Mora Custodio, RicardoRodríguez Rosell, DavidYáñez García, Juan ManuelSánchez Moreno, MiguelPareja Blanco, FernandoGonzález Badillo, Juan José2025-01-232025-01-232018Journal of sports sciences, 36(24), 2856–286410.1080/02640414.2018.1480052https://hdl.handle.net/10433/22617This study aimed to analyze the acute effect of inter-repetition rest (IRR) intervals on mechanical and metabolic response during four resistance exercise protocols (REPs). Thirty resistance-trained men were randomly assigned to: continuous repetitions (CR), 10 s (IRR10) or 20 s (IRR20) inter-repetition rest. The REPs consisted of 3 sets of 6, 5, 4 and 3 repetitions against 60, 70, 75 and 80% 1RM, respectively, in the full squat exercise. Muscle fatigue was assessed using: percentage of velocity loss over three sets, percentage of velocity loss against the ~1 m·s−1 load (V1 m·s−1), and loss of countermovement jump(CMJ) height pre-post exercise. Blood lactate was measured before and after exercise. The percentage ofvelocity loss over three sets and lactate concentration were significantly lower (P < 0.05) for IRR groups compared to CR in all REPs. The CR group showed a significantly higher (P < 0.05) velocity loss against V1 m·s−1 load and loss of CMJ height pre-post exercise than IRR groups in REP against 60% 1RM. In conclusion, both IRR groups produced a significant lower degree of fatigue compared to CR group. However, no significant differences were found in any measured variables between IRR configurations.application/pdfenAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Resistance trainingFatigueMetabolic stressCluster configurationsjournal articleopen access