This study sought to examine tenets of Self-Determination Theory by testing a mediation model of physical activity and personality via autonomy. A total of 290 adults were recruited to complete a one-time online survey of exercise habits and individual characteristics. Surveys assessed personality, autonomy, and physical activity. A measurement model specifying direct effects between personality dimensions and physical activity and indirect effects operating through autonomy provided an excellent fit to the data (Χ² = 0.66, df = 3, p = 0.88, RMSEA(90% CI) = 0.00 (0.00⁻0.05), CFI = 0.99, SRMR = 0.01). Results indicated significant (p < 0.05) effects of Extroversion (β = 0.42), Conscientiousness (β = 0.96), and Emotional Stability (β = 0.60) on autonomy, which in turn, was significantly associated with physical activity (β = 0.55). No significant effects were observed for Agreeableness or Intellect. None of the personality constructs were found to be directly associated with physical activity. This model accounted for 27% of the variance in physical activity. The results of this study suggest that autonomy is significantly associated with physical activity. Therefore, attempts to improve autonomy in individuals may be a useful intervention strategy in improving physical activity levels.
Keywords: autonomy; personality; physical activity; self-determination.