Cluster Set Resistance Training Reduces Autonomic Perturbations Compared to Traditional Protocols in Trained Healthy Young Individuals: A Clinical Study

Objectives: This study investigates the effects of cluster set resistance training (RT) on heart rate variability (HRV) parameters in young, healthy individuals. Methods: This trial was registered in the Brazilian Clinical Trials Registry (ReBEC) under the identification number RBR-9857xj3 on 7 December 2024. Sixteen participants (seven female, 25 ± 2 years old) performed both cluster set and traditional RT protocols with equal relative intensity (85% 10RM), volume load (4 × 10 repetitions), and rest intervals (120 s). Cluster set configuration involved the introduction of a shorter rest interval between a cluster of sets [4 × (2 × 5) with 90 s inter-set rest and 30 s intra-set rest]. HRV parameters (RMSSD, HFnu, SD1, LFnu, LF/HF ratio, and SD2) were assessed before and 30 min post-exercise. The rating of perceived exertion (RPE) was assessed immediately after RT protocols. Results: The traditional RT protocol led to a significant reduction in parasympathetic activity (RMSSD, HFnu, SD1) and an increase in sympathetic activity (LFnu, LF/HF ratio, and SD2) (p < 0.05), whereas the cluster set RT protocol did not alter HRV parameters. Additionally, RPE was significantly higher (p < 0.001) in the traditional RT protocol. Conclusion: This study suggests that the cluster set may have a less pronounced impact on HRV parameters 30 min post-exercise compared to traditional sets. These findings can guide exercise physiologists in designing resistance training programs for clinical populations by prescribing protocols that minimize cardiac autonomic stress.