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Journal ArticleDOI

Estudo do comportamento cortisol, gh e insulina apos uma sessao de exercicio resistido agudo

TL;DR: In this article, a comparison of concentracoes plasmaticas of cortisol, GH and insulina for leg press (LP) and supino reto (SR) exercises was conducted.
Abstract: INTRODUCAO: Muitos trabalhos tem estudado o comportamento hormonal nos exercicio resistido, entretanto poucos relacionam os hormonios cortisol, GH e insulina. OBJETIVO: Estudar os ajustes das concentracoes plasmaticas dos hormonios cortisol, GH e insulina em exercicios resistidos de mesma intensidade com relacao a massas musculares distintas. METODOS: Dez voluntarios, com 20,3 ± 4,2 anos, 74,1 ± 10,2 kg de peso, 177,2 ± 4,6 cm de estatura e 23,8 ± 3,2 kg/m2 de IMC, realizaram uma sessao de leg press (LP) e supino reto (SR) com quatro series com 10 repeticoes a 70% 1 RM com tres minutos de intervalo. Foram coletadas amostras de sangue para dosagem das concentracoes plasmaticas de cortisol, GH e insulina em repouso (Pre) e em 0' (Rec. 0'), 30' (Rec. 30') e 90' (Rec. 90') de recuperacao. RESULTADOS: As concentracoes plasmaticas de cortisol foram significativamente reduzidas ao final da recuperacao em LP (2,20±0,37 ng/dl para 1,33±0,38ng/dl) em relacao a pre-dosagem. As concentracoes de GH e insulina elevaram-se significativamente durante a recuperacao. GH em LP foi significativamente maior em Rec. 0' (2,75±3,29 ng/ml para 9,60±5,32 ng/dl) do que em pre. A insulina elevou-se significativamente em Rec. 30' em LP (14,70±7,92 ulU/ml para 21,66 ± 8,61 ulU/ml) e em SR (6,17 ± 2,99 ulU/ml para 19,70 ± 13,8 ulU/ml) em relacao a pre. As concentracoes plasmaticas de insulina pre em LP foram significativamente superiores a SR (14,70 ulU/ml e 6,17 ± 2,99 ulU/ml). CONCLUSAO: O exercicio resistido promoveu diferentes ajustes nas concentracoes hormonais de cortisol, GH e insulina durante o periodo de recuperacao.

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TL;DR: Variables for muscular injury showed no evidence of alterations 24 hours after the CT sessions, hence confirming that the workload did not generate significant post-stress muscular injury.
Abstract: Introduction: Complex Training (CT) has been used to achieve Post-activation Potentiation (PAP) of physical capabilities and, in doing so, improve the sports performance of athletes. However, few studies have considered alterations in serum Cortisol, Metabolic Creatine Kinase (MB-CK), Total Creatine Kinase (Total-CK), and Lactate concentrations ([La]) resulting from this training method. Objective: This study determined the behavior of the following blood serum substances in a CT session: Cortisol, MB-CK, Total CK and [La]. Method: Ten military athlete volunteers aged 28.5 ± 4.8 years; 66.2 ± 2.8 kg, 171.4 ± 3.7 cm, 22.6 ± 1.2 kg/m2; 11.3 ± 2.9% of fat tissue took part in the study. The study had a quasi-experimental, intrasubject design. The variable measurements were: Cortisol, MB-CK, Total-CK, and [La], measured before physical exercise and 24 hours post-stress. The CT session consisted of: four series of five repetitions at 30% of 1RM, plus four repetitions at 60% of 1RM, plus three throws of a 575 g projectile, 15 seconds apart. The statistical analysis was carried out through repeated measure ANOVA for Lactate and a Wilcoxon Matched Pairs t-Test for Cortisol, MB-CK and Total-CK. Results: There was no evidence of alterations in the indicators for fatigue ([La] p = 0.36), and muscular injury (Cortisol p = 0.16; MB-CK p = 0.23; Total-CK p = 0.64) after the training sessions. Conclusion: Variables for muscular injury showed no evidence of alterations 24 hours after the CT sessions, hence confirming that the workload did not generate significant post-stress muscular injury. Level of Evidence I; Therapeutic Study: Investigating Treatment Results.

3 citations

Journal ArticleDOI
TL;DR: In this paper, a high-intensity resistance exercise (RE) performed at high intensity cause an inflammatory response and electrolyte abnormalities in blood plasma, which are associated with delayed onset muscle soreness (DOMS).
Abstract: Introduction Resistance exercises (RE) performed at high intensity cause an inflammatory response and electrolyte abnormalities in blood plasma. Objectives To study the plasma electrolyte changes resulting from a high-intensity session of RE in untrained volunteers, and to correlate these with delayed onset muscle soreness (DOMS). Methods Twenty volunteers, aged 26.9 (±4.4) years, underwent an RE session. The workout (leg extension, squat and leg press) consisted of four sets of 10 maximum repetitions. Electrolytes (Na+, K+, Ca2+ e Mg2+) were evaluated before the training (baseline), immediately (0 min), and 30 minutes after the RE. The DOMS was assessed 24 hours after the sessions. Results The Na+ increased immediately after the RE and returned to normal after 30 min (p<0.001). After 30 min, K+ increased compared to baseline levels and immediately after the RE (p<0.001). Ca2+ and Mg2+ levels did not change throughout the study. Changes in Na+ and K+ levels were correlated immediately (r=-0.511; p=0.021) and 30 min (r=-0.455; p=0.049) after RE. Plasma concentrations of Na+ 0 min were correlated (r=-0.520; p=0.018) with the DOMS. Conclusion High-intensity RE in untrained volunteers leads to changes in plasma concentrations of Na+ and K+. Na+ concentrations immediately after RE were related to DOMS; individuals that presented smaller alterations in this electrolyte reported more muscular pain. Level of evidence II; Diagnostic Studies - Development of diagnostic criteria on consecutive patients (with universally applied reference “gold” standard).

1 citations

References
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TL;DR: A triaxial accelerometer worn at the waist can be used to estimate resistance exercise energy expenditure but appears to offer no benefit over uniaxial accelerometry, which may prove useful for individuals and athletes who participate in resistance training and are focused on maintaining a tightly regulated energy balance.
Abstract: Recently, it was demonstrated that a uniaxial accelerometer worn at the hip could estimate resistance exercise energy expenditure. As resistance exercise takes place in more than 1 plane, the use of a triaxial accelerometer may be more effective in estimating resistance exercise energy expenditure. The aims of this study were to estimate the energy cost of resistance exercise using triaxial accelerometry and to determine the optimal location for wearing triaxial accelerometers during resistance exercise. Thirty subjects (15 men and 15 women; age = 21.7 ± 1.0 years) performed a resistance exercise protocol consisting of 2 sets of 8 exercises (10RM loads). During the resistance exercise protocol, subjects wore triaxial accelerometers on the wrist, waist, and ankle; a heart rate monitor; and a portable metabolic system. Net energy expenditure was significantly correlated with vertical (r = 0.67, p < 0.001), horizontal (r = 0.43, p = 0.02), third axis (r = 0.36, p = 0.048), and sum of 3 axes (r = 0.50, p = 0.005) counts at the waist, and horizontal counts at the wrist (r = -0.40, p = 0.03). Regression analysis using fat-free mass, sex, and the sum of accelerometer counts at the waist as variables was used to develop an equation that explained 73% of the variance of resistance exercise energy expenditure. A triaxial accelerometer worn at the waist can be used to estimate resistance exercise energy expenditure but appears to offer no benefit over uniaxial accelerometry. The use of accelerometers in estimating resistance exercise energy expenditure may prove useful for individuals and athletes who participate in resistance training and are focused on maintaining a tightly regulated energy balance.

28 citations

Journal Article
TL;DR: These results suggest the possible presence of adaptation of TES responses to resistance exercise in long-term strength-trained men, with these subjects presenting higher responses to the same stimulus, compared with untrained subjects, while no such adaptation was seen at the adrenocortical level in these subjects.
Abstract: AIM The aim of the present study was to investigate if there are differences in salivary hormonal responses to resistance exercise between long-term strength-trained and untrained men. METHODS Twenty-eight subjects were recruited to this study, matched into a strength-trained group (SG, N=13) and an untrained group (UG, N=15). Upper and lower body absolute muscle strength was measured through the one-repetition maximum (1-RM) test. Saliva samples were collected at rest and after a resistance exercise protocol (REP) with intensity relative to 1-RM values. With these samples, testosterone (TES), dehydroepiandrosterone (DHEA) and cortisol (COR) were determined. RESULTS SG subjects demonstrated significantly higher values in all muscle strength variables. While a significant increase in TES after REP was found in the SG (0.114 + or - 0.1 vs. 0.15 + or - 0.09 pg/mL, P<0.05), no differences were observed in the UG (0.144 + or - 0.1 vs. 0.17 + or - 0.1 pg/mL). In both groups, there were increases in salivary COR (SG: 1.4 + or - 0.6 vs. 2.06 + or - 1; UG: 1.5 + or - 0.8 vs. 2.3 + or - 1.2 ug/dL, P<0.05) and DHEA (SG: 0.6 + or - 0.3 vs. 0.9 + or - 0.6; UG: 0.65 + or - 0.3 vs. 0.97 + or - 0.7 ng/dL, P<0.05). CONCLUSIONS These results suggest the possible presence of adaptation of TES responses to resistance exercise in long-term strength-trained men, with these subjects presenting higher responses to the same stimulus, compared with untrained subjects, while no such adaptation was seen at the adrenocortical level in these subjects as the responses observed were similar in both groups.

27 citations

Journal ArticleDOI
TL;DR: The findings of this study indicate that the intense resistance exercise can lead to changes in blood concentrations of IGF-1 system components which are observable in blood circulation over time and the amounts of changes depend on subjects’ fitness levels and exercise variables.
Abstract: To investigate the effect of heavy resistance exercise on IGF-1 system, 19 healthy trained men and 15 healthy untrained men volunteered to participate in this study. The subjects were randomly divided into experimental and control groups. Subjects of experimental groups were forced to perform a heavy resistance exercise with the intensity of 70–80% of 1RM in selected movements. The blood samples were taken from all subjects four times; before (T1), immediately after (T2), 5 (T3), and 8 (T4) hours after exercise. Analysis of data showed that a session of heavy resistance exercise induced significant increase in GH at T2 (P < 0.05) and a significant decrease in insulin at T4 (P < 0.05) and a significant decrease in IGFBP3 at T4 (P < 0.05) in trained group. In untrained group, no significant change in any of the variables was observed. However, the procedure of response in variables was almost similar in two experimental groups. Although, the exercise did not appreciably affect IGF-1 levels, it decreased in all groups at length of time after exercise. In addition, the exercise did not have any notable effect on IGFBP1 levels over time. In conclusion, the findings of this study indicate that the intense resistance exercise can lead to changes in blood concentrations of IGF-1 system components which are observable in blood circulation over time and the amounts of changes depend on subjects’ fitness levels and exercise variables.

26 citations

Journal ArticleDOI
TL;DR: Findings indicate that an evidence-based resistance training program administered in the community setting for those with or at risk of developing type 2 diabetes, can lead to favorable health benefits, including reductions in central obesity and improved physical function.
Abstract: To examine the effects of a community-based resistance training program (Lift for Life®) on waist circumference and functional measures in adults with or at risk of developing type 2 diabetes. Lift for Life is a research-to-practice initiative designed to disseminate an evidence-based resistance training program for adults with or at risk of developing type 2 diabetes to existing health and fitness facilities in the Australian community. A retrospective assessment was undertaken on 86 participants who had accessed the program within 4 active providers in Melbourne, Australia. The primary goal of this longitudinal study was to assess the effectiveness of a community-based resistance training program, thereby precluding a randomized, controlled study design. Waist circumference, lower body (chair sit-to-stand) and upper body (arm curl test) strength, and agility (timed up-and-go) measures were collected at baseline and repeated at 2 months (n = 86) and again at 6 months (n = 32). Relative to baseline, there was a significant decrease in mean waist circumference (-1.9 cm, 95% CI: -2.8 to -1.0) and the timed agility test (-0.8 secs, 95% CI: -1.0 to -0.6); and significant increases in lower body (number of repetitions: 2.2, 95% CI: 1.4-3.0) and upper body (number of repetitions: 3.8, 95% CI: 3.0-4.6) strength at the completion of 8 weeks. Significant differences remained at the 16 week assessment. Pooled time series regression analyses adjusted for age and sex in the 32 participants who had complete measures at baseline and 24-week follow-up revealed significant time effects for waist circumference and functional measures, with the greatest change from baseline observed at the 24-week assessment. These findings indicate that an evidence-based resistance training program administered in the community setting for those with or at risk of developing type 2 diabetes, can lead to favorable health benefits, including reductions in central obesity and improved physical function.

25 citations

Journal ArticleDOI
TL;DR: WBV stimulates GH secretion and LA production, with no additive effect when combined with repeated isometric voluntary contractions, and optimization of protocols based on WBV seems important to maximize the positive effects of this intervention on the somatotropic function.
Abstract: Background: In contrast with maximal voluntary resistance exercise, which is allegedly considered a potent GH stimulus in young subjects, evaluation of GH response to whole-body vibrations (WBV) has yielded conflicting results. Methods: The acute effects of WBV alone (test A), maximal voluntary isometric contractions (MVC) (test B), and combination of WBV and MVC (test C) on serum GH and blood lactate (LA) levels were studied in 9 healthy adult males. Muscle soreness was assessed 24 and 48 h after exercise by a visual analogue scale. Results: GH responses were significantly higher after tests B and C than after test A (GH peaks: 18.8±9.5 ng/ml or 20.8±13.7 ng/ml, respectively, vs 4.3±3.5 ng/ml; p<0.05), with no difference between tests B and C. LA concentrations significantly increased after tests A, B, and C, being significantly higher after tests B and C than after test A (LA peaks: 2.0±0.5 mmol/l or 6.7±2.3 mmol/l, respectively, vs 7.6±0.9 mmol/l; p<0.05). Peak LA values were significantly correlated to GH peaks in the 3 tests (r=0.48; p<0.05). Muscle soreness was significantly higher 24–48 h after tests B and C than after test A, no significant differences being present between tests B and C. Conclusions: WBV stimulates GH secretion and LA production, with no additive effect when combined with repeated isometric voluntary contractions. Optimization of protocols based on WBV seems important to maximize the positive effects of this intervention on the somatotropic function. tis

19 citations