Abstract: | In accordance with self-determination theory (SDT; Deci & Ryan, 1985 ), this study examined the relationship between autonomy support, psychological need satisfaction, motivational regulations, and exercise behavior. Participants ( N =369) were recruited from fitness, community, and retail settings. Fulfillment of the 3 basic psychological needs (i.e., competence, autonomy, and relatedness) related to more self-determined motivational regulations. Identified and introjected regulations emerged as positive predictors of strenuous and total exercise behaviors. Competence need satisfaction also predicted directly—and indirectly via identified regulation—strenuous exercise. For participants engaged in organized fitness classes, perceptions of autonomy support provided by exercise class leaders predicted psychological need satisfaction. Furthermore, competence need satisfaction partially mediated the relationship between autonomy support and intrinsic motivation. These findings support SDT in the exercise domain. |