Background In Bangladesh, many children do not get enough opportunities for active play because safe play spaces are limited, school culture often prioritises academic success over physical activity, and many families have safety concerns about outdoor play. These factors reduce the time children spend being active, despite the fact that active play is known to be crucial for children's healthy growth and development. Active play helps children move more, stay physically fit, and develop important social and emotional skills such as teamwork, confidence, and enjoyment. It also supports motor skill development, which includes basic skills like running, jumping, throwing, and catching. The lack of active play in everyday life suggests a strong need for school based programs that can safely introduce regular, structured, and enjoyable physical activity opportunities for children.

Objective The main objective of this study is to find out whether a school based active play program can help children increase their daily physical activity, reduce the amount of time they spend sitting, and improve their sleep patterns. The study also aims to examine whether the program improves children's fundamental movement skills, such as running, jumping, throwing, and catching.

Methods This study will use a randomised controlled trial design. Randomisation will be at the school level to ensure fairness and reduce bias. This study will test a 12-week school-based AP programme designed to help primary school children in Bangladesh be more active, sit less, sleep better, and improve their basic movement skills. The study will involve eight primary schools, with each school acting as one cluster. Four schools will receive the AP programme and the remaining four will continue their usual routine. About 43 children from each school will join, giving a total sample of around 343 students.

Eligibility Criteria Children can take part if they are students at a primary school, healthy, staying in their school for at least six months, able to understand basic Bengali or English, and are Bangladeshi citizens. Children will not be included if they are outside the age range, not attending school, or regularly involved in organised sports, dance, or athletic training. These rules help ensure that the programme is safe and that the comparison between the AP group and the control group is fair.

Intervention Description The AP programme will run twice a week for 60 minutes. Each session will include 30 minutes of free play where children choose their own games and 30 minutes of researcher-led guided play. Activities will help children practise running, jumping, throwing, catching, and other fundamental skills. Weekly themes will keep the sessions enjoyable. Students will earn activity points for being active during sessions, reducing screen time at home, and following healthy sleep routines. Each week, the top three "Active Champions'' from every school will receive a small reward.

Orientation Sessions Before the programme begins, orientation sessions will be held for parents, teachers, and children. Parents will learn how to support safe play at home, especially when outdoor play is limited due to dengue or safety concerns. They will also receive tips on reducing screen time and encouraging good sleep habits. Teachers will be trained to integrate active breaks, organise movement-friendly classrooms, use outdoor areas safely, and give feedback to students. Children will learn why active play is important and how it can help their health, learning, confidence, and friendships.

Data Collection Plan Data will be collected at three time points: before the programme (T1), immediately after 12 weeks (T2), and eight weeks later (T3). Researchers will collect questionnaire responses, measure height, weight and use wrist-worn accelerometers to measure physical activity, sitting time, and sleep. Teachers and parents will help children wear the devices correctly and keep usage records. Fundamental motor skills will be assessed using the (Test of Gross Motor Development) TGMD 3 tool.

Data Analysis Researchers will check all data for accuracy and compare results between the AP and control groups. The study will examine changes in PA, sedentary behaviour, sleep patterns, and FMS. It will also explore whether age, gender, or family background affects how children respond to the programme. The results will help determine whether the AP programme is practical for Bangladeshi schools and effective in improving children's movement behaviours and FMS.

Expected Results It is expected that children who participate in the AP program will show clear improvements in PA levels, movement skills, sitting time, and sleep patterns compared with children in the control group. Schools may also learn simple and low-cost ways to support children's activity within limited time and space, making the program valuable beyond the study itself.

Background Children in Bangladesh experience limited opportunities for regular physical activity (PA) due to structural and environmental constraints, including the absence of adequate playgrounds in many schools and parental concerns related to outdoor safety and mosquito borne disease outbreaks. These barriers contribute to prolonged periods of sedentary behaviour (SB), increased screen exposure, and reduced engagement in movement rich activities, all of which negatively affect children's physical health, sleep patterns, and fundamental movement skill (FMS) development.

Active Play (AP) has been identified as a low cost, developmentally appropriate approach that promotes PA, enhances confidence, and supports the acquisition of essential motor skills such as running, jumping, and throwing. Given these benefits, implementing guided AP with free play within school environments may offer a feasible and scalable strategy to improve children's movement behaviours and FMS in low resource settings. This study therefore aims to evaluate whether a school based AP programme can be effective to improve movement behaviours and FMS in Bangladeshi primary schools.

Objective The primary objective of this study is to evaluate whether a school based AP programme can improve children's movement behaviours-FMS in Bangladeshi primary school children.

Specific Objectives

1. To measure changes in children's physical activity levels, including daily minutes of moderate to vigorous physical activity (MVPA), Low PA and step counts.
2. To assess changes in sedentary behaviour and recreational screen time.
3. To evaluate changes in sleep duration.
4. To determine changes in children's FMS Hypotheses Primary Hypotheses

1. Children in the intervention group (IG) will show a greater increase in daily LPA, MVPA and Step Count 2. Children in the IG will demonstrate a greater improvement in FMS Secondary Hypotheses

1. SB will decrease more in the IG than in the control group (CG)
2. Sleep duration will improve more in the IG group than in the CG
3. AP duration during non-school hours will increase more among IG children Study Design for Randomised Controlled Trials The RCT will be designed to promote PA, SB, Sleep and FMS among primary school-aged children of Bangladesh. The study will be conducted in selected schools, serving as clusters, to evaluate the effectiveness of a school-based AP intervention over a period of 12 weeks. The study will utilize a two-arm cluster RCT design, comparing the intervention group to a control group across eight primary schools. To meet the inclusion criteria, a minimum of 43 students will be recruited from each school.

Sample Size Calculation In the proposed study, the sample size for the cluster RCT involving Bangladeshi primary school children is calculated based on the expectation of an increase of 10 minutes per day of MVPA in the intervention group compared to the control group. This is consistent with a school-based intervention aimed at increasing MVPA among adolescents in Bangladesh [1]. To achieve 80% power at a 5% significance level, a minimum of 36 students per cluster was determined to be necessary, given a standard deviation of 31.98 minutes and an intra-cluster correlation of 0.03 [2,3]. With 8 clusters (schools) involved in the study, the total sample size calculated was approximately 154 students per group, leading to a total of 308 students across both groups. Considering an attrition rate of 10%, the adjusted sample size required was approximately 343 students. This translates to about 43 students per cluster from the eight selected schools, ensuring adequate power to detect the desired difference in moderate PA levels.

Randomisation The participants will be selected from eight primary schools, with a convenience sampling method agreed upon, being randomly assigned to the intervention and control groups.

After recruitment, baseline data will be collected, and eligible individuals will be randomly assigned to either the IG or CG. This process will utilise allocation concealment through a computer-generated sequence (IBM SPSS 27), with the entire allocation sequence managed by a statistician. The results of this random allocation will be communicated to the researchers overseeing the study and will not be disclosed to the participants.

The pre-validated questionnaire will be used for data collection at baseline (T1), endline (T2) and follow-up (T3). All information will be stored in printed copies of the questionnaire and saved for seven years for publication purposes. The researcher will photograph students whose parents grant permission for their pictures to be used in the research. The intervention will last for 12 weeks and will take place on the school premises. Before the intervention, the principals of the selected schools will be contacted to ensure their support, and written consent forms will also be collected from them. The class teachers will also be invited to participate in weekly group discussions to promote AP and enhance PA among the children. Also, they will keep records of the children's participation in the AP sessions. If a class teacher cannot participate, the principal will be asked to appoint another teacher for the study.

Orientation for Children, Parents and Teachers Orientation session will be organised for the IG students, parents and teachers, offering a comprehensive briefing on the AP interventions process.

Orientation Content for Parents: Promoting Active Play in Non-school Hours In the proposed study, parents will learn effective strategies to promote AP in the context of Bangladesh, where outdoor play poses risks such as child trafficking and dengue fever.

Promoting Active Play at Home: Parents will be encouraged to create a stimulating indoor environment by providing engaging, low-cost toys, such as balls, jump ropes, and to play hide and seek, which promote movement. They will be guided to set aside dedicated time for activities like dance, yoga, or simple exercises, making PA enjoyable. Additionally, organising family games or challenges, such as obstacle courses or scavenger hunts, during outdoor leisure activities will be suggested to enhance PA.

Reducing Sedentary Behaviour (SB): The study will emphasise the importance of establishing "screen-free" periods during the day to combat excessive screen time. Parents will be advised to promote alternative activities, such as reading, arts and crafts, or cooking together, keeping children engaged while fostering creativity and movement.

Establishing Proper Sleep Routines: Parents will receive guidance on creating consistent bedtime routines to ensure adequate sleep. This will include setting regular sleep schedules, creating a calming environment, and limiting stimulating activities before bed.

To further engage parents, a WhatsApp group will be created for those who use the platform. It will provide video content demonstrating how parents can encourage PA during non-school hours. This platform will serve as a resource for sharing effective strategies, enabling parents to exchange valuable insights and techniques that have successfully promoted AP at home.

Additionally, all parents in the IG will receive weekly push notifications on their mobile devices, reminding them of the benefits of AP and movement behaviours for overall health and well-being.

Orientation Content for Teachers: Promoting Active Play During School Hours In the proposed study, teachers will be equipped with strategies to promote AP during school hours, fostering AP and FMS among students.

Incorporating Active Breaks: Teachers will be encouraged to integrate short, structured activity breaks into the school day. These breaks could include stretching, quick games, or movement-based activities that help re-energise students and improve focus.

Active Learning Environments: Classrooms will be designed to facilitate movement. Teachers will be guided to arrange furniture to allow for easy transitions between activities and to create spaces for group work that encourage collaboration and physical engagement.

Utilising Outdoor Spaces Safely: When appropriate, teachers will be encouraged to use outdoor areas for lessons, allowing students to engage in AP while learning. They will be trained to implement outdoor games and activities that promote teamwork and AP, ensuring that safety measures are in place to mitigate risks.

Encouraging Peer Interaction: Teachers will promote cooperative games that require teamwork and communication. This approach will not only enhance PA but also foster social connections among students.

Monitoring and Feedback: Teachers will be advised to regularly observe and assess student participation in PA, providing constructive feedback to encourage improvement and sustained engagement.

By implementing these strategies, the proposed study will empower teachers to create a vibrant, active learning environment that promotes AP, enhances student well-being, and contributes to a healthier school culture.

Orientation Content for Children: Engaging in Active Play In the proposed study, children will learn how to actively engage in play to improve their PA, FMS and sleep.

Embrace Active Play: Children will be encouraged to participate in fun activities that get them moving, such as playing tag, riding bikes, or jumping rope. They will learn that AP can happen anywhere-at home, in the park, or even in the schoolyard.

Take Movement Breaks: During school and homework time, children will be reminded to take short breaks to stretch, stand up, or do a quick dance. These breaks will help refresh their minds and bodies, making learning more enjoyable.

Explore New Activities: Trying different sports or games will be encouraged, as this helps develop FMS. Whether it's cricket, football, or traditional games, exploring various activities will keep things exciting and build confidence.

Establish a Sleep Routine: Children will learn the importance of a consistent bedtime routine. They will be encouraged to wind down with calming activities, like reading or listening to music, to help them get a good night's sleep.

Be a Team Player: Engaging in team games will be promoted, as these activities not only improve FMS but also teach teamwork and cooperation with friends.

By participating in these activities, children will discover how AP can enhance their physical health, improve their movement skills, and lead to better sleep, ultimately contributing to their overall well-being.

Guiding Principle for Active Play Sessions AP interventions, particularly for children, often centre around establishing an engaging and benefits-driven framework. Various studies highlight the potential advantages of such interventions, particularly in fostering social, cognitive, and physical development among participants. The recommended frequency and length of these sessions can vary based on the objectives of the intervention, the age group of the children involved, and the specific outcomes being targeted. Extensive empirical findings suggest that AP interventions should ideally occur twice a week to maximise PA levels. A study indicated that children aged 5 to 11 engaged in AP sessions lasting approximately 60 minutes per session, twice weekly, over a span of 12 weeks, had a positive change in PA [4]. Several studies implemented AP interventions with a frequency of once per week. For example, a 10-week school-based intervention included a 1-hour session per week [5]. The length of each session varied across studies. Commonly, sessions lasted between 30 to 60 minutes. For example, a 10-week intervention included 1-hour sessions split into 30 minutes of guided games and 30 minutes of free play [6]. Another study implemented 60-minute weekly sessions over six weeks [7]. Some interventions used shorter but more frequent sessions. For instance, scheduling three 15-minute periods of outdoor free play per day effectively increased PA levels [8]. Sustained duration of AP, particularly within safe environments such as schools, instils motivation and enthusiasm in children who flourish during AP [9,10].

The recommended frequency and length of AP intervention sessions vary depending on the specific goals and settings of the intervention. Generally, sessions lasting 30 to 60 minutes once a week are common in intervention studies. However, increasing the frequency to multiple times per week or even multiple times per day with shorter sessions can enhance the effectiveness in promoting PA and FMS. The proposed intervention will consist of guided and unstructured AP activities. The guiding principles for these sessions emphasise that they should be enjoyable, inclusive, and physically engaging, promoting high levels of MVPA and the development of FMS following the FITT (Frequency: Twice a week, Intensity: MVPA and LPA, Time: 60 minutes, Type: both guided and unstructured) framework. All planned activities will be conducted on the school premises twice a week, ensuring that intervention children can easily access the facilities and resources available within the campus. Each week will feature a different theme or focus, ensuring variety and sustained interest. The activities will be structured to encourage MVPA and will incorporate elements that enhance FMS, such as running, jumping, throwing, and catching.

Before starting the guided play, children will be shown short videos explaining the game's rules. Additionally, the research team will verbally describe the rules to the students. One volunteer parent will be invited each week to participate in the play sessions to help manage the children and the teacher. They will be given 30 minutes of unstructured play within the school playground every session. Teachers, volunteer parents and researchers will encourage children to play during this time. The research team will record the start and end times of the guided and unstructured play sessions. Also, the researcher will maintain a daily activity tracker for each child. Each week, children will be divided into groups based on their activities. After each session, children will earn activity points from the research team. They will also earn points from their teacher for remaining physically active during recess. Parents will be encouraged to award points to their children for spending less time on RST at home and staying active. Furthermore, parents will be asked to provide points for adhering to proper sleep guidelines. Three children will be chosen as "Active Champions" at the end of each week based on their cumulative points from each school. These champions will receive a coupon to visit a nearby amusement park over the weekend, motivating children to be more mindful of adhering to movement behaviour.

Data Collection Plan Baseline data will be collected three weeks prior to the start of the intervention, and end-line data will be gathered after the intervention period. Additionally, follow-up data will be collected eight weeks after the intervention to assess ongoing progress.

Demographic data Demographic data will be collected using the same questionnaire as in the cross-sectional study.

Anthropometric Data Collection This study will collect anthropometric data to assess participants' physical characteristics. All the measurements will use the WHO STEPwise Approach to Surveillance [11]. protocols to ensure accuracy and reliability. The height will be measured in m using a measuring tape. The tape will be pasted on a wall, and the student will be asked to stand still in the bare feet while taking the measurement, and data will be recorded to the nearest 0.1 cm. The weight will be measured in Kg nearest to 0.1 kg using a digital scale with minimal dress and barefoot. Using stretch-resistant tape, the waist circumference will be measured in cm at approximately the midpoint between the lower edge of the last palpable rib and the top of the iliac crest. The participant will be asked to stand still, distributing body weight in two feet, with arm positioning at the side and feet close together. Hip circumference should be taken around the widest part of the buttocks in cm. The tape should not be snug too tightly while taking measurements. All the measurements will be taken by the researchers on school premises. A teacher will be asked to remain in the room where measurements will be conducted.

Physical Activity, Sedentary Behaviour and Sleep PA, SB and sleep will be measured using accelerometers and questionnaires used during the cross-sectional study. All the participants will be asked to wear a tri-axial accelerometer, ActiGraph GT3X-BT (ActiGraph, Pensacola, FL, USA), on their non-dominant wrist for seven days. The researcher will demonstrate the proper technique by showing a video and then provide hands-on assistance to parents and teachers to ensure they can correctly affix the device to the children's hands. The parents and teacher will be asked to remove the device during bathing, water and contact sports. The accelerometer will be placed on the student's hand on the first day of T1 and removed after seven days. The same procedure will be repeated during T2 and T3. The teachers will be asked to check the students' devices daily during school hours, maintaining a tally sheet. Parents will be asked to maintain a record in the notebook to track when their child wears the device and when it does not. This will help in monitoring the usage and non-usage time of the device.

Fundamental Movement Skills The motor competency of the participating children will be measured Test of Gross Motor Development-3 (TGMD-3). The test includes twelve motor proficiency tests divided into locomotor skills and object control skills. Each skill consists of 6 to 10 components. Score 0 indicates absence and score 1 denotes the presence of a particular skill component [11]. The raw score for each skill is calculated by summing all component scores. The raw scores can be combined across skills to create a locomotor or object control score, with a total possible range of 0 to 48 points. Before conducting the test, the researcher will explain and demonstrate the procedure to each student. Each motor skill test will include two trials for every child. Children will be asked to line up behind a designated marked line and perform each test in a clear area covering 50 feet. After each test, the participants will be rearranged to ensure that no one consistently goes first or last. All test performances will be scored in hard copy and recorded for archival and data accuracy.

Data Analysis All the collected data will be analysed using the IBM Statistical Package for Social Sciences (SPSS v 27.0), setting a significant level at p<0.05. The data analysis process will begin with thoroughly examining the dataset for inaccuracies, inconsistencies, and outliers. This will involve checking for any entry errors, such as implausible values for demographic or movement behaviour data. For example, height and weight values will be screened to ensure they fall within reasonable ranges based on age and gender norms. Any identified outliers will be scrutinised further to determine if they represent genuine data points or errors, and appropriate action will be taken, such as correction or exclusion, depending on the context.

Additionally, categorical variables will be checked for consistency in coding. Responses related to gender, socioeconomic status, or other demographic factors will be standardised to ensure that all entries are uniform. Data transformation may also be applied where necessary, such as deriving composite scores for movement behaviours or FMS proficiency from individual assessment items.

The final dataset will be prepared for analysis once the data cleaning and missing data handling processes are complete. This will involve creating derived variables for specific analyses, such as total daily AP time or average FMS proficiency scores. The cleaned data will then undergo rigorous checks to confirm that it meets the assumptions required for the planned statistical analyses, ensuring that the research findings are reliable and valid.

The first step in the analysis will involve examining demographic, socioeconomic, and anthropometric data. Descriptive statistics will be computed to summarise the characteristics of the participants, including age, gender, socioeconomic status, and measures of height and weight. This will provide insights into the sample population and ensure that randomisation was successful in achieving comparable groups. Additionally, inferential statistics such as t-tests or chi-square tests will be used to assess differences in these demographic variables between the intervention and control groups. This will help identify potential confounding factors that need to be controlled for in subsequent analyses.

Next, the analysis of the AP intervention will involve evaluating the extent of participation and engagement among the children. This will be quantified by collecting data on the frequency and duration of AP sessions, which will be analysed using repeated measures ANOVA to determine the differences in AP engagement over time between the intervention and control groups. The aim is to ascertain whether the intervention successfully increased AP participation and to understand the variability in engagement levels across different sessions.

The evaluation of PA, SB, sleep, and FMS will be approached through a combination of descriptive and inferential statistics. For PA, SB, and sleep data, accelerometer data will be analysed to calculate the average daily minutes spent in MVPA and total sedentary time. This will involve using cut-off points established in the literature to classify activity levels. Pre- and post-intervention comparisons will be made using paired t-tests or Wilcoxon signed-rank tests, depending on the data distribution. Sleep data will also be analysed to determine sleep duration and quality changes using self-reported sleep diaries, employing similar statistical methods to assess changes pre-and post-intervention.

For the assessment of FMS, the scores will be analysed using mixed-model ANOVA to account for repeated measures on the same individuals over time, allowing for the assessment of changes in FMS proficiency as a result of the AP intervention.

Correlation analyses will be conducted to explore the relationship between AP and improvements in composite movement behaviours and FMS. Specifically, Pearson or Spearman correlation coefficients will be calculated to establish the strength and direction of relationships between AP engagement and changes in PA, SB, sleep, and FMS proficiency. Following this, multiple regression analysis will be employed to determine whether demographic factors-such as the child's age, gender, parental socioeconomic status, marital status, and school environment moderate the relationships among the changes in PA, SB, sleep, and FMS. This analysis will assess interaction effects to identify significant moderators that influence the intervention outcomes using the Structural Equation Modelling (SEM).

Inclusion Criteria for Study Participants

• Primary school children aged 6-12 years
• Must be apparently healthy with no medical conditions limiting participation in physical activity.
• Should not plan to change schools within 6 months to allow consistent follow-up.
• Must understand basic Bengali or English.
• Must be Bangladeshi citizens.

Exclusion Criteria for Study Participants

• Children who are currently out of school will be excluded.
• Children under 6 years of age or over 11 years of age will not be included.
• Children who regularly participate in structured sports activities, such as cricket, football, or any other sports clubs, will be excluded.
• Children who are athletes or compete in any organised athletic events will not be included in the study.
• Children who are involved in dance performances or dance-related activities regularly will be excluded.

March 2026

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