אימונים Post-exercise hypertrophic adaptations: A re-examination of the hormone hypothesis an

[Mike Bikov]

J Strength Cond Res. 2013 Feb 25. [Epub ahead of print]
Post-exercise hypertrophic adaptations: A re-examination of the hormone hypothesis and its applicability to resistance training program design.
Schoenfeld B.
Source
Department of Health Sciences, Program of Exercise Science, APEX Building, Room # 265, Lehman College, CUNY, 250 Bedford Park Blvd West, Bronx, NY 10468, Email: [email protected].
Abstract
ABSTRACT: It has been well-documented in the literature that resistance training can promote marked increases in skeletal muscle mass. Post-exercise hypertrophic adaptations are mediated 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 protein balance 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 and catabolic 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 these hormones 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 at moderate intensities with shortened rest intervals as compared to high-intensity strength-oriented training. The observed positive relationship between anabolic hormones and hypertrophy-type training has led to the hormone hypothesis, which postulates that acute post-exercise hormonal secretions mediate increases muscle size. Several researchers have suggested that these transient hormonal elevations 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 with receptors, which may have particular hypertrophic importance in the post-workout period when muscles are primed for anabolism. Moreover, hormonal spikes may enhance intracellular signaling so that post-exercise protein breakdown is rapidly attenuated and anabolic processes are heightened, thereby leading to a greater supercompensatory response. While the hormone hypothesis has received considerable support in the literature, however, several researchers have questioned its veracity, with some speculating that the purpose of post-exercise hormonal elevations is to mobilize fuel stores rather than promote tissue anabolism. Therefore, the purpose of this paper will be to critically and objectively review the current literature, and then draw relevant conclusions as to the potential role of acute systemic factors on muscle protein accretion.
PMID: 23442269 [PubMed - as supplied by publisher]​

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