A Mobile App to Improve 24-Hour Movement Guideline Adherence in Preschoolers

The Shining Star study is a randomized controlled trial designed to evaluate the feasibility and preliminary effectiveness of a 12-week home-based mHealth intervention aimed at improving adherence to the 24-Hour Movement Guidelines (physical activity, sedentary behavior, and sleep) among preschool-aged children (3-4 years old). The trial consists of two groups: an intervention group receiving the mHealth intervention and a waitlist control group.

The primary objective is to determine if the intervention increases the proportion of children meeting all three 24-Hour Movement Guidelines. The intervention focuses on engaging parents through a mobile app, which delivers weekly lessons and behavior-related goals to promote healthy movement behaviors in children. Secondary objectives include assessing changes in child motor skills, cognition, behavioral problems and executive function, and BMI.

Study Design and Procedures:

Participants will be randomly assigned to either the intervention group or a waitlist control group. The intervention group will use the Shining Star mobile app, which provides short, weekly messages (less than 500 characters) and links to additional resources. The app will also include gamification elements, behavior trackers, and a forum for parents to connect with each other. Participants in the control group will receive access to the app after the 12-week intervention period.

Key measurements will be taken at three time points: baseline (Week 0), mid-point (Week 6), and at the end of the intervention (Week 12). Measurements include accelerometer data to assess physical activity, sedentary time, and sleep, anthropometrics to assess BMI, as well as parent-reported screen time, child motor skills, behavioral problems and executive function, and cognition. Usability and feasibility of the mobile app will be assessed through weekly app usage and feedback questionnaires.

Sample Size and Statistical Plan:

A total of 80 parent-child dyads (40 per group) will be enrolled in the study. A sample size of 30 families per group is expected to provide 80% power to detect a meaningful difference in the proportion of children meeting all three recommendations after 12 weeks. Based on a projected dropout rate of 25%, the target enrollment is 80 families.

Statistical analysis will focus on two primary hypotheses:

1. Whether a greater proportion of children in the intervention group meet the 24-Hour Movement Guidelines compared to the control group at 12 weeks. 2. Whether parents report that the intervention is feasible, with a target feasibility rating of ≥4.0/5.0 on a Likert scale.

Additional exploratory analyses will evaluate changes in child motor skills, behavioral problems, cognition, and growth as well as home-level and parent-level correlates.

Quality Assurance and Data Management:

Data will be collected using validated measures, and all data will be securely stored in REDCap. Clinical data collected at screening and follow-up visits, including accelerometer data and questionnaires, will be stored in a secure database at the University of Kansas Medical Center (KUMC). The data will undergo validation and consistency checks before analysis.

* Quality Assurance Plan: The research coordinator will ensure that accurate and complete data is transcribed from paper sources into REDCap. To maintain data quality, accuracy, and integrity, data entry will be performed twice. The REDCap data comparison tool will then be used to produce a final \"Clean\" entry. * Missing Data Plan: Participants who do not complete the required assessments at baseline (Week 0), mid-point (Week 6), and end of the intervention (Week 12) will be excluded from the final analysis. Efforts will be made to retain participants throughout the study to minimize missing data. * Statistical Analysis Plan: The primary analysis will compare the proportion of participants in the intervention and control groups meeting all three recommendations at 12 weeks using chi-square analysis. The secondary analysis will average the Likert scale responses across all weeks completed. Exploratory analyses will utilize linear regression to examine changes in outcomes between the treatment and control groups, along with iso-temporal substitution analysis to assess the impact of behavior substitution on child developmental outcomes. Additionally, the investigators will examine the relationship between meeting specific movement recommendations and child outcomes, with changes in theoretical components as potential mediators. Statistical significance will be set at p = 0.05 for analyses.

The study will also adhere to KUMC standard operating procedures for data collection, data analysis, and confidentiality as outlined in the study protocol.

• Weight (kg) [Срок оценки: Baseline, Week 6, and Week 12]
• Height (cm) [Срок оценки: Baseline, Week 6, and Week 12]
• BMI (kg/m²) [Срок оценки: Baseline, Week 6, and Week 12]
• Motor Skills - Grip Strength Test [Срок оценки: Baseline, Week 6, and Week 12]
• Motor Skills - 9-Hole Pegboard Dexterity Test [Срок оценки: Baseline, Week 6, and Week 12]
• Motor Skills - Standing Balance Test [Срок оценки: Baseline, Week 6, and Week 12]
• 24-Hour Movement Behaviors [Срок оценки: Week 6 and Week 12]
• Motor Skills - 2-Minute Walk Endurance Test [Срок оценки: Baseline, Week 6, and Week 12]
• Cognition - Picture Vocabulary Test [Срок оценки: Baseline, Week 6, and Week 12]
• Cognition - Flanker Inhibitory Control and Attention Test [Срок оценки: Baseline, Week 6, and Week 12]
• Cognition - Dimensional Change Card Sort Test [Срок оценки: Baseline, Week 6, and Week 12]
• Cognition - Picture Sequence Memory Test [Срок оценки: Baseline, Week 6, and Week 12]