Handgrip Strength, Trunk Muscle Endurance, and Functional Mobility in Adolescents With Mild Intellectual Disability

Overview

This comparative, cross-sectional observational study examined handgrip strength, trunk muscle endurance, and functional mobility in adolescents aged 12-18 years with mild intellectual disability and compared their performance with typically developing peers. A total of 51 participants were evaluated during a single assessment session, including 24 adolescents with mild intellectual disability and 27 typically developing adolescents. Handgrip strength was measured using a digital hand dynamometer, trunk muscle endurance was assessed using the McGill trunk endurance test battery, and functional mobility was evaluated using the Timed Up and Go Test and the Timed Up and Down Stairs Test. The study also examined the relationships among handgrip strength, trunk muscle endurance, and functional mobility.

Study Design This was a comparative, cross-sectional observational study. Participants were not assigned to any treatment, exercise program, or other intervention. All assessments were completed during a single study visit, and no 8-week intervention or follow-up assessment was conducted. Participants The study included 51 adolescents aged 12-18 years. The mild intellectual disability group consisted of 24 adolescents with a clinical diagnosis of mild intellectual disability according to DSM-5 criteria. The comparison group consisted of 27 typically developing adolescents without a diagnosis of intellectual disability, neurodevelopmental disorder, neurological disease, orthopedic condition, or serious systemic disease affecting assessment performance. Assessments Handgrip strength was measured separately for the right and left hands using a digital hand dynamometer. Three trials were performed for each hand, and the mean of the three trials was recorded in kilograms. Trunk muscle endurance was assessed using the McGill trunk endurance test battery, including the trunk flexor endurance test, trunk extensor endurance test, right side bridge test, and left side bridge test. Performance duration was recorded in seconds. Functional mobility was assessed using the Timed Up and Go Test and the Timed Up and Down Stairs Test. Completion times were recorded in seconds, with shorter times indicating better functional mobility. Study Objective The primary objective was to compare handgrip strength, trunk muscle endurance, and functional mobility between adolescents with mild intellectual disability and typically developing peers. The study also examined the relationships among these variables. Registry Clarification The initial registry version contained outcome-measure labels and assessment time points that did not correspond to the final assessment battery. After study completion, the record was updated to reflect the actual enrollment, the single-visit assessment schedule, and the outcome measures that were administered. Previous versions of the registry record remain accessible through the record history.