## 4 Discussion  
This study aimed to investigate the effects of a 12-week LL-HV resistance training compared to the traditional HL-LV approach focusing on the bench press on maximal strength, mechanical performance at submaximal loads, and arm and chest circumferences in powerlifters. Our main findings reveal that LL-HV resistance training is comparable to HL-LV in promoting functional and structural adaptations in well-trained powerlifters, with specific advantages observed in certain performance metrics. Both training methodologies significantly improved MV across various submaximal intensities, but the LL-HV group demonstrated distinct advantages at MV at 80% of 1 RM, while the HL-LV group did not display comparable changes at this intensity. These results align with the load-velocity relationship, suggesting that LL-HV may better enhance velocity at submaximal loads due to the high-repetition nature of this protocol [45]. In terms of maximal strength, both groups achieved substantial improvements in 1 RM, contrasting with findings from some previous studies. For instance, [PERSON] et al. [24] observed that HL-LV training led to significantly greater gains in knee extension 1 RM and voluntary isometric contraction (MVIC) in untrained men, while [PERSON] et al. [19] found greater strength improvements in both 1 RM leg press and elbow flexion with HL-LV protocols in young, untrained men. Conversely, [PERSON] et al. [46] reported no significant differences between HL-LV and LL-HV groups in untrained adolescents over a 9-week period for bench press 1 RM, and [PERSON] et al. [26] found comparable increases in maximal muscle strength and skeletal muscle mass with both protocols among elite weightlifters after an eight-week intervention. This discrepancy can be attributed to the advanced training expertise of our participants, who had over a year of experience employing autoregulation techniques, specifically RIR, in their training programs. These practices likely enhanced their ability to dynamically adjust effort and intensity, ensuring consistent engagement across all repetitions and maximizing adaptations even when utilizing lower loads. These findings are consistent with prior research, including the work of [PERSON] et al. [47], which demonstrated that autoregulation through RIR facilitates the optimization of training load and volume while preserving neuromuscular efficiency in experienced lifters. The capacity to maintain consistent effort with their respective loads may have benefited both groups, potentially explaining the absence of significant differences in most outcomes related to maximal strength and MV between the two training protocols. Intentional velocity further emerged as a critical factor influencing strength gains. Participants in both groups were instructed to perform all repetitions with maximal intended  
velocity, regardless of load, a methodological approach supported by [PERSON] et al. [35], who demonstrated that maintaining maximal intentional velocity during training enhances strength gains. This focus on intentional velocity likely explains the comparable strength gains observed in the LL-HV group relative to the HL-LV group, contrasting with previous studies where participants were often not instructed to lift with maximal intent. Without such instructions, lighter loads may elicit less effortful engagement, potentially limiting adaptations, whereas heavy loads naturally require maximal effort regardless of guidance. Therefore, the observed differences among studies may not solely arise from variations in load but also from whether participants were explicitly directed to lift with maximal intent. These findings underscore the importance of combining intentional velocity with precise effort regulation to achieve optimal strength outcomes, highlighting the adaptability of trained powerlifters to diverse training stimuli.