Acute mechanical, physiological and perceptual responses in older men to traditional-set or different cluster-set configuration resistance training protocols

PURPOSE: The aims of this study were to compare mechanical outputs (i.e. power and impulse), physiological (i.e. heart rate) and perceptual (i.e. effort and fatigue) responses in older men to traditional-set or different cluster-set configuration resistance training protocols. METHODS: In a randomized cross-over design, 20 healthy old men (aged 67.2 ± 2.1 years) completed four resistance training sessions using the back squat exercise loaded with optimal power loads. Training configurations were: traditional (TRA), three sets of six repetitions with 120-s rest between each set; Cluster-set 1 (CLU1), 24 single-repetition clusters with 10 s of rest after every cluster; Cluster-set 2 (CLU2), 12 double-repetition clusters with 20-s rest after every cluster; and Cluster-set 4 (CLU4), 6 quadruple-repetition clusters with 40-s rest after every cluster. RESULTS: Cluster-set configurations resulted in greater power outputs compared to traditional-set configuration (range 2.6–9.2%, all p [Formula: see text] 0.07 for main effect and protocol [Formula: see text] set interactions). CLU1 and CLU2 induced higher heart rate (range 7.1–10.5%, all p < 0.001 for main effect and protocol [Formula: see text] set interactions), lower rating of perceived exertion (range − 1.3 to − 3.2 AU, all p [Formula: see text] 0.006 for pairwise comparisons) and lower ratings of fatigue (range − 0.15 to − 4 AU, all p [Formula: see text] 0.012 for pairwise comparisons) compared to TRA and CLU4. Finally, an absolute preference for CLU2 was reported. CONCLUSIONS: Findings presented here support the prescription of CLU2 as an optimal resistance training configuration for trained older men using the back squat.