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

NCT ID: NCT07338058

Last Updated: 2026-01-13

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 220 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-09-01
• Study Completion Date: 2026-03-01

Brief Summary

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.

Detailed Description

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.

Conditions

Smartphone Addiction; Sedentary Behaviors; Adolescent Behavior

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Exercise Snacks Group

Participants in this group follow a 5-month structured "Exercise Snacks" protocol. The intervention consists of daily short bursts of high-intensity exercise (e.g., 1-minute sprints, squats) performed during school breaks, supplemented by weekly collective HIIT sessions. The program progresses through adaptation, enhancement, and consolidation phases.

Group Type: EXPERIMENTAL

Exercise Snacks Protocol

Intervention Type: 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.

Control Group

Participants in this group are instructed to maintain their usual daily campus life and academic routines without altering their existing physical activity habits. They do not participate in the structured exercise snacks program during the study period.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Exercise Snacks Protocol

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.

Intervention Type: BEHAVIORAL

Other Intervention Names

Fragmented High-Intensity Exercise

Eligibility Criteria

Inclusion Criteria

1. Adolescents aged 12-18 years enrolled in the participating middle/high school.

2. Owner of a smartphone with daily usage time > 2 hours.

3. Score on the Smartphone Addiction Scale-Short Version (SAS-SV) indicating a risk of addiction (e.g., score > 31 for males, > 33 for females).

4. Physically capable of participating in high-intensity exercise (PAR-Q screening negative).

5. Provided written informed consent (from both student and guardian).

Exclusion Criteria

1. Diagnosed with severe physical disabilities or cardiovascular diseases that contraindicate high-intensity exercise (e.g., congenital heart disease).

2. Currently participating in other professional sports training or weight loss programs.

3. Diagnosed with severe psychiatric disorders (e.g., severe depression, schizophrenia) requiring medication.

4. Taking medications that affect heart rate or cognitive function.

• Minimum Eligible Age: 12 Years
• Maximum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Jinan University Guangzhou

OTHER

Sponsor Role: lead

Responsible Party

Ma Ruisi

Lecturer, School of Physical Education, Jinan University

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Rui Si Ma

Role: PRINCIPAL_INVESTIGATOR

Jinan University

Locations

School of Physical Education, Jinan University

Shatin, New Territories, Hong Kong

Countries

Hong Kong

Other Identifiers

SBRE-25-0472

Identifier Type: OTHER

Identifier Source: secondary_id

SBRE-25-0472

Identifier Type: -

Identifier Source: org_study_id