The effect of different velocities of strength training in indirect markers of muscle damage

Abstract

Eccentric muscle contractions require a muscle stretch during force production. It is well established that eccentric exercises induce high levels of muscle injury. However, there is no consensus about the influence of contraction velocity on muscle damage and recovery. So, the aim of this study was to verify the influence of eccentric velocity contractions in the extent of muscle damage. Eight trained men, without neuromuscular injury, executed two training sessions with 30 maximal isokinetic eccentric muscle contractions with low velocity (20°.s-1) and high velocity (180°.s-1) using the dominant arm. The two sessions was separated by five weeks and were performed randomly. The isometric moment (TI), range of motion (ROM), arm perimeter (PER) and muscle soreness (DMT) were analyzed before, immediately after (except DMT) 24 h, 72 h and 120 h after each eccentric training session. Comparisons were made by analysis of variance (ANOVA) with repeated-measures, Bonferroni post-hoc and paired t-test (p ≤ 0.05). Both training sessions showed a reduction in TI immediately after exercise (20°.s-1: 82 ± 9.4 N.m x 53.8 ± 12.3 N.m; 180°.s-1: 79 ± 11 N.m x 63.1 ± 11.7 N.m), however were rapidly recovered in 180°.s-1, while in 20°.s-1, TI remained diminished 72 h after exercise (73 ± 6.4 N.m). The ROM diminished immediately after and 24 h only in 180°.s-1 (127 ± 12° x 117 ± 7.64°). Otherwise, the PER increased immediately after, remaining higher 24 h after the 20°.s-1 (34 ± 3.4 cm x 35.2 ± 3.57 cm), with no alterations after the 180°.s-1. The DMT was increased after 24 h and remained elevated 72 h after both velocities (20°.s-1: 2.7 ± 1.3 ; 180°.s-1: 2.1 ± 1). We concluded that eccentric contraction velocity affects differently the recovery of muscle damage markers but not the extent of the response.