Background There is limited evidence that self-affirmation
manipulations can promote health behavior change.
Purpose The purpose of this study was to explore whether the
efficacy of a self-affirmation manipulation at promoting exercise
could be enhanced by an implementation intention
intervention.
Methods Participants (Study 1N =120, Study 2N =116) were
allocated to one of four conditions resulting from the two
(self-affirmation manipulation: no affirmation, affirmation)
by two (implementation intention manipulation: no implementation intention, implementation intention) experimental design. Exercise behavior was assessed 1 week post intervention.
Results Contrary to prediction, those participants receiving both manipulations were significantly less likely to increase
the amount they exercised compared to those receiving only the self-affirmation manipulation.
Conclusion Incorporating an implementation intention manipulation alongside a self-affirmation manipulation had a
detrimental effect on exercise behavior; participants receiving both manipulations exercised significantly less in the week
following the intervention.