Hormonal responses to high- and moderate-intensity strength exercise.
TL;DR: In both trials, IGF-1 concentrations were significantly lower after exercise as compared to concentrations found at 0800 hours the morning before exercise, and it is not known if this reduction observed 22 hours after exercise is of physiological significance.
Abstract: The hormonal responses of nine male, strength athletes to strength exercise were examined. The athletes performed one moderate- and one high-intensity strength exercise workout. In the high-intensity workout, the load was 100% of each subject's three-repetition maximum (3-RM) for squats and front squats, and 100% of each subject's six-repetition maximum (6-RM) for leg extensions. In the moderate-intensity workout, the load was 70% of the high-intensity protocol. Rest periods between sets were 4-6 min for both workouts. Blood samples were taken before, 30 min into, and every 15 min for the 1st h after exercise, and then 3, 7, 11, 22 and 33 h after exercise, thus allowing examination of both the acute and prolonged hormonal responses. Blood samples were analyzed for testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, adrenocorticotrophic hormone (ACTH), growth hormone (GH), insulin-like growth factor (IGF-1), insulin, sex hormone binding globulin, creatine kinase, total protein, glucose and lactate. The acute responses of testosterone and cortisol were greater during the high-intensity protocol as compared to the moderate-intensity protocol. The cortisol response was associated with an increase in ACTH concentration. LH and FSH showed no response to either protocol. Acute GH responses were not different between protocols. There were great inter-individual differences in acute GH responses to both protocols. There were no significant differences between protocols with regard to prolonged responses for any hormone. In both trials, IGF-1 concentrations were significantly lower at 0800 hours the morning after exercise as compared to concentrations found at 0800 hours the morning before exercise. The mechanisms responsible for reducing IGF-1 concentration in these trials are unclear, and it is not known if this reduction observed 22 hours after exercise is of physiological significance.
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TL;DR: In this article, the optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single and multiple-joint exercises.
Abstract: In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises) For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM) For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC) When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number The recommendation for training frequency is 2-3 d·wk -1 for novice training, 3-4 d·wk -1 for intermediate training, and 4-5 d·wk -1 for advanced training Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity Higher volume, multiple-set programs are recommended for maximizing hypertrophy Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets) It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (>15) using short rest periods (<90 s) In the interpretation of this position stand as with prior ones, recommendations should be applied in context and should be contingent upon an individual's target goals, physical capacity, and training status
3,421 citations
TL;DR: In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary and emphasis should be placed on multiple-joint exercises, especially those involving the total body.
Abstract: In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exercises). For initial resistances, it is recommended that loads corresponding to 8-12 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1-12 RM in a periodized fashion, with eventual emphasis on heavy loading (1-6 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1-2 s concentric, 1-2 s eccentric). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice and intermediate training and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion, with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30-60% of 1 RM) performed at a fast contraction velocity with 2-3 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (> 15) using short rest periods (< 90 s). In the interpretation of this position stand, as with prior ones, the recommendations should be viewed in context of the individual's target goals, physical capacity, and training status.
2,845 citations
Journal Article•
2,160 citations
TL;DR: It appears that this acute response to resistance exercise 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.
Abstract: 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.
1,197 citations
Journal Article•
TL;DR: It is concluded that development of ovarian hyperandrogenism may be a central mechanism relating nutritional lifestyle factors to endometrial cancer risk, and in premenopausal women, ovarian hyper androgenism likely increases risk by inducing chronic anovulation and progesterone deficiency.
Abstract: Endometrial cancer is a disease of the affluent, developed world, where epidemiological studies have shown that > or =40% of its incidence can be attributed to excess body weight. An additional proportion may be because of lack of physical activity. Alterations in endogenous hormone metabolism may provide the main links between endometrial cancer risk, and excess body weight and physical inactivity. Epidemiological studies have shown increased endometrial cancer risks among pre- and postmenopausal women who have elevated plasma androstenedione and testosterone, and among postmenopausal women who have increased levels of estrone and estradiol. Furthermore, there is evidence that chronic hyperinsulinemia is a risk factor. These relationships can all be interpreted in the light of the "unopposed estrogen" hypothesis, which proposes that endometrial cancer may develop as a result of the mitogenic effects of estrogens, when these are insufficiently counterbalanced by progesterone. In our overall synthesis, we conclude that development of ovarian hyperandrogenism may be a central mechanism relating nutritional lifestyle factors to endometrial cancer risk. In premenopausal women, ovarian hyperandrogenism likely increases risk by inducing chronic anovulation and progesterone deficiency. After the menopause, when progesterone synthesis has ceased altogether, excess weight may continue increasing risk through elevated plasma levels of androgen precursors, increasing estrogen levels through the aromatization of the androgens in adipose tissue. The ovarian androgen excess may be because of an interaction between obesity-related, chronic hyperinsulinemia with genetic factors predisposing to the development of ovarian hyperandrogenism.
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TL;DR: Changes in PV calculated from the increase in plasma protein concentration averaged 7.5(z compared with 12.2 y0 calculated from changes in Hb and Hct, the difference could be accounted for by a loss of 6v10 plasma protein from the circulation.
Abstract: DILL, D. B., AND I>. L. &STILL. Calculation of pcrccntage changes in volumes of blood, plasma, and red cells in dehydration. J. Appl. Physiol. 37(2): 247-248. 1974.-Observations on hematocrit (Hct) and hemoglobin (Hb) were Inade in six men before and after running long enough to cause a 4y0 decrease in body weight. Subscripts B and A were used to denote before dehydration and after dehydration, respectively. Relations were derived between BVn, BVA, Hbn, HbA, Hctg, and HctA with which one can calculate the percentage decreases in BV, CV, and PV, as well as the concentration of hemoglobin in red cells, g. 100 ml-l (MCHC). When subjects reach the same level of dehydration the water loss from the various body compartments may vary reflecting difference in salt losses in sweat. Changes in PV calculated from the increase in plasma protein concentration averaged 7.5(z compared with 12.2 y0 calculated from changes in Hb and Hct. The difference could be accounted for by a loss of 6v10 plasma protein from the circulation.
3,405 citations
"Hormonal responses to high- and mod..." refers methods in this paper
...This method has been compared to the method of Dill and Costill (1974), in a similar strength protocol with 6-RM loads....
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20 Mar 1989
TL;DR: The data indicate that the release patterns observed are complex functions of the type of HREPs utilized and the physiological mechanisms involved with determining peripheral circulatory concentrations (e.g., clearance rates, transport, receptor binding).
Abstract: : To examine endogenous anabolic hormone and growth factor responses to various heavy resistance exercise protocols (HREPs), nine male subjects performed each of six randomly assigned HREPs which consisted of identically ordered exercises carefully designed to control for load (5RM vs 10RM), rest period length (1 min vs 3 min) and total work (J) effects. Serum human growth hormone (hGH), tesosterone (T), somatomedin-C (SM-C), serum glucose and whole blood lactate (HLa) concentrations were determined pre-exercise, mid-exercise and at 0, 5, 15, 20, 60, 90, and 120 min post-exercise. All HREPs produced significant increases in serum T concentrations although the magnitude and frequency above resting values varied across HREPs. The highest hGH concentrations were observed consequent to high total work, 1 min rest periods and 10RM load. All HREPs did not produce increases in serum hGH. The pattern of SM-C increases varied among HREPs and did not follow hGH changes. These data suggest that the release patterns and the magnitude of increases are functions of the type of HREPs utilized. Thus, all HREPs may not effect muscle and connective tissue growth in the same manner due to differences in hormonal and growth factor responses. Keywords: HUman growth hormone, Somatomedins, Insulin- like growth factors, Testosterone, Resistance exercise, Lactate, Males.
659 citations
"Hormonal responses to high- and mod..." refers background in this paper
...Several studies have shown that strength exercises of moderate-to-high volume combined with short rest periods (1 min) between sets results in the greatest acute GH increases (Kraemer et al. 1990, 1991, 1993b)....
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...Serum concentrations of growth hormone (GH), testosterone and cortisol have all been shown to increase during, and to be elevated for 0.5±1 h after di erent protocols of strength exercise (Kraemer et al. 1990, 1993a)....
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...Kraemer et al. (1990, 1991) have shown that high-intensity strength exercise (5-RM) with large muscle groups and with 3-min rests between sets elevates testosterone concentrations....
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TL;DR: Growth hormone increases in both males and females following the P-2 HREP were significantly greater at all time points than corresponding P-1 values; Females exhibited significantly higher pre-exercise hGH levels compared to males.
Abstract: To examine endogenous anabolic hormonal responses to two different types of heavy resistance exercise protocols (HREPs), eight male and eight female subjects performed two randomly assigned protocols (i.e. P-1 and P-2) on separate days. Each protocol consisted of eight identically ordered exercises carefully designed to control for load, rest period length, and total work (J) effects. P-1 utilized a 5 RM load, 3-min rest periods and had lower total work than P-2. P-2 utilized a 10 RM load, 1-min rest periods and had a higher total work than P-1. Whole blood lactate and serum glucose, human growth hormone (hGH), testosterone (T), and somatomedin-C [SM-C] (i.e. insulin-like growth factor 1, IGF-1) were determined pre-exercise, mid-exercise (i.e. after 4 of the 8 exercises), and at 0, 5, 15, 30, and 60 min post-exercise. Males demonstrated significant (p less than 0.05) increases above rest in serum T values, and all serum concentrations were greater than corresponding female values. Growth hormone increases in both males and females following the P-2 HREP were significantly greater at all time points than corresponding P-1 values. Females exhibited significantly higher pre-exercise hGH levels compared to males. The P-1 exercise protocol did not result in any hGH increases in females. SM-C demonstrated random significant increases above rest in both males and females in response to both HREPs.(ABSTRACT TRUNCATED AT 250 WORDS)
479 citations
"Hormonal responses to high- and mod..." refers background in this paper
...Elevations of GH and cortisol have been observed in both genders, but increased testosterone concentration has not normally been observed in females (Weiss et al. 1983; Kraemer et al. 1991, 1993b)....
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...Several studies have shown that strength exercises of moderate-to-high volume combined with short rest periods (1 min) between sets results in the greatest acute GH increases (Kraemer et al. 1990, 1991, 1993b)....
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...Kraemer et al. (1990, 1991) have shown that high-intensity strength exercise (5-RM) with large muscle groups and with 3-min rests between sets elevates testosterone concentrations....
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TL;DR: The results of this study suggest that measurement of plasma somatomedin C provides a sensitive indicator of nitrogen loss and may be useful in monitoring the changes in protein metabolism that occur during alterations in nutritional status.
Abstract: We have assessed the effect of fasting for 10 days on plasma concentrations of immunoreactive somatomedin C and urinary urea excretion in seven obese male volunteers. From a mean prefast value of 0.83 U/ml, plasma somatomedin C fell to 0.21 U/ml after 10 days of fasting. A prompt increase was observed with refeeding. The change in somatomedin C during fasting showed a highly significant correlation with the change in urinary urea nitrogen excretion (r = 0.74; P < 0.001). It also was shown that inhibitors which interfere with quantitation in somatomedin bioassays are not observed in the RIA for somatomedin C. The results of this study suggest that measurement of plasma somatomedin C provides a sensitive indicator of nitrogen loss and may be useful in monitoring the changes in protein metabolism that occur during alterations in nutritional status.
373 citations
"Hormonal responses to high- and mod..." refers background in this paper
...A negative energy balance is another possible IGF-1-reducing mechanism (Clemmons et al. 1981), but the meals were served ad libitum during both trials, and no change in body mass was observed....
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TL;DR: The delay in the serum SM-C response to the administration of hGH suggests that SM is not stored in a readily releasable form and that the effect of GH on SM production may be through the stimulation of de novo synthesis.
Abstract: The induction of somatomedin C (SM-C) was evaluated in 30 hypopituitary patients and in normal subjects using a sensitive, specific RIA for SM-C. Two hypopituitary patients each received an iv bolus of 0.1 U human GH (hGH)⁄kg BW, followed by continuous infusion of 0.01 U hGH⁄kg-h for 12 h. The earliest rise in SM-C was detectable between 6-8 h. In response to the im administration of hGH, hypopituitary patients demonstrated a delay of 8 h before the rise in SM-C, a peak response between 16-28 h, and a fall nearly to basal levels by 48 h. The delay in the serum SM-C response to the administration of hGH suggests that SM is not stored in a readily releasable form and that the effect of GH on SM production may be through the stimulation of de novo synthesis. Graded doses of hGH in a sequence of 0.1, 0.2, 0.4, and 0.8 U/kg (im) elicited a stairstep pattern of SM-C response. When the sequence of administration of these doses was altered, however, it was apparent that the magnitude of the SM-C response was dete...
365 citations
"Hormonal responses to high- and mod..." refers background in this paper
...GH stimulates IGF-1 secretion from the liver, and peak IGF-1 concentrations in blood have been observed 16±28 h after GH injections in humans (Copeland et al. 1980)....
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