Introduction

The need for adequately designed and well-delivered interventions successfully increasing physical activity and exercise has long been highlighted [1]. Furthermore, interventions based on adequate theory and examined by proper analyses enable researchers to identify central mechanisms of change [2], important for successful intervention design [3].

Methods

The present study examined potential effects of a short theory based intervention on exercise motivation and behaviour in a randomized controlled trial design. Self-Determination Theory, Cognitive Behavioural Therapy, Motivational Interviewing and Relapse-Prevention Model were used as guiding frameworks. The research questions concerned whether the intervention would influence (a) exercise level and intensity, (b) motivation quality, (c) autonomy and competence need satisfaction, and (d) potential indirect effects of self-determined motivation on exercise were also examined. The participants (N=64) completed self-reported measures of exercise level and intensity (Leisure Time Exercise Questionnaire; LTEQ), of motivational quality (Behavioral Regulations in Exercise Questionnaire-2; BREQ-2) and of autonomy and competence need satisfaction (Psychological Needs in Exercise Scale; PNSE) at baseline and after the six weeks of intervention.

Results

The results showed significant intervention effects for both exercise level and intensity, as well as in motivation quality. Furthermore, the effect of the intervention on exercise was   mediated by motivational profile, in particular identified regulation.

Discussion

Despite the short-term and small scale nature of the intervention, effects were found on exercise behaviour and this effect was mediated by self-determined motivation. The results are generally in line with theoretical expectations from an SDT perspective. Furthermore, the study adds interesting findings of potential mechanisms behind exercise behaviour and motivation. Future research should further explore the theoretical mechanisms of behaviour change in order to facilitate tailoring of effective exercise interventions and enhancing motivation.

References

1. WHO, Global recommendations on physical activity for health. 2010, World Health Organization.: Geneva.
2. Rhodes, R.E. and L.A. Pfaeffli, Mediators of physical activity behaviour change among adult non-clinical populations: a review update. Int J Behav Nutr Phys Act, 2010. 7: p. 37.
3. Fortier, M.S., et al., Promoting physical activity: development and testing of self-determination theory-based interventions. International Journal of Behavioral Nutrition and Physical Activity 2012. 9(20).