Affiliations: [a] Department of Physical Education, Federal University of Paraíba, João Pessoa, Brazil | [b] Faculty of Physical Education and Sport, Federal University of Juiz de Fora, Juiz de Fora, Brazil | [c] Superior School of Physical Education, University of Pernambuco, Recife, Brazil | [d] Department of Physical Education and Sport Sciences, Federal University of Pernambuco, Recife, Brazil | [e] Department of Physical Education, Federal University of Rio Grande do Norte, Natal, Brazil | [f] Department of Physical Education, State University of Londrina, Londrina, Brazil
Correspondence:
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Corresponding author: Leonardo S. Fortes, Department of Physical Education, Federal University of Paraíba, Joakim Schuller Street, 40/807 Jardim Oceania, João Pessoa/PB, 58037760, Brazil. Tel.: +55 83 981444085; E-mail: leodesousafortes@hotmail.com.
Abstract: BACKGROUND: The volume in resistance training (RT) perhaps improve the autonomic modulation cardiac in untrained adults. OBJECTIVE: The aim was to analyze the effect of RT volume on heart rate variability (HRV) in young adults. METHODS: The intervention order was randomized and counterbalanced. Participants (n= 27) performed 1, 3 or 5 sets of the same exercises with equalized intensity (loading zones) and rested for eight weeks following eight weeks of washout between each experimental condition (1 vs. 3 vs. 5 sets). The researchers assessed HRV by cardiac monitoring seventy-two hours, both before (pre) and after (post) each experimental RT condition (1 vs. 3 vs. 5 sets). Factorial repeated measures ANOVA 2 × 3 were used to analyze the interaction between time (pre vs. post) and intervention (1 set vs. 3 sets vs. 5 sets) for the HRV index (RMSSD, SDNN, and pNN50). RESULTS: An interaction was identified between time and condition for RMSSD (F(5,22)= 37.02, p< 0.01), SDNN (F(5,22)= 32.80, p< 0.01), and pNN50 (F(5,22)= 29.92, p< 0.02). Five set conditions (p= 0.01) showed improvement in HRV indicators when compared to one set and three set conditions. CONCLUSION: The study concluded that 5 set conditions improved HRV in young untrained adults.
Keywords: Heart rate, health, exercise, strength training
