The Moderating Influence of Situational Motivation on the Relationship Between Preferred Exercise and Positive Affect

Despite convincing evidence supporting the association between exercise and positive affect, this complex relationship requires further theoretical and person-centered explanation. The nature of one’s motivation for exercise, as postulated by Self-Determination Theory (SDT), may supply a missing and understudied link. The primary aim of this experimental study was to examine the moderating influence of situational motivation from SDT on the relationship between an acute bout of preferred exercise, namely running (vs. control), and changes in positive affect. Forty-one active women attended two sessions to engage in (a) a 30-min moderate-intensity self-paced treadmill run and (b) a 30-min quiet activity (i.e., newspaper reading). Participants with high introjection versus those with low introjection reported a greater increase in positive affect from pre- to postrunning and a greater decrease in positive affect from pre- to postcontrol. A “relief from guilt” effect was postulated to explain these results. Motivational variables accounted for 7% of variance in postrun positive affect. Consistent with SDT, running because one values this behavior and its benefits (i.e., identified regulation) was significantly associated with postrun positive affect.