Psychometric properties of the Muscle Appearance Satisfaction Scale among Irish and British men.

The psychometric soundness of the Muscle Appearance Satisfaction Scale (MASS; Mayville, Williamson, White, Netemeyer, & Drab, 2002), a measure of muscle dysmorphia symptoms, was investigated using two independent online samples of Irish and British men (ns=307 and 306, respectively). Exploratory and confirmatory factor analyses showed that, compared to the original 5-component solution for the 19-item MASS, a 6-item unidimensional version offered better fit to the data. Findings further upheld the internal consistency reliability, construct validity (e.g., via its associations with internalization of the muscular ideal and physical appearance comparisons), and discriminant validity (e.g., via its nonsignificant relationship with social desirability) of the MASS's scores. The limitations associated with the current research are discussed and directions for future research are articulated.