This thesis aimed to develop a measure to investigate the perceived motivational climate in individual sports. In particular, it aimed to address some of the knowledge gaps in the current literature examining motivational climates: by developing a measure whose intended population participate in individual sports; that incorporates the perceived motivational climate created by multiple significant others; and that incorporates the 'impact' or salience of each of these perceptions of the motivational climate. In order to achieve this, the thesis is comprised of four studies.

A positive psychosocial intervention comprised of high autonomy support, task-involvement, and caring was implemented in physical activity classes to examine its effects on college women’s basic psychological needs (i.e. autonomy, competence, relatedness), exercise regulations (i.e. external, introjected, identified, integrated, intrinsic) and social physique anxiety (SPA). We hypothesized that at the end of the semester, participants in the intervention group (N = 73) would report greater need satisfaction, more self-determined regulations and less SPA than participants in the non-intervention group (N = 60). At T1 and T2, both the intervention and non-intervention participants reported “agreeing” with experiencing an autonomy supportive, task-involving, and caring environment. Furthermore, both groups at T1 and T2 reported moderate SPA. No significant group differences were found at T1. At T2, significant group differences were observed in the intervention and non-intervention groups’ report of external regulation and intrinsic regulation. The results suggests that group exercise instructors are capable of creating a positive psychosocial environment to enhance students’ intrinsic motivation.