title: Resistance training with excessive training load and insufficient recovery alters skeletal muscle mass-related protein expression.
abstract: The aim of this study was to investigate the effects of a resistance training program with excessive training load and insufficient recovery time between bouts on muscle hypertrophy- and atrophy-related protein expression. Male Wistar rats were randomly assigned to either a trained (TR, N = 9) or a sedentary (SE, N = 9) group. The TR group was subjected to a 12-week resistance training program with excessive training load and insufficient recovery between bouts that was designed to induce plantaris muscle atrophy. After the 12-week experiment, the plantaris muscle was collected to analyze the cross-sectional area (CSA) of the muscle fibers, and MAFbx, MyoD, myogenin, and IGF-I protein expression (Western blot). The CSA was reduced significantly (-17%, p ≤ 0.05) in the TR group compared with the SE group. Reciprocally, there was a significant (p ≤ 0.05) 20% increase in MAFbx protein expression, whereas the MyoD (-27%), myogenin (-29%), and IGF-I (-43%) protein levels decreased significantly (p ≤ 0.05) in the TR group compared with the SE group. In conclusion, our data indicated that muscle atrophy induced by resistance training with excessive training load and insufficient recovery was associated with upregulation of the MAFbx catabolic protein and downregulation of the MyoD, myogenin, and IGF-I anabolic proteins. These findings suggest that quantitative analysis of these proteins can be important and complementary with other biochemical markers to confirm a possible overtraining diagnosis.
authors: 1Department of Morphology, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil; 2Centre of Biological and Health Sciences, North University of Paraná (UNOPAR), Londrina, Paraná, Brazil; and 3Department of Anatomy, Cell Biology, Physiology and Biophysics, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
authors: Rodrigo Wagner
authors: RW
authors: Alves Souza
authors: Andreo F
authors: AF
authors: Aguiar
authors: Ivan J
authors: IJ
authors: Vechetti-Júnior
authors: Warlen Pereira
authors: WP
authors: Piedade
authors: Gerson Eduardo
authors: GE
authors: Rocha Campos
authors: Maeli
authors: M
authors: Dal-Pai-Silva
mesh_terms: D000818:Animals; D001284:Atrophy / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology*; D017570:MyoD Protein / Q000378:metabolism; D018008:Myogenin / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000009:adverse effects*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D055070:Resistance Training / Q000009:adverse effects*; D012146:Rest / Q000502:physiology; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism
chemical_list: D015415:Biomarkers; D009124:Muscle Proteins; D017570:MyoD Protein; D018008:Myogenin; D007334:Insulin-Like Growth Factor I; C486692:Fbxo32 protein, rat; D044843:SKP Cullin F-Box Protein Ligases