Exercise capacity plays a significant role in the performance athletes exhibit during training. Athletes use different loading strategies and warm-up approaches to improve strength, power, speed, endurance, and cognitive performance; one of these is post-activation performance enhancement (PAPE) practices, which aim for acute performance improvement after conditioning activity. However, mental fatigue induced by methods such as the Stroop task can alter these acute responses. RESULTS: This study investigated the effects of mental fatigue conditions (control, Stroop, documentary), two PAPE intensities (60% and 80% 1RM), and measurement time (0, 3, 6, 9 min) on explosive performance in athletes aged 18–23 years. While the triple interaction of mental fatigue × intensity × time was not found to be significant for bench press throw (BPT) (p=0.058), the same triple interaction was found to be significant for jump height (p=0.007). The lack of significant triple interactions in perceived exertion (Borg) values ​​in both BPT and jump protocols suggests that the perceived exertion response may follow a similar pattern in the presence/absence of mental fatigue. In contrast, BRUMS results indicated a significant interaction between mental fatigue × intensity × time; in the Stroop condition, mood was observed to change negatively over time. CONCLUSIONS, mental fatigue may affect the PAPE response in a variable-specific manner, and lower extremity explosive performance, in particular, may be more affected by mental state in the context of PAPE; therefore, individualization of the rest window in practice and extension of the measurement interval to 12–15 minutes in future studies, supported by neuromuscular measures, is recommended.