Sigitas Kamandulis1, Mantas Mickevicius2, Audrius Snieckus2, Vytautas Streckis2, Diego Montiel-Rojas3, Thomas Chaillou3, Hakan Westerblad4, Tomas Venckunas2. 1. Institute of Sport Science and Innovations, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania. sigitas.kamandulis@lsu.lt. 2. Institute of Sport Science and Innovations, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania. 3. School of Health Sciences, Örebro University, 701 82, Örebro, Sweden. 4. Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden.
Abstract
PURPOSE: Unaccustomed eccentric contractions generally result in a long-lasting contractile impairment, referred to as prolonged low-frequency force depression (PLFFD), and delayed-onset muscle soreness (DOMS). We here used repeated drop jumps (DJs) as an eccentric contraction model and studied the effects of increasing the time between DJs from 20 s to 5 min. We hypothesized that both PLFFD and DOMS would be less marked at the longer DJ interval due to the longer time to restore structural elements between DJs. METHODS: Young men (n = 12) randomly performed 50 DJs with either 20-s (DJ-20 s) or 5-min (DJ-5 min) rest between DJs. Voluntary, 20 Hz and 100 Hz electrically stimulated isometric knee extension torques and muscle soreness were monitored before and for 7 days after DJs; serum CK activity was measured to assess muscle fibre protein leakage. In additional experiments, changes in mRNA levels were assessed in muscle biopsies collected before and 1 h after exercise. RESULTS: A marked PLFFD was observed with both protocols and the extent of 20 Hz torque depression was smaller immediately and 1 day after DJ-5 min than after DJ-20 s (p < 0.05), whereas the MVC and 100 Hz torques were similarly decreased with the two protocols. Markedly larger differences between the two protocols were observed for the muscle soreness score, which 1-4 days after exercise was about two times larger with DJ-20 s than with DJ-5 min (p < 0.01). CONCLUSIONS: The larger protective effect of the longer DJ interval against DOMS than against PLFFD indicates that their underlying mechanisms involve different structural elements.
PURPOSE: Unaccustomed eccentric contractions generally result in a long-lasting contractile impairment, referred to as prolonged low-frequency force depression (PLFFD), and delayed-onset muscle soreness (DOMS). We here used repeated drop jumps (DJs) as an eccentric contraction model and studied the effects of increasing the time between DJs from 20 s to 5 min. We hypothesized that both PLFFD and DOMS would be less marked at the longer DJ interval due to the longer time to restore structural elements between DJs. METHODS: Young men (n = 12) randomly performed 50 DJs with either 20-s (DJ-20 s) or 5-min (DJ-5 min) rest between DJs. Voluntary, 20 Hz and 100 Hz electrically stimulated isometric knee extension torques and muscle soreness were monitored before and for 7 days after DJs; serum CK activity was measured to assess muscle fibre protein leakage. In additional experiments, changes in mRNA levels were assessed in muscle biopsies collected before and 1 h after exercise. RESULTS: A marked PLFFD was observed with both protocols and the extent of 20 Hz torque depression was smaller immediately and 1 day after DJ-5 min than after DJ-20 s (p < 0.05), whereas the MVC and 100 Hz torques were similarly decreased with the two protocols. Markedly larger differences between the two protocols were observed for the muscle soreness score, which 1-4 days after exercise was about two times larger with DJ-20 s than with DJ-5 min (p < 0.01). CONCLUSIONS: The larger protective effect of the longer DJ interval against DOMS than against PLFFD indicates that their underlying mechanisms involve different structural elements.
Authors: Jakob Agergaard; Søren Reitelseder; Troels G Pedersen; Simon Doessing; Peter Schjerling; Henning Langberg; Benjamin F Miller; Per Aagaard; Michael Kjaer; Lars Holm Journal: Muscle Nerve Date: 2013-03-21 Impact factor: 3.217
Authors: Arthur J Cheng; Thomas Chaillou; Sigitas Kamandulis; Andrejus Subocius; Håkan Westerblad; Marius Brazaitis; Tomas Venckunas Journal: Scand J Med Sci Sports Date: 2020-03-18 Impact factor: 4.221