Analysis of the Physical Fitness Development Trajectory of Children and Adolescents With Severe Intellectual Disabilities in Orphanages: A Three-year Longitudinal Follow-up Study

This observational cohort study was designed to describe how physical fitness changes over time in children and adolescents with severe intellectual disabilities living in orphanages in China. A total of 132 participants aged 7-18 years were recruited from four state-run orphanages and followed prospectively for three years. At baseline and every 3 months thereafter (12 assessments in total), trained assessors measured body mass index and simple field-based fitness tests, including beanbag throwing for upper limb strength, sit-ups for core strength, standing long jump for lower limb explosive strength, and one-leg standing for static balance. The main aim of the study is to characterize the long-term trajectories of physical fitness in this highly vulnerable population and to examine whether patterns of change differ by age group (children 7-12 years vs adolescents 13-18 years) and by sex. The findings are intended to provide evidence to guide physical education programming and health management strategies for children and adolescents with severe intellectual disabilities living in institutional care settings.