LifestyleExercise

A 3-month school-based exercise and data recording intervention reduces excessive screen time and increases trunk muscle mass in Japanese junior high school students.

A 3-month school-based intervention with biweekly group exercise and daily activity recordings was conducted in 127 Japanese junior high school students. Screen time significantly decreased in students with baseline screen time ≥4 h/day, while it increased in those with <4 h/day. Body mass index and trunk muscle mass increased significantly in both groups, but psychological measures and sleep duration showed no significant changes.

Last updated: Aug 28, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score32/100
Human RCT☆☆☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Preliminary Impacts of a 3-Month School-Based Exercise and Data Recording Intervention on Lifestyle Habits, Psychological Health, and Physical Health in Japanese Adolescents.

observational

Kusumoto Y, Takahashi E, Endo Y, Okazaki K, Asao A, Tanaka Y · Children (Basel, Switzerland) (2026)

Participants: 127
Duration: 3 months
Intervention: 3-month school-based program with biweekly group exercise sessions and daily activity recordings
Outcome: Screen time, body mass index, trunk muscle mass, skeletal muscle index, psychological health (General Self-Efficacy Scale, Communicative and Critical Health Literacy), eHealth literacy, sleep duration
Effect Size: N/A
Population: Japanese junior high school students (initial n=235, final n=127)

Result: A 3-month school-based intervention with biweekly group exercise and daily activity recordings was conducted in 127 Japanese junior high school students. Screen time significantly decreased in students with baseline screen time ≥4 h/day, while it increased in those with <4 h/day. Body mass index and trunk muscle mass increased significantly in both groups, but psychological measures and sleep duration showed no significant changes.

PubMed: 42650319DOI: 10.3390/children13080980

Mechanism Graph

Biweekly group exercise sessions provide structured physical activity
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Daily activity recordings increase self-monitoring and awareness
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Reduced screen time may be due to increased awareness and alternative activities
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Increased trunk muscle mass from exercise sessions

Limitations

  • ⚠Single-arm pre-post design without a control group, so changes cannot be definitively attributed to the intervention
  • ⚠High dropout rate (from 235 to 127 students), potentially introducing selection bias

Frequently Asked Questions

What was the duration of the intervention?▼

The intervention lasted 3 months.

How many students completed the study?▼

127 students completed the program out of 235 initially enrolled.

Did the intervention affect sleep duration?▼

No significant changes in sleep duration were observed.

What was the effect on screen time?▼

Screen time significantly decreased in students with baseline screen time ≥4 h/day, but increased in those with <4 h/day.

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References

  1. 1.Kusumoto Y, Takahashi E, Endo Y, Okazaki K, Asao A, Tanaka Y. "Preliminary Impacts of a 3-Month School-Based Exercise and Data Recording Intervention on Lifestyle Habits, Psychological Health, and Physical Health in Japanese Adolescents.." Children (Basel, Switzerland), 2026. PMID: 42650319 DOI: 10.3390/children13080980
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.