A Theory-Informed, Personalized mHealth Intervention for Adolescents (Mobile App for Physical Activity): Development...

Area of Science:

• Adolescent Health
• Mobile Health Interventions
• Behavioral Science

Background:

• Childhood and adolescent physical activity (PA) is critical for lifelong health.
• Smartphones offer a viable platform for PA interventions in adolescents.
• Few evidence-based smartphone PA apps exist for this demographic.

Purpose of the Study:

• To systematically develop and evaluate a theory-informed mobile app for PA in adolescents (16-18 years).
• To assess the intervention's effectiveness on step count, sedentary time, and moderate-to-vigorous PA (MVPA).
• To evaluate the impact of personalized PA prompts within the app.

Main Methods:

• A 4-week within-subject trial involving 18 adolescents (mean age 16.33 years).
• Participants used a mobile app with a Fitbit tracker, receiving daily personalized PA prompts.
• Paired t-tests and change-point analysis were used to assess intervention effectiveness.

Main Results:

• The intervention significantly reduced sedentary time during the first week (P=.02).
• Personalized prompts significantly increased heart rate per minute in week two (P=.04).
• Marginally significant increases in step counts per minute were observed with personalized prompts (P=.05).

Conclusions:

• The mobile app intervention shows preliminary benefits in reducing adolescent sedentary time.
• Personalized PA prompts appear beneficial and effective for smartphone-based interventions.
• This study offers a model for developing mobile health PA interventions for adolescents.