• Does Workout Hormone Release Matter?



      By Flex Staff

      Hormones such as human growth hormone (GH), testosterone, and IGF-1 have been shown to play a role in muscle hypertrophy and strength gains. Many of the great bodybuilders in the early í90s trained with short rest periods between sets, as earlier research found that short rest periods in conjunction with intense training led to significant increases in GH and testosterone. The anabolic effects of testosterone on muscle mass are dose and concentration dependent. The prevalent dogma for the past 50 years has been that testosterone increases muscle mass by stimulating fractional muscle protein synthesis. Testosterone administration also results in increases in GH secretion, androgen receptor number, satellite cell activity, and increased IGF-I expression in skeletal muscle. Itís also been demonstrated that the increase in muscle anabolism is associated with an increase in the expression of intramuscular mRNA IGF-I. GH is also highly recognized for its role in muscle growth. Resistance exercise stimulates the release of GH from the anterior pituitary gland, with released levels being very dependent on exercise intensity. GH helps to trigger fat metabolism for energy use in the muscle growth process. As well, GH stimulates the uptake and incorporation of amino acids into protein in skeletal muscle. In humans, GH administration is known to increase both whole-body and muscle protein synthesis and almost unequivocally to increase lean body mass and decreased fat mass. Human growth hormone also stimulates hepatic production of circulating IGF-1 concentrations and may also stimulate IGF-1 production in other tissue such as skeletal muscle. So itís well established that testosterone and GH are important for muscle hypertrophy and strength, but what about the acute increases that occur during resistance exercise? Are they important?

      Researchers at the Exercise Metabolism Group at McMaster University reported that muscle hypertrophy took place without acute increases in anabolic hormone concentrations. Ten healthy young male subjects performed unilateral resistance training for eight weeks (three days/week). Unilateral resistance exercise is basically where you train one arm or leg, while the other arm or leg is used as a control or untrained muscle. Exercises performed in the study were knee extensions and leg presses performed at 80Ė90% of the subjectís single-repetition maximum (1RM). Blood samples were collected before, immediately aſt er, 30, 60, 90, and 120 minutes post-exercise. The first training bout and the last training bout were analyzed for total testosterone, free-testosterone, GH, and insulin-like growth factor-1, along with other hormones. Thigh muscle cross-sectional area (CSA) and muscle fiber CSA by biopsy (vastus lateralis) were also measured preand post-training.

      Acutely, no changes in GH, testosterone, or IGF-1 concentrations were observed in the 90-minute period following exercise and there was no influence of training on the anabolic hormones measured. Human growth hormone did show a moderate increase 30 minutes post-exercise, but returned to baseline values by 90 minutes. Training-induced increases were observed in type IIb and IIa muscle fiber CSA. No changes were observed in fiber CSA in the untrained leg. Whole-muscle CSA increased in the trained leg and remained unchanged in the untrained leg.

      In conclusion, unilateral training induced local muscle hypertrophy only in the exercised limb, which occurred in the absence of testosterone, GH, or IGF-1 circulating levels. To further support the evidence that acute anabolic hormones have little impact on muscle growth, an excellent review was published in Medicine in Sports Science and Exercise, which further supports the notion, that acute anabolic hormones have little to do with muscle hypertrophy. The reviewers suggested that the interpretation of the current literature to support that post-exercise hormone levels have an effect on the extent of muscular hypertrophy is lacking.

      - See more at: http://www.flexonline.com/nutrition/....uUIaaXQ7.dpuf
      Comments 8 Comments
      1. jbryand101b's Avatar
        jbryand101b -
        Physiological responses from training don't matter for physiological adaptations?
        Really?
      1. wiseman's Avatar
        wiseman -
        This is why leg press is just as good as a squat for leg growth.
      1. Adrena1ine's Avatar
        Adrena1ine -
        Originally Posted by wiseman View Post
        This is why leg press is just as good as a squat for leg growth.
        Growth maybe. Power no.
      1. wiseman's Avatar
        wiseman -
        Originally Posted by Adrena1ine View Post

        Growth maybe. Power no.
        Maybe not as much power as a person gets from squat but they can still get power of they train right.
      1. Adrena1ine's Avatar
        Adrena1ine -
        Originally Posted by wiseman View Post

        Maybe not as much power as a person gets from squat but they can still get power of they train right.
        Yeah no doubt about that. At the end of the day you're still moving weight.
      1. sanguine's Avatar
        sanguine -
        if it served no purpose, it wouldnt happen. biology is simple.
      1. mt_powers's Avatar
        mt_powers -
        Poorly constructed study. The conclusion of the study may or may not be true, but cannot be drawn based on how this study was set up. Earlier in the article it talks about how shorter rest periods between sets and intense exercise increases hormone production. Research also indicates that whole body exercises, such as squats, stimulate the body to produce higher levels of anabolic hormones. The fact that there was minimal production of hormones for the study subjects indicates that the workout probably did not include short rest periods and intensity. The study also did not simulate a typical workout, but only focused on a couple isolated exercises. The conclusion should have been, "Isolated exercises and lack of intense exercise without short rest periods result in minimal anabolic hormone production, and no whole body hypertrophy." Piss poor design to come to that conclusion and typical of a lot of poorly constructed research out there.
      1. Fizzeek's Avatar
        Fizzeek -
        "Resistance exercise stimulates the release of GH from the anterior pituitary gland, with released levels being very dependent on exercise intensity".....

        "Researchers at the Exercise Metabolism Group at McMaster University reported that muscle hypertrophy took place without acute increases in anabolic hormone concentrations."

        If the aim of the study was to examine if acute hormone release DID matter, then why didn't they perform the study with INCREASED ACUTE HORMONE CONCENTRATIONS? Duh. By doing the opposite then they've only studied half of it...

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