<P> The general purpose of this dissertation was to use a psychobiological approach to
examine the psychosocial, biological and behavioural factors associated with social physique
anxiety (SPA) in women. With this perspective in mind, the broad objectives of the present
dissertation were as follows: (1) to examine the relationship between social physique anxiety and
cortisol, (2) to implement an exercise intervention to change social physique anxiety and cortisol,
and (3) to understand the mechanisms responsible for exercise-induced changes in social
physique anxiety. </p> <P> Specifically, in Study 1, the purpose was to experimentally manipulate physique
evaluative threat in a controlled laboratory setting to determine if physique evaluative threat
(i.e., social physique anxiety; SPA) produces concomitant changes in cortisol secretion.
Additionally, this study examined if perceptions of physique evaluative threat were related to
cortisol responses. Participants were 50 women who were randomly assigned to an
experimental, or a control condition. Results indicated that post-manipulation, the experimental
condition had higher cortisol levels than the control condition. Furthermore, regression analyses
indicated that a post-manipulation measure of physique evaluative threat explained 7.2% of the
variance in post-manipulation cortisol levels. Taken together, these findings suggest that acute
changes in physique evaluative threat cause changes in cortisol levels and provide an empirical
basis for studying cortisol's role in body image disturbance and related pathologies (e.g., eating
disorders). </P> <P> In Study 2, a controlled experimental design was used to compare the effects of an 8-
week exercise (aerobic versus resistance) training intervention on changes in SPA and changes in
cortisol. In addition, this study examined the physical and psychosocial mechanisms underlying the effects of exercise training on SPA and explored the possible protective effects of exercise
training on state SPA and cortisol responses to an acute physique evaluative threat situation.
Forty six women were randomly assigned to one of two exercise conditions: aerobic or resistance
training. Analyses indicated that the aerobic condition experienced greater improvements in trait
SPA than the resistance training condition and both groups exhibited significant decreases in
cortisol levels (compared to baseline). In addition, changes in aerobic self-efficacy and perceived
physical endurance partially mediated the effect of the exercise intervention on trait SPA.
Finally, the results demonstrated that 8-weeks of exercise training (regardless of mode) may
buffer the state SPA response to a physique evaluative threat manipulation. </p> <P> In summary, these studies provide a broader understanding of the factors associated with
SPA. The results demonstrated that for women, situations that elicit physique evaluative threat
elicit concomitant changes in cortisol. Exercise training is an effective strategy for improving
SPA, reducing cortisol responses, and possibly providing a protective effect against the state
SPA response among young women. Aerobic exercise training is more effective for improving
SPA than resistance training and this is due in part to increases in aerobic self-efficacy and
perceived physical endurance. The dissertation studies provide momentum for extending the
scope of research on SPA and for determining the best approach for improving SPA among
women. </p> / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19202 |
| Date | 01 1900 |
| Creators | Strong, Heather |
| Contributors | Martin Ginis, Kathleen, Kinesiology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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