The influence of resistance exercise with emphasis on specific contractions (concentric vs. eccentric) on muscle strength and post-exercise autonomic modulation: a randomized clinical trial

Abstract

BackgroundCompared to eccentric contractions, concentric contractions result in higher cardiovascular stress. However, we do not know how these two types of contractions influence cardiac autonomic modulation during the post-exercise recovery period.Objectiveto compare the effect of resistance training that is performed with concentric vs. eccentric emphasis on muscle strength and on post-exercise recovery which was assessed by examining heart rate variability (HRV), for the knee extensor muscle group in young healthy adults.MethodsFor this study, 105 men between 18 and 30 years of age were randomized into 4 groups: concentric control (CONCC), eccentric control (ECCC), concentric training (CONCT) and eccentric training (ECCT). The CONCC and ECCC groups underwent one session of resistance exercise (RE) using the knee extensor muscle group (3 sets of 1 repetition at 100% of the maximal repetition [1MR]) and the CONCT and ECCT groups performed 10 training sessions. The HRV was analyzed at baseline and across four recovery periods (T1, T2, T3 and T4). ResultsThe ECCT group exhibited increased muscle strength at the end of the study. Regarding cardiac autonomic modulation, the CONCC and ECCC groups exhibited increases in overall variability (SDNN and SD2) at T1 compared to baseline, and the ECCT group demonstrated increases in variables reflecting vagal modulation and the recovery process (RMSSD, SD1 and HF [ms2]) at T1, T2 and T4 compared to baseline. ConclusionsResistance training with emphasis on eccentric contractions promoted strength gain and an increase in cardiac vagal modulation during recovery compared to baseline.

The effects of cold water immersion with different dosages (duration and temperature variations) on heart rate variability post-exercise recovery: A randomized controlled trial

“…In order to capture the RR-intervals parameters, for further analysis of HRV, a chest belt was placed over the precordium region and a heart rate receiver (Polar RS800CX, Polar Electro-Oy, Finland) on the wrist. 12 During capture, the participants remained at rest in a sitting position breathing spontaneously.…”

“…Digital filtering was supplemented by manual filtering in order to remove the artifacts, ectopic and premature beats, and only series with more than 95% sinus beats were included. 12 The extraction of each cardiac period (RR-interval) was analyzed using Kubios HRV Analysis Software 2.0 for Windows software (The Biomedical Signal Analysis Group, Department of Applied Physics, University of Kuopio, Finland), and a fixed number of 256 consecutive RR-intervals 12 was considered at baseline (20 min with the participants at rest, of which the final 256 RR-intervals were selected), during the recuperative technique (TRec) (for intervention groups, the final 256 RR-intervals for 5 min for G1 and G2, for 15 min for G3 and G4, and for 5 or 15 min, for subsequent comparison with the appropriate intervention groups) and at 20, 30, 40, 50 and 60 min after exercise (128 RR-intervals before and after each time).…”

“…In the frequency domain (FD) the spectral components of very low frequency (VLF) (0.00-0.04 Hz); low frequency (LF) (0.04-0.15 Hz) and high frequency (HF) (0.15-0.4 Hz) 29 were utilized, expressed in ms 2 , calculated using Fast Fourier Transform. 12 VLF assessed from short-term recordings, although tedious measure, was considered here for analysis.…”

“…2 The balance between sympathetic and parasympathetic activity reflects autonomic recovery and restoration of cardiovascular homeostasis which is an important component of overall recovery. 20 Considering that exercise acts as a stressor agent, which causes metabolic and autonomic changes, 4,12 it is important to understand the possible post-exercise effects of CWI on ANS. Studies 2,5,8 suggest that CWI results in better ANS activity post-exercise, anticipating the recovery of HRV indices.…”

Duplo-Produto E Variação Da Frequência Cardíaca Após Esforço Isocinético Em Adultos E Idosos

“…∆1: variação entre medida basal e de intervalo; ∆2: variação entre medida basal e final. ∆1-G1 ∆1-G2 ∆1-G3 ∆2-G1 ∆2-G2 ∆2-G3 * * Nosso estudo mostrou que o tempo de retorno à FC basal após o esforço isocinético foi menor em G1 em comparação a G2 e G3, semelhante ao estudo de Góis et al 21 que utilizou esforço isotônico concêntrico de extensão de joelho em três séries de uma repetição à 100% da RM. O tempo de retorno à FC basal também foi estudado por Queiroz et al 22 , no entanto a amostra era composta por idosos fisicamente ativos, que foram submetidos a 9 exercícios resistidos para membros inferiores, com três séries de oito repetições de moderada a alta intensidade.…”