RESUMO
Across various social cognitive theories, behavioral intention is broadly argued to be the most proximal and important predictor of behavior (Ajzen, 1991; Gibbons, Gerrard, Blanton, & Russell, 1998; Rogers, 1983). It seems probable that an intention to increase behavior might be differentially determined from an intention to maintain behavior. Thus, the purpose of the current study was to examine (1) the change in two types of behavioral intention over time and (2) the relationship between intention and the social-cognitive factor mental imagery. Behavioral intention, exercise imagery, and observed exercise behavior was measured in 68 exercise initiates participating in a 12-week exercise program. Results revealed that behavioral intention to increase exercise behavior decreased over the exercise program, whereas intentions to maintain exercise behavior increased. Appearance and technique imagery were found to be significant predictors of intention to increase behavior during the first 6 weeks of the program, and only appearance imagery predicted intention to maintain exercise behavior during the last 6 weeks. These findings suggest that the two types of behavioral intention are distinguishable and may be useful targets for exercise behavior interventions.