The Impact of Exercise Intensity Variations Within Treadmill Trials of Similar Work on Psychological Responses

Abstract

Rating of perceived exertion (RPE) and affective responses are important aspects of the exercise experience. Limited research suggests that exercise intensity may be important in the formation of the overall view of the exercise experience. PURPOSE: Determine the impact of varying the intensity of an exercise bout relative to the ventilatory threshold on RPE, affect, and self-efficacy. METHODS: Eight participants (6 male, 2 female, mean age = 24 years) were tested for aerobic fitness to determine VO2max (mean = 49 ml × kg-1 × min-1). Participants completed five 30-minute trials of treadmill exercise prescribed to be equivalent in terms of external work and distance travelled. Each trial differed with respect to the variation of the workload: 1) steady throughout, 2) increasing, 3) decreasing, 4) peak in middle, and 5) valley in middle. All workload changes occurred at the 10 and 20 minute marks of the trial. Measures of RPE, affect, arousal, and heart rate (HR) were taken before, every five minutes during, immediately after, and 15 minutes after exercise. Enjoyment and self-efficacy were assessed immediately and 15 minutes after exercise. RESULTS: Data were analyzed using ANOVA and pairwise comparisons. No differences were noted for anticipated or post-exercise RPE (P > 0.05), despite numerous differences in RPE and HR during exercise (P < 0.05). Similarly, no differences were noted for post-exercise ratings of exercise self-efficacy (P > 0.05). Several differences were noted within the affective data including lower post-exercise affect scores in the trial with reduced effort in the middle and higher post-exercise enjoyment in the trial with greatest effort in the middle (P < 0.05). Several other comparisons trended toward significance but did not reach acceptable alpha levels due in part to lack of statistical power. CONCLUSIONS: Findings suggest that variations in intensity during trials of exercise sufficient to induce significant in-task differences in HR and RPE do not impact post-exercise RPE. This data also suggests that affective and enjoyment responses post-exercise can be impacted by within trial variations in exercise intensity. However, more research is needed in larger and more diverse samples to more fully understand how varied exertion during exercise impacts post-exercise perceptions.