Hormonal responses after resistance exercise performed with maximum and submaximum movement velocities

Acute Hormonal Responses to Multi-Joint Resistance Exercises with Blood Flow Restriction

The purpose of this study was to investigate the acute effects of multi-joint resistance exercises (MJRE) with blood flow restriction on hormonal responses. Ten men participated in the study and underwent two experimental protocols in random order: four sets (30, 15, 15, and 15 reps, respectively) of MJRE (half squat and horizontal chest press) were performed with 20% of 1RM and a rest time between sets of 30 s, combined with intermittent blood flow restriction (LI + BFR protocol); and four sets (8, 8, 8, 20 reps, respectively) of the same MJRE performed with 75% of 1RM load (HI protocol), with a 90 s rest between the first three sets and 30 s between the third to the fourth set. Blood samples were collected before (PRE), immediately after (POST), and 15 min after the performance of MJRE (POST15). A time effect was observed for growth hormone (GH) and insulin-like-growth-factor-1-binding-protein-3 (IGFPB-3), but no protocol effects or interactions between protocol and times were observed (p > 0.05). There was no effect of either protocol or time (p > 0.05) on total testosterone, free testosterone, or cortisol concentrations. However, significant (p < 0.05) increases were observed in the GH serum concentrations of 2072.73% and 2278.5%, HI, and LI + BFR protocols, respectively, from the PRE to POST15 test. In addition, there was an increase of 15.30% and 13.29% in the IGFPB-3 concentrations (p < 0.05) from PRE to POST0 times for HI and LI + BFR protocols, respectively. Furthermore, there was a decrease of −6.17% and −11.54%, p = 0.00, between the times POST0 to POST15 in the IGFPB-3 for the HI and LI + BFR protocols, respectively. It is concluded that multi-joint resistance exercises combined with intermittent blood flow restriction seemed to promote acute hormonal responses in a manner similar to traditional exercise with high loads. Future studies may investigate whether chronic use of LI + BFR with MJRE may promote muscle hypertrophy.

Fast Eccentric Movement Tempo Elicits Higher Physiological Responses than Medium Eccentric Tempo in Ice-Hockey Players

BACKGROUND

Resistance training is a significant part of ice-hockey players' conditioning, where optimal loading should ensure strength development and proper recovery. Therefore, this study aimed to compare the acute physiological responses to fast and medium movement tempo resistance exercises in ice-hockey players.

METHODS

Fourteen ice-hockey players (26.2 ± 4.2 years; 86.4 ± 10.2 kg; squat one repetition maximum (1RM) = 130.5 ± 18.5) performed five sets of the barbell squat and barbell bench press at 80% 1RM until failure in a crossover design one week apart using either 2/0/2/0 or 6/0/2/0 (eccentric/isometric/concentric/isometric) tempo of movement. The blood samples to evaluate the concentration of cortisol, testosterone, insulin-like growth factor 1 (IGF-1), and growth hormone (hGH) were taken before exercise, 3 min after the last set of the squat exercise, 3 min after the last set of the bench press exercise, and after 30 min of recovery.

RESULTS

The 2/0/2/0 tempo resulted in a higher number of repetitions (p < 0.001) and lower time under tension (p < 0.001) in the squat and bench press exercises compared to the 6/0/2/0 movement tempo. The endocrine responses to exercise were significantly higher during the 2/0/2/0 compared to the 6/0/2/0 movement tempo protocol for IGF-1, hGH, and cortisol (p < 0.01). There were no differences in testosterone responses between exercises performed with fast and medium movement tempos.

CONCLUSION

Fast eccentric tempo induced higher cortisol, IGF-1, and hGH responses compared to the medium tempo. Therefore, fast eccentric movement tempo seems to be more useful in eliciting training stimulus than medium eccentric tempo during resistance training in ice-hockey players. However, future studies are needed to confirm our findings.

The Impact of Professional Sports Activity on GH-IGF-I Axis in Relation to Testosterone Level

The study was designed to investigate whether sports-induced elevation of testosterone level impacts on the growth hormone/insulin-like growth factor-I (GH-IGF-I) axis and body composition, especially skeletal muscle mass. The study included 12 male wrestlers aged 21.1 ± 1.7 years and 10 male nonathletes aged 21.1 ± 1.2 years. Anthropometric and biochemical measurements in the group of nonathlete men were carried out once, while for wrestlers they were carried out twice, that is, on the 1st and 14th days of the training camp.

The levels of resting free testosterone (fT), cortisol (C), and human growth hormone (hGH) were significantly higher in the athletes than in nonathletes. A 2-week sports training induced a significant reduction in fT, IGF-I, and IGF binding protein-3 (IGFBP-3) levels and a rise in C level. Increased C level and reduced fT level in the athletes’ blood caused a rise in C/fT from the level of 39.95 ± 4.97 nmol/L to 59.73 ± 10.09 nmol/L (p < .05). A negative correlation was demonstrated between C/fT ratio and IGF-I level (r = −0.474, p < .05), which may indicate an inhibitory impact of high C level and low fT concentration on IGF-I release in response to sports training.

Sports activity induces significant changes in the C/fT ratio that can impact on the secretion of GH and IGF-I from the liver and finally on the fat-free body mass. The quantification of GH-IGF-I axis in relation to testosterone level could be a useful diagnostic tool in biochemical assessment of the regenerative ability of skeletal muscle or provide evidence of the early stages of muscle functional overload.

The Influence of Movement Tempo on Acute Neuromuscular, Hormonal, and Mechanical Responses to Resistance Exercise-A Mini Review

Wilk, M, Tufano, JJ, and Zajac, A. The influence of movement tempo on acute neuromuscular, hormonal, and mechanical responses to resistance exercise-a mini review. J Strength Cond Res 34(8): 2369-2383, 2020-Resistance training studies mainly analyze variables such as the type and order of exercise, intensity, number of sets, number of repetitions, and duration and frequency of rest periods. However, one variable that is often overlooked in resistance training research, as well as in practice, is premeditated movement tempo, which can influence a myriad of mechanical and physiological factors associated with training and adaptation. Specifically, this article provides an overview of the available scientific literature and describes how slower tempos negatively affect the 1-repetition maximum, the possible load to be used, and the number of repetitions performed with a given load, while also increasing the total time under tension, which can mediate acute cardiovascular and hormonal responses. As a result, coaches should consider testing maximal strength and the maximal number of repetitions that can be performed with each movement tempo that is to be used during training. Otherwise, programming resistance training using various movement tempos is more of a trial-and-error approach, rather than being evidence or practice based. Furthermore, practical applications are provided to show how movement tempo can be adjusted for a variety of case study-type scenarios.

Testosterone and cortisol variation due to training and fight in Judokas

BACKGROUND

The aim of this study was to evaluate the effectiveness of judo workout by determining the testosterone (T) and cortisol (C) responses and their associations with the results of a judo fight.

METHODS

A prospective study involved 17 judokas. Three blood samples were taken from each athlete: at rest, immediately after a 90 min training session and 72 hours later immediately after a 5 min fight , to evaluate T, C and lactic acid.

RESULTS

Results showed no significant difference for T (p = 0.17), C (p = 0.51) or testosterone/cortisol (T/C) ratio (t = 0.901 (16), p =0.38) after training. A significant difference was found for the C (p =0.002) and the T/C ratio (p =0.04) after the fight. In contrast with the losers, the winner judokas reported a significant increase in the C (p = 0.002) and T (p = 0.013) concentrations at rest and after the fight. No significant difference was found for C (p = 0.77) or T (p = 0.43) at rest and after training.

CONCLUSIONS

The "fight" effort induced more biological stress than the "training" effort. In addition, the cortisol response and the T/C ratio revealed an association with a subsequent victorious judo fight. Thus, the hormonal response, particularly the C concentration, to a training could allow the assessment of the readiness of judokas for a future competition. This new strategy can allow to better manage the capacity of judoka at the training for the sake of an improvement of performance during competitions.

Fat-bone interaction within the bone marrow milieu: Impact on hematopoiesis and systemic energy metabolism

The relationship between fat, bone and systemic metabolism is a growing area of scientific interest. Marrow adipose tissue is a well-recognized component of the bone marrow milieu and is metabolically distinct from current established subtypes of adipose tissue. Despite recent advances, the functional significance of marrow adipose tissue is still not clearly delineated. Bone and fat cells share a common mesenchymal stem cell (MSC) within the bone marrow, and hormones and transcription factors such as growth hormone, leptin, and peroxisomal proliferator-activated receptor γ influence MSC differentiation into osteoblasts or adipocytes. MSC osteogenic potential is more vulnerable than adipogenic potential to radiation and chemotherapy, and this confers a risk for an abnormal fat-bone axis in survivors following cancer therapy and bone marrow transplantation. This review provides a summary of data from animal and human studies describing the relationship between marrow adipose tissue and hematopoiesis, bone mineral density, bone strength, and metabolic function. The significance of marrow adiposity in other metabolic disorders such as osteoporosis, diabetes mellitus, and estrogen and growth hormone deficiency are also discussed. We conclude that marrow adipose tissue is an active endocrine organ with important metabolic functions contributing to bone energy maintenance, osteogenesis, bone remodeling, and hematopoiesis. Future studies on the metabolic role of marrow adipose tissue may provide the critical insight necessary for selecting targeted therapeutic interventions to improve altered hematopoiesis and augment skeletal remodeling in cancer survivors.

Salivary cortisol and testosterone responses to resistance and plyometric exercise in 12- to 14-year-old boys

This study examined changes in salivary testosterone and cortisol following resistance and plyometric exercise protocols in active boys. In a crossover experimental design, 26 peri-pubertal (12- to 14-year-old) soccer players performed 2 exercise trials in random order, on separate evenings, 1 week apart. Each trial included a 30 min control session followed by 30 min of either resistance or plyometric exercise. Saliva was collected at baseline, post-control (i.e., pre-exercise), and 5 and 30 min post-exercise. There were no significant differences in the baseline hormone concentrations between trials or between weeks (p > 0.05). A significant effect for time was found for testosterone (p = 0.02, [Formula: see text] = 0.14), which increased from pre-exercise to 5 min post-exercise in both the resistance (27% ± 5%) and plyometric (12% ± 6%) protocols. Cortisol decreased to a similar extent in both trials (p = 0.009, [Formula: see text] = 0.19) from baseline to post-control and then to 5 min post-exercise, following its typical circadian decrease in the evening hours. However, a significant protocol-by-time interaction was observed for cortisol, which increased 30 min after the plyometrics (+31% ± 12%) but continued to decrease following the resistance protocol (-21% ± 5%). Our results suggest that in young male athletes, multiple modes of exercise can lead to a transient anabolic state, thus maximizing the beneficial effects on growth and development, when exercise is performed in the evening hours.

Obesity-driven disruption of haematopoiesis and the bone marrow niche

Obesity markedly increases susceptibility to a range of diseases and simultaneously undermines the viability and fate selection of haematopoietic stem cells (HSCs), and thus the kinetics of leukocyte production that is critical to innate and adaptive immunity. Considering that blood cell production and the differentiation of HSCs and their progeny is orchestrated, in part, by complex interacting signals emanating from the bone marrow microenvironment, it is not surprising that conditions that disturb bone marrow structure inevitably disrupt both the numbers and lineage-fates of these key blood cell progenitors. In addition to the increased adipose burden in visceral and subcutaneous compartments, obesity causes a marked increase in the size and number of adipocytes encroaching into the bone marrow space, almost certainly disturbing HSC interactions with neighbouring cells, which include osteoblasts, osteoclasts, mesenchymal cells and endothelial cells. As the global obesity pandemic grows, the short-term and long-term consequences of increased bone marrow adiposity on HSC lineage selection and immune function remain uncertain. This Review discusses the differentiation and function of haematopoietic cell populations, the principal physicochemical components of the bone marrow niche, and how this environment influences HSCs and haematopoiesis in general. The effect of adipocytes and adiposity on HSC and progenitor cell populations is also discussed, with the goal of understanding how obesity might compromise the core haematopoietic system.