The majority of physical activity initiatives have been directed toward promoting cardiorespiratory fitness and general health. Far less attention has been devoted to encouraging or understanding muscular fitness-promoting behaviors. The purpose of this study was to determine if constructs from the Transtheoretical Model, a contemporary behavior change framework, could be adapted and applied to the study of muscular fitness-promoting behaviors. Participants were 429 college students who completed measures of stage of change, the behavioral and cognitive processes of change, and self-efficacy. All measures were modified to relate specifically to muscular fitness-promoting behaviors. Two direct discriminant function analyses were performed, revealing that the behavioral processes of change and self-efficacy were the major correlates of the stages of change for muscular fitness-promoting behaviors.