Stress Inoculation Training and Mental Fatigue

Purpose: The purpose of this study is to examine the effectiveness of stress inoculation training on reducing the effect of mental fatigue on physical performance. Methods: Moderately trained runners completed three lab visits: familiarization, pretest, and posttest. During the pre and posttest, all participants completed a 5 km time trial in a mentally fatigued state, induced by watching a video that elicits joy, sadness, and disgust while not showing any emotion. Participants were randomly assigned to the control or experimental group. Both groups were asked to watch a video every day for the 14-day intervention period. The experimental group watched the same emotion-eliciting video as they did during the testing sessions, while the control watched a short nature documentary. Results: Nine participants (experimental group n = 5) completed all testing sessions. The experimental group had an average time to completion of 24.65 min and 24.67 min in the pretest and posttest (respectively), while the control group had an average time of 20.35 min and 20.19 min in the pretest and posttest (respectively). No significant differences were found in time to completion, heart rate, lactate, effort, pain, self-rated emotion felt, and difficulty to suppress that emotion (except the difficulty suppressing sadness). However, a large change in self-rated disgust felt and difficulty suppressing disgust was seen in the experimental group from pre to posttest (disgust felt: 63.4 ± 27.7 vs. 31.8 ± 28.8 and difficulty suppressing 57.8 ± 29.8 vs. 27.6 ± 33.4), which was not seen in the control group (disgust felt: 68.5 ± 25.4 vs. 65.8 ± 29.6, difficulty suppressing: 60 ± 30.0 vs. 59.0 ± 24.5). The EMG data collected had large inter and intra-variability and did not correlate with performance metrics. Conclusion: There were no negative impacts of the intervention, which indicates the stress inoculation may be a low-risk, low-cost method of improving stress response, but further studies need to be done to show efficacy.