# Utility of a high-intensity interval training app as a remote exercise support strategy in children with obesity: An exploratory study of adherence, effect, and perceptions of its use PMID: 39465221 Journal: Digital health Published: 2024 Jan-Dec Authors: de Freitas F, Antônio MÂ, Zago MR, Zambon M, Videira-Silva A ## Question Can a HIIT app be useful as a remote exercise support strategy for children with obesity by improving adherence, obesity-related outcomes, and child/parent perceptions of app-supported counseling? ## Summary This exploratory uncontrolled study asked children with overweight or obesity from a pediatric obesity clinic to use a Tabata Timer-based HIIT app plan for 6 weeks, then followed them for another 6 weeks. The prescribed plan was brief and home based, but actual use averaged only 2.5 sessions per week versus at least 5 prescribed. Body composition, movement behaviors, screen time, sleep duration, and water intake did not significantly change, while sugary beverage intake decreased. Children often perceived improvements in nutritional behavior and wellbeing, but parents mostly did not, and no child reported continuing the app during follow-up. ## Population - Children aged 7-13 years with overweight or obesity, smartphone access, and follow-up in a pediatric obesity outpatient clinic. - Sample size: 37 - Age: Mean 10.4 +/- 1.8 years - Sex: 45.9% girls - Health status: 94.6% with obesity; mean BMI z-score 3.31 +/- 1.09 ## Methodology - Mixed-methods exploratory longitudinal intervention with 6-week app-supported HIIT phase, 6-week no-contact follow-up, and semistructured interviews at week 6; no control group. - 6-week intervention plus 6-week follow-up - Pediatric obesity outpatient clinic with home-based app-guided exercise and weekday phone contact to parents during the intervention. ## Protocol - HIIT app bodyweight plan. - Modality: Bodyweight calisthenics timed by Tabata Timer app. - Work intervals: 20 seconds. - Recovery: 10 seconds between exercises and 50 seconds between cycles. - Sets or repetitions: 4 cycles of jumping jacks, single-leg hop-to-foot, dynamic squats, and isokinetic plank. - Intensity: HIIT prescribed; perceived exertion measured on adapted Borg 0-10 scale, highest mean 4.1 in week 1. - Session duration: 10 minutes. - Frequency: At least 5 days per week prescribed; actual mean 2.5 times per week. - Program length: 6 weeks plus 6-week no-contact follow-up. - Progression: No progression reported. ## Outcomes ### App adherence Status: mixed Children used the app on average 2.5 times per week, peaking at 3.4 times in week 2 and decreasing significantly by weeks 4-6; none continued during follow-up. Mean 2.5 uses/week (95% CI 1.9 to 3.0); week 4 delta -1.2, p = .038; week 5 delta -1.2, p = .024; week 6 delta -1.5, p = .007 versus week 2. ### Body composition Status: no clear change No significant over-time changes were found for BMI, BMI z-score, body fat mass, or muscle mass at intervention end or follow-up. No significant over-time differences at week 6 or week 12; boys had greater muscle mass increase than girls at week 6 (beta = 1.7, 95% CI 0.0 to 3.3, p = .030). ### Movement behaviors Status: no clear change Light physical activity, moderate-vigorous physical activity, screen time, and sleep duration did not significantly change. No significant over-time changes reported. ### Sugary beverage intake Status: improved Sugary beverage intake decreased over time. Delta -0.9, 95% CI -1.6 to -0.1, p = .019. ### Perceptions Status: mixed Children often perceived improved nutritional behavior and wellbeing, while most parents perceived no improvements. 64.5% of children reported improvement in nutritional behavior and general wellbeing; parents reporting no improvement: nutritional behavior 90.9%, general wellbeing 77.4%, fitness 81.3%. ## Practical Insights - A 10-minute, no-equipment app-guided HIIT plan is feasible to prescribe remotely, but actual use may be much lower than prescribed without stronger engagement. - For pediatric obesity, family involvement and parent engagement are likely critical to sustaining app-supported HIIT behavior. - This study should not be used as evidence that a very-low-volume remote HIIT app improves body composition in children with obesity. ## Limitations - Small sample - No control group - Single HIIT app - Subjective physical activity assessment - Semistructured interview guide was expert-developed but not pilot-tested or validated - Limited week 12 follow-up data - Low adherence reduced intervention dose ## Safety And Adherence - No adverse events or injuries were reported in the extracted full-text sections. - No children or parents perceived intervention-related impairments in nutritional behavior, general wellbeing, or fitness. - Children with psychiatric disorders, specified concomitant diseases, and menarche in girls were excluded. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/39465221/) (pubmed) - [DOI](https://doi.org/10.1177/20552076241291386) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11504280/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.