Association Between Physical Fitness and Quality of Life in Children and Adolescents with Down Syndrome

<b>Background/Objectives</b>: Multiple studies have reported that the quality of life (QoL) among children and adolescents with Down syndrome (DS) is lower than that among typically developing children. Meanwhile, physical fitness is crucial for improving QoL throughout childhood and adolescence. Combining these insights, this cross-sectional study aimed to examine the association between physical fitness and QoL in children and adolescents with DS. <b>Methods</b>: Participants were 56 children and adolescents (aged 8-16 years) enrolled in one DS center in Saudi Arabia. Cardiorespiratory fitness, muscular strength, and muscular power were measured to assess physical fitness. The PedsQL^TM (parents' proxy scale) was used to measure participants' QoL. Multiple linear regression with pooled analysis was used to examine the association between physical fitness and QoL. <b>Results</b>: Boys showed higher muscular power than girls (<i>p</i> = 0.024). Weak to moderate correlations were observed between muscular power, muscular strength, and QoL domains. Regression results suggested that children and adolescents with high muscular power had better scores in social functioning (<i>B</i> = 0.693, R² = 0.22, <i>p</i> = 0.013). Children and adolescents with high muscular strength had better scores in overall QoL (<i>B</i> = 2.665, R² = 0.21, <i>p</i> = 0.027). <b>Conclusions</b>: Children and adolescents with DS who have higher muscular fitness had better scores in social functioning and overall QoL. Increasing muscular fitness in children and adolescents with DS appears to be particularly important for improving QoL.