title: Muscle damage of resistance-trained men after two bouts of eccentric bench press exercise.
abstract: The present study tested the hypothesis that resistance-trained individuals would also show less muscle damage in the second than in the first eccentric exercise bout (i.e., repeated bout effect) as shown in untrained individuals. This study investigated changes in indirect markers of muscle damage after 2 bouts of free weight eccentric exercise performed by 8 resistance-trained men. The participants (24.4 ± 1.2 years) performed 4 sets of 8 eccentric actions (3 seconds for each repetition) at 70% of eccentric 1 repetition maximum (1RM) load in a bench press exercise with 2 minutes of rest between sets, and repeated the same exercise 2 weeks later. Bench press 1RM, delayed onset muscle soreness (DOMS) assessed by a 6-point Likert scale, serum creatine kinase (CK) activity, and plasma prostaglandin E2 concentration (PGE2) were measured before and 24, 48, 72, and 96 hours after the exercise, and the changes were compared between bouts. The changes in the variables were smaller (p ≤ 0.05) after the second than the first bout indicated by a smaller decline in 1RM strength (first bout: -10.2 ± 1.0% vs. second bout: -5.7 ± 1.5%), peak DOMS (3.8 ± 0.4 vs. 1.7 ± 0.5), peak CK (637.3 ± 133.3 vs. 305.4 ± 63.6 IU·L), and peak PGE2 (761.2 ± 171.0 vs. 307.2 ± 48.3 pg·mL). These results show a typical repeated bout effect. Thus, it is concluded that the repeated bout effect occurs in resistance-trained individuals.
authors.affiliation: 1Human Performance Research Group-College of Health Science, Methodist University of Piracicaba (UNIMEP), Piracicaba, Sao Paulo, Brazil; 2School of Arts, Sciences and Humanities, University of Sao Paulo (USP), Sao Paulo, Brazil; 3School of Exercise and Health Sciences, Edith Cowan University (ECU), Joondalup, Australia; 4Department of Sport Sciences-Post-Graduation Program in Physical Education, Federal University of Triangulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil; and 5Adventist University of Hortolandia (UNASP), Hortolandia, Sao Paulo, Brazil.
authors.forename: Adilson J
authors.initials: AJ
authors.lastname: Meneghel
authors.forename: Rozangela
authors.initials: R
authors.lastname: Verlengia
authors.forename: Alex H
authors.initials: AH
authors.lastname: Crisp
authors.forename: Marcelo S
authors.initials: MS
authors.lastname: Aoki
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nosaka
authors.forename: Gustavo R
authors.initials: GR
authors.lastname: da Mota
authors.forename: Charles R
authors.initials: CR
authors.lastname: Lopes
mesh_terms: D000328:Adult; D003402:Creatine Kinase / Q000097:blood; D015232:Dinoprostone / Q000097:blood; D005080:Exercise Test; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology* / Q000502:physiology; D063806:Myalgia / Q000209:etiology*; D055070:Resistance Training / Q000009:adverse effects*; D014891:Weight Lifting; D055815:Young Adult
chemical_list: D003402:Creatine Kinase; D015232:Dinoprostone