Post-exercise hypertrophic adaptations: A re-examination of the hormone hypothesis and its applicability to resistance training programdesign.
Department of Health Sciences, Program of Exercise Science, APEX Building, Room # 265, Lehman College, CUNY, 250 Bedford Park Blvd West, Bronx, NY 10468, Email:firstname.lastname@example.org.
ABSTRACT: It has been well-documented in the literature that resistance training can promote marked increases in skeletal muscle mass. Post-exercise hypertrophic adaptations aremediated by a complex enzymatic cascade whereby mechanical tension is molecularly transduced into anabolic and catabolic signals that ultimately leads to a compensatory response, shifting muscle proteinbalance to favor synthesis over degradation.Myocellular signaling is influenced, in part, by the endocrine system. Various hormones have been shown to alter the dynamic balance between anabolic andcatabolic stimuli in muscle, helping to mediate an increase or decrease in muscle protein accretion.Resistance training can have an acute impact on the post-exercise secretion of several of thesehormones including insulin-like growth factor (IGF)-1, testosterone, and growth hormone (GH). Studies show that hormonal spikes are magnified following hypertrophy-type exercise that involves training atmoderate intensities with shortened rest intervals as compared to high-intensity strength-oriented training. The observed positive relationship between anabolic hormones and hypertrophy-type traininghas led to the hormone hypothesis, which postulates that acute post-exercise hormonal secretions mediate increases muscle size. Several researchers have suggested that these transient hormonalelevations may be more critical to hypertrophic adaptations than chronic changes in resting hormonal concentrations. Theoretically, high levels of circulating hormones increase the likelihood of interaction...