Effects of a School-Based Physical Activity Intervention for Obesity and Health-Related Physical Fitness in Adolescents With Intellectual Disability: Protocol for a Randomized Controlled Trial

Background: Childhood obesity accompanied with lower levels of health-related physical fitness (HRPF) is a major threat to public health both internationally and locally. Children with intellectual disability (ID), especially adolescents, have a higher risk of being overweight/obese and having poor HRPF levels. More interventions, therefore, are needed to help this population attain their optimal health levels. However, there has been limited research on this population compared with studies designed for their typically developing (TD) peers.

Objective: The proposed study aims to fill this knowledge gap by developing and examining the success of a physical activity (PA) intervention for the target population.

Methods: The proposed study will be a school-based randomised controlled trial lasting for 12 weeks. The participants (N=48) will be recruited from special schools for students with mild ID and then randomly allocated to either the intervention group (IG) or the waiting-list control group (CG). During the intervention period, the participants in the IG will receive a fun, game-based moderate-to-vigorous physical activity (MVPA) training programme (twice/week, 60-min/session, a total of 24 sessions). The intensity of the activities will increase in a progressive manner. Those in the CG will receive no intervention. To observe and evaluate the sustaining effects of the intervention, follow-up testing will be scheduled for the participants 12 weeks after the intervention concludes. The study outcomes will include primary outcomes (fatness-related outcomes and fitness-related outcomes) and secondary outcomes (blood pressure). All of the measurements will be taken three times. After the follow-up tests, the same PA training programme will be provided to the participants in the CG.

Results: This study is ongoing. The participants were recruited from October 2020 to November 2020. Total duration of the study is 13 months. Study results are expected at the end of 2021.

Conclusions: The proposed study is expected to reduce fatness and improve HRPF levels in children with ID. If proven effective, the intervention will be made accessible to more special schools and mainstream schools with students with ID. Furthermore, the study can serve as an example for international researchers, policymakers and the public who are seeking to tackle the problem of obesity and poor HRPF among children with ID. Clinical Trial: This trial is prospectively registered at the ClinicalTrials.gov PRS (Trial ID: NCT04554355; Date of First Posted: September 17, 2020).