Scale-up of the Diactive-1 mHealth program integrating tailored resistance training as an educational strategy for self-management in children and adolescents with type 1 diabetes: protocol for an 11-hospital multicenter randomized controlled trial.

The Diactive-1 trial is designed as a 12-week parallel-group multicenter randomized controlled trial conducted across 11 Spanish pediatric endocrinology units.

• The study targets children and adolescents aged 10-18 years with type 1 diabetes.
• Target sample size is 158 participants, with 79 allocated to each group.
• Participants will be randomized to either the Diactive-1 intervention or usual clinical care.
• Analyses will follow the intention-to-treat principle using mixed-effects models.
• Ethical approval was granted by the Research Ethics Committee for Medicinal Products of the Government of Navarra.

The primary outcome of the trial is the change in age- and sex-standardized handgrip strength z-score from baseline to 12 weeks.

• Handgrip strength z-score will be standardized by age and sex.
• Measurement will occur at baseline and again at 12 weeks.
• The choice of handgrip strength as a primary outcome reflects the goal of improving muscular strength through resistance training in pediatric type 1 diabetes.

The Diactive-1 (v2.0) app provides individualized resistance-training programs combined with glucose-management educational support and safety features.

• The app includes individualized resistance-training programs, glucose-related educational prompts, and safety thresholds for exercise.
• Engagement strategies such as gamification are incorporated into the app.
• The program is designed to deliver tailored resistance-training sessions combined with glucose-management educational support.
• The intervention is delivered via a mobile health (mHealth) platform, emphasizing scalability and real-world applicability.

Secondary outcomes include glycemic stability, insulin requirements, cardiometabolic markers, physical literacy, quality of life, psychological well-being, app usability, and intervention engagement.

• Glycemic stability and insulin requirements are included as secondary outcomes relevant to diabetes management.
• Cardiometabolic markers, physical literacy, and quality of life are also assessed.
• Psychological well-being, app usability, and intervention engagement are measured to evaluate feasibility and acceptability of the digital intervention.

Fear of hypoglycemia is identified as a key barrier preventing children and adolescents with type 1 diabetes from meeting exercise guidelines.

• Many children and adolescents with type 1 diabetes do not meet current exercise guidelines, partly because of fear of hypoglycemia.
• Resistance training is noted to offer metabolic and musculoskeletal benefits but its implementation in routine pediatric diabetes care remains limited.
• The Diactive-1 program specifically incorporates safety thresholds for exercise and glucose-related educational prompts to address this barrier.

The trial is designed to provide evidence on the external validity, feasibility, and potential clinical integration of digitally supported exercise education for youth with type 1 diabetes.

• The multicenter design across 11 hospitals and real-world settings is intended to assess external validity.
• The study aims to evaluate whether a scalable mHealth-supported resistance-training program can improve muscular strength and support diabetes self-management in routine pediatric care.
• Findings will be disseminated through scientific conferences, peer-reviewed publications, and summaries shared with participating families.
• The trial is registered at ClinicalTrials.gov with identifier NCT07290868.