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

Background

Compared to eccentric contractions, concentric contractions result in highercardiovascular stress. However, we do not know how these two types ofcontractions influence cardiac autonomic modulation during the post-exerciserecovery period.

Objective

to compare the effect of resistance training that is performed withconcentric vs. eccentric emphasis on muscle strength and onpost-exercise recovery which was assessed by examining heart ratevariability (HRV), for the knee extensor muscle group in young healthyadults.

Methods

For this study, 105 men between 18 and 30 years of age were randomized into 4groups: concentric control (CONCC), eccentric control (ECCC), concentrictraining (CONCT) and eccentric training (ECCT). The CONCC and ECCC groupsunderwent one session of resistance exercise (RE) using the knee extensormuscle group (3 sets of 1 repetition at 100% of the maximal repetition[1MR]) and the CONCT and ECCT groups performed 10 trainingsessions. The HRV was analyzed at baseline and across four recovery periods(T1, T2, T3 and T4).

Results

The ECCT group exhibited increased muscle strength at the end of the study.Regarding cardiac autonomic modulation, the CONCC and ECCC groups exhibitedincreases in overall variability (SDNN and SD2) at T1 compared to baseline,and the ECCT group demonstrated increases in variables reflecting vagalmodulation and the recovery process (RMSSD, SD1 and HF[ms²]) at T1, T2 and T4 compared to baseline.

Conclusions

Resistance training with emphasis on eccentric contractions promoted strengthgain and an increase in cardiac vagal modulation during recovery compared tobaseline.