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Completed

NCT Number: NCT07338058

High-Intensity Exercise Snacks for Reducing Mobile Phone Addiction in Adolescents

This study is a randomized controlled trial (RCT) designed to evaluate the long-term effectiveness of "Exercise Snacks" (fragmented, high-intensity bouts of exercise) in reducing mobile phone addiction among adolescents.

Participants will be randomly assigned to either an intervention group or a control group. The intervention spans 5 months and is followed by a 1-month follow-up period (Month 6). The intervention group will perform short bursts of exercise (e.g., 1-minute sprints, squats) multiple times daily during school breaks. The program is divided into three progressive phases: adaptation, enhancement, and consolidation. The study aims to determine whether this sustained "snack-style" exercise regimen can significantly lower mobile phone addiction scores, improve physical fitness, and enhance psychological traits such as self-control and resilience over a semester-long period.

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Key information

Conditions

Smartphone Addiction Adolescent Behavior Behavior Behavior, Addictive Compulsive Behavior Impulsive Behavior Internet Addiction Disorder Sedentary Behavior Sedentary Behaviors Self-Control Social Behavior Technology Addiction

Age range

12 year–18 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Physical Education, Jinan University

Shatin, New Territories, Hong Kong

About this study

Background and Rationale: Adolescents face increasing risks of mobile phone addiction, which is associated with sedentary behavior. "Exercise Snacks"-isolated bouts of vigorous exercise performed periodically throughout the day-offer a time-efficient solution. This study applies the COMB model and Self-Determination Theory to a long-term, semester-based intervention.

Study Design: This is a single-blind, randomized controlled trial conducted over a 6-month period (5 months of intervention + 1 month of follow-up).

Intervention Protocol: The intervention group follows a progressive "Exercise Snacks" program:

Adaptation Phase (Month 1 / Weeks 1-4): Focus on habit formation. Participants perform "Sprint Snacks" (e.g., stair climbing) 3 times daily and "Strength Snacks" (e.g., squats) 2 times weekly. Intensity is monitored to ensure safety and correct posture.

Enhancement Phase (Months 2-3 / Weeks 5-12): Focus on physiological adaptation. Frequency increases to 4 daily Sprint Snacks and 3 weekly Strength Snacks. A weekly collective High-Intensity Interval Training (HIIT) session is introduced to maximize cardiorespiratory benefits.

Consolidation Phase (Months 4-5 / Weeks 13-20): Focus on psychological integration. Daily snacks continue. Collective HIIT sessions increase to twice weekly. A cognitive-behavioral guidance component is added (bi-weekly) to help students identify phone use triggers and internalize healthy behaviors.

Follow-up Phase (Month 6 / Weeks 21-24): The structured intervention ceases. Participants are encouraged to maintain self-guided exercise. Final assessments are conducted at the end of Month 6 to evaluate the retention of intervention effects and any "rebound" in mobile phone addiction.

Outcome Measures: The primary outcome is Mobile Phone Addiction (SAS-SV), assessed at baseline, Month 3, Month 5 (post-intervention), and Month 6 (follow-up). Secondary outcomes include physical activity levels (PARS-3 and wearables), self-control (BSCS), resilience (RSCA), and mental health status.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adolescents aged 12-18 years enrolled in the participating middle/high school.
  • Owner of a smartphone with daily usage time > 2 hours.
  • Score on the Smartphone Addiction Scale-Short Version (SAS-SV) indicating a risk of addiction (e.g., score > 31 for males, > 33 for females).
  • Physically capable of participating in high-intensity exercise (PAR-Q screening negative).
  • Provided written informed consent (from both student and guardian).

Exclusion criteria

  • Diagnosed with severe physical disabilities or cardiovascular diseases that contraindicate high-intensity exercise (e.g., congenital heart disease).
  • Currently participating in other professional sports training or weight loss programs.
  • Diagnosed with severe psychiatric disorders (e.g., severe depression, schizophrenia) requiring medication.
  • Taking medications that affect heart rate or cognitive function.

Treatment and study plan

Exercise Snacks Protocol

Behavioral

The intervention consists of a structured 5-month "Exercise Snacks" program. Participants perform "snacks"-defined as isolated bouts of vigorous-intensity physical activity (<2 min)-distributed 3-4 times throughout the school day during breaks.

Content: The regimen includes "Sprint Snacks" (e.g., stair climbing, high knees) and "Strength Snacks" (e.g., squats, push-ups). Intensity: Participants are instructed to reach a subjective effort level of Borg RPE > 14 (Somewhat Hard to Hard). Progression: The program follows a phased approach:

Adaptation (Month 1): Focus on habit formation and movement quality.

Enhancement (Months 2-3): Increased frequency and inclusion of weekly collective HIIT sessions.

Consolidation (Months 4-5): Integration of cognitive-behavioral guidance to replace mobile phone usage habits.

Other names: Fragmented High-Intensity Exercise

Primary outcomes

  1. Change in Mobile Phone Addiction Severity (assessed by SAS-SV)

    Time frame: Baseline, Month 3, Month 4, and Month 6

    The severity of mobile phone addiction is measured using the Smartphone Addiction Scale-Short Version (SAS-SV). This self-report scale consists of 10 items. Each item is rated on a 6-point Likert scale ranging from 1 ("Strongly Disagree") to 6 ("Strongly Agree"). The total score is calculated by summing the scores of all 10 items, resulting in a range from 10 to 60. Higher scores indicate a higher level of mobile phone addiction risk.

Secondary outcomes

  1. Psychological Resilience(CD-RISC-10 Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6

    Psychological resilience is assessed using the Child and Youth Resilience Measure (CYRM). Higher scores indicate greater resilience.

  2. Self-Control Capacity (BSCS Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6.

    13 items, 1-5 scale. Range 13-65. Higher scores indicate better self-control.

  3. Objectively Measured Sleep Parameters via Wrist-Worn Accelerometer

    Time frame: Baseline, Month 3, Month 5, and Month 6

    Sleep parameters are continuously monitored using a consumer-grade wrist-worn accelerometer (Xiaomi Mi Band) for 7 consecutive days at each assessment time point. Primary sleep outcomes include total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE). Data are extracted from the device via the companion application and processed to derive nightly averages across the 7-day monitoring period. Participants are instructed to wear the device 24 hours per day, removing it only during water-based activities if the device is not waterproof.

  4. Objectively Measured Daily Physical Activity via Wrist-Worn Accelerometer

    Time frame: Baseline, Month 2,Month 4, and Month 6

    Daily physical activity is continuously monitored using a consumer-grade wrist-worn accelerometer (Xiaomi Mi Band) for 7 consecutive days at each assessment time point. Outcomes include daily step count, duration of moderate-to-vigorous physical activity (MVPA), light physical activity, and sedentary time. Data are extracted from the device via the companion application and averaged across valid wear days (defined as ≥10 hours of wear time per day, with a minimum of 4 valid days required).

  5. Psychological Distress (DASS-21 Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6

    Psychological distress is assessed using the Depression Anxiety Stress Scales-21 (DASS-21). The scale measures symptoms of depression, anxiety, and stress over the past week. Higher scores indicate greater psychological distress.

  6. Well-Being (WHO-5 Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6

    Well-being is assessed using the WHO-5 Well-Being Index. Higher scores indicate better well-being.

  7. Basic Psychological Need Satisfaction (SDT Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6

    Basic psychological need satisfaction is assessed using a self-determination theory-based scale. Higher scores indicate greater basic psychological need satisfaction.

  8. Emotion Regulation: Cognitive Reappraisal (ERQ Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6

    Cognitive reappraisal is assessed using the Emotion Regulation Questionnaire (ERQ). Higher scores indicate greater use of cognitive reappraisal.

  9. Emotion Regulation: Expressive Suppression (ERQ Score)

    Time frame: Baseline, Month 2, Month 4, and Month 6

    Expressive suppression is assessed using the Emotion Regulation Questionnaire (ERQ). Higher scores indicate greater use of expressive suppression.

Sponsors and collaborators

Lead sponsor

Jinan University Guangzhou

Other

Registry information

Official study title

Effect of Fragmented Exercise Snacks on Mobile Phone Addiction and Psychophysical Health in Adolescents: A Randomized Controlled Trial

Acronym: ES-MPA

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Jan 13, 2026
Registry last updated
Apr 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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