## 4 Discussion  
This study analyzed the influence of exercise order using the bench press and squat as the first or second exercise of the session on velocity performance. The main findings show that performing the squat as the first exercise of the resistance training session negatively impacted subsequent bench press velocity performance. On the other hand, performing the bench press as the first exercise of the resistance training session did not decrease subsequent squat velocity performance. Therefore, these results align with our first study hypothesis which was designed based on previous results [4; 5]. Considering the possibility of the order of exercises impacting the level of effort and metabolic contributions [24; 25], it was expected that blood lactate and heart rate values would be higher when performing the squat as the last exercise (i.e., this exercise induces higher metabolic and hemodynamic stress than the bench press) [6]. Nevertheless, our results did not demonstrate significant differences between the BP + S and S + BP protocols in terms of blood lactate and heart rate responses, thus challenging our second hypothesis of observing a higher hemodynamic and metabolic response when performing the squat after the bench press exercise. Figure 4: Relative differences between bench press followed by squat (BP + S) protocol (black circles) and squat followed by bench press (S + BP) protocol (black squares) in terms of blood lactate (**A**) and heart rate (**B**). g: Hedge’s g effect size. The impact of exercise order on performance outcomes is well documented in the literature, with a consensus that exercises performed earlier in a session tend to benefit from greater performance due to lower levels of fatigue [3,4]. [PERSON] et al. [4] highlighted that exercise order significantly influences repetition performance, with exercises at the beginning of a session allowing for greater total repetitions and training volume. This aligns with our findings where bench press performance was compromised when preceded by the squat. In the bench press, the MPV was lower in the S + BP protocol in the first and second sets, and this trend was similar to that of the PV. Moreover, almost all repetitions of the first set were performed with a lower MPV, and this dropped to half of the repetitions in subsequent sets, even when the mean value analysis did not indicate significant differences (i.e., the third set). It can be hypothesized that the difference in the muscle mass recruited in the bench press and squat exercises (more prominent in the latter) played a significant role in these observations [4,5]. The observed reduction in bench press velocity following the squat-first sequence can be attributed to several mechanisms, primarily related to fatigue and neuromuscular demands. The squat, being a multi-joint exercise that recruits large muscle groups, induces substantial neuromuscular fatigue, which likely diminishes the central nervous system's ability to effectively recruit the muscles needed for the bench press, reducing force production [3, 4, 5]. Previous findings noted that when larger muscle group exercises are performed first, they can create a level of fatigue that impairs the performance of subsequent smaller muscle group exercises [3, 4, 5]. Furthermore, energy expenditure is higher when an exercise is performed later in a session, likely due to accumulated fatigue [26]. [PERSON] et al. [27] further support these findings by demonstrating that upper body exercises performed later in a session, such as after a squat, suffer from reduced repetition performance, particularly when shorter rest intervals are used. In fact, cumulative total force production was shown to be higher when structural, multi-joint exercises like squats were performed first, with subsequent exercises exhibiting reduced force output [28]. This likely stems from the neuromuscular fatigue induced by the initial high-demand exercise, which can impair performance in subsequent exercises involving smaller muscle groups, as seen in our study.