L'allenamento della forza e potenza impone un potente stimolo per il sistema muscolo-scheletrico. Questa forma di stress suscita una varietà di adattamenti (immediati e cronici).
Uno di questi, essenziale per la prestazione sportiva è l'efficenza del sistema neuroendocrino.
I livelli ormonali si modificano in risposta all'entità dello stimolo cui l'organismo viene sottoposto (intensità e durata)
Una varietà di meccanismi ormonali influenza la crescita e il rimodellamento del tessuto (ad esempio muscoli, ossa e altri tessuti connettivi), che si rivelano fondamentali per la prestazione.
Diversi ormoni vengono discussi da Kraemer in questi due articoli.
Ovviamente per noi è importante porre l'accento su quelli anabolici e
catabolici.
Hormonal responses and adaptations to resistance exercise and training.
Sports Med. 2005;35(4):339-61.
Kraemer WJ, Ratamess NA.
Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, 06269, USA. William.Kraemer@uconn.edu
Resistance exercise has been shown to elicit a significant acute hormonal response. It appears that this acute response is more critical to tissue growth and remodelling than chronic changes in resting hormonal concentrations, as many studies have not shown a significant change during resistance training despite increases in muscle strength and hypertrophy. Anabolic hormones such as testosterone and the superfamily of growth hormones (GH) have been shown to be elevated during 15-30 minutes of post-resistance exercise providing an adequate stimulus is present. Protocols high in volume, moderate to high in intensity, using short rest intervals and stressing a large muscle mass, tend to produce the greatest acute hormonal elevations (e.g. testosterone, GH and the catabolic hormone cortisol) compared with low-volume, high-intensity protocols using long rest intervals. Other anabolic hormones such as insulin and insulin-like growth factor-1 (IGF-1) are critical to skeletal muscle growth. Insulin is regulated by blood glucose and amino acid levels. However, circulating IGF-1 elevations have been reported following resistance exercise presumably in response to GH-stimulated hepatic secretion. Recent evidence indicates that muscle isoforms of IGF-1 may play a substantial role in tissue remodelling via up-regulation by mechanical signalling (i.e. increased gene expression resulting from stretch and tension to the muscle cytoskeleton leading to greater protein synthesis rates). Acute elevations in catecholamines are critical to optimal force production and energy liberation during resistance exercise. More recent research has shown the importance of acute hormonal elevations and mechanical stimuli for subsequent up- and down-regulation of cytoplasmic steroid receptors needed to mediate the hormonal effects. Other factors such as nutrition, overtraining, detraining and circadian patterns of hormone secretion are critical to examining the hormonal responses and adaptations to resistance training.
Endocrine responses to resistance exercise.
Med Sci Sports Exerc. 1988 Oct;20(5 Suppl):S152-7.
Kraemer WJ.
Exercise Physiology Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007.
The purpose of this brief review is to examine resistance training responses of selected hormones related to acute stress and growth promoting actions. Hormonal mechanisms appear to be involved with both short-term homeostatic control and long-term cellular adaptations. Few studies have modeled the exercise stimulus in resistance training to determine the role of different exercise variables to the hormonal response. A variety of resistance exercise protocols result in increases in peripheral hormonal concentrations. It appears that single factor variables such as the intensity (% of RM) of exercise and amount of muscle mass utilized in the exercise protocol are important determinants of hormonal responses. The volume (sets x repetitions x intensity) of exercise also appears to be an important determinant of hormonal response. Still, little is known with regard to other single and multiple factor variables (e.g., rest period length) and their relationships to peripheral hormonal alterations. Collectively, such information will allow greater understanding concerning the nature of the exercise stimulus and its relationship to training adaptations resulting from heavy resistance exercise.
Lettura consigliata :
Kraemer W.J., Ratamess N.A. Endocrine Responses and Adaptations to
Strength and Power Training. In "Komi P.V. (Ed) (2003) Strength and power in sport. Blackwell publishing, Oxford"
Uno di questi, essenziale per la prestazione sportiva è l'efficenza del sistema neuroendocrino.
I livelli ormonali si modificano in risposta all'entità dello stimolo cui l'organismo viene sottoposto (intensità e durata)
Una varietà di meccanismi ormonali influenza la crescita e il rimodellamento del tessuto (ad esempio muscoli, ossa e altri tessuti connettivi), che si rivelano fondamentali per la prestazione.
Diversi ormoni vengono discussi da Kraemer in questi due articoli.
Ovviamente per noi è importante porre l'accento su quelli anabolici e
catabolici.
Hormonal responses and adaptations to resistance exercise and training.
Sports Med. 2005;35(4):339-61.
Kraemer WJ, Ratamess NA.
Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, 06269, USA. William.Kraemer@uconn.edu
Resistance exercise has been shown to elicit a significant acute hormonal response. It appears that this acute response is more critical to tissue growth and remodelling than chronic changes in resting hormonal concentrations, as many studies have not shown a significant change during resistance training despite increases in muscle strength and hypertrophy. Anabolic hormones such as testosterone and the superfamily of growth hormones (GH) have been shown to be elevated during 15-30 minutes of post-resistance exercise providing an adequate stimulus is present. Protocols high in volume, moderate to high in intensity, using short rest intervals and stressing a large muscle mass, tend to produce the greatest acute hormonal elevations (e.g. testosterone, GH and the catabolic hormone cortisol) compared with low-volume, high-intensity protocols using long rest intervals. Other anabolic hormones such as insulin and insulin-like growth factor-1 (IGF-1) are critical to skeletal muscle growth. Insulin is regulated by blood glucose and amino acid levels. However, circulating IGF-1 elevations have been reported following resistance exercise presumably in response to GH-stimulated hepatic secretion. Recent evidence indicates that muscle isoforms of IGF-1 may play a substantial role in tissue remodelling via up-regulation by mechanical signalling (i.e. increased gene expression resulting from stretch and tension to the muscle cytoskeleton leading to greater protein synthesis rates). Acute elevations in catecholamines are critical to optimal force production and energy liberation during resistance exercise. More recent research has shown the importance of acute hormonal elevations and mechanical stimuli for subsequent up- and down-regulation of cytoplasmic steroid receptors needed to mediate the hormonal effects. Other factors such as nutrition, overtraining, detraining and circadian patterns of hormone secretion are critical to examining the hormonal responses and adaptations to resistance training.
Endocrine responses to resistance exercise.
Med Sci Sports Exerc. 1988 Oct;20(5 Suppl):S152-7.
Kraemer WJ.
Exercise Physiology Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007.
The purpose of this brief review is to examine resistance training responses of selected hormones related to acute stress and growth promoting actions. Hormonal mechanisms appear to be involved with both short-term homeostatic control and long-term cellular adaptations. Few studies have modeled the exercise stimulus in resistance training to determine the role of different exercise variables to the hormonal response. A variety of resistance exercise protocols result in increases in peripheral hormonal concentrations. It appears that single factor variables such as the intensity (% of RM) of exercise and amount of muscle mass utilized in the exercise protocol are important determinants of hormonal responses. The volume (sets x repetitions x intensity) of exercise also appears to be an important determinant of hormonal response. Still, little is known with regard to other single and multiple factor variables (e.g., rest period length) and their relationships to peripheral hormonal alterations. Collectively, such information will allow greater understanding concerning the nature of the exercise stimulus and its relationship to training adaptations resulting from heavy resistance exercise.
Lettura consigliata :
Kraemer W.J., Ratamess N.A. Endocrine Responses and Adaptations to
Strength and Power Training. In "Komi P.V. (Ed) (2003) Strength and power in sport. Blackwell publishing, Oxford"
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