ACTing with Self-Determination: Psychological Flexibility and Motivation for Physical Activity
This research project explored the relationships amongst psychological flexibility, motivation for physical activity (PA), and PA behaviour. The overarching rationale was that increased psychological flexibility facilitates psychological need satisfaction and subsequent autonomous extrinsic motivation (autonomous-EM) for PA, therefore increasing the likelihood of PA maintenance. Study one was a cross-sectional study (N = 456), designed to explore the relationships between psychological flexibility, motivation for PA, and PA behaviour. In line with the study hypotheses, results showed that cognitive acceptance and behavioural commitment (as proxies for psychological flexibility) and present moment awareness each positively predicted autonomous-EM. There was also evidence for indirect effects between psychological flexibility, present moment awareness, and autonomous-EM via psychological need satisfaction, indicating partial mediation. Also, in line with hypotheses, there was evidence that cognitive acceptance and behavioural commitment positively predicted self-reported weekly PA, with indirect effects via autonomous-EM. However, contrary to hypotheses, present moment awareness negatively predicted PA. Study two was a qualitative study (N = 9) which explored the role of the psychological flexibility processes (acceptance, committed action, present moment awareness, cognitive defusion, self-as-context, and value clarification), in supporting participants’ capacity to successfully maintain PA. Results indicated that the processes of acceptance, committed action, cognitive defusion, and value clarification each played a positive role in participants’ PA maintenance. Evidence for the roles of present moment awareness and self-as-context were inconclusive, with more research suggested to clarify the role of these processes in PA maintenance. Study three used a single-case design (N = 3) to investigate the effect of a four-session intervention based on Acceptance and Commitment Therapy (ACT), designed to support participants to increase and maintain PA in line with PA weekly guidelines. Data were obtained on a weekly basis from baseline to immediate post- intervention, and at three and six months’ post-intervention. It was hypothesised that the intervention would result in increased self-reported PA, cognitive acceptance and behavioural commitment from baseline to all post-intervention time points, alongside increases in psychological need satisfaction and autonomous-EM. Results indicated no support for the hypothesis that the intervention would increase PA immediately post-intervention, but there was partial support for increased PA six months’ post- intervention. Partial support was also obtained for the intervention to increase behavioural commitment and competence satisfaction immediately post-intervention. Hypotheses predicting increased cognitive acceptance, autonomy and relatedness satisfaction, and autonomous-EM were not supported.Overall, results provided initial evidence for positive relationships between psychological flexibility, autonomous-EM, and PA behaviour. However, a lack of consistent intervention effects precluded conclusions being made regarding the viability of an ACT-based intervention to facilitate increased psychological flexibility, need satisfaction, and autonomous-EM for PA. Further research, including the development of PA-specific measurement tools for psychological flexibility processes, should endeavour to continue investigating the role of psychological flexibility in supporting long-term maintenance of PA.
Advisor: Hargreaves, Elaine; Hodge, Ken
Degree Name: Doctor of Philosophy
Degree Discipline: School of Physical Education, Sport, and Exercise Sciences
Publisher: University of Otago
Keywords: physical activity; psychological flexibility; acceptance; commitment; self-determination theory; autonomous extrinsic motivation
Research Type: Thesis