Date of Award


Degree Type


Degree Name

Doctor of Philosophy




Dr. Craig Hall


The purpose of this dissertation was to test the effectiveness of mental imagery

interventions for enhancing exercise-related cognitions during long-term exercise programs. In order to ensure the integrity of the imagery intervention, a secondary purpose of this dissertation was to test the dependent variables within the context of their respective theories to confirm their distinctive nature and therefore suitability as targets of an imagery intervention. To achieve these purposes, four studies were conducted using a multi-dimensional conceptualization of self-efficacy for exercise (Rodgers & Sullivan, 2001) and Self-Determination Theory (SDT; Deci & Ryan, 1985) as theoretical frameworks.

In Study 1 the multi-dimensional conceptualization of SE for exercise was examined in order to demonstrate the distinctive nature of task, coping, and scheduling SE in an exercise context. Study 2 examined the effectiveness of a mental imagery intervention within the context of SE theory. Specifically, Study 2 sought to determine if three types of SE could be differentially influenced using guided imagery interventions in an experimental design controlling for overt mastery experiences. Studies 3 and 4 employed self-determination theory as the framework for testing the effectiveness of an imagery intervention. The purpose of study 3 was to examine how different types of motivation contribute to various characteristics of exercise behaviour. Finally, Study 4 examined the effects o f a mental imagery intervention designed to enhance integrated

regulation. The results of Study 1 revealed that scheduling SE was the strongest predictor of

exercise frequency, duration and weekly METS for males and females. Coping SE added

to the prediction of frequency and weekly METS for males and females, as well as iii

duration and number of years of exercising for males only. Task SE added to the prediction of duration for males and females and was a unique predictor of number of years for females only. The findings revealed that task, coping, and scheduling SE for exercise can differentially predict various components o f regular exercise supporting the contention that the three types of SE are distinct. All three types of SE were determined to be important for both males and females however, the relative importance of each type might be gender specific.

Study 2 demonstrated that targeting each type of SE through an imagery intervention has separable effects that are primarily restricted to the targeted SE type. Furthermore, the imagery intervention was successful in enhancing task, coping, and scheduling SE beyond the levels that occurred as a result of overt experience. The results of Study 2 provided support for the use of imagery interventions for influencing SE for exercise.

The results of Study 3 supported previous research and demonstrated that integrated and identified regulations predicted exercise frequency for males and females. Integrated regulation was found to be the only predictor of exercise duration across both genders. Finally, introjected regulation predicted exercise intensity for females only. These findings suggested that exercise regulations that vary in their degree of internalization can differentially predict characteristics o f exercise behaviour.

Study 4 provided additional support for the effectiveness of imagery interventions for enhancing exercise-related cognitions. Specifically, participants in the imagery group experienced greater changes in integration compared to control participants.


Overall these four studies offer practical considerations and directions for future exercise imagery research. This dissertation demonstrates that imagery interventions can be employed to enhance exercise-related cognitions among female exercise initiates in a laboratory setting. Future research should examine whether or not imagery-induced changes in SE and motivation as conceptualized in SDT can translate into increases in exercise behaviour or physical activity.



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