Intervention to Reduce Sedentary Behavior During School Recess Among Adolescents

Effectiveness of an Intervention to Reduce Sedentary Behavior During School Recess Among Adolescents: A Cluster Randomized Controlled Trial

This cluster randomized controlled trial evaluated the effectiveness of an 8-week, school-based behavioural intervention grounded in the Multi-Process Action Control (M-PAC) framework in promoting interruption of sedentary behaviour during school breaks among adolescents. Twelve primary and secondary schools in China, were recruited and randomly allocated (at the school level) to either an intervention group or a control group to minimise contamination and support pragmatic delivery within the school setting. Schools assigned to the intervention group implemented a multi-component programme comprising educational materials, teacher-delivered guidance, peer reminders, and health lectures, whereas control schools continued their usual routines without receiving intervention materials. The primary outcome was interruption of sedentary behaviour during school breaks assessed using self-reported measures. Secondary outcomes included physical activity levels, emotional and behavioural problems, executive function, and psychological factors related to behaviour regulation, such as motivation, planning, and habit. Findings from this trial are intended to inform the development and implementation of feasible, theory-informed school strategies to reduce sedentary behaviour during school breaks.

Study Overview

• Status: Active, not recruiting
• Conditions: Physical Activity; Sedentary Behaviour; Adolescents; School-based Intervention
• Intervention / Treatment: Behavioral: Sedentary Interruption Intervention

Detailed Description

This study was a cluster randomized controlled trial designed to evaluate the effectiveness of a school-based intervention grounded in the Multi-Process Action Control (M-PAC) framework to promote interruption of sedentary behaviour during school breaks among adolescents. A cluster randomization design was adopted, with schools as the unit of randomization, to minimise contamination between participants and to enhance the feasibility of intervention delivery within the school setting.

Twelve primary and secondary schools in China were recruited using convenience sampling and randomly allocated to either an intervention group or a control group. Schools were recruited through existing school partnerships and administrative feasibility considerations. The majority of participating schools were located in Guangdong Province (n=9), reflecting the location of the coordinating research team and the primary recruitment network. To enhance the diversity of school contexts and improve the external validity of findings, additional schools were recruited from Hainan (n=1) and Shanxi (n=2) using the same eligibility criteria and standardized implementation procedures across sites. The intervention was implemented over an 8-week period. Schools assigned to the intervention group received a multi-component programme informed by the M-PAC framework, designed to target key behaviour regulation processes relevant to sedentary behaviour interruption, including reflective, regulatory, and reflexive mechanisms. Intervention components included weekly educational leaflets, guidance delivered by physical education teachers, peer reminders during school breaks, and health lectures. Schools assigned to the control group continued their usual school routines and did not receive intervention materials during the study period.

The primary outcome was interruption of sedentary behaviour during school breaks, assessed using self-reported measures. Secondary outcomes encompassed physical activity levels, emotional and behavioural problems, executive function, and social-cognitive variables derived from the M-PAC framework (e.g., attitudes, intention, and habit). In addition, process evaluation indicators (e.g., intervention fidelity) and relevant covariates (e.g., demographic characteristics, academic stress, and the school physical activity environment) were assessed to support interpretation of intervention effects.The study involved a non-clinical population and did not include biomedical or medical health outcomes. The study protocol was approved by the institutional ethics committee, and written informed consent was obtained from all participants prior to participation.

• Study Type: Interventional
• Enrollment (Estimated): 1000
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Foshan, Guangdong, China, 528300
      • Jingshi Liyun Experimental School
    • Foshan, Guangdong, China, 528315
      • Dongping Primary School, Foshan
    • Guangzhou, Guangdong, China, 510006
      • Zhixin Middle School (Pazhou Experimental School)
    • Guangzhou, Guangdong, China, 510420
      • Experimental Secondary School of Guangdong University of Foreign Studies
    • Guangzhou, Guangdong, China, 510520
      • Gaotangshi Primary School
    • Guangzhou, Guangdong, China, 511436
      • Guangdong University of Education (Panyu Affiliated Junior Secondary School)
    • Shenzhen, Guangdong, China, 518053
      • Overseas Chinese Town Primary School
    • Zhuhai, Guangdong, China, 519040
      • Lin Weimin Memorial Primary School
    • Zhuhai, Guangdong, China, 519085
      • Lihe Primary School
  • Hainan
    • Haikou, Hainan, China, 570102
      • Haikou No.9 Middle School
  • Shanxi
    • Jinzhong, Shanxi, China, 031100
      • Pingyao Middle School - Junior High Division
    • Jinzhou, Shanxi, China
      • Pingyao Middle School - Primary Division

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria

1. Students aged 10-17 years
2. Enrolled in participating primary or secondary schools
3. Able to participate in regular school physical activities and daily routines
4. Able to understand and complete study questionnaires
5. Willing to comply with study procedures
6. Written informed consent obtained from parents or legal guardians

Exclusion Criteria

1. Diagnosed medical conditions that contraindicate participation in physical activity
2. Physical disabilities, injuries, or health conditions that limit normal participation in school-based activities
3. Participation in other structured physical activity or sedentary behavior intervention programs during the study period
4. Cognitive or language difficulties that preclude understanding of study procedures or completion of questionnaires
5. Inability or unwillingness to comply with study procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Usual Pratice Control; Schools allocated to the control group continued their usual school routines during the 8-week study period and did not receive any intervention materials or behaviour-change components related to sedentary behaviour interruption. No additional guidance, reminders, or educational materials were provided. Data collection procedures were conducted in the same manner as in the intervention group.
Experimental: Sedentary Interruption Intervention; The intervention was grounded in the Multi-Process Action Control (M-PAC) framework and targeted behaviour regulation processes relevant to sedentary interruption. Intervention components included: 1) Weekly educational leaflets providing information on the health risks of prolonged sedentary behaviour and practical strategies to interrupt sitting during school breaks. 2) Guidance delivered by physical education teachers, reinforcing key messages and encouraging active break behaviours. 3) Peer reminders were delivered during school breaks by class-appointed student PE representatives-one student per class nominated by the PE teacher (typically a high-performing student in PE) to support the organization and promotion of physical activity. 4) Health lectures delivered by members of the research team to enhance awareness and motivation related to sedentary behaviour interruption.	Behavioral: Sedentary Interruption Intervention; A multi-component, school-based behavioural program implemented over 8 weeks to promote interruption of sedentary behaviour during school breaks. The program was informed by the Multi-Process Action Control framework and designed to support behaviour regulation related to break-time sedentary interruption.; Educational leaflets (weekly): brief printed materials distributed once per week, providing information on sedentary behaviour and practical strategies to interrupt sitting during school breaks.; Teacher guidance: physical education (PE) teachers provided brief guidance and reinforcement of key messages during routine school activities/classes, encouraging students to interrupt sedentary time during breaks.; Peer reminders during school breaks: reminders were delivered by class-appointed student PE representatives.; Health lectures: health lectures were delivered by members of the research team during the intervention period to support awareness and and motivation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Interruption of sedentary behaviour during school breaks	Interruption of sedentary behaviour during routine school breaks (between lessons; excluding longer "big recess" periods) was assessed over the past 7 school days using a single-item self-report measure adapted from the Workplace Sitting Breaks Questionnaire (SITBRQ) for the school context. Students reported the average time spent standing or walking to interrupt sitting during a typical routine class break (0 min, ≤5 min, >5-<10 min, ≥10 min); higher categories indicate greater break-time sedentary interruption. The item wording was modified to reflect school break periods while retaining the original construct of sedentary break behaviour.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Self-reported physical activity	Self-reported physical activity (PA) was assessed over the past 7 days using the Chinese version of the Adolescent Physical Activity Questionnaire (PAQ-A), a validated instrument for measuring general moderate-to-vigorous physical activity among adolescents. Higher scores indicate higher overall physical activity levels.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Emotional and behavioural problems	Emotional and behavioural problems were assessed using the Strengths and Difficulties Questionnaire (SDQ), a 25-item self-report instrument comprising five subscales: Emotional Symptoms, Conduct Problems, Hyperactivity/Inattention, Peer Problems, and Prosocial Behaviour. An example item is "I worry a lot." Items are rated on a 3-point Likert scale (0 = Not true, 1 = Somewhat true, 2 = Certainly true). Subscale scores are calculated by summing relevant items (range 0-10 per subscale), and a Total Difficulties score (range 0-40) is derived by summing the four problem subscales (excluding Prosocial Behaviour), with higher scores indicating greater emotional and behavioural difficulties.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Executive function	Executive function was assessed using the Amsterdam Executive Function Inventory (AEFI), a 13-item self-report questionnaire designed to measure executive functioning in adolescents. The AEFI comprises three subscales: Attention, Self-Control, and Planning. An example item is "I have difficulty concentrating for a long time." Items are rated on a 3-point Likert scale (1 = Not true, 2 = Partly true, 3 = True). Subscale scores are calculated by summing relevant items, and a total executive function score can be derived by summing all items, with higher scores indicating better executive functioning (after reverse scoring negatively worded items as appropriate).	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Affective attitude toward interrupting sedentary behaviour during school breaks	Affective attitude toward interrupting sedentary behaviour during school breaks was assessed using three bipolar adjective pairs (unpleasant-pleasant, boring-interesting, and unenjoyable-enjoyable) adapted from established Theory of Planned Behaviour questionnaires. Participants responded to a common stem ("In the next week, interrupting sitting by standing up and moving during routine class breaks is …"), followed by three items. Responses were recorded on a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree). A mean score was calculated across the three items, with higher scores indicating a more positive affective attitude toward taking active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention)
Instrumental attitude toward interrupting sedentary behaviour during school breaks	Instrumental attitude toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using three bipolar adjective pairs (harmful-beneficial, worthless-valuable, and bad-good) adapted from established Theory of Planned Behaviour measures. Participants responded to a common stem ("In the next week, interrupting sitting by standing up and moving during routine class breaks is …"), followed by three items (e.g., "In the next week, interrupting sitting by standing up and moving during routine class breaks is harmful-beneficial"). Responses were recorded on a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree). A mean score was calculated across the three items, with higher scores indicating a more positive instrumental attitude toward taking active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention)
Perceived capability toward interrupting sedentary behaviour during school breaks	Perceived capability toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using three items adapted from established Theory of Planned Behaviour measures. Participants responded to a common stem ("In the next week, interrupting sitting by standing up and moving during routine class breaks is …"), followed by items assessing perceived ease and capability (e.g., "It is easy for me to interrupt sitting by standing up and moving during routine class breaks in the next week"). Responses were recorded on a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree). A mean score was calculated across the three items, with higher scores indicating greater perceived capability to take active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Intention toward interrupting sedentary behaviour during school breaks	Intention toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using three items adapted from established Theory of Planned Behaviour measures. Participants responded to a common stem ("In the next week, interrupting sitting by standing up and moving during routine class breaks is …"), followed by items assessing behavioural intention (e.g., "I intend to interrupt sitting by standing up and moving during routine class breaks in the next week"). Responses were recorded on a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree). A mean score was calculated across the three items, with higher scores indicating stronger intention to take active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Perceived opportunity toward interrupting sedentary behaviour during school breaks	Perceived opportunity toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using three items adapted from a Multi-Process Action Control (M-PAC) questionnaire applied to physical activity. Items captured students' perceived availability of opportunities to interrupt sitting during routine class breaks over the subsequent week (e.g., "If I really wanted to interrupt sitting by standing up and moving during routine class breaks over the next week, I would have the opportunity to do so"). Responses were recorded on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree). A mean score was calculated across the three items, with higher scores indicating greater perceived opportunity to take active breaks during school breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Planning toward interrupting sedentary behaviour during school breaks	Planning toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using six items adapted from questionnaires based on the Health Action Process Approach. Items assessed students' use of planning strategies related to interrupting sitting during routine class breaks over the previous week (e.g., "I made regular plans concerning how to interrupt sitting by standing up and moving during routine class breaks in the last week"). Responses were recorded on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree). A mean score was calculated across the six items, with higher scores indicating greater use of planning strategies for taking active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Self-monitoring toward interrupting sedentary behaviour during school breaks	Self-monitoring toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using three items adapted from questionnaires based on the Health Action Process Approach. Items assessed students' engagement in monitoring their break-time sedentary interruption over the previous week (e.g., "I kept track of whether I interrupted sitting by standing up and moving during routine class breaks over the last week"). Responses were recorded on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree). A mean score was calculated across the three items, with higher scores indicating greater use of self-monitoring strategies for taking active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Identity toward interrupting sedentary behaviour during school breaks	Identity toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using four items adapted from the Exercise Identity Scale. Items captured the extent to which engaging in break-time sedentary interruption was integrated into students' self-concept (e.g., "When I describe myself to others, I usually include that I interrupt sitting by standing up and moving during school breaks"). Responses were recorded on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree). A mean score was calculated across the four items, with higher scores indicating stronger identity integration related to taking active breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).
Habit strength	Habit strength toward interrupting sedentary behaviour during school breaks (i.e., taking active breaks) was assessed using twelve items adapted from the Self-Report Habit Index. Participants responded to a common stem ("In the last month, interrupting sitting by standing up and moving during routine class breaks was …"), followed by items assessing behavioural automaticity and repetition (e.g., "…something I do frequently"). Responses were recorded on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree). A mean score was calculated across the twelve items, with higher scores indicating stronger habit strength for taking active breaks during school breaks.	Baseline, Week 8 (Post-intervention), Week 16 (Follow-up, 8 weeks post-intervention), and Week 24 (Follow-up, 16 weeks post-intervention).

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Process evaluation variables	Based on the implementation during the first eight weeks, students will complete a survey to assess the specific implementation of (1) the distribution of educational leaflets by teachers and (2) the execution of sedentary-break reminders by class health committee members within their classes.	Week 8 (Post-intervention)

Collaborators and Investigators

• Sponsor: South China Normal University
• Investigators: Principal Investigator: Ru ZHANG, South China Normal University

Study record dates

Study Major Dates

• Study Start (Actual): October 8, 2025
• Primary Completion (Estimated): July 30, 2026
• Study Completion (Estimated): July 30, 2026

Study Registration Dates

• First Submitted: February 27, 2026
• First Submitted That Met QC Criteria: February 27, 2026
• First Posted (Actual): March 5, 2026

Study Record Updates

• Last Update Posted (Actual): March 5, 2026
• Last Update Submitted That Met QC Criteria: February 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Cluster randomized controlled trial; sedentary interruption; school breaks; Multi-Process Action Control
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: SCNU-SPT-2025-041

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No