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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Physiol. | doi: 10.3389/fphys.2019.01203

Protective effect conferred by isometric pre-conditioning again slow- and fast-velocity eccentric exercise-induced muscle damage

  • 1São Paulo State University, Campus Rio Claro, Brazil
  • 2Centro Universitário Herminio Ometto de Araras, Brazil
  • 3Salesian University Center of São Paulo, Brazil

We investigated if the same isometric preconditioning protocol (IPP) attenuates the magnitude of muscle damage induced by different maximal eccentric exercise protocols in the elbow flexors. Sixty-four untrained men were assigned to either two experimental or two control groups. Participants in the experimental groups performed an IPP prior to either slow (60°·s-1 – ISO+ECC-S) or fast (180°·s-1 – ISO+ECC-F) maximal eccentric contractions (MaxECC). Subjects in the control groups performed slow (ECC-S) or fast (ECC-F) MaxECC without IPP. Maximal isokinetic concentric torque (MVC), muscle soreness (SOR) and muscle thickness (MT) were assessed before, immediately after, and 1-4 days following the MaxECC. Significant (p < 0.05) group vs time interactions were found for MVC (F = 4,517), SOR (F = 6,318), and MT (F = 1,863). The ECC-S group presented faster (p<0.05) recovery of MVC and MT and less (p<0.05) SOR at 96h post-MaxECC compared with ECC-F group. No significant differences in MVC and MT were found between ECC-S and ECC-F groups following MaxECC. The ISO+ECC-S group showed faster (p<0.05) recovery of MVC and SOR compared to the ECC-S group. No significant differences were evident between ISO+ECC-S and ECC-S in any variable. The ISO+ECC-F group showed faster (p<0.05) recovery of all assessed variables compared with the ECC-F group. MVC was greater (p<0.05) at 48-72h and SOR was less (p<0.05) at 48-96h in the ISO+ECC-F compared to the ECC-F group. No significant differences were evident between ISO+ECC-S and ISO+ECC-F for any variable. These results show that the IPP accelerated recovery of MVC and SOR for the slow-eccentric exercise condition and attenuated strength loss and SOR in addition to faster recovery of all assessed variables for the fast-eccentric exercise condition. Therefore, the IPP can be used as a strategy to attenuate and accelerate recovery of muscle damage induced by different-velocity eccentric exercises, resulting in greater protection against muscle damage induced by faster velocity.

Keywords: muscle damage, eccentric exercise, Repeated bout effect, Force loss, Delayed-Onset Muscle Soreness (DOMS)

Received: 24 May 2019; Accepted: 03 Sep 2019.

Copyright: © 2019 Barreto, Lima, Greco and Denadai. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mr. Renan V. Barreto, São Paulo State University, Campus Rio Claro, Rio Claro, 13506-900, São Paulo, Brazil, reenanvb@gmail.com