1. Effects of different intensities of resistance exercise on regulators of myogenesis
- Author
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Lemuel W. Taylor, Colin D. Wilborn, Darryn S. Willoughby, Richard B. Kreider, and Mike Greenwood
- Subjects
Male ,medicine.medical_specialty ,Time Factors ,Biopsy ,Physical Therapy, Sports Therapy and Rehabilitation ,Myostatin ,Muscle Development ,Muscle hypertrophy ,Young Adult ,Internal medicine ,medicine ,Humans ,Orthopedics and Sports Medicine ,RNA, Messenger ,Muscle, Skeletal ,Myogenin ,Analysis of Variance ,Cross-Over Studies ,biology ,Myosin Heavy Chains ,Myogenesis ,Chemistry ,Reverse Transcriptase Polymerase Chain Reaction ,Skeletal muscle ,Resistance Training ,General Medicine ,Up-Regulation ,Endocrinology ,medicine.anatomical_structure ,Myogenic Regulatory Factors ,Myogenic regulatory factors ,biology.protein ,Exercise intensity ,Intercellular Signaling Peptides and Proteins ,MYF5 ,Biomarkers - Abstract
A single bout of high-intensity resistance exercise is capable of activating the expression of various genes in skeletal muscle involved in hypertrophy such as myosin heavy chain (MHC) isoforms, myogenic regulatory factors (MRFs), and growth factors. However, the specific role exercise intensity plays on the expression of these genes is not well defined. The purpose of this study was to investigate the effects of exercise intensity on MHC (type I, IIA, IIX), MRF (Myo-D, myogenin, MRF-4, myf5), and growth factor (insulin-like growth factor [IGF]-1, IGF-1 receptor [IGF-R1], mechano-growth factor [MGF]) mRNA expression. Thirteen male participants (21.5 +/- 2.9 years, 86.1 +/- 19.5 kg, 69.7 +/- 2.7 in.) completed bouts of resistance exercise involving 4 sets of 18-20 repetitions with 60-65% 1 repetition maximum (1RM) and 4 sets of 8-10 repetitions with 80-85% 1RM. Vastus lateralis biopsies were obtained immediately before exercise, and at 30 minutes, 2 hours, and 6 hours after each bout. The levels of mRNA expression were determined using real-time polymerase chain reaction. Data were analyzed using 2 x 4 multivariate analysis of variance (p
- Published
- 2009