Impact of a Mental Fatigue Protocol on Performance in Extreme Conditioning Programs

Abstract The aim of this study was to assess whether mental fatigue can influence the perception of effort and the performance of individuals engaged in extreme conditioning programs. A cross-sectional, experimental, and randomized study was conducted with 25 CrossFit® practitioners randomly divided into two groups: Stroop Group (n = 13; 28.9 ± 4.9 years; 172 ± 0.1 cm; 74 ± 12.5 kg; 3.4 ± 1.8 years of practice; 5.5 ± 0.5 days of training per week) and Neutral Group (n = 12; 29.8 ± 5.3 years; 168 ± 0.1 cm; 69.89 ± 16.1 kg; 2.9 ± 1.4 years of practice; 5.2 ± 0.6 days of training per week). The first group underwent a mental stress protocol using the Stroop Color and Word Test, while the second group watched a neutral content video. Subsequently, both groups performed an adapted "Angie" exercise session. The Stroop Group, after just one application of the protocol, showed increased perception of effort (p = 0.0169) and completed the exercise session in a longer time (p = 0.038), compared to the Neutral Group. The Stroop Group also presented a higher Visual Analogue Scale (VAS) score after the mental stress protocol (p = 0.0005). A single application of a mental fatigue protocol had an immediate effect on the performance of practitioners during a training session.