## 4 Discussion  
At the outset of this study, our primary objective was to investigate the effects of high-intensity interval training (HIIT) on acute physical fatigue, alongside an exploration of the physiological and psychological responses across genders. Based on the comprehensive analysis of our results, we can affirm that our hypothesis--that HIIT significantly impacts acute physical fatigue, with potential variations in responses between genders--has been addressed. Our findings demonstrate that HIIT induces notable changes in physiological and psychological states, yet, contrary to our initial hypothesis, these effects were consistent across both male and female participants, suggesting a universal applicability of HIIT in inducing acute physical fatigue without significant gender-specific differences. In this study, the significant elevations observed in lactate levels, heart rate, and RPE following the HIIT protocol are consistent with established findings in the sports science literature. These physiological responses are well-documented markers of the intense metabolic and cardiovascular stress imposed by high-intensity exercise regimens [22; 24]. In this line, elevated lactate levels post-HIIT reflect enhanced glycolytic activity, a hallmark of intensive anaerobic metabolism. This metabolic shift is a direct consequence of the body's efforts to meet the high energy demands during short, intense bursts of exercise, characteristic of HIIT. The lactate accumulation can be interpreted not merely as a byproduct of anaerobic metabolism but also as a valuable energy source that muscles utilize during prolonged exercise [35]. Additionally, the analysis of the data did not reveal any significant gender-specific differences in response to high-intensity interval training (HIIT). Both male and female participants exhibited similar physiological and psychological responses to the HIIT regimen. This finding suggests that, within the context of this study, HIIT can be equally effective for both genders in terms of acute physical fatigue, recovery, and overall performance outcomes. However, it is important to note that individual variability in training response exists, and further research could explore potential subtle differences or tailor training programs to individual needs. The significant elevation in heart rate observed during our study is a direct reflection of the cardiovascular system's adaptive response to the increased demands for oxygen and nutrients by the muscles engaged in high-intensity interval training (HIIT). This pronounced increase not only demonstrates the effectiveness of HIIT in stimulating cardiovascular adaptations but also highlights its role in augmenting aerobic capacity. Such \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Variable** & **Pre (1)** & **1 st Series (2)** & **2 nd Series (3)** & **F** &
\begin{tabular}{c} **Moment** \\ **Comparison** \\ \end{tabular} \\ \hline Heart rate (bpm) & 69.8 \(\pm\) 9.1 & 163.5 \(\pm\) 23.3 & 167.7 \(\pm\) 23.9 & 143.278 & 2 \(>\) 1; 3 \(>\) 1 \\ \hline Rate of perceived exertion & 6.2 \(\pm\) 0.8 & 14.4 \(\pm\) 2.4 & 16.3 \(\pm\) 1.8 & 419.129 & 2 \(>\) 1; 3 \(>\) 1; 3 \(>\) 2 \\ \hline Horizontal jump (cm) & 145.0 \(\pm\) 33.4 & 150.0 \(\pm\) 34.3 & 169.7 \(\pm\) 18.3 & 11.354 & 2 \(>\) 1; 3 \(>\) 1; 3 \(>\) 2 \\ \hline Isometric hand strength (N) & 36.1 \(\pm\) 7.1 & 36.9 \(\pm\) 6.2 & 38.1 \(\pm\) 5.7 & 3.651 & 3 \(>\) 1 \\ \hline Reaction Time (ms) & 283.4 \(\pm\) 25.6 & 289.7 \(\pm\) 35.6 & 280.4 \(\pm\) 30.9 & 1.720 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Changes in heart rate, rate of perceived exertion, horizontal jump, isometric hand strength, and reaction time before and after the first and second HIIT series.