Effects of Varying Antagonist Exercise Volume in Upper-Body Supersets on Mechanical, Metabolic, and Perceptual Responses in Resistance-Trained Men

<b>Objectives</b>: This study aimed to analyze the effects of varying antagonist volume in upper-body supersets on mechanical (lifting velocity), metabolic (blood lactate), and perceptual (perceived exertion) variables. <b>Methods</b>: A randomized crossover study was conducted in which 14 resistance-trained men performed three strength training conditions. In the control condition (CTR), participants performed four sets of bench press with 8 repetitions at their 12-repetition maximum load, whereas in the experimental conditions, a prone bench pull was performed immediately after the bench press using 33% (SS1) or 66% (SS2) of the individual's maximum possible repetitions. Lifting velocity, lactate concentration, and perceived exertion were measured. Repeated-measures ANOVA or Friedman test was applied to compare conditions, with Bonferroni-corrected post hoc tests and effect sizes reported. <b>Results</b>: Despite a progressive decrease in mean set velocity (<i>p</i> < 0.001) and fastest set velocity across sets (<i>p</i> = 0.014) in the agonist exercise (i.e., bench press), these variables did not significantly differ between conditions. The only difference observed was a lower mean set velocity during the prone bench pull in the SS2 condition compared to the SS1 condition (<i>p</i> = 0.011). Perceived exertion also increased across sets (<i>p</i> < 0.001), with no differences between protocols. Blood lactate concentration, measured before the final set, was significantly higher in SS2 compared to CTR (<i>p</i> = 0.003) and SS1 (<i>p</i> < 0.001), indicating a greater metabolic load during training. <b>Conclusions</b>: Agonist-antagonist supersets allow for reduced training time without negatively impacting acute mechanical performance in the agonist exercise. Low-fatigue configurations (SS1) in the secondary exercise do not significantly increase lactate levels, while moderate-fatigue configurations (SS2) in the secondary exercise increase metabolic load.