Self-control strength depletion reduces self-efficacy to exert self-control, task self-efficacy, and impairs resistance exercise performance


Recent research based on the strength model (Baumeister, 2014) showed self-control depletion led to a reduction in task self-efficacy, which was found to mediate the effect of depletion on physical endurance (Graham & Bray, 2015). However, because self-control strength reflects a generalized capacity, we reasoned that self-control depletion should lead to an overall reduction in self-efficacy to exert self-control (SESC), which then informs task self-efficacy. This study investigated the effects of self-control depletion on perceived SESC, task self-efficacy, and endurance performance of resistance exercise. We tested a sequential mediation model predicting self-control depletion --> SESC --> task self-efficacy --> task performance. Participants (N = 50) completed a baseline measure of SESC and then performed one set of maximum repetitions on bench press (at 60% of 1RM) and leg extension (at 40% of 1RM) followed by either an incongruent (depletion) or congruent (control) Stroop task. They then completed measures of SESC and task self-efficacy, followed by a second set of maximum repetitions. Participants in the depletion condition reported lower SESC and task self-efficacy, and performed fewer repetitions compared to controls (ps < .01). Mediation analyses revealed an indirect (mediation) effect for task self-efficacy in the relationship between self-control depletion and performance for bench press (95% C.I. = 0.28-1.98) and leg extension (95% C.I. = 0.19-1.38). However, the effects for SESC were not significant. Although sequential mediation was not evident, findings supported theorizing that self-control depletion should weaken SESC. Results also extend prior research and are the first to have used resistance exercise as a physical performance task.