Impact of Muscle Mass and Muscle Strength on Quality of Life of Individuals with Intellectual and Developmental Disabilities

This study aimed to investigate the relationship between muscle strength and perceived quality of life in individuals with Intellectual and Developmental Disabilities (IDDs). A cross-sectional study was carried out, which involved 37 participants with a mean age of 39.08 years (SD = 0.05), ranging from 20 to 58 years. The participants were assessed on anthropometric and body composition parameters, a 30 s chair stand test and isokinetic dynamometry. Quality of life was assessed using the Portuguese version of the Personal Outcomes Scale. Pearson’s correlation analyses were carried out to examine the associations between strength measures and quality of life. Significant correlations were observed between strength measures and quality of life. In addition, lower limb muscle strength, particularly in flexion (left: r = 0.450; p ≤ 0.001; right: r = 0.504; p ≤ 0.001) and extension (r = 0.328; p = 0.05), showed positive correlations with quality of life. These findings provide preliminary evidence suggesting that muscle mass and strength may serve as potential predictors of quality of life in individuals with IDD.