Hormonal responses and adaptations to resistance exercise and training

Acute Effects of Mental Activity on Response of Serum BDNF and IGF-1 Levels in Elite and Novice Chess Players

Background and Objectives: Although the effects of physical exercise on brain functions are well studied, the influence of mental activity is unknown. The aim of this study was to assess the influence of a session of mental activity on brain neurobiological factors in chess players. Materials and Methods: Ten elite and novice chess players were recruited to participate in this study as volunteers. The subjects performed a session of standard chess matches as a mental activity. Before and after each chess match, blood samples were drawn to analyze changes in serum brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1). Results: After each chess match, both the elite and novice groups showed significant increases in serum BDNF and IGF-1 concentrations. The elite group also showed significantly greater changes in BDNF and IGF-1 levels (p ≤ 0.05) than the novice group. Conclusions: Our findings indicate that a session of standard chess matches as a mental activity is effective for elevating BDNF and IGF-1 levels, and that their elevation in elite players seems to be more pronounced than those in novice players.

Blood Flow Restriction During Futsal Training Increases Muscle Activation and Strength

The aim of this study was to investigate the effect of leg blood flow restriction (BFR) applied during a 3-a-side futsal game on strength-related parameters. Twelve male futsal players were randomly assigned into two groups (n = 6 for each group) during 10 training sessions either with or without leg BFR. Prior to and post-training sessions, participants completed a series of tests to assess anabolic hormones and leg strength. Pneumatic cuffs were initially inflated to 110% of leg systolic blood pressure and further increased by 10% after every two completed sessions. In comparison with baseline, the resting post-training levels of myostatin (p = 0.002) and IGF-1/MSTN ratio (p = 0.006) in the BFR group changed, whereas no change in the acute level of IGF-1 and myostatin after exercise was observed. Peak torque of knee extension and flexion increased in both groups (p < 0.05). A trend of increased neural activation of all heads of the quadriceps was observed in both groups, however, it was statistically significant only for rectus femoris in BFR (p = 0.02). These findings indicated that the addition of BFR to normal futsal training might induce greater neuromuscular benefits by increasing muscle activation and augmenting the hormonal response.

Signaling responses to high and moderate load strength exercise in trained muscle

We examined signaling responses in the skeletal muscle of strength athletes after strength exercises under high and moderate load. Eight trained male powerlifters were recruited. The volunteers performed four sets of leg presses to volitional fatigue using a moderate load (65% 1-repetition maximum [1RM]) for one leg, and a high load (85% 1RM) for the contralateral leg. The work volume performed by the leg moving a moderate load was higher than that of the contralateral leg moving a high load. Biopsy of the m. vastus lateralis was performed before, and at 1, 5, and 10 h after, cessation of exercise. Phosphorylation of p70S6kThr389 , 4E-BP1Thr37/46 , and ACCSer79 increased after moderate load exercises, whereas phosphorylation of ERK1/2Thr202/Tyr204 increased, and that of eEF2Thr56 decreased, after high load exercises. Exercise under a moderate load and a high work volume activated mTORC1-dependent signaling in trained skeletal muscle, whereas exercise under a high load but lower work volume activated the MEK-ERK1/2 signaling cascade and eEF2.

The effects of training on hormonal concentrations in young soccer players

To test the hypothesis that football training would be accompanied by physiological adaptations and hormonal changes, we analyzed the effects of a whole football season on physical fitness and hormonal concentrations in youth football players. Male football players (n = 29, age 16.51 ± 0.7 years) in a regional professional league and male healthy control subjects (n = 30, age 17.1 ± 1 years) participated to the study. Blood cortisol, testosterone, and growth hormone (hGH) concentrations were assayed before the beginning of the training period (T0), just after the training period (T1), at the middle of the season (T2), and at the end of the season (T3). In each period physical tests and anthropometric measurements were also performed. Results showed significant differences in basal values of cortisol, testosterone, and growth hormone (hGH) in the four time points evaluated (P < 0.01). In addition, the concentrations of hGH were higher in the soccer players group than in control subjects (P < 0.001). Between the start of the training period and the end of the football season significant differences were observed in the anthropometric characteristics and in the physical form of the football players. Furthermore, the hormonal status was significantly correlated with the indicators of the lower limb power (squat-jump [SqJ], and counter-movement-jump [CMJ]) and those of aerobic performance (Yo-Yo intermittent recovery test level 1 (YYIRT1) and maximal oxygen consumption (VO_2max )).These data underscore the importance of establishing training protocols that present the potential to promote positive adaptations without, at the same time, provoking overtraining of young players.

Analysis of Foot Morphology in Habitually Barefoot Group

Accurate method to identify foot morphology would further contribute to understand foot mechanism. The aim of this study is to identify foot morphology feature between habitually barefoot and shod population with 3D technology of scan. Sixty subjects both 30 habitually barefoot and 30 habitually shod participated foot scanning test. A 3-dimension laser device was applied to execute foot scanning. The findings of this study showed that habitually barefoot group displayed the foot features of the large ball perimeters, large minimal distance between hallux and other toes and the smaller hallux angle than habitually shod group. To conclude, the significant differences of foot morphology between habitually barefoot and habitually shod was mainly in forefoot area, this morphological features would provide some sights for the exploration of barefoot locomotion.

Exercise with blood flow restriction: an effective alternative for the non-pharmaceutical treatment for muscle wasting

Significant muscle wasting is generally experienced by ill and bed rest patients and older people. Muscle wasting leads to significant decrements in muscle strength, cardiorespiratory, and functional capacity, which increase mortality rates. As a consequence, different interventions have been tested to minimize muscle wasting. In this regard, blood flow restriction (BFR) has been used as a novel therapeutic approach to mitigate the burden associated with muscle waste conditions. Evidence has shown that BFR per se can counteract muscle wasting during immobilization or bed rest. Moreover, BFR has also been applied while performing low intensity resistance and endurance exercises and produced increases in muscle strength and mass. Endurance training with BFR has also been proved to increase cardiorespiratory fitness. Thus, frail patients can benefit from exercising with BFR due to the lower cardiovascular and join stress compared with traditional high intensity exercises. Therefore, low intensity resistance and endurance training combined with BFR may be considered as a novel and attractive intervention to counteract muscle wasting and to decrease the burden associated with this condition.

A Tutorial of the Effects of Sex Hormones on Laryngeal Senescence and Neuromuscular Response to Exercise

Purpose The purpose of this tutorial is to summarize how sex hormones affect both laryngeal senescence and neuromuscular response to exercise, highlighting the importance of considering sex differences in developing treatment for the senescent voice. Conclusion Men and women's voices are sexually dimorphic throughout the life span, including during the laryngeal adaptations observed during senescence. Therefore, presbyphonia (age-related dysphonia) likely clinically manifests differently for men and women due to differences in how the male and the female larynx change in response to aging. Because sexual dimorphism is evident in both laryngeal aging and response to exercise, voice therapy programs aimed at treating the typical and disordered aged voice should consider sex differences in their design.

Effects of physical activity on children's growth

OBJECTIVE

To describe the current scientific knowledge on the effects of physical exercise on the growth of children and adolescents since intrauterine life.

SOURCE OF DATA

A search was carried out in the Medline, Embase, Scielo, and Cochrane databases of studies published from 1990 to 2018. The authors included studies with different designs: clinical trials, cohort, cross-sectional and review studies.

SYNTHESIS OF DATA

Studies that addressed the subject of physical exercise or physical activity, and weight-height growth or bone or muscle tissue growth were identified. These studies were analyzed, classified, and presented by age group: fetuses, preterm newborns, preschoolers, schoolchildren, and adolescents. It was observed that almost all studies indicated the safety of physical exercises, of mild to moderate intensity, for pregnant women, as well as children and adolescents, including both aerobic and anaerobic exercises. The retrieve studies did not demonstrate that the practice of physical exercises or certain sports, especially basketball and floor gymnastics, influenced the linear growth of children or adolescents. Some studies showed an increase in bone and muscle tissue growth in child and adolescent athletes.

CONCLUSIONS

Despite the small number of studies with adequate methodology, especially randomized clinical trials, evidence appears to indicate that physical exercise is safe for both the pregnant woman and the child, from fetal life to adolescence. Physical exercise does not appear to impair the child's linear growth and contributes to the ideal shaping of bone and muscle tissues, ensuring possible beneficial effects throughout life.

Endocrine responses after a single bout of moderate aerobic exercise in healthy adult humans

Exercise is a stress stimulus for the human organism affecting the homeostatic mechanisms of the body, depending on the type, duration, intensity and frequency of exercise. The aim of this study was to determine the effects of a moderate aerobic exercise bout on the Hypothalamo-Pituitary-Adrenal (HPA) axis acute hormonal responses in healthy adult humans. Twelve healthy male and female volunteers (age: 30.6 ± 4.4 years), performed a single bout of a 30-minute aerobic exercise at 70% of VO2max on a treadmill, following standard diet. Blood samples were collected before (t0), at the end of the exercise bout (t30), and 30 min after the completion of exercise (t60). Serum adrenocorticotropic hormone (ACTH), cortisol (COR), aldosterone (ALDO) and renin (REN) were measured. One-way ANOVA was used for statistics. ACTH and COR decreased after exercise, reaching significance (p < 0.01) 30 min after the completion of the exercise bout. ALDO increased at the end of exercise and remained elevated 30 min after its completion. REN significantly increased at the end of exercise (p < 0.05) and remained elevated. The exercise regimen used in this study had beneficial effects on the stress axis, suggesting that specific exercise protocols can be characterised by mild physiological stress-inducing effects hence be prescribed for special diseased populations.

The type of training program affects appetite-regulating hormones and body weight in overweight sedentary men

Exercise-induced weight loss can occur for several reasons, including changes in circulatory levels of appetite-regulating hormones. The purpose of this study was to compare the effect of various training programs on fasting serum levels of acylated ghrelin, peptide YY 3-36 (PYY3-36) and glucagon-like peptide-1 (GLP-1), as well as weight and body mass index (BMI) changes. Forty-four overweight men were randomly assigned into 4 groups of 11 individuals, which included (i) endurance group (3 sets of 10 min with 80%–90% of maximum heart rate), (ii) resistance group (4 sets of 8 repetitions with 80% of 1-repetition maximum), (iii) concurrent group (combination of programs of endurance and resistance groups in an alternate manner), and (iv) control group. Training protocols were conducted for 12 weeks for 3 sessions per week. Results showed that all 3 types of training programs resulted in weight loss (p = 0.000, p = 0.000, and p = 0.036 for resistance, concurrent, and endurance groups, respectively), BMI reduction (p = 0.000, p = 0.000, and p = 0.034), decreased serum acylated ghrelin (p = 0.000, p = 0.000, and p = 0.004), and increased PYY hormone levels (p = 0.028, p = 0.035, and p = 0.036). However, the effect of resistance training on these changes was more pronounced. Moreover, none of the exercise programs had any effect on serum levels of GLP-1. In addition, there was a significant positive correlation between weight (p = 0.003) and BMI (p = 0.009) changes with ghrelin while a negative correlation was observed between weight (p = 0.003) and BMI (p = 0.03) changes with PYY. The findings suggest that regular exercise training, in particular resistance training, is likely to reduce body weight and improve body composition of overweight inactive people by suppressing orexigenic hormones and stimulating the anorexigenic hormones.

Acute Response to Endurance Exercise Stress: Focus on Catabolic/anabolic Interplay Between Cortisol, Testosterone, and Sex Hormone Binding Globulin in Professional Athletes

Background

Endocrine system plays a major role in both permissive and regulatory activities in order to adequately respond to physical stress of exercise. But level and direction of activation depend on many factors and are not easily interpreted.

Methods

We tested a group of male professional athletes (21 water polo players and 15 wrestlers), together with 20 sedentary controls matched by age. All participants took a continuous progressive exercise stress test on a treadmill until exhaustion and plateau of oxygen consumption (VO₂). Blood samples for cortisol, sex hormone binding globulin (SHBG) and testosterone were drawn in four time points: baseline (B), start of the test (S), point of maximal strain (MAX) and in the 3^rd minute of recovery period (R).

Results

Cortisol levels significantly increased in both groups, but the response between S and MAX was more pronounced in controls (p=0.036). The athletes had significantly higher levels of cortisol in all points in test, except during R (p=0.118), when their cortisol levels gradually started to decline. Significant increase in total testosterone was in great deal a consequence of increase in SHBG level (p<0.01 for both). Consequently, calculated free testosterone significantly decreased during test (p=0.008), and the drop was more pronounced in athletes. This was in concordance with significant correlation between SHBG and cortisol level demonstrated in athletes, but not in controls.

Conclusions

It seems that high intensity endurance exercise favors catabolic response, but the level of response highly depends on a previous level of training.

Sarcopenia, frailty and their prevention by exercise

Sarcopenia is a major component of the frailty syndrome, both being considered as strong predictors of morbidity, disability, and death in older people. In this review, we explore the definitions of sarcopenia and frailty and summarize the current knowledge on their relationship with oxidative stress and the possible therapeutic interventions to prevent or treat them, including exercise-based interventions and multimodal strategies. We highlight the relevance of the impairment of the nervous system and of the anabolic response (protein synthesis) in muscle aging leading to frailty and sarcopenia. We also discuss the importance of malnutrition and physical inactivity in these geriatric syndromes. Finally, we propose multimodal interventions, including exercise programs and nutritional supplementation, as the strategies to prevent and treat both sarcopenia and frailty.

Higher- Versus Lower-Intensity Strength-Training Taper: Effects on Neuromuscular Performance

PURPOSE

To investigate the effects of strength-training tapers of different intensities but equal volume reductions on neuromuscular performance.

METHODS

Eleven strength-trained men (21.3 [3.3] y, 92.3 [17.6] kg, relative 1-repetition-maximum deadlift 1.9 [0.2] times bodyweight) completed a crossover study. Specifically, two 4-wk strength-training blocks were followed by a taper week with reduced volume (∼70%) involving either increased (5.9%) or decreased (-8.5%) intensity. Testing occurred pretraining (T1), posttraining (T2), and posttaper (T3). Salivary testosterone and cortisol, plasma creatine kinase, a Daily Analysis of Life Demands in Athletes questionnaire, countermovement jump (CMJ), isometric midthigh pull, and isometric bench press were measured.

RESULTS

CMJ height improved significantly over time (P < .001), with significant increases from T1 (38.0 [5.5] cm) to both T2 (39.3 [5.3] cm; P = .010) and T3 (40.0 [5.3] cm; P = .001) and from T2 to T3 (P = .002). CMJ flight time:contraction time increased significantly over time (P = .004), with significant increases from T1 (0.747 [0.162]) to T2 (0.791 [0.163]; P = .012). Isometric midthigh-pull relative peak force improved significantly over time (P = .033), with significant increases from T1 (34.7 [5.0] N/kg) to T2 (35.9 [4.8] N/kg; P = .013). No significant changes were found between tapers. However, the higher-intensity taper produced small effect-size increases at T3 vs T1 for isometric midthigh-pull relative peak force, CMJ height, and flight time:contraction time, while the lower-intensity taper only produced small effect-size improvements at T3 vs T1 for CMJ height.

CONCLUSIONS

A strength-training taper with volume reductions had a positive effect on power, with a tendency for the higher-intensity taper to produce more favorable changes in strength and power.

Strength Training Improves Metabolic Health Markers in Older Individual Regardless of Training Frequency

The main purpose of the present study was to investigate the effect of frequency, thereby increasing training volume, of resistance training on body composition, inflammation markers, lipid and glycemic profile in healthy older individuals (age range 65–75 year). Ninety-two healthy participants were randomly assigned to one of four groups; performing strength training one- (EX1), two- (EX2), or three- (EX3) times-per-week and a non-training control (CON) group. Whole-body strength training was performed using 2–5 sets and 4–12 repetitions per exercise and 7–9 exercises per session. All training groups attended supervised resistance training for 6 months. Body composition was measured by dual X-ray absorptiometry and fasting blood samples were taken pre- and post-training. There were significant main effects of time for total fat mass (F = 28.12, P < 0.001) and abdominal fat mass (F = 20.72, P < 0.001). Pre- to post-study, statistically significant reductions in fat mass (Δ = -1.3 ± 1.4 kg, P < 0.001, n = 26) were observed in EX3. Pre- to post-study reductions in low density lipoprotein (LDL) concentration (Δ = -0.38 ± 0.44 mmol⋅L^-1, P = 0.003, n = 19) were observed only in EX3, whereas a significant pre- to post-study increases in high density lipoprotein (HDL) concentration (0.14–0.19 mmol⋅L^-1) were observed in all training groups. Most variables at baseline demonstrated a significant (negative) relationship when correlating baseline values with their change during the study including: Interleukin-6 (IL-6) (r = -0.583, P < 0.001), high-sensitivity c-reactive protein (hs-CRP) (r = -0.471, P < 0.001, and systolic blood pressure (r = -0.402, P = 0.003). The present study suggests that having more than two resistance training sessions in a week could be of benefit in the management of body composition and lipid profile. Nevertheless, interestingly, and importantly, those individuals with a higher baseline in systolic blood pressure, IL-6 and hs-CRP derived greatest benefit from the resistance training intervention, regardless of how many times-a-week they trained. Finally, the present study found no evidence that higher training frequency would induce greater benefit regarding inflammation markers or glycemic profile in healthy older adults.

The effect of red-fleshed pitaya ( Hylocereus polyrhizus) on heat shock protein 70 and cortisol expression in strenuous exercise induced rats

Background: Oxidative stress from exercise can contribute to damaging cells, increasing heat shock protein 70 (HSP70) and suppressing the immune system in the body. This research aimed to determine the antioxidant potential of red-fleshed pitaya extract on HSP70 and cortisol expression in rats which were subjected to strenuous exercise. Methods: The subjects of this research were 32 Sprague Dawley male rats, aged 3 months, with an average weight of 200 g. Red-fleshed pitaya extract was obtained from methanol extraction process; a maceration technique was performed and the extract was concentrated using an air-drying method. Rats were randomly divided into four groups. Group 1 were subjected to strenuous exercise and treated with distilled water only; while Groups 2, 3 and 4 were subjected to strenuous exercise and treated with 100 mg/kg body weight, 200 mg/kg body weight and 300 mg/kg body weight of red-fleshed pitaya extract, respectively. Strenuous exercises in rats was performed by intense swimming of 20 min/day, 3 days a week for 3 weeks. HSP70 expression and cortisol were measured with Enzyme-Linked Immune Sorbent Assay (ELISA) method. Results: There was a significant reduction of HSP70 (p=0.000) and cortisol expression (p=0.000) between the groups. Also, there was a significant difference in the average decreasing of HSP70 expression between group 4 and either groups 1 or 2 (p=0.000). However, a significant difference between groups 4 and 3 was not observed (p=0.813). Lastly, a significant difference was found in the average decrease of cortisol expression between groups 4 and 1 (p=0.000), 2 (p=0.000), and 3 (p=0.000) respectively. Conclusion: Red-fleshed pitaya is potential to be utilized as antioxidant to decrease the HSP70 and cortisol expression.

The effect of red-fleshed pitaya ( Hylocereus polyrhizus) on heat shock protein 70 and cortisol expression in strenuous exercise induced rats

Background: Oxidative stress from exercise can contribute to damaging cells, increasing heat shock protein 70 (HSP70) and suppressing the immune system in the body. This research aimed to determine the antioxidant potential of red-fleshed pitaya extract on HSP70 and cortisol expression in rats which were subjected to strenuous exercise. Methods: The subjects of this research were 32 Sprague Dawley male rats, aged 3 months, with an average weight of 200 g. Red-fleshed pitaya extract was obtained from methanol extraction process; a maceration technique was performed and the extract was concentrated using an air-drying method. Rats were randomly divided into four groups. Group 1 were subjected to strenuous exercise and treated with distilled water only; while Groups 2, 3 and 4 were subjected to strenuous exercise and treated with 100 mg/kg body weight, 200 mg/kg body weight and 300 mg/kg body weight of red-fleshed pitaya extract, respectively. Strenuous exercises in rats was performed by intense swimming of 20 min/day, 3 days a week for 3 weeks. HSP70 expression and cortisol were measured with Enzyme-Linked Immune Sorbent Assay (ELISA) method. Results: There was a significant reduction of HSP70 (p=0.000) and cortisol expression (p=0.000) between the groups. Also, there was a significant difference in the average decreasing of HSP70 expression between group 4 and either groups 1 or 2 (p=0.000). However, a significant difference between groups 4 and 3 was not observed (p=0.813). Lastly, a significant difference was found in the average decrease of cortisol expression between groups 4 and 1 (p=0.000), 2 (p=0.000), and 3 (p=0.000) respectively. Conclusion: Red-fleshed pitaya is potential to be utilized as antioxidant to decrease the HSP70 and cortisol expression.

Lifting cognition: a meta-analysis of effects of resistance exercise on cognition

The health benefits of resistance exercises are well established; however, the effects of resistance training on cognition are not as well understood. The purpose of this meta-analysis was to evaluate the evidence of resistance exercise's effects on cognition. A systematic search identified 24 studies that were included in the analyses. These articles ranged in the protocols utilized and in how they studied the effects of resistance training on cognition. Four primary analyses were carried out to assess the effects of resistance exercise on cognitive outcomes: (1) composite cognitive scores, (2) screening measures of cognitive impairment, (3) measures of executive functions, and (4) measures of working memory. Results revealed positive effects of resistance training on composite cognitive scores (SMD 0.71, 95% CI 0.30-1.12), screening measures of cognitive impairment (SMD 1.28, 95% CI 0.39-2.18), and executive functions (SMD 0.39, 95% CI 0.04-0.74), but no effect on measures of working memory (SMD 0.151, 95% CI - 0.21 to 0.51). High heterogeneity was observed in all analyses. Resistance training appears to have positive effects on cognition; however, future research will need to determine why the effects are so variable.

Effects of bilateral or unilateral lower body resistance exercises on markers of skeletal muscle damage

BACKGROUND

It is known that different intensity exercises create skeletal muscle damage at different levels. The purpose of the study was to compare effects of bilateral or unilateral lower body resistance exercise on markers of skeletal muscle damage.

METHODS

The Brzycki Formula was used to calculate participants' one repetition maximum strength for each movement and limb, separately. Blood samples were obtained before exercise, immediately after exercise, and 30 min after exercise for both types of exercise. Creatine Kinase (CK), Lactate Dehydrogenase (LDH), Aspartate Aminotransferase (AST), and Alanine Aminotransferase (ALT) levels were analyzed. Data was analyzed using two-way repeated measures ANOVA.

RESULTS

When CK, AST, and ALT levels were compared according to time points, a statistical difference was found (p < 0.05). Furthermore, it was revealed that LDH levels were statistically significant according to exercise types (p < 0.05).

CONCLUSION

Unilateral lower body resistance exercise caused higher skeletal muscle damage than the bilateral lower body resistance exercise. This result suggests that unilateral lower body resistance exercise should be preferred for short preparation period as opposed to bilateral lower body resistance exercise.

Blood Biomarkers in Sports Medicine and Performance and the Future of Metabolomics

The field of sports medicine and performance has undergone an important transformation in the past years where the scientific approach is becoming increasingly more important for teams and athletes. Physical and physiological fitness, nutrition, fatigue and recovery, as well as injury prevention are key elements of the scientific monitoring of athletes nowadays. Many different methods are used nowadays as part of the scientific monitoring and testing of the competitive athlete. Among them, physiological and metabolic testing, biomechanical and movement assessments, GPS-based tracking systems, heart rate monitors, power meters, and training software are an integrative part of the scientific monitor program of many teams and athletes.Blood biomarkers through traditional blood analysis have been used for over three decades (mainly in Europe) to monitor athletic performance. In the same manner that different cells in the body respond to the stress of an infection or a disease, cells in athletes respond to the stress of competition and training. Nowadays, the area of blood biomarkers is an emerging field in the US offering important level of possibilities to monitor athletes. The field of metabolomics can offer a significantly higher level of blood biomarkers for sports medicine and performance monitoring.

Influence of Resistance Exercise on Appetite and Affect Following Pre-Sleep Feeding

To determine changes in appetite, affect and cortisol in response to an acute bout of resistance exercise (RE) the morning after consuming whey (WP) and casein (CP) protein and a non-caloric placebo (PLA) consumed pre-sleep, 14 active men (n = 5) and women (n = 9) consumed a single dose of 24 g WP, 48 g WP, 24 g CP, 48 g CP, or PLA 30 min pre-sleep. Prior to and immediately after RE, appetite, affect and cortisol were assessed. Significant time effects were observed for Energetic Arousal and Tense Arousal (p = 0.017) and Feeling Scale and Felt Arousal Scale (p < 0.001). Appetite did not change over time or condition. Cortisol levels increased after RE (p = 0.007). Pre-RE, Tense Arousal was correlated with hunger (r = 0.25, p = 0.047) and desire to eat (r = 0.35, p = 0.005). Post-RE, cortisol was found to be significantly related to Feeling Scale (r = 0.32, p = 0.018), Felt Arousal Scale (r = 0.33, p = 0.015) and Energetic Arousal (r = 0.32, p = 0.018). Varying doses of WP and CP pre-sleep did not have an effect on morning appetite and cortisol, but cortisol was found to be related to affect and appetite.

Endocrine responses following exhaustive strength exercise with and without the use of protein and protein-carbohydrate supplements

The aim of this study was to determine the effect of carbohydrate-protein supplementation with whey protein (CHO-PROw) after resistance training, and casein protein (PROc) before bedtime on the concentration of growth hormone (GH), insulin (I) and insulin-like growth factor (IGF-1), as well as serum creatine kinase (CK) activity. Twelve strength trained male subjects (age: 25.8 ± 4.7 years; training experience 6.1 ± 0.79 years; body mass 75.9 ± 2.7 kg; body height 171.8 ± 13.3 cm) were recruited for the study. They were randomly divided into an experimental group (group E, n = 6) and a control group (group C, n = 6). All study participants completed full barbell squats with a constant external load of 90% one-repetition maximum (1RM) and a volume of 12 sets. In each set three repetitions were performed with 3 min rest periods after each set. Immediately after the exercise protocol, the subjects from the experimental group received a carbohydrate-protein complex (CHO-PROw) with a dose of 0.5 g/kg of body mass, while before bedtime they ingested a protein supplement (PROc) consisting of 90% casein protein with a dose of 0.3 g/kg of body weight The results indicate that a ignificant increase in GH concentration occurred in the experimental group between the pre-exercise level and after 24 h of recovery (p<0.01), as well as between 1 h and 24 hours of recovery (p<0.01). Significantly higher levels of GH were also found between the control group and the experimental group 24 hours after exercise (p<0.01). The results showed significantly higher levels of IGF-1 in the experimental than in the control group after 24 hours of recovery (p<0.05). In the case of insulin, no significant differences were observed when comparing levels before exercise, after exercise, after 1 hour of recovery and after 24 hours of recovery. The CHO-PROw and the PROc supplements did not reduce post-exercise muscle membrane damage as evidenced by serum CK activity. The intake of these supplements after high-intensity resistance exercise caused an increase in GH and IGF-1 concentration, which could stimulate muscle hypertrophy and inhibit proteolysis.

Sport, doping and male fertility

It is universally accepted that lifestyle interventions are the first step towards a good overall, reproductive and sexual health. Cessation of unhealthy habits, such as tobacco, alcohol and drug use, poor nutrition and sedentary behavior, is suggested in order to preserve/improve fertility in humans. However, the possible risks of physical exercise per se or sports on male fertility are less known. Being "fit" does not only improve the sense of well-being, but also has beneficial effects on general health: in fact physical exercise is by all means a low-cost, high-efficacy method for preventing or treating several conditions, ranging from purely physical (diabetes and obesity) to psychological (depression and anxiety), highly influencing male reproduction. If male sexual and reproductive health could be positively affected by a proper physical activity, inadequate bouts of strength - both excessive intensity and duration of exercise training - are more likely to have detrimental effects. In addition, the illicit use of prohibited drugs (i.e. doping) has reached pandemic proportions, and their actions, unfortunately very often underestimated by both amateur and professional athletes, are known to disrupt at different levels and throughout various mechanisms the male hypothalamic-pituitary-gonadal axis, resulting in hypogonadism and infertility.

Effects of 4-Week Creatine Supplementation Combined with Complex Training on Muscle Damage and Sport Performance

Creatine supplementation has an ergogenic effect in an acute complex training bout, but the benefits of chronic creatine supplementation during long-term complex training remain unknown. The study aimed to evaluate the effects of 4-week complex training combined with creatine supplementation on sport performances and muscle damage biomarkers. Thirty explosive athletes were assigned to the creatine or placebo group, which consumed 20 g of creatine or carboxymethyl cellulose, respectively, per day for 6 days followed by 2 g of the supplements until the end of the study. After 6 days of supplementation, subjects performed tests of one repetition maximum (1-RM) strength of half squat and complex training bouts to determine the optimal individual post-activation potentiation time. Thereafter, all subjects performed a complex training programme consisting of six sets of 5-RM half squats and plyometric jumps 3 times per week for 4 weeks. Body composition, 30-m sprint and jump performances were assessed before and after the training period. Moreover, blood creatine kinase (CK) activity was analysed at the first and the last training bout. After the training, the 1-RM strength in the creatine group was significantly greater than in the placebo group (p < 0.05). CK activity after the complex training bout in the creatine group was significantly reduced compared with the placebo group (p < 0.05). No differences were noted for other variables. This study concluded that creatine supplementation combined with complex training improved maximal muscular strength and reduced muscle damage during training.

The effects of daily food ingestion on improved immune functions and health promotion of bodybuilding athletes

The purpose of this study was to investigate the effects of different weight reduction methods on the body composition characteristics, cardiopulmonary functions, and health promotion of elite bodybuilding athletes in a comprehensive manner. For this purpose, the study analyzed the effects of two different weight reduction methods on 25 elite bodybuilding athletes registered at the Bodybuilding Association over a period of 6 weeks. There were interactive effects on macronutrients, macrominerals, and antioxidants according to weight reduction methods as the experiment group (6%±2%) maintained a certain amount of food intakes across various nutrients including energy intakes or made a slow decrease it, whereas the traditional group (16%±4%) made a sharp decrease in it due to relatively greater weight reduction than the experiment group and thus showed pattern differences from it. As for immunity variables, there was an increase to certain cytokines despite the traditional high weight reduction method, but it caused no excessive reduction of immunity or rapid decrease to certain factors of body composition. In addition, there were no significant differences in main and interactive effects on the one-repetition maximum of bench press and squat, which are two functional indicators of health promotion. These findings imply that the low weight reduction method within the range of 6%±2% minimized or maintained changes to muscle circumference or mass while causing no improvement to muscular strength.

Protocol for a phase III RCT and economic analysis of two exercise delivery methods in men with PC on ADT

BACKGROUND

Androgen deprivation therapy (ADT) is commonly used to treat prostate cancer. However, side effects of ADT often lead to reduced quality of life and physical function. Existing evidence demonstrates that exercise can ameliorate multiple treatment-related side effects for men on ADT, yet adherence rates are often low. The method of exercise delivery (e.g., supervised group in-centre vs. individual home-based) may be important from clinical and economic perspectives; however, few studies have compared different delivery models. Additionally, long-term exercise adherence and an understanding of predictors of adherence are critical to achieving sustained benefits, but such data are lacking. The primary aim of this multi-centre phase III non-inferiority randomized controlled trial is to determine whether a home-based delivery model is non-inferior to a group-based delivery model in terms of benefits in fatigue and fitness in this population. Two other key aims include examining cost-effectiveness and long-term adherence.

METHODS

Men diagnosed with prostate cancer of any stage, starting or continuing on ADT for at least 6 months, fluent in English, and living close to a study centre are eligible. Participants complete five assessments over 12 months (baseline and every 3 months during the 6-month intervention and 6-month follow-up phases), including a fitness assessment and self-report questionnaires. Biological outcomes are collected at baseline, 6, and 12 months. A total of 200 participants will be randomized in a 1:1 fashion to supervised group training or home-based training supported by smartphones, health coaches, and Fitbit technology. Participants are asked to complete 4 to 5 exercise sessions per week, incorporating aerobic, resistance and flexibility training. Outcomes include fatigue, quality of life, fitness measures, body composition, biological outcomes, and program adherence. Cost information will be obtained using patient diary-based self-report and utilities via the EQ-5D.

DISCUSSION

To disseminate publicly funded exercise programs widely, clinical efficacy and cost-effectiveness have to be demonstrated. The goals of this trial are to provide these data along with an increased understanding of adherence to exercise among men with prostate cancer receiving ADT.

TRIAL REGISTRATION

The trial has been registered at clinicaltrials.gov (Registration # NCT02834416 ). Registration date was June 2, 2016.

V, Kulkarni S, Diwekar-Joshi M, Watve M. Inferring causal pathways among three or more variables from steady-state correlations in a homeostatic system

Cross-sectional correlations between two variables have limited implications for causality. We examine here whether it is possible to make causal inferences from steady-state data in a homeostatic system with three or more inter-correlated variables. Every putative pathway between three variables makes a set of differential predictions that can be tested with steady state data. For example, among 3 variables, A, B and C, the coefficient of determination, rAC2 is predicted by the product of rAB2 and rBC2 for some pathways, but not for others. Residuals from a regression line are independent of residuals from another regression for some pathways, but positively or negatively correlated for certain other pathways. Different pathways therefore have different prediction signatures, which can be used to accept or reject plausible pathways using appropriate null hypotheses. The type 2 error reduces with sample size but the nature of this relationship is different for different predictions. We apply these principles to test the classical pathway leading to a hyperinsulinemic normoglycemic insulin-resistant, or pre-diabetic, state using four different sets of epidemiological data. Currently, a set of indices called HOMA-IR and HOMA-β are used to represent insulin resistance and glucose-stimulated insulin response by β cells respectively. Our analysis shows that if we assume the HOMA indices to be faithful indicators, the classical pathway must in turn be rejected. In effect, among the populations sampled, the classical pathway and faithfulness of the HOMA indices cannot be simultaneously true. The principles and example shows that it is possible to infer causal pathways from cross sectional correlational data on three or more correlated variables.

The effects of nutrient timing on training adaptations in resistance-trained females

OBJECTIVES

The purpose of this study was to determine the effects of pre- vs. post-workout nutrition on strength, body composition, and metabolism in trained females over 6 weeks of high intensity resistance training (HIRT).

DESIGN

Forty-three trained females (mean±SD; age: 20.5±2.2 yrs; height: 165.2±5.7cm; body mass: 66.5±11.4kg) were measured for strength, body composition, and metabolic variables before and after a HIRT intervention. Participants were randomized using a 2:2:1 matched block randomization scheme by baseline leg press strength into a group that consumed a 1:1.5 carbohydrate-protein supplement (16g CHO/25g PRO) pre-training (PRE), post-training (POST), or no supplement (CON).

METHODS

Dual-energy X-ray absorptiometry was used to evaluate fat mass (FM), lean mass (LM), and percent fat (%fat). Strength was analyzed using a one repetition max on the leg and bench press (LP1RM and BP1RM, respectively). Participants completed HIRT twice per week for 6 weeks. At the first and last trainings, metabolic variables [resting energy expenditure (REE) and respiratory exchange ratio, RER] were measured.

RESULTS

There were no significant differences between groups for any changes in body composition variables or LP1RM (p=0.170-0.959). There were significant differences for BP1RM (p=0.007), with PRE and POST experiencing greater increases than CON (p=0.010 and 0.015, respectively). REE changes were not significant between groups (p=0.058-0.643). PRE demonstrated greater fat oxidation (RER) at 30min post-exercise (p=0.008-0.035).

CONCLUSION

Peri-workout nutrition is potentially important for upper body strength and metabolism. PRE may be more effective for promoting fat utilization immediately post-workout.

Effects of Protein Supplementation on Performance and Recovery in Resistance and Endurance Training

There is robust evidence which shows that consuming protein pre- and/or post-workout induces a significant rise in muscle protein synthesis. It should be noted, however, that total daily caloric and protein intake over the long term play the most crucial dietary roles in facilitating adaptations to exercise. However, once these factors are accounted for, it appears that peri-exercise protein intake, particularly in the post-training period, plays a potentially useful role in terms of optimizing physical performance and positively influencing the subsequent recovery processes for both resistance training and endurance exercise. Factors that affect the utility of pre- or post-workout feeding include but are not necessarily limited to: training status (e.g., novice vs. advanced, or recreational vs. competitive athlete), duration of exercise, the number of training sessions per day, the number of competitive events per day, etc. From a purely pragmatic standpoint, consuming protein post-workout represents an opportunity to feed; this in turn contributes to one's total daily energy and protein intake. Furthermore, despite recent suggestions that one does not “need” to consume protein during the immediate (1 h or less) post-training time frame, it should be emphasized that consuming nothing offers no advantage and perhaps even a disadvantage. Thus, based on performance and recovery effects, it appears that the prudent approach would be to have athletes consume protein post-training and post-competition.

Effects of blood flow restriction during moderate-intensity eccentric knee extensions

We investigated if blood flow restriction (BFR, cuff pressure 20 mmHG below individual occlusion pressure) increases metabolic stress, hormonal response, release of muscle damage markers, and muscle swelling induced by moderate-intensity eccentric contractions. In a randomized, matched-pair design, 20 male subjects (25.3 ± 3.3 years) performed four sets of unilateral eccentric knee extensions (75% 1RM) to volitional failure with (IG) or without (CG) femoral BFR. Despite significant differences of performed repetitions between IG (85.6 ± 15.4 repetitions) and CG (142.3 ± 44.1 repetitions), peak values of lactate (IG 7.0 ± 1.4 mmol l-1, CG 6.9 ± 2.7 mmol l-1), growth-hormone (IG 4.9 ± 4.8 ng ml-1, CG 5.2 ± 3.5 ng ml-1), insulin-like growth factor 1 (IG 172.1 ± 41.9 ng ml-1, CG 178.7 ± 82.1 ng ml-1), creatine-kinase (IG 625.5 ± 464.8 U l-1, CG 510.7 ± 443.5 U l-1), the absolute neutrophil count (IG 7.9 ± 1.3 103 µl-1, CG 8.7 ± 2.0 103 µl-1), induced muscle swelling of rectus femoris and vastus lateralis and perceived pain did not differ. The present data indicate that BFR is suitable to intensify eccentric exercises.

Acute effects of whole body vibration combined with blood restriction on electromyography amplitude and hormonal responses

The purpose of this study was to investigate the effects of whole body vibration (WBV) exercise with and without blood flow restriction (BFR) on electromyography (EMG) amplitude and hormonal responses. Eight healthy male adults who lacked physical activity participated in this study and completed 10 sets of WBV and WBV + BFR sessions in a repeated measures crossover design. In the WBV + BFR session, the participants wore a BFR device inflated to 140 mmHg around the proximal region of the thigh muscles. The results indicated that the EMG values from the rectus femoris and vastus lateralis during the WBV + BFR session were significantly higher than those during the WBV session (p < 0.05). Two-way analysis of variance with repeated measures showed that the WBV + BFR and WBV exercise sessions induced a significant (simple main effect for time) increase in lactate (LA) (0.61–4.68 vs. 0.46–3.44 mmol/L) and growth hormone (GH) (0.48–3.85 vs. 0.47–0.82 ng/mL) responses after some of the post-exercise time points (p < 0.05). WBV + BFR elicited significantly higher LA and GH (simple main effect for trial) responses than did WBV after exercise (p < 0.05). Although no significant time × trial interactions were observed for testosterone (T) (604.5–677.75 vs. 545.75–593.88 ng/dL), main effects for trial (p < 0.05) and for time (p < 0.05) were observed. In conclusion, WBV + BFR produced an additive effect of exercise on EMG amplitude and LA and GH responses, but it did not further induce T responses compared to those with WBV alone.

ESTIMATING FATIGUE LEVEL OF FEMORAL AND GASTROCEMIUS MUSCLES BASED ON SURFACE ELECTROMYOGRAPHY IN TIME AND FREQUENCY DOMAIN

This paper presents a new method for estimating muscle fatigue level based on surface electromyography (EMG) of femoral and gastrocnemius muscles during repetitive motions with various load. The relationship between fatigue level and EMG signals was examined through repetitive movements of the femoral and gastrocnemius muscles with the use of leg extension and squat machines. The fatigue level was based on the maximum voluntary contraction (MVC) levels with various loads. The integrated EMG (IEMG) value and the mean frequency value for each load cycle were obtained through the surface EMG signal. This work presents a global EMG index map by using the new analytical technique based on the relationship between the average IEMG and mean power frequency (MPF) values. The proposed method enables simultaneous estimation of muscle fatigue level and force using real-time EMG signals from the femoral and gastrocnemius muscles.

Soy protein supplementation is not androgenic or estrogenic in college-aged men when combined with resistance exercise training

It is currently unclear as to whether sex hormones are significantly affected by soy or whey protein consumption. Additionally, estrogenic signaling may be potentiated via soy protein supplementation due to the presence of phytoestrogenic isoflavones. Limited also evidence suggests that whey protein supplementation may increase androgenic signaling. Therefore, the purpose of this study was to examine the effects of soy protein concentrate (SPC), whey protein concentrate (WPC), or placebo (PLA) supplementation on serum sex hormones, androgen signaling markers in muscle tissue, and estrogen signaling markers in subcutaneous (SQ) adipose tissue of previously untrained, college-aged men (n = 47, 20 ± 1 yrs) that resistance trained for 12 weeks. Fasting serum total testosterone increased pre- to post-training, but more so in subjects consuming WPC (p < 0.05), whereas serum 17β-estradiol remained unaltered. SQ estrogen receptor alpha (ERα) protein expression and hormone-sensitive lipase mRNA increased with training regardless of supplementation. Muscle androgen receptor (AR) mRNA increased while ornithine decarboxylase mRNA (a gene target indicative of androgen signaling) decreased with training regardless of supplementation (p < 0.05). No significant interactions of supplement and time were observed for adipose tissue ERα/β protein levels, muscle tissue AR protein levels, or mRNAs in either tissue indicative of altered estrogenic or androgenic activity. Interestingly, WPC had the largest effect on increasing type II muscle fiber cross sectional area values (Cohen's d = 1.30), whereas SPC had the largest effect on increasing this metric in type I fibers (Cohen's d = 0.84). These data suggest that, while isoflavones were detected in SPC, chronic WPC or SPC supplementation did not appreciably affect biomarkers related to muscle androgenic signaling or SQ estrogenic signaling. The noted fiber type-specific responses to WPC and SPC supplementation warrant future research.

Testosterone and Cortisol Responses to Five High-Intensity Functional Training Competition Workouts in Recreationally Active Adults

To determine the salivary steroid response to high-intensity functional training (HIFT) competition workouts, saliva samples were collected from ten recreationally trained male and female competitors during a 5-week (WK1–WK5) international competition. Competitors arrived at their local affiliate and provided samples prior to (PRE) their warm-up, immediately (IP), 30-min (30P), and 60-min (60P) post-exercise. Samples were analyzed for concentrations of testosterone (T), cortisol (C), and their ratio (TC). Generalized linear mixed models with repeated measures revealed significant main effects for time (p < 0.001) for T, C, and TC. Compared to PRE-concentrations, elevated (p < 0.05) T was observed at IP on WK2–WK5 (mean difference: 135–511 pg·mL⁻¹), at 30P on WK3 (mean difference: 81.0 ± 30.1 pg·mL⁻¹) and WK5 (mean difference: 56.6 ± 22.7 pg·mL⁻¹), and at 60P on WK3 (mean difference: 73.5 ± 29.7 pg·mL⁻¹) and WK5 (mean difference: 74.3 ± 28.4 pg·mL⁻¹). Compared to PRE-concentrations, elevated (p < 0.05) C was noted on all weeks at IP (mean difference: 9.3–15.9 ng·mL⁻¹) and 30P (mean difference: 6.0–19.9 ng·mL⁻¹); significant (p < 0.006) elevations were noted at 60P on WK1 (mean difference: 9.1 ± 3.0 ng·mL⁻¹) and WK5 (mean difference: 12.8 ± 2.9 ng·mL⁻¹). Additionally, TC was significantly reduced from PRE-values by 61% on WK1 at 60P (p = 0.040) and by 80% on WK5 at 30P (p = 0.023). Differences in T, C, and TC were also observed between weeks at specific time points. Although each workout affected concentrations in T, C, and/or the TC ratio, changes appeared to be modulated by the presence of overload and workout duration. During periods of elevated training or competition, athletes and coaches may consider monitoring these hormones for consistency and as a means of assessing workout difficulty.

Low- and high-intensity one-week occlusion training improves muscle oxygen consumption and reduces muscle fatigue

BACKGROUND

Low-intensity resistance exercises with blood flow restriction have been shown is effective to increase muscular strength and hypertrophy. However, the effects of combined training: one-week occlusion training with various exercise intensities by using less occlusion pressure on muscle strength improvement, fatigability and their work capacity are not clear.

METHODS

Participants (N.=24) were middle-distance runners with 4-6 years of training experience. A control group without blood flow restriction (N.=12, age 23±1 years) and an experimental group with blood flow restriction (N.=12, age 22±1 years). In this study, the calf muscles were impacted by the training with occlusion 120 mmHg. We used intensive one-week daily training, whereby exercise intensity was gradually increased daily from 20% to 80% of maximal voluntary contraction (MVC) and then decreased to 60% by the end of the week.

RESULTS

MVC of foot flexion muscles after the one-week occlusion training in the experimental group and control group increased (P<0.05) by 5.6±1.3% and 5.3±1.2%, respectively. Meanwhile in experimental group work capacity improved only 2.4±3.5% (P>0.05) and in control group it significantly decreased 11.8±2.5% (P<0.05). StO2 decreased during exercise test from the baseline 100% to 45.2±4.3% before occlusion training and to 34.6±6.2% after the week of occlusion training (P<0.05).

CONCLUSIONS

Intensive one-week training with occlusion with varying intensity improves resistance to fatigue and recovery after training. This kind of training improves oxygen consumption while exercising.

El efecto de los programas de fuerza muscular sobre la capacidad funcional. Revisión sistemática

Introducción. El número de estudios relacionados con la fuerza muscular y la funcionalidad invitan al análisis en profundidad de sus resultados antes de su aplicación profesional.Objetivo. Desarrollar una revisión sistemática para la construcción de programas de actividad física centrados en el entrenamiento de fuerza muscular y la capacidad funcional de sedentarios entre los 19 y 79 años.Materiales y métodos. Se emplearon los parámetros PRISMA, Chocrane y de la Universidad de York para el diseño y ejecución de revisiones sistemáticas. Además, se garantizaron criterios de calidad y especificidad estrictos que permitieron identificar 14 categorías de análisis, de las cuales emergieron las pautas de programación que se informan en la revisión sistemática.Resultados. 49 estudios con nivel de evidencia 1+ (24%), 1- (33%), 2++ (4%), 2+ (29%) y 2- (10%) cumplieron con los criterios de selección establecidos y permitieron alimentar las 14 categorías propuestas y hacer una síntesis de contenido.Conclusión. Es posible elevar el efecto de los programas de actividad física sobre la fuerza muscular y la funcionalidad a partir de la identificación y consideración de unas variables de programación (categoría) básicas que se sustentan en la calidad de evidencia científica circulante.

Hypogonadotropic Hypogonadism in Men With Diabesity

One-third of men with obesity or type 2 diabetes have subnormal free testosterone concentrations. The lower free testosterone concentrations are observed in obese men at all ages, including adolescents at completion of puberty. The gonadotropin concentrations in these males are inappropriately normal; thus, these patients have hypogonadotropic hypogonadism (HH). The causative mechanism of diabesity-induced HH is yet to be defined but is likely multifactorial. Decreased insulin and leptin signaling in the central nervous system are probably significant contributors. Contrary to popular belief, estrogen concentrations are lower in men with HH. Men with diabesity and HH have more fat mass and are more insulin resistant than eugonadal men. In addition, they have a high prevalence of anemia and higher mortality rates than eugonadal men. Testosterone replacement therapy results in a loss of fat mass, gain in lean mass, and increase in insulin sensitivity in men with diabesity and HH. This is accompanied by an increase in insulin-signaling genes in adipose tissue and a reduction in inflammatory mediators that interfere with insulin signaling. There is also an improvement in sexual symptoms, anemia, LDL cholesterol, and lipoprotein (a). However, testosterone therapy does not consistently affect HbA_1c in men with diabetes. The effect of testosterone replacement on cardiovascular events or mortality in men with diabesity is not known and remains to be studied in prospective trials.

Role of androgens in energy metabolism affecting on body composition, metabolic syndrome, type 2 diabetes, cardiovascular disease, and longevity: lessons from a meta-analysis and rodent studies

Testosterone is a sex hormone produced by testicular Leydig cells in males. Blood testosterone concentrations increase at three time-periods in male life-fetal, neonatal (which can be separated into newborn and infant periods), and pubertal stages. After peaking in the early 20s, the blood bioactive testosterone level declines by 1-2% each year. It is increasingly apparent that a low testosterone level impairs general physical and mental health in men. Here, this review summarizes recent systematic reviews and meta-analyses of epidemiological studies in males (including cross-sectional, longitudinal, and androgen deprivation studies, and randomized controlled testosterone replacement trials) in relation to testosterone and obesity,  body composition, metabolic syndrome, type 2 diabetes, cardiovascular disease, and longevity. Furthermore, underlying mechanisms are discussed using data from rodent studies involving castration or androgen receptor knockout. This review provides an update understanding of the role of testosterone in energy metabolism. Abbreviations AR: androgen receptor; CV: cardiovascular; FDA: US Food and Drug Administration; HFD: high-fat diet; KO: knockout; MetS: metabolic syndrome; RCT: randomized controlled trial; SHBG: sex hormone binding globulin; SRMA: systematic review and meta-analysis; TRT: testosterone replacement therapy; T2DM:type 2 diabetes mellitus.

Metabolic and hormonal responses to different resistance training systems in elderly men

OBJECTIVE

To compare acute and sub-acute responses in hormonal profile and metabolic parameters in elderly people who participated in two methods of strength training (ST) with equalized loads.

METHODS AND MATERIALS

A total of 12 elder individuals (65 ± 3 years) were randomly assigned to two training methods: constant intensity (CI, 3 sets of 10 repetitions with 75% of 1RM) and variable intensity (VI, 1st set: 12 repetitions at 67% of 1RM > 2nd set: 10 repetitions at 75% of 1RM and 3rd set: 8 repetitions at 80% of 1RM). Both methods included the following exercises: leg press, knee extension, and squat with 1 min rest intervals between sets. Free speed of execution and maximum range of movement were encouraged throughout each set for both protocols. Blood samples were analyzed included glucose, testosterone (T), cortisol (C), T/C rate, growth hormone (GH), and lactate at 2 and 24 h post intervention.

RESULTS

There were no observed differences in glucose, testosterone, GH, and lactate concentrations both at 2 and 24 h after the execution of the two training methods. However, significant increases in the levels of T/C rate and decrease on cortisol were observed immediately post exercise for both protocols.

CONCLUSIONS

Although no significant differences were observed between the two interventions in relation to the hormonal and metabolic parameters analyzed, both training methods promoted a favorable response, with a slight superiority noted for the CI method relative to the hormonal profile.

Hormonal responses to striking combat sports competition: a systematic review and meta-analysis

Striking combat sports are challenging, commonly stressing the endocrinological system based on a mixture of body-contact actions and physiological efforts. The aims of this systematic review and meta-analysis were to discuss the hormonal responses related to striking combat sports competitions and to investigate the moderator and mediator variables of the hormonal response-competition/outcome relationship. Three electronic databases (i.e., PubMed, Google Scholar and ScienceDirect) were systematically searched (up to February 2016) followed by a manual search of retrieved papers. The data showed a moderate increase in cortisol (C) (ES = 0.79; 95% CI 0.31-1.28; p = 0.001), an extremely large increase in adrenaline (ES = 4.22; 95% CI 2.62-5.82; p < 0.001), and a very large increase in noradrenaline (ES = 3.40; 95% CI 1.03-5.76; p = 0.005) and human growth hormone (HGH) levels (ES = 3.69; 95% CI 1.96-5.42; p < 0.001) immediately following the combat events, compared to the control condition i.e., "pre-combat". Furthermore, amateur athletes had a larger increase in C levels compared to highly trained athletes (ES = 2.91 [very large] vs ES = 0.56 [small]), while evening events showed greater alterations in C levels compared to morning events (ES = 1.91 [large] vs ES = 0.48 [small]), without significant differences between them (p = 0.26 and p = 0.06, respectively). The present meta-analysis also showed a small, insignificant increase in testosterone (T) (ES = 0.47 [small]; 95% CI -0.45-0.99; p = 0.074) and a decrease in insulin-like growth factor 1 levels (ES = -0.20 [trivial]; 95% CI -0.78-0.37; p = 0.486) immediately following the combat events, compared to the control condition. The type of combat sports practised, participants' gender, and the nature of competition contests (i.e., official vs simulation) did not moderate the relationship between competition and hormonal response. Additionaly, sub-analysis results showed a significant difference between younger and older athletes (Q = 4.05, p = 0.044), suggesting that after combat, younger individuals (less than 17 years of age) had a small decrease in T levels (ES = -0.58), compared with the moderate increase observed in older individuals (ES = 0.76). In conclusion, irrespective of striking combat sports types, the results showed that both official and simulated bouts are a real stressor of the hormonal system of practitioners. Coaches and applied practitioners should adopt "pre-competitive cognitive/coping strategies" to improve the psychological state that mediates the hormonal changes-competition/outcome relationship of their athletes in order to mitigate athletes' stress.