The aim of the present study was to investigate a think aloud protocol as a novel way to measure indicators of self-control during acts of physical persistence. Using a within-person design, 35 participants (9 males, 26 females) completed two wall-sit persistence tasks, one employing a think aloud protocol, and the other silent. A two-way mixed ANOVA found no significant differences in persistence between conditions, indicating that using the think aloud protocol during the wall-sit did not have a significant effect on persistence. Think aloud scripts of 34 participants (one participant's script was inadmissible) revealed that all participants verbalized negative affect, an essential characteristic of a desire-goal conflict. Thirty-two participants (94%) verbalized conflict resolution strategies. A multiple linear regression found that the length of time from the beginning of the task to the first verbalization of negative affect positively predicted persistence on the wall-sit task ([beta] =0.61; p < 0.001), but the length of time to the first verbalization of conflict resolution did not ([beta] =0.16; p =0.30). This indicates that the time at which negative affect is initially verbalized is a reliable predictor of persistence. The study supports the use of the think aloud protocol in postural persistence tests and other simple physical tasks and supports the possibility that verbalization of negative affect may be an indicator of the initiation of a desire-goal conflict.