Modeling longitudinal variation in affective response to exercise across a 16-week randomized control trial (RCT)

Abstract

Objective: Consistent with the Science of Behavior Change (SOBC) experimental medicine approach, this early phase intervention development study examines the influence of an intervention strategy (exercise training) on a behavioral health outcome (exercise engagement) in the service of addressing a widespread threat to public health (physical inactivity). Method: Physically inactive participants (N = 201) were randomly assigned to one of four exercise training conditions fully crossed on intensity (moderate, vigorous) and duration (short, long). Training occurred over 16-weeks and in-bout assessments of affective response (valence) and ratings of perceived exertion (RPE) were collected during Weeks 1, 4, 8, and 16. Cardiorespiratory fitness (VO₂max) was assessed pre- or postintervention and exercise behavior was assessed at 6-months postintervention follow-up. Results: Across conditions, affective response to exercise did not change, on average, over 16-weeks. Conversely, RPE decreased slightly, on average, over time. Participants completing vigorous intensity exercise reported more negatively valenced affective response and higher RPE, on average, across weeks. Greater total exercise volume completed and greater change in VO₂max were associated with more negatively valenced affective response, on average. Baseline affective response scores were positively associated with exercise minutes at follow-up; however, average affective response scores across the intervention were not associated with minutes of exercise at follow-up. Conclusions: Affective response to exercise did not become more positive in valence over time as a function of training volume or change in VO₂max. Implications for translating these findings to inform future intervention development efforts are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Trial registration: ClinicalTrials.gov NCT02032628.

Figures

Figure 1.

CONSORT Diagram showing participant flow throughout the study *This number is slightly variable as some participants started the baseline survey but did not finish, or never started, or dropped out at various stages of the baseline visit. **This number differs from those who finished and completed the second VO2max testing session because some participants dropped after giving their last visit info, or had health issues preventing eligibility of testing at follow-up.

Figure 2a.

Pattern of average affective valence means (FS ratings) across time by condition. Scores on the Feeling Scale (FS) range from −5 – +5, with higher numbers indicating more positive valence.

Figure 2b.

Pattern of average perceived exertion (RPE ratings) across time by condition. Scores on the RPE scale range from 6 – 20, with higher scores indicating higher perceived exertion. Note. Mod/Short = moderate intensity–short (20min) duration condition; Mod/Long = moderate intensity–long (40min) duration condition; Vig/Short = vigorous intensity–short duration condition; Vig/Long = vigorous intensity–long duration condition; SD = standard deviation.