The PLAYCE cohort was established to address a fundamental gap in child health research. Childhood is a critical period for establishing movement behaviours, including regular physical activity, adequate sleep and limited sedentary time, and these behaviours provide the foundation for lifelong health. They influence weight status, cardiorespiratory fitness, the musculoskeletal system, and cognitive and psychosocial development. Yet most research on children’s movement behaviours has been cross-sectional, capturing a single moment in time rather than tracking how behaviours change and interact as children grow. Australia and Canada were the first countries to release integrated 24-hour movement guidelines for young children in 2018, treating physical activity, sedentary behaviour and sleep as three co-dependent behaviours rather than isolated targets. Meeting all three recommendations together is considered optimal for child health, but until now it has been unclear whether children who achieve this balance in their early years sustain it as they move into middle childhood, or what that trajectory means for their health and development.

The scale of the measurement challenge is considerable. Between April 2015 and April 2018, researchers recruited 1,918 children aged 2 to 5 years through early childhood education and care services across Perth, Western Australia. Services were randomly sampled and evenly distributed across low, medium and high socio-economic areas and across service sizes. Of 273 services invited, 126 directors consented, a response rate of 46.2 percent. At the first wave, the median age of participating children was 3.3 years and 53 percent were male. The cohort has since been followed through junior primary school at ages 5 to 7, middle childhood at ages 8 to 10, and a fourth wave of data collection at ages 11 to 13 is underway and expected to be completed in early 2026. In total, 434 children have participated at all three completed waves, providing the kind of sustained individual tracking that longitudinal behavioural science depends on.

The technical core of the study is its use of ActiGraph GT3X+ accelerometers, small devices worn on the right hip that record acceleration in three dimensions. Children wore the devices for seven consecutive days, initially excluding water activities and sleep, and from the second wave onward across the full 24-hour cycle to capture sleep as well as waking movement. Valid wear time was defined as a minimum of eight hours on at least three weekdays and one weekend day. Rather than relying on traditional cut-point methods, which classify activity intensity using fixed thresholds, the researchers applied a random forest machine learning model to the raw tri-axial acceleration signals. This algorithm classifies behaviour into sedentary activity, light-intensity games, walking, running and moderate-to-vigorous activity with an overall accuracy exceeding 80 percent, agreeing more closely with measured intensity than cut-point approaches and showing equivalence with direct observation. The distinction matters because young children’s activity is notoriously sporadic and difficult to categorise, and more accurate classification yields a sharper picture of the actual doses and combinations of movement linked to health outcomes.

The environmental measurement is equally ambitious. A subset of 237 children at the first wave also wore Qstarz GPS devices on the same belt as their accelerometers, recording location coordinates, distance, speed and elevation with a median dynamic accuracy of 2.9 metres. Combining these spatial traces with Geographic Information Systems data allowed researchers to calculate measures around each child’s home and care centre, including outdoor space, vegetation, public open space quality, blue space, traffic exposure, public transport, street connectivity, residential density and access to child-relevant services, all within 500-metre and 1,600-metre buffers. Physical and policy audits of early childhood education and care centres assessed indoor and outdoor play spaces, play and media equipment, built and natural features, and the presence of service policies on physical activity, screen time and sun protection. Educator surveys captured staff practices, and parent surveys recorded structured and unstructured activity, sleep, screen time, diet, social-emotional development measured with the Strengths and Difficulties Questionnaire, motor development, and neighbourhood perceptions using the Neighbourhood Walkability Scale for Youth.

The baseline results are striking. On average, preschoolers in the cohort accumulated 373 minutes of total physical activity per day, of which just 39.1 minutes was energetic play such as running and vigorous games. They averaged 106.9 minutes of daily screen time and 11.5 hours of sleep. Individually, 42 percent met the physical activity guideline, 67 percent met the screen time recommendation and 92 percent met the sleep guideline, but only 8 percent satisfied all three simultaneously. Meeting all three recommendations was positively associated with social-emotional development in boys, consistent with emerging international evidence that the combination of behaviours, not any single behaviour alone, drives developmental benefit. Other analyses from the cohort have linked moderate-to-vigorous physical activity with self-regulation and cognitive school readiness, and shown that children from dog-owning households had reduced odds of social-emotional problems, with those who walked or played with their dog more often showing improved prosocial behaviours.

The environmental findings offer concrete design clues. Features of the home yard, including its size, the presence of play equipment and natural features, were positively associated with preschoolers’ outdoor play. At childcare centres, tree canopy in outdoor areas served both as sun protection and as an enabler of children’s outdoor time, while more portable play equipment was linked to greater outdoor activity. A novel analysis combining accelerometer, GPS and on-site audit data mapped physical activity hot spots within centres, finding them concentrated in open areas and adjacent outdoor play spaces where children could move freely between them. Air pollution monitoring revealed a troubling overlap: pollution concentrations at childcare centres were highest at exactly the times children were likely to be active outdoors, prompting a recommendation to avoid locating services in high-traffic areas. Neighbourhood perceptions mattered too, with parents’ positive views of traffic safety, crime safety and land use mix associated with lower odds of social-emotional difficulties in their children.

The study has not been without challenges. Retention fell to 39.9 percent of eligible and contactable participants at wave 2 and 38.7 percent at wave 3, reflecting the three-year recruitment window that left some children outside the age criteria for follow-up, the disruption of COVID-19 restrictions during wave 2 data collection, and the time burden of parental questionnaires. The researchers note, however, that the representativeness of the sample remained largely unaffected and the cohort remains sufficiently powered for longitudinal analyses. The study is limited to a single site in Perth and underrepresents families with lower relative socio-economic status, single-parent households, First Nations families and culturally and linguistically diverse communities, gaps the team identifies as priorities for future research. A community-based consumer reference group of parents now provides input into recruitment, methodology and the translation of findings, meeting at least three times a year.

As the fourth wave concludes, the team plans traditional longitudinal and compositional analyses to map in detail how movement behaviours shift across the transition from early childhood education to full-time school, a period when previous small studies have recorded increases of around 40 minutes of daily sedentary time and declines in physical activity. Whether those changes are permanent or transitional remains unknown, and the PLAYCE data should answer it. The findings are expected to inform future revisions of national and international 24-hour Movement Guidelines, which have called for more rigorous and consistent accelerometer processing methods, and to guide setting-specific and population-level interventions, from childcare policy to neighbourhood design, aimed at curbing childhood obesity and ensuring children have the opportunity to lead active, healthy lives from their earliest years through adolescence.

Subject of Research: A longitudinal cohort study of children's physical activity, sedentary behaviour and sleep across early to middle childhood in Western Australia

Article Title: Profile of the PLAY spaces & environments for children’s physical activity, sedentary behaviour and sleep (PLAYCE) cohort study, Western Australia

Article References: Christian, H., Nathan, A., Trost, S. G., Schipperijn, J., Boruff, B., Adams, E. K., George, P., Moore, H. L., & Henry, A. (2025). Profile of the PLAY spaces & environments for children’s physical activity, sedentary behaviour and sleep (PLAYCE) cohort study, Western Australia. Journal of Activity, Sedentary and Sleep Behaviors, 4(1), Article 7. https://doi.org/10.1186/s44167-025-00078-8

Image Credits: AI Generated

DOI: 10.1186/s44167-025-00078-8

Keywords: PLAYCE cohort study, children's physical activity, sedentary behaviour, sleep, 24-hour movement guidelines, accelerometry, built environment, early childhood education, child development, obesity, GPS tracking, Western Australia

The research team drew on the QUALITY cohort, an ongoing investigation into the natural history of childhood obesity that recruited 630 Quebec families between 2005 and 2008. To be eligible, children had to be eight to ten years old and have at least one parent living with obesity, a design that deliberately targets families at elevated cardiometabolic risk. For the neighbourhood analysis, the investigators retained 326 Montreal participants with complete data at both visits, including 183 boys and 143 girls. The children were assessed twice: once in childhood at ages eight to ten, and again two years later in pre-adolescence at ages ten to twelve, a window when independence from parents expands and behaviour patterns begin to consolidate.

What makes the study technically notable is its insistence on objective measurement at both ends of the equation. Physical inactivity and sedentary behaviour were captured with seven-day uniaxial accelerometry, with children required to wear the devices for at least four days of ten hours or more. Excess physical inactivity was defined as averaging fewer than sixty minutes of moderate-to-vigorous physical activity per day, the international recommendation for youth, while excess sedentary behaviour time meant spending more than half of accelerometer wear time below one hundred counts per minute. Screen time, by contrast, was self-reported through interviewer-administered questionnaires covering television, video games, and computer use, with more than two hours of daily recreational screen use classified as excessive. The correlations between the three measures were surprisingly weak, with screen time barely tracking either accelerometer-based outcome.

The neighbourhood itself was measured with equal rigour. Trained auditors walked the ten street segments adjacent to each family’s home, recording sidewalks, pedestrian aids, traffic calming measures, physical activity structures, signs of social disorder such as graffiti and vandalism, and whether buildings were exclusively residential. Geographic information systems added a second layer, computing within one-kilometre street-network buffers the number of parks, three-way or larger intersections, land use mix, rush-hour traffic exposure, and residential density. Seventeen distinct features in total entered gender-specific logistic regression models adjusted for age, parental body mass index, parental education, and area-level material deprivation.

The headline result concerns parks. Each additional park in a child’s neighbourhood was associated with lower odds of excessive screen time in boys and girls alike, at both ages, with odds ratios ranging from 0.70 to 0.81. This was the only neighbourhood feature that behaved consistently across every age and sex group, and it did so for screen time specifically, not for sedentary behaviour or physical inactivity. The authors interpret this as evidence that parks act as a competing activity: a green space down the street offers children something to do that directly displaces hours in front of a screen, even if the time spent there is not always vigorous.

Beyond parks, the picture fractured along gender lines. Among boys aged eight to ten, the presence of physical activity structures such as outdoor playgrounds was strongly linked to lower odds of excessive sedentary behaviour time, with an odds ratio of 0.44. Among girls, however, the protective features only emerged in the ten-to-twelve age group: more sidewalks were associated with lower odds of excess sedentary time, and living in an exclusively residential neighbourhood carried a dramatic odds ratio of 0.13. Yet the same girls’ environments contained apparent risks, with neighbourhood disorder and greater land use mix each associated with higher odds of excessive sedentary behaviour. The researchers caution that disorder and sidewalks are both hallmarks of denser urban environments, which give children more destinations they can reach independently, sometimes involving sitting-based activities like cafes.

Screen time among girls proved especially responsive to urban form. In the older girls, living in an exclusively residential neighbourhood nearly doubled the odds of excessive screen time, while greater land use mix cut those odds nearly in half. This echoes earlier work showing that girls with access to twelve or more youth-related destinations near home recorded 109 fewer minutes of weekly screen time than girls with three or fewer. Boys’ screen habits, by contrast, seemed largely indifferent to their surroundings, with only sidewalks and street intersections showing any association. The authors point to possible explanations: girls may be more likely to substitute screen time with social outings when destinations exist, while boys tend to use screens regardless of what the neighbourhood offers, and girls additionally face barriers such as parental safety concerns and fear of peer judgement that shape how they can use public space.

Perhaps the most sobering finding was what did not matter. Physical inactivity, the outcome with the clearest clinical guidelines, was almost untouched by any of the seventeen neighbourhood features. The sole exception was neighbourhood disorder among younger boys, which was associated with higher odds of inactivity. The authors suggest that young children’s activities are heavily orchestrated by parents, who may drive families well beyond the neighbourhood boundaries the study measured, so the local built environment simply has less leverage over whether a nine-year-old accumulates sixty minutes of moderate-to-vigorous activity. A systematic review cited in the paper reached a similar conclusion: built environment features predict adolescent activity levels far better than those of children.

The study’s behavioural trade-off framework offers the most provocative idea for policymakers. A park may reduce screen time by offering an alternative, yet increase sedentary time if it is used passively. Sidewalks may promote active transport, yet deliver children to destinations where they sit. These interactions mean that a single intervention, however well-intentioned, will not uniformly improve all movement behaviours, and may not benefit all groups equally. The authors highlight low-cost Montreal initiatives such as ruelles actives, which convert alleyways with traffic calming, greenery, and play facilities, as the kind of targeted transformation that could work, provided planners know which behaviour they are trying to change.

The context gives the findings urgency. In Canada, thirty percent of children live with overweight or obesity, and only two in five met physical activity recommendations in 2018, trends the World Health Organization has urged countries to confront as a cardiometabolic priority. In this cohort, the numbers worsened with age: physical inactivity rose from 68 percent to 79 percent between the two visits, average sedentary time climbed from 4.5 to 5.2 hours daily, and excessive screen time jumped from 53 to 70 percent. The authors acknowledge limitations, including a sample largely of Western European descent with socioeconomically advantaged families, and the risk of false positives across many tested models, though they note the consistency of key trends. Replication in more diverse populations is needed. But the core message stands: physical inactivity, sedentary behaviour, and screen time are not interchangeable labels for the same problem, and treating them as such risks building neighbourhoods that help some children while leaving others, particularly girls and boys in different ways, exactly where they started.

Subject of Research: Associations between neighbourhood built environment features and physical inactivity, sedentary behaviour, and screen time in boys and girls at risk of obesity

Article Title: Distinguishing associations between neighbourhood features and physical inactivity, sedentary behaviour time, and screen time in boys and girls

Article References: Lungu, A. A., Ghenadenik, A. E., Van Hulst, A., Mathieu, M.-E., Henderson, M., Kestens, Y., & Barnett, T. A. (2025). Distinguishing associations between neighbourhood features and physical inactivity, sedentary behaviour time, and screen time in boys and girls. Journal of Activity, Sedentary and Sleep Behaviors, 4(1), Article 8. https://doi.org/10.1186/s44167-025-00074-y

Image Credits: AI Generated

DOI: 10.1186/s44167-025-00074-y

Keywords: physical inactivity, sedentary behaviour, screen time, built environment, neighbourhood, childhood obesity, accelerometry, parks, walkability, gender differences, QUALITY cohort, urban planning

The new study, published in the Journal of Activity, Sedentary and Sleep Behaviors, drew on five consecutive waves of the National Survey of Children’s Health, a nationally representative, parent-reported survey administered by the U.S. Census Bureau in partnership with the Maternal and Child Health Bureau. Researchers analyzed responses covering 135,309 children and adolescents aged six to seventeen, a weighted sample representing roughly 48.4 million young Americans. The data spanned 2018 through 2022, a window that captures life before the COVID-19 pandemic, the disruption of lockdowns and remote schooling, and the partial return to normalcy that followed.

The framework behind the analysis is the concept of 24-hour movement behaviors, an increasingly influential idea in pediatric health research. Rather than treating physical activity, sedentary screen use, and sleep as separate concerns, the approach recognizes that these behaviors are locked in a zero-sum relationship: every hour devoted to one is an hour taken from another. Under the relevant guidelines, children and adolescents should accumulate at least sixty minutes of moderate-to-vigorous physical activity daily, limit recreational screen time to two hours or less per day, and sleep between nine and eleven hours per night for children aged six to twelve, or eight to ten hours for adolescents aged thirteen to seventeen.

The pooled results paint a stark picture. Across all five years combined, just 20.8 percent of young people met the physical activity guideline, 49.6 percent met the screen time guideline, and 64.7 percent met the sleep guideline. Only 9.7 percent managed all three simultaneously. Because meeting multiple guidelines together is associated with the strongest health benefits, from cardiometabolic risk factors to mental well-being, that last number may be the most consequential in the entire analysis.

The trend lines are what make the findings genuinely alarming. Using robust Poisson regression models adjusted for age, sex, race and ethnicity, household income relative to the federal poverty level, metropolitan status, and weight status, the researchers calculated predicted prevalences for each guideline in each year. Every combination of guidelines showed significantly lower adherence in 2022 than in 2018, with sleep the lone exception, remaining stable across the period. Screen time adherence fell from 52 percent in 2018 to 47 percent in 2022, while physical activity adherence dropped from 21 percent to 17 percent. Concurrent adherence to all three guidelines slipped from 9 percent to 7 percent. Cochran-Armitage tests for trend confirmed statistically significant downward trajectories across the board.

The single most dramatic shift occurred between 2019 and 2020, when screen time guideline adherence plummeted from 52 percent to 40 percent, a twelve-percentage-point collapse in a single year. The timing points unmistakably to the COVID-19 pandemic, when quarantine policies, remote learning, and the disappearance of structured routines reshaped children’s daily lives. Intriguingly, screen time adherence crept back upward in each year after 2020, though it never returned to its pre-pandemic level. The researchers interpret this partial recovery as evidence that screen behaviors are modifiable and responsive to environmental change, a potentially encouraging signal that schools reopening and routines resuming can pull behavior back toward healthier patterns.

Sleep tells a different story. Adherence to sleep duration guidelines held essentially steady across the five years, even rising slightly between 2018 and 2021 before dipping in 2022. The authors suggest several possible explanations: sleep duration may be biologically regulated and less sensitive to external disruption, parental control over bedtimes tends to be strong, and the pandemic may have produced offsetting effects, with the loss of early morning commutes and extracurricular commitments potentially allowing some children to sleep longer even as stress and disrupted routines eroded sleep quality. The researchers caution, however, that the guidelines measure only duration, not sleep quality, consistency, or timing, all of which influence health. Stable duration should not be read as evidence that sleep health went untouched.

The analysis also revealed persistent disparities that did not narrow over time. Girls showed significantly lower adherence than boys to the physical activity guideline and to every combination involving it, while showing higher adherence to screen time guidelines. Children fared better than adolescents on nearly every measure, a gap the authors attribute in part to the transition to secondary school, which brings heavier academic demands, more homework, and extended evening screen use, as well as the growing autonomy of adolescence, which brings less parental oversight, more device access, and shifting chronotypes that push bedtimes later while school start times stay fixed. Young people with overweight or obesity had significantly lower adherence to every guideline than those without, a bidirectional relationship the authors note cannot be untangled with cross-sectional data but which prior research suggests runs in both directions.

The public health stakes are considerable. Meeting these guidelines is linked to cognition, academic achievement, motor skills, mental health, and the risk of non-communicable diseases including obesity and diabetes. A generation that increasingly fails to meet them faces elevated risks of chronic disease and added strain on an already burdened healthcare system. The authors argue the findings support multi-level interventions tailored to the subgroups at greatest risk, and they make a pointed structural recommendation: unlike Canada, Australia, and several other countries, the United States still lacks integrated 24-hour movement guidelines, relying instead on separate recommendations for activity, screens, and sleep. Recognizing these behaviors as a single, co-dependent cycle, they argue, could set the stage for the widespread adoption and promotion that individual guidelines have so far failed to achieve. With fewer than one in ten young Americans currently clearing all three bars, and the trend moving in the wrong direction, the case for treating the whole day as one health target has rarely been clearer.

Subject of Research: Trends in adherence to 24-hour movement behavior guidelines among U.S. children and adolescents from 2018 to 2022

Article Title: Five-year trends in U. S. child and adolescent 24-hour movement behavior guideline adherence, 2018–2022

Article References: Pfledderer, C. D., Mullane, E. J., Brown, D. M. Y., Burkart, S., Hunt, E. T., Johnson, A., Parker, H., & Salvo, D. (2025). Five-year trends in U. S. child and adolescent 24-hour movement behavior guideline adherence, 2018–2022. Journal of Activity, Sedentary and Sleep Behaviors, 4(1), Article 16. https://doi.org/10.1186/s44167-025-00086-8

Image Credits: AI Generated

DOI: 10.1186/s44167-025-00086-8

Keywords: 24-hour movement behaviors, physical activity, screen time, sleep, children and adolescents, National Survey of Children's Health, COVID-19 pandemic, public health, obesity, health disparities, pediatric health, behavioral interventions

The intervention, called Happy Homework 2.0, is a digital application designed to weave movement-based activities into the routines children already follow at home. Rather than adding another demand to crowded school timetables, the programme exploits a slot that already exists in every child’s evening. The concept builds on a growing body of evidence that school-based interventions, while scalable, often lose their impact once children leave the school gates. Homework, the researchers reasoned, could act as a bridge, extending the reach of classroom health messaging into the living room, the garden and the bedroom, where most sedentary time and sleep actually occur.

To test whether the idea could work in practice, the team conducted an eight-week pilot cluster randomised controlled trial across four primary schools in the West of Scotland. In a cluster randomised design, entire classes rather than individual children were allocated to either the intervention or the control condition, a method that reduces the risk of contamination between participants who see each other every day. A total of 82 children aged between 8 and 12 years took part, representing 60 percent of those invited, and 87 percent of them were still providing data at follow-up. Those retention figures, the researchers report, indicate good feasibility for a trial of this kind, which is precisely what a pilot study is designed to establish before larger, fully powered trials are attempted.

The evaluation went beyond simple attendance numbers. Feasibility, usability and acceptability were assessed through basic app-usage analytics and questionnaires completed by three separate constituencies: the children themselves, their parents, and their teachers. Gathering perspectives from all three groups matters because a digital health intervention for children sits at the intersection of competing interests. Children must find the app engaging enough to open it voluntarily, parents must be willing to accommodate it in the evening routine, and teachers must see enough value to integrate it into their homework expectations without it becoming a burden.

The study also collected objective data on the outcomes that matter most. Children wore activPAL devices, small sensors attached to the thigh that distinguish between sitting, standing and stepping based on posture rather than relying on self-report. This technology provided multiple posture- and movement-based metrics, giving the researchers a far more reliable picture of sedentary behaviour than questionnaires alone could offer. Sleep was measured through self-report questionnaires, and children’s motivation was assessed using instruments based on basic psychological need satisfaction, a framework rooted in self-determination theory, which holds that motivation flourishes when people feel autonomous, competent and connected to others.

The statistical analysis used linear mixed-effects models, a technique well suited to this kind of trial because it accounts for two sources of dependency in the data: the clustering of children within schools, and the fact that each child was measured repeatedly over time. By modelling group-by-time interactions, the researchers could ask whether children in the intervention arm changed differently from those in the control arm, rather than simply comparing average values at the end of the study. This approach is now standard in behavioural trials, but its careful application in a small pilot is notable, because it demonstrates that the study design can detect genuine signals even before scaling up.

What did those signals show? The most striking finding concerned sedentary behaviour. The activPAL data revealed a significant group-by-time difference, with sedentary time increasing more in the intervention group than in the control group, a difference of 66.2 minutes per day that reached statistical significance. Self-reported sleep also showed a significant interaction, with smaller increases in reported sleep duration among children using the app relative to controls. No other secondary outcomes, including measures of physical activity, showed significant group-by-time differences. Taken at face value, these results are not the triumphant headline one might hope for from a movement intervention: the app did not reduce sitting or boost activity in the intended direction during this pilot period.

The researchers are candid about the most likely explanation: engagement. The app-use analytics showed repeated engagement among participants, but overall use was modest, defined by declining frequency and duration of interactions over the eight weeks. In other words, children tried the app, returned to it for a while, and then gradually drifted away, a pattern familiar to anyone who has downloaded a fitness app with good intentions in January and abandoned it by March. When the dose of an intervention falls, its effects tend to attenuate with it. The team concludes that Happy Homework 2.0 was feasible and acceptable as a homework-based health intervention, but that engagement levels likely limited its effectiveness, and the unexpected shifts in sedentary time and sleep may reflect this weak implementation rather than any inherent failure of the concept.

That interpretation is where the real scientific value of the study lies. Pilot trials are not meant to deliver definitive answers; they are meant to expose the practical friction points that would otherwise sabotage a large trial. Here, the friction is clear: sustaining children’s voluntary engagement with a digital health tool over weeks, not days, remains the central challenge of mHealth interventions for young people. The authors emphasise the need to strengthen implementation strategies, sustain engagement, and enhance the involvement of parents and teachers, the two adult groups whose encouragement could counteract the natural decay of novelty. The study was retrospectively registered as NCT07631754, funded through a University of the West of Scotland Vice-Chancellor’s Studentship Scheme, and published open access in the Journal of Activity, Sedentary and Sleep Behaviors.

The broader lesson extends well beyond one Scottish app. Digital interventions promise scale and personalisation that classroom programmes cannot match, but they also compete for attention in an ecosystem saturated with far more compelling screen content. The paradox is sharp: an app designed to pull children away from screens must first win a battle for screen time. Future iterations of Happy Homework, and similar tools now in development through co-design studies with children and families, will need to treat engagement not as an afterthought but as the primary design target, using gamification, family involvement and curriculum integration to keep the dose high enough for biology to respond. The 24-hour movement behaviours of children remain a modifiable target, and the homework slot remains an underexploited opportunity. What this pilot establishes is that the pipeline from idea to evidence works; what it also establishes is that the hardest variable to move is not the child’s body, but the child’s attention.

Subject of Research: A pilot cluster randomised controlled trial testing the feasibility, acceptability and usability of a digital homework app targeting physical activity, sedentary behaviour and sleep in primary school children.

Article Title: Happy Homework 2.0: effects on 24-hour movement behaviours in children—findings from a pilot cluster randomised controlled trial

Article References: Forrest, A., Buchan, D. S., Sculthorpe, N., & Robinson, S. (2026). Happy Homework 2.0: effects on 24-hour movement behaviours in children—findings from a pilot cluster randomised controlled trial. Journal of Activity, Sedentary and Sleep Behaviors. https://doi.org/10.1186/s44167-026-00111-4

Image Credits: AI Generated

DOI: 10.1186/s44167-026-00111-4

Keywords: physical activity, sedentary behaviour, sleep, children, homework, digital intervention, mHealth, cluster randomised controlled trial, 24-hour movement behaviours, app development, school-based intervention, activPAL

The study followed 119 child–guardian pairs over two years, using objective activity monitoring. Children wore wrist-based monitors to quantify MVPA, while families also completed structured questionnaires. The research focused on how different types of guidance—content-only versus motivation-focused coaching—shape children’s drive to keep exercising.

Instead of relying on external pressure, the team grounded the coaching strategy in Self-Determination Theory (SDT). SDT emphasizes three psychological needs—autonomy, competence, and relatedness—that, when supported, can sustain intrinsic motivation. Accordingly, guardians were encouraged to offer exercise choices, provide specific positive feedback, and create short parent–child interaction moments during activity sessions.

Participants were randomly assigned to four conditions: an Exercise Only group received video workouts; a Coach Only group received SDT-informed coaching videos; an Exercise-plus-coaching group received both; and a Control group received no intervention. This randomized controlled design allowed the researchers to isolate which components actually changed real-world activity patterns.

After implementation, children in the Exercise Only and Exercise-plus-coaching groups increased average daily MVPA from 34.6 minutes to roughly 41–42 minutes, an improvement of about 6–7 minutes per day. Meanwhile, the Control group’s activity decreased by approximately 14 minutes, highlighting how quickly routines can deteriorate without structured support.

Dr Gary Chow Chi-ching, who led the project, noted that parenting styles based purely on pressure may produce short-lived compliance. In contrast, autonomy-supportive communication appeared to help children maintain motivation and better satisfy their psychological needs—an effect the team believes is key to long-term behavior change.

The exercise library was co-designed with students, aiming for short, fun, and household-friendly sessions that fit space constraints and varying schedules. Importantly for real families, the intervention also worked for parents with full-time jobs, who reportedly found time to join activities with their children.

Funded by the Research Grants Council’s Early Career Scheme, the results were published in the Journal of Exercise Science & Fitness. The team is now planning school-integrated digital platforms and additional support pathways to keep children active beyond the initial trial—an approach that could make home exercise both measurable and viral.

Subject of Research: People
Article Title: An SDT-informed online intervention supporting children’s home-based exercise: A randomized controlled trial
News Publication Date: 1-Jul-2026
Web References: https://www.sciencedirect.com/science/article/pii/S1728869X26000390 , https://www.sdtgames.com/en
References: Journal of Exercise Science & Fitness
Image Credits:
Keywords: physical activity, children, Hong Kong, Self-Determination Theory, randomized controlled trial, MVPA, home-based exercise, parental support, intrinsic motivation