Michel Arias Brentano

Hormonal responses to resistance exercise in long-term trained and untrained middle-aged men.

Cadore, EL, Lhullier, FLR, Brentano, MA, Silva, EM, Ambrosini, MB, Spinelli, R, Silva, RF, and Kruel, LFM. Hormonal responses to resistance exercise in long-term trained and untrained middle-aged men. J Strength Cond Res 22(5): 1617-1624, 2008-This cross-sectional study compared hormonal responses to resistance exercise between trained and untrained men to investigate the adaptations of the endocrine system to long-term strength training in middle-aged men. Twenty-one middle-aged men were recruited for this study and matched into a strength-trained group (SG) (n = 10) and an untrained group (UG) (n = 11). In the SG, the individuals had practiced strength training for hypertrophy for at least 3 years. Upper- and lower-body muscle strength was measured with a 1 repetition maximum (1RM) test. Blood samples were collected at rest and after multiple sets of a superset strength training protocol (SSTP), with an intensity of 75% of 1RM values. With these blood samples, the levels of total testosterone (TT), free testosterone (FT), dehydroepiandrosterone (DHEA), cortisol, and sex hormone-binding globulin (SHBG) were determined. In addition, the TT-to-cortisol ratio and TT-to-SHBG ratio were calculated. There was no difference at rest between groups in hormonal values for TT, FT, DHEA, cortisol, the TT-to-SHBG ratio, and the TT-to-cortisol ratio. There were increases after SSTP in the levels of TT, FT, DHEA, and cortisol and the TT-to-SHBG ratio in the UG, but only FT increased in the SG. The SG demonstrated lower values in the TT-to-SHBG ratio after the training session. These results suggest the presence of alterations in anabolic and catabolic hormonal responses to resistance exercise in long-term trained middle-aged men, with the trained subjects demonstrating lower responsiveness in the hormone values. Long-term trained men seem to require a higher volume of training, at least similar to their daily workout, to stimulate greater hormone responses.

Correlations between serum and salivary hormonal concentrations in response to resistance exercise

Abstract The aim of present study was to examine the relationships between serum and salivary values of free testosterone, dehydroepiandrosterone, and cortisol before and after a session of resistance exercise. Twenty-eight healthy men (mean age 40 years, s = 4) participated in the present study. Serum and salivary samples were collected at rest and after a multiple-sets resistance exercise protocol, of approximately 25 minutes duration. Concentrations of free testosterone, dehydroepiandrosterone, and cortisol were measured using radioimmunoassay kits. No significant correlation was observed between serum free testosterone and salivary testosterone (r = 0.22 to 0.26, P > 0.05). Serum cortisol was significantly correlated with salivary cortisol before (r = 0.52, P = 0.005) and after (r = 0.62, P = 0.001) the exercise protocol. Serum and salivary concentrations of dehydroepiandrosterone were significantly correlated before (r = 0.68, P < 0.001) and after (r = 0.7, P < 0.001) exercise. The results of the present study suggest that even under exercise conditions, the salivary values of cortisol and dehydroepiandrosterone can reflect the behaviour of these hormones in blood. However, further studies are necessary to verify if salivary testosterone reflects the behaviour of serum free testosterone during resistance exercise.

Physiological adaptations to strength and circuit training in postmenopausal women with bone loss.

Brentano, MA, Cadore, EL, Da Silva, EM, Ambrosini, AB, Coertjens, M, Petkowicz, R, Viero, I, Kruel, LFM. Physiological adaptations to strength and circuit training in postmenopausal women with bone loss. J Strength Cond Res 22(6): 1816-1825, 2008-Strength training (ST; high intensity/low volume/long rest) has been used in several populations, including children, young adults, and older adults. However, there is no information about circuit weight training (CWT; low intensity/high volume/short rest) in apparently healthy postmenopausal women. The purpose of the present study was to analyze the effects of high-intensity ST and circuit training on isometric strength (IS), upper limb dynamic strength (ULS) and lower limb dynamic strength (LLS), muscle activation of quadriceps (EMGquad), maximal oxygen uptake (&OV0312;o2max), time to exhaustion (TE), and bone mineral density (BMD). Twenty-eight postmenopausal women were divided into 3 groups: 1) ST group (STG, n = 9, 45-80% 1 repetition maximum (1RM), 2-4 sets, 20-6 reps), 2) circuit training group (CTG, n = 10, 45-60% 1RM, 2-3 sets, 20-10 reps), and 3) a control group (CON, n = 9, no exercise). Significance level was defined as p ≤ 0.05 for all analyses. After 24 weeks of training, increases were observed in STG and CTG. However, whereas in the STG, the IS (32.7%), ULS (28.7%), LLS (39.4%), EMGquad (50.7%), &OV0312;o2max (22%), and TE (19.3%) increased, CTG showed changes only in IS (17.7%), ULS (26.4%), LLS (42.2%), &OV0312;o2max (18.6%), and TE (16.8%). BMD did not change in any experimental group. In the CON, there were no changes in the variables analyzed. Our results suggest that ST and circuit training positively affect postmenopausal womens muscular strength, muscular activation, and cardiorespiratory fitness, with no changes in BMD.

Perceived exertion in different strength exercise loads in sedentary, active, and trained adults.

Tiggemann, CL, Korzenowski, AL, Brentano, MA, Tartaruga, MP, Alberton, CL, and Kruel, LFM. Perceived exertion in different strength exercise loads in sedentary, active, and trained adults. J Strength Cond Res 24(8): 2032-2041, 2010-The aim was to analyze the relationship between the perceived exertion (PE) and different loads in strength exercises (SEs), in sedentary, active, and trained adult subjects. Thirty young men (18-34 years) were divided into 3 groups (experimental group [EG]): sedentary EG (SEG), physically active group (PAG), and the strength trained group (STG). Maximum strength was established using the 1 repetition maximum test (1RM). Using series of 12 repetitions, different loads were applied until the 4 ratings of PE (RPEs) (11, 13, 15, and 17) from 15 category Borg Perceived Exertion Scale (RPE 6-20). The pace of the repetitions and the intervals between the sets were controlled, the loads were blind, the order of the RPE randomized, whereas the PE was localized and determined after completion of the series. Strength correlations between the RPE and the %1RM, according to the EGs and SEs (0.826-0.922, p < 0.001), were observed. Similar behavior was seen in the SEs. Higher loads are related to higher RPEs and are differentiated between the EGs. The STG used higher %1RM when compared to the SEG, whereas the PAG, displayed an intermediary behavior in relation to the other groups. The use of PE represents a reliable instrument for the measurement of intensity in strength training.

Analysis of muscle activation during different leg press exercises at submaximum effort levels.

Da Silva, EM, Brentano, MA, Cadore, EL, De Almeida, APV, and Kruel, LFM. Analysis of muscle activation during different leg press exercises at submaximum effort levels. J Strength Cond Res 22: 1059-1065, 2008-Many studies have analyzed muscle activity during different strength exercises. Although the leg press (LP) is one of the most common exercises performed, there is little evidence of lower limb muscle activity patterns during this exercise and its variations. Thus, this study aimed to verify how mechanical changes and loads affect lower limb muscle activity during the performance of different LP exercises. Fourteen women performed 3 LP exercises: 45° LP (LP45), LP high (LPH), and LP low (LPL) at 40% and 80% of the 1 repetition maximum. The electromyographic activity of the rectus femoris, vastus lateralis, biceps femoris, gastrocnemius, and gluteus maximus was recorded. Results suggested that mechanical changes affect lower limb muscle activity and that it is related to the load used. At moderate effort levels, the rectus femoris and gastrocnemius were more active during the LP45 and LPL than during the LPH. At a high effort level, the rectus femoris and vastus lateralis (quadriceps) were more active during the LPL than the LPH. Again, the rectus femoris and gastrocnemius were more active during the LP45 and LPL than the LPH. On the other hand, gluteus maximus activity was greater during the LPH than the LPL. This study found that coordination patterns of muscle activity are different when performing LP variations at high or moderate effort levels because of mechanical changes and different loads lifted during the different LP exercises. These results suggest that if the goal is to induce greater rectus femoris and vastus lateralis (quadriceps) activation, the LPL should be performed. On the other hand, if the goal is to induce gluteus maximus activity, the LPH should be performed.

Efeitos da atividade física na densidade mineral óssea e na remodelação do tecido ósseo

The purpose of this article is to make a review on different sportive modalities and the power training on the bone remodeling, and to discuss the possible relationship of the bone mineral density (BMD) to the muscular power and body composition. Several studies indicate that the high impact physical activity or physical activities demanding a high power production may have a benefic effect on the BMD due to the deformation that occurs in such tissue during the activity. Some authors have been assessing the effects of the physical training on some biochemical markers of the bone remodeling, since the variation on the concentrations of these markers might indicate a bone turnover or reabsorption state. Nevertheless, the inconsistency of the results found suggests that the analysis of the effects of the physical activity on the bone remodeling through these markers must be further investigated. There are many discrepancies as to the relationship of the BMD to the muscular power and body composition, mainly to determine what factors are most associated to the BMD. The determination of what type of physical activity is the ideal to increase the bone mass peak during the adolescence or even aiming to keep it later in the adult years is quite important in order to prevent and possibly treat the osteoporosis.ABSTRACTEffects of the physical activity on the bone mineral densityand bone remodelation The purpose of this article is to make a review on different sport-ive modalities and the power training on the bone remodeling,and to discuss the possible relationship of the bone mineral densi-ty (BMD) to the muscular power and body composition. Severalstudies indicate that the high impact physical activity or physicalactivities demanding a high power production may have a beneficeffect on the BMD due to the deformation that occurs in suchtissue during the activity. Some authors have been assessing theeffects of the physical training on some biochemical markers ofthe bone remodeling, since the variation on the concentrations ofthese markers might indicate a bone turnover or reabsorption state.Nevertheless, the inconsistency of the results found suggests thatthe analysis of the effects of the physical activity on the boneremodeling through these markers must be further investigated.There are many discrepancies as to the relationship of the BMD tothe muscular power and body composition, mainly to determinewhat factors are most associated to the BMD. The determinationof what type of physical activity is the ideal to increase the bonemass peak during the adolescence or even aiming to keep it laterin the adult years is quite important in order to prevent and possi-bly treat the osteoporosis.

Effects of different strength training methods on postexercise energetic expenditure.

Da Silva, RL, Brentano, MA, and Kruel, LFM. Effects of different strength training methods on postexercise energetic expenditure. J Strength Cond Res 24(8): 2255-2260, 2010-Although many studies have demonstrated the efficacy of strength training in increasing energetic expenditure (EE) both during and after training sessions, there are no studies available that analyze the influence on EE of the order in which exercises are performed. Accordingly, the objective of this study was to verify whether the order in which exercises are performed, represented by 2 different methods of strength training (circuit [CT] and pre-exhaustion [PE]), influences the magnitude of the excess postexercise oxygen consumption (EPOC) as well as the EE. Eight nonstrength-trained women participated in the study. Two strength training sessions, with different orders of execution, were held with 7 exercises performed with loads of between 50% and 55% of 1 repetition maximum (1RM). The oxygen uptake was measured before the training sessions, and the difference between the values found was taken as the EPOC of each training session and used in later analysis. No significant differences were found in either the EPOC (CT: 7.19 L ± 6.17 an. PE: 7.22 ± 5.84 L) or the postexercise EE (CT: 34.67 ± 29.76 Kcal, PE: 34.77 ± 28.15 Kcal) of the 2 training methodologies. Our results indicate that, in strength training, the magnitude of the EPOC is not linked to the order in which the exercises are performed. However, the absence of recovery periods between the sets and the exercises promotes an increase in the magnitude of the EPOC to the levels found in training sessions with higher percentages of 1RM.

Effects of the physical activity on the bone mineral density and bone remodelation

The purpose of this article is to make a review on different sportive modalities and the power training on the bone remodeling, and to discuss the possible relationship of the bone mineral density (BMD) to the muscular power and body composition. Several studies indicate that the high impact physical activity or physical activities demanding a high power production may have a benefic effect on the BMD due to the deformation that occurs in such tissue during the activity. Some authors have been assessing the effects of the physical training on some biochemical markers of the bone remodeling, since the variation on the concentrations of these markers might indicate a bone turnover or reabsorption state. Nevertheless, the inconsistency of the results found suggests that the analysis of the effects of the physical activity on the bone remodeling through these markers must be further investigated. There are many discrepancies as to the relationship of the BMD to the muscular power and body composition, mainly to determine what factors are most associated to the BMD. The determination of what type of physical activity is the ideal to increase the bone mass peak during the adolescence or even aiming to keep it later in the adult years is quite important in order to prevent and possibly treat the osteoporosis.ABSTRACTEffects of the physical activity on the bone mineral densityand bone remodelation The purpose of this article is to make a review on different sport-ive modalities and the power training on the bone remodeling,and to discuss the possible relationship of the bone mineral densi-ty (BMD) to the muscular power and body composition. Severalstudies indicate that the high impact physical activity or physicalactivities demanding a high power production may have a beneficeffect on the BMD due to the deformation that occurs in suchtissue during the activity. Some authors have been assessing theeffects of the physical training on some biochemical markers ofthe bone remodeling, since the variation on the concentrations ofthese markers might indicate a bone turnover or reabsorption state.Nevertheless, the inconsistency of the results found suggests thatthe analysis of the effects of the physical activity on the boneremodeling through these markers must be further investigated.There are many discrepancies as to the relationship of the BMD tothe muscular power and body composition, mainly to determinewhat factors are most associated to the BMD. The determinationof what type of physical activity is the ideal to increase the bonemass peak during the adolescence or even aiming to keep it laterin the adult years is quite important in order to prevent and possi-bly treat the osteoporosis.

Fatores relacionados com as respostas da testosterona e do cortisol ao treinamento de força

This study aims to review the results found in the literature concerning a variety of factors related to the acute and chronic hormonal response to strength training. It has been observed that there is a close relationship between the trainability of individuals submitted to strength training and the circulating testosterone levels in these subjects. Moreover, other hormonal parameters, such as the ratios between testosterone and its binding protein and between testosterone and cortisol, were also related to the ability to increase strength. Besides the characteristics of the population investigated, several factors associated with the training session affect the acute and chronic hormonal response to training. Among them, volume and intensity are the main variables associated with the magnitude of this response. Determining which factors might be closely related to the hormonal response to strength training may be important to establish a training session and a periodization that optimize the anabolic environment determined by the testosterone and cortisol concentrations, and thus enhance the neuromuscular adaptations resulting from this type of training.

Estimativa da força máxima dinâmica através de coeficientes e de análise de regressão linear baseados em parâmetros antropométricos de homens destreinados em força

Porcentagens do teste de uma repeticao maxima (1 RM) sao utilizadas na prescricao da intensidade no treinamento de forca, conforme os objetivos. Porem esse teste envolve um longo tempo de execucao, principalmente pela dificuldade de encontrar carga teste inicial. Valores estimados de 1 RM tem sido propostos atraves de parâmetros antropometricos; entretanto, poucos exercicios foram investigados. Sendo assim, o presente estudo teve objetivo de criar coeficientes de estimativa de 1 RM atraves da massa corporal e da massa corporal magra em tres exercicios de musculacao. Dezesseis homens, estudantes universitarios, destreinados em forca, tiveram a sua composicao corporal (dobras cutâneas) e forca maxima dinâmica (1 RM nos exercicios puxada pela frente, voador e triceps) mensurados. As correlacoes entre forca maxima dinâmica em cada exercicio e a massa corporal e massa corporal magra dos individuos foram feitas atraves do teste de correlacao de Pearson (p ≤ 0,05). Comparacoes entre os valores de forca estimados pelos coeficientes, pelas equacoes de regressao linear e os valores “reais” de forca, foram efetuadas atraves de analise da variância com medidas repetidas (ANOVA), alem do teste post hoc” Bonferroni. Foi observada uma correlacao significativa apenas entre a massa magra e os valores de 1 RM nos exercicios puxada pela frente (r = 0,538, p < 0,05), voador (r = 0,502, p < 0,05) e triceps pulley alto (r = 0,556,p < 0,05), resultando nos coeficientes de 1,01, 0,92 e 0,52, respectivamente. Concluimos que os coeficientes estabelecidos a partir da massa corporal magra podem ser usados para estimar a forca maxima dinâmica de homens destreinados.