Expectation manipulation shows no additional benefit on students' post-exercise stress perception - a randomized controlled online trial

Single physical activity (PA) bouts may have an immediate positive effect on perceived stress. Overall, acute psychological benefits of PA may be enhanced by manipulating expectations but it is unclear, whether this also applies to acute stress. This study aimed to investigate whether a brief workout can reduce acute stress and whether manipulating expectations can enhance this effect in a student sample. Furthermore, associated factors with the stress-reduction of PA were analyzed. In an online trial with randomized group allocation, 121 participants completed a ten-minute workout (PA), a ten-minute workout following expectation manipulation (PA+EM), or a control intervention (CG). Data on acute perceived stress, student burnout, longer-term stress experience, and habitual PA were collected via questionnaires before and after the intervention. Analysis of covariance indicated that after the intervention, PA+EM (d=-1.15) and PA (d=-0.91) showed significantly lower values in acute perceived stress than CG, while PA groups did not differ (d=-0.24). Exploratory analyses revealed that students with lower burnout efficacy scores benefited more from the workout than those with higher scores. Although the manipulation had no additional effect, the results suggest that a brief workout can strongly reduce perceived stress and may therefore be a suitable coping strategy for students.