A study on acute expectation effects on affective state and intention after a brief full-body workout in a student sample

Introduction & Purpose Research shows that even short exercise programs can have positive effects on affective state (Focht, 2009), which in turn could have a positive influence on the intention to exercise in the future (Finne et al., 2022). The state of research in recent years also indicates that such benefits can be enhanced by manipulating expectations (Helfer et al., 2015). However, most of these studies on expectation effects were conducted in laboratory settings, meaning that the results are transferable to a natural context or everyday situations only to a limited extent. The aim of this study was therefore to examine whether the manipulation of affective expectations can influence affective state after physical activity in a more naturalistic setting; in addition, it was investigated whether the expectation manipulation has an effect on the intention for future exercise. Methods In an online experiment, 121 physically active students (25.58 ± 5.11 years), 70.2% female, were randomly assigned to either a ten-minute, virtually-guided whole-body workout (PA), a ten-minute, virtually-guided whole-body workout after manipulation of affective expectations via audio file (PA + EM), or a sedentary control intervention (CG). In the audio file, a purported speaker for the research team highlighted that recent research indicates that brief workouts would have particularly positive effects on stress experience and affective state. Pre- and post-intervention data, including affective state and intention, were collected using questionnaires, such as the Mood Survey Scales by Abele-Brehm and Brehm (1986). Results After controlling for the baseline level before the intervention via analyses of covariance (ANCOVAs), PA and PA + EM showed significantly more positive scores than CG in several parameters of affective state (e.g., scale Activation, Elation, Fatigue) after the intervention, in some scales (e.g., Affective Valence, Depression) only PA + EM differed significantly from CG. The mean scores in intention after the intervention did not differ significantly between PA + EM (27.00 ± 4.57), PA (27.41 ± 6.79), and CG (27.70 ± 5.78), p = .836. Discussion Even a short, virtually-guided workout can have strong positive effects on affective state. No direct effects of the expectation manipulation on affective state or intention were found. Possible reasons for this include ceiling effects in the participants’ expectations, or that the form of expectation manipulatio