meeting screen time guidelines (OR: 1.29, 95% CI: 0.65,2.57) and meeting screen time guidelines with smartphone (OR: 1.66, 95% CI: 0.37,7.40). There was a significant intervention effect on reducing TV time (ß = - 37.1, 95% CI: - 73.0, - 1.3) among 8th grade students only. CONCLUSIONS: The Movimente intervention was effective only for TV time among 8th grade students. Understanding how school-based interventions can improve adolescents' device specific screen time across age groups is needed. Future strategies should cover all screen-based devices. Further, there is a need for more studies in low- and-middle income countries to assist in the development of effective strategies. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT02944318 (25/10/2016).

The Use of Digital Platforms for Adults' and Adolescents' Physical Activity During the COVID-19 Pandemic (Our Life at Home): Survey Study.

BACKGROUND: Government responses to managing the COVID-19 pandemic may have impacted the way individuals were able to engage in physical activity. Digital platforms are a promising way to support physical activity levels and may have provided an alternative for people to maintain their activity while at home. OBJECTIVE: This study aimed to examine associations between the use of digital platforms and adherence to the physical activity guidelines among Australian adults and adolescents during the COVID-19 stay-at-home restrictions in April and May 2020. METHODS: A national online survey was distributed in May 2020. Participants included 1188 adults (mean age 37.4 years, SD 15.1; 980/1188, 82.5% female) and 963 adolescents (mean age 16.2 years, SD 1.2; 685/963, 71.1% female). Participants reported demographic characteristics, use of digital platforms for physical activity over the previous month, and adherence to moderate- to vigorous-intensity physical activity (MVPA) and muscle-strengthening exercise (MSE) guidelines. Multilevel logistic regression models examined differences in guideline adherence between those who used digital platforms (ie, users) to support their physical activity compared to those who did not (ie, nonusers). RESULTS: Digital platforms include streaming services for exercise (eg, YouTube, Instagram, and Facebook); subscriber fitness programs, via an app or online (eg, Centr and MyFitnessPal); facilitated online live or recorded classes, via platforms such as Zoom (eg, dance, sport training, and fitness class); sport- or activity-specific apps designed by sporting organizations for participants to keep up their skills (eg, TeamBuildr); active electronic games (eg, Xbox Kinect); and/or online or digital training or racing platforms (eg, Zwift, FullGaz, and Rouvy). Overall, 39.5% (469/1188) of adults and 26.5% (255/963) of adolescents reported using digital platforms for physical activity. Among adults, MVPA (odds ratio [OR] 2.0, 95% CI 1.5-2.7), MSE (OR 3.3, 95% CI 2.5-4.5), and combined (OR 2.7, 95% CI 2.0-3.8) guideline adherence were higher among digital platform users relative to nonusers. Adolescents' MVPA (OR 2.4, 95% CI 1.3-4.3), MSE (OR 3.1, 95% CI 2.1-4.4), and combined (OR 4.3, 95% CI 2.1-9.0) guideline adherence were also higher among users of digital platforms relative to nonusers. CONCLUSIONS: Digital platform users were more likely than nonusers to meet MVPA and MSE guidelines during the COVID-19 stay-at-home restrictions in April and May 2020. Digital platforms may play a critical role in helping to support physical activity engagement when access to facilities or opportunities for physical activity outside the home are restricted.