RESEARCH SUMMARY Empirical research into social physique anxiety has greatly advanced our understanding of its correlates and consequences in sport and exercise settings (e.g., Haase, Prapavessis, & Owens, 2002; Raedeke, Focht, & Scales, 2007). However, despite a plethora of research pertaining to this dispositional construct there generally remains a lack of conceptual focus. This hinders advancements in researchers' and practitioners' understanding of its psychological processes and as such the implementation of appropriate intervention strategies aimed at reducing social physique anxiety and facilitating exercise adherence. Therefore, the main objective of the present programme of research was to determine the antecedents and consequences of social physique anxiety amongst individuals considering or currently participating in recreational and health-related physical activities. Specifically, this research aims to examine individual differences in motivational factors implicated in the appraisal processes that contribute to anxiety amongst exercisers and its associated behavioural consequences. Chapter One will frrst draw upon current empirical research on social physique anxiety to demonstrate the potentially debilitating nature of this construct. Second, it will further provide an outline of the theoretical frameworks guiding the individual studies in this programme of research. Chapter Two shows that one motivational factor implicated as an antecedent of state anxiety is the achievement goal (task, ego) that individuals adopt (Nicholls, 1984, 1989; Stipek, 1992). Exercise domains provide an ideal setting for social evaluation and self-presentation (Conroy & Motl, 2003; Shields, Paskevich, & Brawley, 2003), with characteristics of the environment and individuals' personalities heightening the extent to which they are motivated to seek others' approval (Leary & Kowalski, 1995). It is therefore plausible that the endorsement of ego-oriented goals would intensify the negative affective responses experienced by physique anxious exercisers. However, current reservations over an existing exercise-related goal orientation measure (Kilpatric~ Bartholomew, & Reimer, 2003) led to the development of a new one. Chapter Two therefore describes the development and initial validation of a four-factor measure of achievement goals through confirmatory factor analytic procedures that distinguished between socially-driven and self-directed goal orientations (Wilson, Harwood, & Hardy, 2003). However, the social goal factors were found to hold little discriminant validity. In Chapter Three social goals were re-conceptualised by examining the theoretical framework of self-determination theory (Oeci & Ryan, 1985,2000) as a viable alternative of their assessment. Specifically, it was proposed that the endorsement of social goals and achievement goals serves to satisfy a sense of relatedness amongst physique anxious exercisers. This study expanded on study one by further assessing the mediating role of individuals' basic psychological needs on the relationship between goal orientations and social physique anxiety and exercise intention. Additionally, the variables' ability to predict social physique anxiety longitudinally was considered. Chapter Four describes the fmal study in which the notion of fitness-assessment procrastination was introduced as a potentially important maladaptive behavioural strategy among gym club participants. Using rigorous qualitative methods, the study provided an in-depth account of the motivational processes contributing to fitness-assessment procrastination amongst physique anxious exercisers. The concept of self-versus other-directed goals (study one) was re-assessed and the target of others' social goals (study two) was clarified in the fonn of individual differences in self-oriented and socially-prescribed perfectionistic tendencies (Hewitt & Fle~ 1991; Flett & Hewi~ 2002). Motivational processes influencing fitness-assessment procrastination amongst physique anxious exercisers were identified which hold implications for the facilitation of autonomy-supportive fitness-assessments to satisfy exercisers' basic psychological needs and subsequent attendance.