Hormonal responses to consecutive days of heavy-resistance exercise with or without nutritional supplementation

[Premenstrual dysphoric disorder (PMDD): Drug and psychotherapeutique management, a literature review]

INTRODUCTION

Premenstrual Dysphoric Disorder (PMDD) was first recognised in July 2013 in the DSM-5 after a long journey to identify its existence. It was not until 1983 that the US National Institute of Mental Health determined research criteria for the study of PMS. In 1994, the term "premenstrual dysphoric disorder" (PMDD) replaced this term in the 4th edition of the Diagnostic System Manual (DSM). It was listed in the section "Mood Disorder Not Otherwise Specified" and remained under consideration until the DSM-5, in which it appeared in the depressive disorders section. The legitimisation of the psychiatric diagnosis as well as the determination of clear symptomatology criteria in 2013 opened up possibilities for management, development of clinical, pathophysiological, therapeutic and psychotherapeutic studies. This disabling disorder can affect personal, social, family and professional life. In 2019, the ICD-11 in turn introduced the diagnosis of premenstrual dysphoric disorder, which solidifies the recognition of the disorder.

OBJECTIVE

(I) to review the existing treatments, both medicinal and psychotherapeutic, and (II) to review their effectiveness. At the end of this work we will formulate recommendations for the management of these patients.

METHODOLOGY

A bibliographic search was carried out from 7 June 2021 to 7 July2021 on the databases (bases de données) Psychinfo APA, Scopus, PubMed, as well as the bases de données of the Cochrane organisation and the recommendation documents of the Haute Autorité de la santé. After an initial selection based on keywords, the full text of all articles were read to arrive at the final selection of 32 articles.

RESULTS

Antidepressants and Cognitive Behavioural Therapies (CBT) appear to be the most commonly recommended treatments for PMDD. Other research shows the effectiveness of oral contraceptives including drospirenone. Selective serotonin reuptake inhibitors (SSRIs) were identified as an effective treatment for PMDD. These data are consistent with the current etiological hypothesis of PMDD which has a negative impact of natural hormonal fluctuations on certain neurotransmitters. CBT showed positive results in reducing the functional impact of PMDD.

DISCUSSION

Selective serotonin reuptake inhibitor (SSRI) antidepressants were reported to be first-line treatments for PMDD (sertraline 50-150 mg/d, fluoxetine 10-20 mg/d, escitalopram 10-20 mg/d, paroxetine 12.5-25 mg/d). Drospirenone (EE 3 mg and EE 20 mg/d 24 days of hormonal pills, 4 days inactive) appears to have been a first or second line treatment depending on the articles. Current results clearly point to the effectiveness of CBT in helping to reduce: functional impairment, depressed mood, feelings of hopelessness, anxiety, mood swings, sensitivity, irritability, insomnia, conflict with others, impact of premenstrual symptoms on daily life, intensity of symptoms experienced, and symptom handicap. CBTs could also become a first-line treatment if there were to be more evidence of their effectiveness. In the future, it would seem useful to offer a psychotherapeutic treatment that can be reproduced and to multiply research with a high level of scientific comparability in order to clarify the place of CBT in the management of PMDD. Research on the etiopathology of the disorder and the optimal drug regimen is still ongoing. There is a need to develop appropriate psychotherapeutic techniques to support and accompany these patients.

CONCLUSION

In order to better evaluate treatments for PMDD, there is a need to homogenise studies on the subject at several levels: design, treatment doses, psychotherapeutic techniques, and evaluation measures. At present, some studies include both premenstrual syndrome (PMS) and PMDD patients. PMS and PMDD do not include the same symptoms, nor the same severity and potentially the same aetiology in the patients studied. In order to propose rigorous research that evaluates the effectiveness of treatments for PMDD and to properly support people with both these disorders, it seems essential to distinguish the two conditions. The role of the health practitioner is to be able to identify PMDD by differentiating it from other clinically related disorders. The patient must then be accompanied to make a choice of treatment adapted to her symptoms, their severity, her history, her plans for procreation, contraindications and her preferences. In 2021, the French National Authority for Health did not offer any guidelines or recommendations for the management of premenstrual dysphoric disorder. There is a need to develop research in France.

Effects of resistance training and protein supplementation interventions on muscle volume and muscle function: sex differences in humans

PURPOSE

This review aimed to identify differences in the effects of co-intervention with resistance training (RT) and protein supplementation according to sex and provide meaningful information for future research on the development of exercise programs to improve muscle volume and muscle function.

METHODS

PubMed, Science Direct, and Google Scholar were searched to identify clinical and nonclinical studies that assessed the effects of RT in older adults with sarcopenia; these studies were published between 1990 and 2023. Cross-sectional and double-blind studies (randomized controlled trials, RCTs) were examined in this review.

RESULTS

The effects of parallel intervention with RT and protein supplementation on muscle volume and physical function were found to differ according to sex. Both males and females had improvements in muscle strength, muscle mass, and physical function after RT and protein supplementation; however, many studies found a greater increase in muscle volume and function in males than in females. Such difference may be due to differences in physiological characteristics between males and females.

CONCLUSION

Based on the findings of this review, the effects of combined intervention with RT and protein supplementation on muscle strength, muscle mass, and physical function to differ according to sex. Owing to these sex differences in the response and physiological characteristics caused by the parallel intervention of RT and protein supplementation, such differences must be considered to maximize the effects of RT and protein supplementation.

Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions

Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.

Effects of 4-Week Tangeretin Supplementation on Cortisol Stress Response Induced by High-Intensity Resistance Exercise: A Randomized Controlled Trial

Objective: This study aimed to investigate the effects of 4-week tangeretin supplementation on the cortisol stress response induced by high-intensity resistance exercise.

Methods: A randomized controlled trial of twenty-four soccer players was conducted during the winter training season. The experimental group (EG) took the oral supplement with tangeretin (200 mg/day) and the control group (CG) took placebo for 4 weeks. Before and after the 4-week intervention, all players performed a high intensity bout of resistance exercise to stimulate their cortisol stress responses. Serum cortisol, adreno-corticotropic hormone (ACTH) and superoxide dismutase (SOD) were obtained by collecting blood samples before (PRE), immediately after (P0), and 10 (P10), 20 (P20) and 30 minutes (P30) after the exercise.

Results: The serum cortisol level (PRE, p = 0.017; P10, p = 0.010; P20, p = 0.014; P30, p = 0.007) and ACTH (P10, p = 0.037; P30, p = 0.049) of experimental group significantly decreased after the 4-week intervention. Compared with control group, EG displayed a significantly lower level of the serum cortisol (PRE, p = 0.036; P10, p = 0.031) and ACTH (P30, p = 0.044). Additionally, EG presented significantly higher superoxide dismutase activity level compared with CG at P30 (p = 0.044). The white blood cell of EG decreased significantly (PRE, p = 0.037; P30, p = 0.046) and was significantly lower than CG at P20 (p = 0.01) and P30 (p = 0.003).

Conclusion: Four-week tangeretin supplementation can reduce serum cortisol and ACTH, which may ameliorate the cortisol stress response in soccer players during high-intensity resistance exercise training. It can also enhance antioxidant capacity, accelerate the elimination of inflammation throughout the body, and shorten recovery time after high-intensity exercise.

Does Tribulus terrestris L. affect hormonal responses following high-intensity resistance exercise?

Study aim: To investigate the effect of a 2-week supplementation with Tribulus terrestris L. (TT) on the responses of testosterone, cortisol, and thyroid hormones including triiodothyronine (T3) and thyroxine (T4) following an intensive session of resistance exercise (RE).

Materials and methods: Twenty-two healthy non-athlete men (23.8 ± 3.1 years) participated in this study were divided into two groups and were randomly assigned to receive either TT supplementation (n = 11) or a placebo (n = 11). They consumed two 250-mg capsules with TT or placebo (maltodextrin) per day and performed six REs with the intensity 80-90% of 1RM on the fifteen day of the experiment. Venous blood samples were drawn before supplementation, and before and after the RE session.

Results: The mean values of post-exercise testosterone and cortisol in both groups were significantly higher than pre-exercise and baseline (p < 0.01); however, there were no significant differences between the groups (p > 0.05). Likewise, despite a trend toward different levels of the responses of thyroid hormones with TT supplementation, there were no significant differences either in different time points or the groups (p > 0.05).

Conclusions: Short-term supplementation with TT appears to be ineffective in changing the hormonal responses measured in this study following a session of high-intensity RE.

Fatigue, pain, and the recovery of neuromuscular function after consecutive days of full-body resistance exercise in trained men

PURPOSE

This study measured the self-reported level of fatigue, pain, and neuromuscular function of the knee extensor muscles over a three-day period that included two consecutive days of full-body resistance exercises.

METHODS

10 resistance-trained men performed two consecutive days of full-body resistance exercise. Muscle activation (electromyography and voluntary activation), contractility, and presynaptic inhibition of Ia afferents (homosynaptic and GABA mediated presynaptic inhibition) for the quadriceps were examined from femoral and posterior tibial nerve stimulation.

RESULTS

Fatigue and pain were elevated after Day 1, and were not reduced to pre-exercise levels at the start of Day 2 (p < 0.05). Maximal voluntary torque (- 51.4 Nm, 95% CI = 12.4-90.4 Nm, p = 0.005) and rate of torque development (- 469 Nm.s^-1, 95% CI = 109-829 Nm.s^-1, p = 0.006) were reduced after Day 1, had recovered by Day 2, and did not change after the second training session. The maximal amplitude and rate of rise for the quadriceps twitch were reduced after both training sessions (p < 0.01), with recovery 24 h each session. The maximal amplitude and rate of early muscle activation were reduced after Day 1 (p < 0.01), but no changes were observed for voluntary activation, H-reflex size and shape, or measures of Ia presynaptic inhibition.

CONCLUSION

Resistance exercise in the presence of elevated fatigue and pain from a previous training session does not worsen recovery, or lead to significant alterations in quadriceps neuromuscular function. Reduction in muscle contractility, in the absence of declines in muscle activation, does not lead to decreased voluntary torque.

Time Course of Recovery From Resistance Exercise With Different Set Configurations

Pareja-Blanco, F, Rodríguez-Rosell, D, Aagaard, P, Sánchez-Medina, L, Ribas-Serna, J, Mora-Custodio, R, Otero-Esquina, C, Yáñez-García, JM, and González-Badillo, JJ. Time course of recovery from resistance exercise with different set configurations. J Strength Cond Res 34(10): 2867-2876, 2020-This study analyzed the response to 10 resistance exercise protocols differing in the number of repetitions performed in each set (R) with respect to the maximum predicted number (P). Ten males performed 10 protocols (R(P): 6(12), 12(12), 5(10), 10(10), 4(8), 8(8), 3(6), 6(6), 2(4), and 4(4)). Three sets with 5-minute interset rests were performed in each protocol in bench press and squat. Mechanical muscle function (countermovement jump height and velocity against a 1 m·s load, V1-load) and biochemical plasma profile (testosterone, cortisol, growth hormone, prolactin, IGF-1, and creatine kinase) were assessed at several time points from 24-hour pre-exercise to 48-hour post-exercise. Protocols to failure, especially those in which the number of repetitions performed was high, resulted in larger reductions in mechanical muscle function, which remained reduced up to 48-hour post-exercise. Protocols to failure also showed greater increments in plasma growth hormone, IGF-1, prolactin, and creatine kinase concentrations. In conclusion, resistance exercise to failure resulted in greater fatigue accumulation and slower rates of neuromuscular recovery, as well as higher hormonal responses and greater muscle damage, especially when the maximal number of repetitions in the set was high.

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.

Effects of whey protein supplementation prior to, and following, resistance exercise on body composition and training responses: A randomized double-blind placebo-controlled study

PURPOSE

The composition of protein supplements, the consumption timing immedi¬ately before and after resistance exercise training (RET), and the quantity of protein supplementation may be important factors for the im-provement of muscle mass and function. Although these factors should be considered comprehensively for effective improvement of muscular function in protein supplementation, relatively few studies have focused on this area. Therefore, this study was designed to investigate whether a protein blend supplement before and after resistance exercise for 12 weeks would be effective in increasing muscular function.

METHODS

In total, 18 participants were randomly assigned to a placebo (PLA) or protein blend supplement (PRO) group. All subjects followed the same training routine 3 times per week for 12 weeks, taking placebo or protein supplements immediately before and after each exercise session. The protein supplement consisted of 40 g of blend protein, including hydrolyzed whey protein. The RET consisted of lower body (barbell squat, dead lift, seated leg extension, and lying leg curl) and upper body (bench press, barbell rowing, preacher bench biceps curl, and dumbbell shoulder press) exercises. A repetition was defined as three sets of 10-12 times with 80% of one repetition maximum (1RM).

RESULTS

Although the PRO group had a lower protein intake in terms of total food intake than the PLA group, the mean changes in muscle circumference, strength, and exercise volume increased, especially at week 12, compared to the PLA group.

CONCLUSION

These results suggest that the composition and timing of protein intake are more important than the total amount.

The Effects of Alcohol Consumption on Recovery Following Resistance Exercise: A Systematic Review

BACKGROUND

The aim of this manuscript was to describe the effects of alcohol ingestion on recovery following resistance exercise.

METHODS

A literature search was performed using the following database: Web of Science, NLM Pubmed, and Scopus. Studies regarding alcohol consumption after resistance exercise evaluating recovery were considered for investigation. The main outcomes took into account biological, physical and cognitive measures. Multiple trained researchers independently screened eligible studies according to the eligibility criteria, extracted data and assessed risk of bias.

RESULTS

A total of 12 studies were considered eligible and included in the quantitative synthesis: 10 included at least one measure of biological function, 10 included at least one measure of physical function and one included measures of cognitive function.

CONCLUSIONS

Alcohol consumption following resistance exercise doesn't seem to be a modulating factor for creatine kinase, heart rate, lactate, blood glucose, estradiol, sexual hormone binding globulin, leukocytes and cytokines, C-reactive protein and calcium. Force, power, muscular endurance, soreness and rate of perceived exertion are also unmodified following alcohol consumption during recovery. Cortisol levels seemed to be increased while testosterone, plasma amino acids, and rates of muscle protein synthesis decreased.

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.

ISSN exercise & sports nutrition review update: research & recommendations

Background

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. In the year 2017 alone, 2082 articles were published under the key words ‘sport nutrition’. Consequently, staying current with the relevant literature is often difficult.

Methods

This paper is an ongoing update of the sports nutrition review article originally published as the lead paper to launch the Journal of the International Society of Sports Nutrition in 2004 and updated in 2010. It presents a well-referenced overview of the current state of the science related to optimization of training and performance enhancement through exercise training and nutrition. Notably, due to the accelerated pace and size at which the literature base in this research area grows, the topics discussed will focus on muscle hypertrophy and performance enhancement. As such, this paper provides an overview of: 1.) How ergogenic aids and dietary supplements are defined in terms of governmental regulation and oversight; 2.) How dietary supplements are legally regulated in the United States; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of nutritional approaches to augment skeletal muscle hypertrophy and the potential ergogenic value of various dietary and supplemental approaches.

Conclusions

This updated review is to provide ISSN members and individuals interested in sports nutrition with information that can be implemented in educational, research or practical settings and serve as a foundational basis for determining the efficacy and safety of many common sport nutrition products and their ingredients.

Enhanced Strength and Sprint Levels, and Changes in Blood Parameters during a Complete Athletics Season in 800 m High-Level Athletes

The purpose of this study was to analyze changes in sprint, strength, hematological, and hormonal parameters in high-level 800 m athletes during a complete athletics season. Thirteen male athletes of national and international level in 800 m (personal best ranging from 1:43 to 1:58 min:ss) participated in this study. A total of 5 tests were conducted during a complete athletics season. Athletes performed sprint tests (20 and 200 m), countermovement jump (CMJ), jump squat (JS), and full squat (SQ) tests. Blood samples (red and white blood profile) and hormones were collected in test 1 (T1), test 3 (T3), and test 5 (T5). A general increase in the performance of the strength and sprint parameters analyzed (CMJ, JS, SQ, 20 m, and 200 m) during the season was observed, with a significant time effect in CMJ (P < 0.01), SQ (P < 0.01), and 200 m (P < 0.05). This improvement was accompanied by a significant enhancement of the 800 m performance from T3 to T5 (P < 0.01). Significant changes in some hematological variables: hematocrit (Hct) (P < 0.01), mean corpuscular volume (MCV) (P < 0.001), mean corpuscular hemoglobin content (MCHC) (P < 0.001), white blood cells count (WBC) (P < 0.05), neutrophils (P < 0.05), monocytes (P < 0.05), and mean platelet volume (MPV) (P < 0.05) were observed throughout the season. The hormonal response and creatin kinase (CK) did not show significant variations during the season, except for insulin-like growth factor I (IGF-1) (P < 0.05). In conclusion, our results suggest the importance of strength levels in middle-distance athletes. On the other hand, variations in some hematological parameters and a depression of the immune system occurred during the season. Therefore, monitoring of the mechanical, hematological and hormonal response in athletes may help coaches and athletes to optimize the regulation of training contents and may be useful to diagnose states of overreaching or overtraining in athletes throughout the season.

The Differential Hormonal Milieu of Morning versus Evening May Have an Impact on Muscle Hypertrophic Potential

Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol). Twenty-four male participants (age 21.4±1.9yrs, mass 83.7±13.7kg) with no sustained resistance training experience were allocated to a resistance exercise group (REP). Sixteen of the 24 participants were randomly selected to perform an additional non-exercising control group (CP) protocol. REP performed two bouts of resistance exercise (80% 1RM) in the morning (AM: 0800 hrs) and evening (PM: 1800 hrs), with the sessions separated by a minimum of 72 hours. Venous blood was collected immediately prior to, and 5 min after, each resistance exercise and control sessions. Serum cortisol and IGFBP-3 levels, myogenic index, myotube width, were determined at each sampling period. All data are reported as mean ± SEM, statistical significance was set at P≤0.05. As expected a significant reduction in evening cortisol concentration was observed at pre (AM: 98.4±10.5, PM: 49.8±4.4 ng/ml, P<0.001) and post (AM: 98.0±9.0, PM: 52.7±6.0 ng/ml, P<0.001) exercise. Interestingly, individual cortisol differences pre vs post exercise indicate a time-of-day effect (AM difference: -2±2.6%, PM difference: 14.0±6.7%, P = 0.03). A time-of-day related elevation in serum IGFBP-3 (AM: 3274.9 ± 345.2, PM: 3605.1 ± 367.5, p = 0.032) was also evident. Pre exercise myogenic index (AM: 8.0±0.6%, PM: 16.8±1.1%) and myotube width (AM: 48.0±3.0, PM: 71.6±1.9 μm) were significantly elevated (P<0.001) in the evening. Post exercise myogenic index was greater AM (11.5±1.6%) compared with PM (4.6±0.9%). No difference was observed in myotube width (AM: 48.5±1.5, PM: 47.8±1.8 μm) (P>0.05). Timing of resistance training regimen in the evening appears to augment some markers of hypertrophic potential, with elevated IGFBP-3, suppressed cortisol and a superior cellular environment. Further investigation, to further elucidate the time course of peak anabolic signalling in morning vs evening training conditions, are timely.

Concurrent Training Decreases Cortisol but Not Zinc Concentrations: Effects of Distinct Exercise Protocols

Objectives. To investigate the effects of distinct concurrent training (CT) protocols on zinc and cortisol concentrations and test the correlation between these blood variables. Methods. Samples of serum zinc and cortisol were assessed from 10 male subjects (27.1 ± 4.8 years old; BMI 25.38 ± 0.09) before and immediately after each study session: control (CS = no exercises), concurrent training 1 (CT1 = indoor cycling + strength training), and concurrent training 2 (CT2 = strength training + indoor cycle) with five days of interval between each. Results. There were no significant changes in zinc concentrations after the CS (Δ% = 8.45; p = 0.07), CT1 (Δ% = 4.77; p = 0.49), and CT2 (Δ% = -2.90; p = 0.12) sessions. Cortisol levels showed significant decrease after CS (Δ% = -6.02; p = 0.00), CT1 (Δ% = -26.32; p = 0.02), and CT2 (Δ% = -33.57; p = 0.05) sessions. There was a significant correlation between the variables only at CS (zinc post versus cortisol pre: r = 0.82 and cortisol post: r = 0.82). Conclusions. CT decreases cortisol concentrations regardless of the sequence performed. No changes were found in zinc concentrations after the study sessions. The reduction in serum cortisol concentrations appear to occur by a mechanism independent of the zinc status.

Protein supplementation does not alter intramuscular anabolic signaling or endocrine response after resistance exercise in trained men

The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway appears to be the primary regulator of muscle protein synthesis. A variety of stimuli including resistance exercise, amino acids, and hormonal signals activate mTORC1 signaling. The purpose of this study was to investigate the effect of a protein supplement on mTORC1 signaling following a resistance exercise protocol designed to promote elevations in circulating hormone concentrations. We hypothesized that the protein supplement would augment the intramuscular anabolic signaling response. Ten resistance-trained men (age, 24.7 ± 3.4 years; weight, 90.1 ± 11.3 kg; height, 176.0 ± 4.9 cm) received either a placebo or a supplement containing 20 g protein, 6 g carbohydrates, and 1 g fat after high-volume, short-rest lower-body resistance exercise. Blood samples were obtained at baseline, immediately, 30 minutes, 1 hour, 2 hours, and 5 hours after exercise. Fine-needle muscle biopsies were completed at baseline, 1 hour, and 5 hours after exercise. Myoglobin, lactate dehydrogenase, and lactate concentrations were significantly elevated after resistance exercise (P < .0001); however, no differences were observed between trials. Resistance exercise also elicited a significant insulin, growth hormone, and cortisol response (P < .01); however, no differences were observed between trials for insulin-like growth factor-1, insulin, testosterone, growth hormone, or cortisol. Intramuscular anabolic signaling analysis revealed significant elevations in RPS6 phosphorylation after resistance exercise (P = .001); however, no differences were observed between trials for signaling proteins including Akt, mTOR, p70S6k, and RPS6. The endocrine response and phosphorylation status of signaling proteins within the mTORC1 pathway did not appear to be altered by ingestion of supplement after resistance exercise in resistance-trained men.

Acute protease supplementation effects on muscle damage and recovery across consecutive days of cycle racing

Bromelain, a mixture of proteases obtained from pineapples, has been demonstrated to reduce exercise-induced muscle damage and inflammation, enhancing recovery. This investigation aimed to establish if markers of muscle damage and testosterone were influenced by acute bromelain supplementation in competitive cyclists taking part in a six-day cycle stage race. Fifteen highly trained cyclists [age: 22, [Formula: see text] = 1.2 years, height: 1.79, [Formula: see text] = 0.01 m, body mass: 68.69, [Formula: see text] = 1.97 kg] were supplemented with either bromelain (1000 mg·day(-1)) (n = 8) or a placebo (n = 7) across six days of competitive racing in a randomised, double-blind, placebo-controlled trial. Blood was collected from each cyclist on days one, three and six of racing and analysed for creatine kinase (CK), myoglobin, lactate dehydrogenase (LDH) and testosterone. CK activity (P < 0.001, d = 17.4-18.8), LDH activity (P < 0.004, d = 0.5-2.5) and myoglobin concentration (P < 0.007, d = 3.4-4.8) were elevated from pre-race on days three and six of racing in both groups. Testosterone concentrations were significantly lower on the final day of racing (P = 0.03, d = 1.3) and there was a trend for bromelain to maintain testosterone concentrations across the race period (P = 0.05, d = 1.04-1.70) when compared to placebo. Fatigue rating was lower in the bromelain group on day four of racing (P = 0.01). Consecutive days of competitive cycling were associated with increased markers of muscle damage and a reduction in circulating testosterone across the race period. Bromelain supplementation reduced subjective feelings of fatigue and was associated with a trend to maintain testosterone concentration.

Whey protein does not enhance the adaptations to elbow flexor resistance training

PURPOSE

It is unclear whether protein supplementation augments the gains in muscle strength and size observed after resistance training (RT) because limitations to previous studies include small cohorts, imprecise measures of muscle size and strength, and no control of prior exercise or habitual protein intake. We aimed to determine whether whey protein supplementation affected RT-induced changes in elbow flexor muscle strength and size.

METHODS

We pair-matched 33 previously untrained, healthy young men for their habitual protein intake and strength response to 3-wk RT without nutritional supplementation (followed by 6 wk of no training) and then randomly assigned them to protein (PRO, n = 17) or placebo (PLA, n = 16) groups. Participants subsequently performed elbow flexor RT 3 d · wk(-1) for 12 wk and consumed PRO or PLA immediately before and after each training session. We assessed elbow flexor muscle strength (unilateral 1-repetition maximum and isometric maximum voluntary force) and size (total volume and maximum anatomical cross-sectional area determined with magnetic resonance imaging) before and after the 12-wk RT.

RESULTS

PRO and PLA demonstrated similar increases in muscle volume (PRO 17.0% ± 7.1% vs PLA 14.9% ± 4.6%, P = 0.32), anatomical cross-sectional area (PRO 16.2% ± 7.1% vs PLA 15.6% ± 4.4%, P = 0.80), 1-repetition maximum (PRO 41.8% ± 21.2% vs PLA 41.4% ± 19.9%, P = 0.97), and maximum voluntary force (PRO 12.0% ± 9.9% vs PLA 14.5% ± 8.3%, P = 0.43).

CONCLUSIONS

In the context of this study, protein supplementation did not augment elbow flexor muscle strength and size changes that occurred after 12 wk of RT.

Triphasic multinutrient supplementation during acute resistance exercise improves session volume load and reduces muscle damage in strength-trained athletes

We hypothesized that triphasic multinutrient supplementation during acute resistance exercise would enhance muscular performance, produce a more favorable anabolic profile, and reduce biochemical markers of muscle damage in strength-trained athletes. Fifteen male strength-trained athletes completed two acute lower-body resistance exercise sessions to fatigue 7 days apart. After a 4-hour fast, participants consumed either a multinutrient supplement (Musashi 1-2-3 Step System, Notting Hill, Australia) (SUPP) or placebo (PLA) beverage preexercise (PRE), during (DUR), and immediately postexercise (IP). Session volume loads were calculated as kilograms × repetitions. Lower-body peak power was measured using unloaded repeated countermovement jumps, and blood samples were collected to assess biochemistry, serum hormones, and muscle damage markers at PRE, DUR, IP, 30 minutes postexercise (P30), and 24 hours postexercise (P24h). The SUPP demonstrated increased glucose concentrations at DUR and IP compared with at PRE (P < .01), whereas PLA demonstrated higher glucose at P30 compared with at PRE (P < .001). Session volume load was higher for SUPP compared with PLA (P < .05). Cortisol increased at DUR, IP, and P30 compared with at PRE in both treatments (P < .05); however, SUPP also displayed lower cortisol at P24h compared with at PRE and PLA (P < .01). The total testosterone response to exercise was higher for PLA compared with SUPP (P < .01); however, total creatine kinase and C-reactive protein responses to exercise were lower for SUPP compared with PLA (P < .05). These data indicate that although triphasic multinutrient supplementation did not produce a more favorable anabolic profile, it improved acute resistance exercise performance while attenuating muscle damage in strength-trained athletes.

Amino Acid-carbohydrate intake combined with multiple bouts of resistance exercise increases resting energy expenditure

Increasing the rate of muscle protein synthesis is an energy consuming process that explains the acute elevations in resting energy expenditure (REE) observed 12 to 72 hours after a resistance exercise session. We hypothesized that multiple sessions of resistance exercise combined with the intake of amino acids would increase REE and alter the nonprotein respiratory exchange ratio (RER). Ten male participants completed two separate seven-day trials where REE and RER were measured on each morning via indirect calorimetry. On four consecutive days within each seven-day trial, acute resistance exercise was performed, and nutritional intake was manipulated by providing (1) amino acids and carbohydrate (AA-RT) or (2) nonnitrogenous, isoenergetic carbohydrate (CHO-RT) before and during each resistance exercise session. Average REE within the training period was 3.61% greater in AA-RT (7897 ± 252 kJ) compared to CHO-RT (7622 ± 289 kJ; P = 0.02). RER declined (P < 0.0001) from baseline after each resistance exercise was initiated in both AA-RT (0.82 ± 0.01 to 0.77 ± 0.01) and CHO-RT (0.82 ± 0.02 to 0.77 ± 0.02). We conclude the provision of amino acids with multiple bouts of resistance exercise enhances energy expenditure at rest without altering the utilization of lipid.

The effects of soy and whey protein supplementation on acute hormonal reponses to resistance exercise in men

OBJECTIVE

For many resistance-trained men concerns exist regarding the production of estrogen with the consumption of soy protein when training for muscle strength and size. Thus, the purpose of this investigation was to examine the effects of soy and whey protein supplementation on sex hormones following an acute bout of heavy resistance exercise in resistance trained men.

METHODS

Ten resistance-trained men (age 21.7 ± 2.8 [SD] years; height 175.0 ± 5.4 cm; weight 84.2 ± 9.1 kg) volunteered to participate in an investigation. Utilizing a within subject randomized crossover balanced placebo design, all subjects completed 3 experimental treatment conditions supplementing with whey protein isolate (WPI), soy protein isolate (SPI), and maltodextrin placebo control for 14 days with participants ingesting 20 g of their assigned supplement each morning at approximately the same time each day. Following supplementation, subjects performed an acute heavy resistance exercise test consisting of 6 sets of 10 repetitions in the squat exercise at 80% of the subject's one repetition maximum.

RESULTS

This investigation observed lower testosterone responses following supplementation with soy protein in addition to a positive blunted cortisol response with the use of whey protein at some recovery time points. Although sex hormone binding globulin (SHBG) was proposed as a possible mechanism for understanding changes in androgen content, SHBG did not differ between experimental treatments. Importantly, there were no significant differences between groups in changes in estradiol concentrations.

CONCLUSION

Our main findings demonstrate that 14 days of supplementation with soy protein does appear to partially blunt serum testosterone. In addition, whey influences the response of cortisol following an acute bout of resistance exercise by blunting its increase during recovery. Protein supplementation alters the physiological responses to a commonly used exercise modality with some differences due to the type of protein utilized.

Circulating cell-free DNA: an up-coming molecular marker in exercise physiology

The phenomenon of circulating cell-free DNA (cfDNA) concentrations is of importance for many biomedical disciplines including the field of exercise physiology. Increases of cfDNA due to exercise are described to be a potential hallmark for the overtraining syndrome and might be related to, or trigger adaptations of, immune function induced by strenuous exercise. At the same time, exercise provides a practicable model for studying the phenomenon of cfDNA that is described to be of pathophysiological relevance for different topics in clinical medicine like autoimmune diseases and cancer. In this review, we are summarizing the current knowledge of exercise-based acute and chronic alterations in cfDNA levels and their physiological significance. The effects of acute exercise on cfDNA concentrations have been investigated in resistance exercises and in continuous, stepwise and interval endurance exercises of different durations. cfDNA concentrations peaked immediately after acute exercise and showed a rapid return to baseline levels. Typical markers of skeletal muscle damage (creatine kinase, uric acid, C-reactive protein) show delayed kinetics compared with the cfDNA peak response. Exercise parameters such as intensity, duration or average energy expenditure do not explain the extent of increasing cfDNA concentrations after strenuous exercise. This could be due to complex processes inside the human organism during and after physical activity. Therefore, we hypothesize composite effects of different physiological stress parameters that come along with exercise to be responsible for increasing cfDNA concentrations. We suggest that due to acute stress, cfDNA levels increase rapidly by a spontaneous active or passive release mechanism that is not yet known. As a result of the rapid and parallel increase of cfDNA and lactate in an incremental treadmill test leading to exhaustion within 15-20 minutes, it is unlikely that cfDNA is released into the plasma by typical necrosis or apoptosis of cells in acute exercise settings. Recently, rapid DNA release mechanisms of activated immune-competent cells like NETosis (pathogen-induced cell death including the release of neutrophil extracellular traps [NETs]) have been discovered. cfDNA accumulations might comprise a similar kind of cell death including trap formation or an active release of cfDNA. Just like chronic diseases, chronic high-intensity resistance training protocols induced persistent increases of cfDNA levels. Chronic, strenuous exercise protocols, either long-duration endurance exercise or regular high-intensity workouts, induce chronic inflammation that might lead to a slow, constant release of DNA. This could be due to mechanisms of cell death like apoptosis or necrosis. Yet, it has neither been implicated nor proven sufficiently whether cfDNA can serve as a marker for overtraining. The relevance of cfDNA with regard to overtraining status, performance level, and the degree of physical exhaustion still remains unclear. Longitudinal studies are required that take into account standardized and controlled exercise, serial blood sampling, and large and homogeneous cohorts of different athletic achievement. Furthermore, it is important to establish standardized laboratory procedures for the measurement of genomic cfDNA concentrations by quantitative real-time polymerase chain reaction (PCR). We introduce a new hypothesis based on acute exercise and chronic exposure to stress, and rapid active and passive chronic release of cfDNA fragments into the circulation.

Hormonal response to lipid and carbohydrate meals during the acute postprandial period

Background

Optimizing the hormonal environment during the postprandial period in favor of increased anabolism is of interest to many active individuals. Data are conflicting regarding the acute hormonal response to high fat and high carbohydrate feedings. Moreover, to our knowledge, no studies have compared the acute hormonal response to ingestion of lipid and carbohydrate meals of different size.

Methods

We compared the hormonal response to lipid and carbohydrate meals of different caloric content during the acute postprandial period. Nine healthy men (22 ± 2 years) consumed in a random order, cross-over design one of four meals/beverages during the morning hours in a rested and fasted state: dextrose at 75 g (300 kcals), dextrose at 150 g (600 kcals), lipid at 33 g (300 kcals), lipid at 66 g (600 kcals). Blood samples were collected Pre meal, and at 0.5 hr, 1 hr, 2 hr, and 3 hr post meal. Samples were assayed for testosterone, cortisol, and insulin using ELISA techniques. Area under the curve (AUC) was calculated for each variable, and a 4 × 5 ANOVA was used to further analyze data.

Results

A meal × time effect (p = 0.0003) was noted for insulin, with values highest for the dextrose meals at the 0.5 hr and 1 hr times, and relatively unaffected by the lipid meals. No interaction (p = 0.98) or meal (p = 0.39) effect was noted for testosterone, nor was an interaction (p = 0.99) or meal (p = 0.65) effect noted for cortisol. However, a time effect was noted for both testosterone (p = 0.04) and cortisol (p < 0.0001), with values decreasing during the postprandial period. An AUC effect was noted for insulin (p = 0.001), with values higher for the dextrose meals compared to the lipid meals (p < 0.05). No AUC effect was noted for testosterone (p = 0.85) or cortisol (p = 0.84).

Conclusions

These data indicate that 1) little difference is noted in serum testosterone or cortisol during the acute postprandial period when healthy men consume lipid and dextrose meals of different size; 2) Both testosterone and cortisol experience a drop during the acute postprandial period, which is similar to what is expected based on the normal diurnal variation--feeding with lipid or dextrose meals does not appear to alter this pattern; 3) dextrose meals of either 75 g or 150 g result in a significant increase in serum insulin, in particular at 0.5 hr and 1 hr post-ingestion; 4) lipid meals have little impact on serum insulin.

A review of weight control strategies and their effects on the regulation of hormonal balance

The estimated prevalence of obesity in the USA is 72.5 million adults with costs attributed to obesity more than 147 billion dollars per year. Though caloric restriction has been used extensively in weight control studies, short-term success has been difficult to achieve, with long-term success of weight control being even more elusive. Therefore, novel approaches are needed to control the rates of obesity that are occurring globally. The purpose of this paper is to provide a synopsis of how exercise, sleep, psychological stress, and meal frequency and composition affect levels of ghrelin, cortisol, insulin GLP-1, and leptin and weight control. We will provide information regarding how hormones respond to various lifestyle factors which may affect appetite control, hunger, satiety, and weight control.

Carbohydrate supplementation delays DNA damage in elite runners during intensive microcycle training

The aim of this study was to evaluate the effect of carbohydrate supplementation on free plasma DNA and conventional markers of training and tissue damage in long-distance runners undergoing an overload training program. Twenty-four male runners were randomly assigned to two groups (CHO group and control group). The participants were submitted to an overload training program (days 1-8), followed by a high-intensity intermittent running protocol (10 × 800 m) on day 9. The runners received maltodextrin solution (CHO group) or zero energy placebo solution as the control equivalent before, during, and after this protocol. After 8 days of intensive training, baseline LDH levels remained constant in the CHO group (before: 449.1 ± 18.2, after: 474.3 ± 22.8 U/L) and increased in the control group (from 413.5 ± 23.0 to 501.8 ± 24.1 U/L, p < 0.05). On day 9, LDH concentrations were lower in the CHO group (509.2 ± 23.1 U/L) than in the control group (643.3 ± 32.9 U/L, p < 0.01) post-intermittent running. Carbohydrate ingestion attenuated the increase of free plasma DNA post-intermittent running (48,240.3 ± 5,431.8 alleles/mL) when compared to the control group (73,751.8 ± 11,546.6 alleles/mL, p < 0.01). Leukocyte counts were lower in the CHO group than in the control group post-intermittent running (9.1 ± 0.1 vs. 12.2 ± 0.7 cells/µL; p < 0.01) and at 80 min of recovery (10.6 ± 0.1 vs. 13.9 ± 1.1 cells/µL; p < 0.01). Cortisol levels were positively correlated with free plasma DNA, leukocytes, and LDH (all r > 0.4 and p < 0.001). The results showed that ingestion of a carbohydrate beverage resulted in less DNA damage and attenuated the acute post-exercise inflammation response, providing better recovery during intense training.

Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol

This study was carried out in 2 parts: part 1 was designed to measure the 1 repetition maximum (1RM) bench press with 2 different moderate-velocity tempos (2/0/2) vs. (2/0/4) in male lifters while part 2 compared the hormonal responses at the same tempos as described in part 1. In both parts 1 and 2, the 1RMs (lbs) were higher on the 2/0/2 tempo than on the 2/0/4 tempo. The change in plasma volume (PV) was greater after the 2/0/4 tempo (-5.7 ± 1.7% vs. 0.96 ± 1.2%, p < 0.05). All blood parameters were significantly (p < 0.05) higher post-exercise compared with baseline. With PV corrected, insulin-like growth factor 1 (IGF-1) (ng·mL⁻¹) was higher with the 2/0/2 tempo only (pre-exercise: 277.4 ± 21.8, post-exercise: 308.1 ± 22.9; 2/0/4 tempo pre-exercise: 277.2 ± 17.6, post-exercise: 284.8 ± 21.2). In conclusion, heavier loads can be lifted and more total work can be performed using a (2/0/2) tempo compared with a slower (2/0/4) tempo, but with the exception of IGF-1, the hormonal responses are similar. Individuals may get the same metabolic responses to training by using different tempos, but they will need to use less weight at a slower tempo.

Exercise induces a marked increase in plasma follistatin: evidence that follistatin is a contraction-induced hepatokine

Follistatin is a member of the TGF-β super family and inhibits the action of myostatin to regulate skeletal muscle growth. The regulation of follistatin during physical exercise is unclear but may be important because physical activity is a major intervention to prevent age-related sarcopenia. First, healthy subjects performed either bicycle or one-legged knee extensor exercise. Arterial-venous differences were assessed during the one-legged knee extensor experiment. Next, mice performed 1 h of swimming, and the expression of follistatin was examined in various tissues using quantitative PCR. Western blotting assessed follistatin protein content in the liver. IL-6 and epinephrine were investigated as drivers of follistatin secretion. After 3 h of bicycle exercise, plasma follistatin increased 3 h into recovery with a peak of 7-fold. No net release of follistatin could be detected from the exercising limb. In mice performing a bout of swimming exercise, increases in plasma follistatin as well as follistatin mRNA and protein expression in the liver were observed. IL-6 infusion to healthy young men did not affect the follistatin concentration in the circulation. When mice were stimulated with epinephrine, no increase in the hepatic mRNA of follistatin was observed. This is the first study to demonstrate that plasma follistatin is increased during exercise and most likely originates from the liver. These data introduce new perspectives regarding muscle-liver cross talk during exercise and during recovery from exercise.

Physiological and performance adaptations of elite Greco-Roman wrestlers during a one-day tournament

The aim of this study was to determine the effects of a simulated one-day Greco-Roman wrestling tournament on selected performance and inflammatory status indices. Twelve competitive wrestlers (22.1 ± 1.3 years) completed five matches according to the official Olympic wrestling tournament regulations following a ~6% weight loss. Performance measurements, muscle damage assessment, and blood sampling were performed before and following each match. Performance and inflammatory markers were not affected by weight loss. Mean wrestling heart rate reached ~85% of maximal and lactate concentration exceeded 17 mM. Fatigue rating demonstrated a progressive rise (P < 0.05) throughout the tournament, peaking in match 4. Performance demonstrated a progressive deterioration (P < 0.05) throughout the tournament, especially in the last two matches (P < 0.05), with upper-body measures exhibiting a greater decline (P < 0.05) and remaining below baseline (P < 0.05) until the end of the tournament. Muscle damage markers increased during the course of the tournament with upper limbs affected more. Creatine kinase activity, CRP levels, IL-6 concentration, and leukocyte counts increased (P < 0.05) progressively throughout the tournament, peaking in the last two matches. Cortisol, epinephrine and norepinephrine increased (P < 0.05) after each match, but testosterone declined (P < 0.05) progressively, reaching a nadir before the last match. This inflammatory response was accompanied by a marked increase (p < 0.05) in lipid peroxidation, protein oxidation, and antioxidant status markers indicating the development of oxidative stress. These results suggest that a one-day wrestling tournament may induce significant physiological demands on wrestlers that may adversely affect their performance and inflammatory status especially during the later stages of the tournament.

Time course of changes in performance and inflammatory responses after acute plyometric exercise

The objectives of the present investigation were to study the inflammatory and performance responses after an acute bout of intense plyometric exercise during a prolonged recovery period. Participants were randomly assigned to either an experimental group (P, n = 12) that performed intense plyometric exercises or a control group (C, n = 12) that rested. The delayed onset of muscle soreness (DOMS), knee range of motion (KROM), creatine kinase (CK) and lactate dehydrogenase (LDH) activities, white blood cell count, C reactive protein (CRP), uric acid (UA), cortisol, testosterone, IL-6, IL-1b strength (isometric and isokinetic), and countermovement (CMJ) and static (SJ) jumping performance were measured at rest, immediately postexercise and at 24, 48, 72, 96, and 120 hours of recovery. Lactate was measured at rest and postexercise. Strength remained unchanged throughout recovery, but CMJ and SJ declined (p < 0.05) by 8-20%. P induced a marked rise in DOMS, CK, and LDH (peaked 24-48 hours postexercise) and a KROM decline. An acute-phase inflammatory response consisting of leukocytosis (postexercise and at 24 hours), an IL-6, IL-1b, CRP, and cortisol elevation (during the first 24 hours of recovery) and a delayed increase of UA (peaked at 48 hours) and testosterone (peaked at 72 hours) was observed in P. The results of this investigation indicate that performing an acute bout of intense plyometric exercise may induce a short-term muscle damage and marked but transient inflammatory responses. Jumping performance seems to deteriorate for as long as 72 hours postexercise, whereas strength appears to remain unchanged. The acute-phase inflammatory response after a plyometric exercise protocol appears to follow the same pattern as in other exercise models. These results clearly indicate the need of sufficient recovery between successive plyometric exercise training sessions.

l-Carnitine l-tartrate supplementation favorably affects biochemical markers of recovery from physical exertion in middle-aged men and women

The purpose of this study was to examine the effects of Carnipure tartrate (Lonza, Allendale, NJ) supplementation (total dose of 2 g/d of l-carnitine) on markers of performance and recovery from physical exertion in middle-aged men and women. Normally active and healthy men (n = 9, 45.4 +/- 5.3 years old) and women (n = 9, 51.9 +/- 5.0 years old) volunteered to participate in the investigation. Double-blind, placebo, balanced treatment presentation and crossover design were used with 3 weeks and 3 days of supplementation followed by a 1-week washout period before the other counterbalanced treatment was initiated. After 3 weeks of each supplementation protocol, each participant then performed an acute resistance exercise challenge of 4 sets of 15 repetitions of squat/leg press at 50% 1-repetition maximum and continued supplementation over the recovery period that was evaluated. Blood samples were obtained at preexercise and at 0, 15, 30, and 120 minutes postexercise during the acute resistance exercise challenge and during 4 recovery days as well. Two grams of l-carnitine supplementation had positive effects and significantly (P < or = .05) attenuated biochemical markers of purine metabolism (ie, hypoxanthine, xanthine oxidase), free radical formation (malondialdehyde), muscle tissue disruption (myoglobin, creatine kinase), and muscle soreness after physical exertion. However, markers of physical performance (ie, strength, power, get up and go) were not affected by supplementation. These findings support our previous findings of l-carnitine in younger people that such supplementation can reduce chemical damage to tissues after exercise and optimize the processes of muscle tissue repair and remodeling.

Effects of carbohydrate supplementation on competitive runners undergoing overload training followed by a session of intermittent exercise

This study evaluated the effects of a micro cycle of overload training (1st-8th day) on metabolic and hormonal responses in male runners with or without carbohydrate supplementation and investigated the cumulative effects of this period on a session of intermittent high-intensity running and maximum-performance-test (9th day). The participants were 24 male runners divided into two groups, receiving 61% of their energy intake as CHO (carbohydrate-group) and 54% in the control-group (CON). The testosterone was higher for the CHO than the CON group after the overload training (694.0 +/- 54.6 vs. CON 610.8 +/- 47.9 pmol/l). On the ninth day participants performed 10 x 800 m at mean 3 km velocity. An all-out 1000 m running was performed before and after the 10 x 800 m. Before, during, and after this protocol, the runners received solution containing CHO or the CON equivalent. The performance on 800 m series did not differ in either group between the first and last series of 800 m, but for the all-out 1000 m test the performance decrement was lower for CHO group (5.3 +/- 1.0 vs. 10.6 +/- 1.3%). The cortisol concentrations were lower in the CHO group in relation to CON group (22.4 +/- 0.9 vs. 27.6 +/- 1.4 pmol/l) and the IGF1/IGFBP3 ratio increased 12.7% in the CHO group. During recovery, blood glucose concentrations remained higher in the CHO group in comparison with the CON group. It was concluded that CHO supplementation possibly attenuated the suppression of the hypothalamic-pituitary-gonadal axis and resulted in less catabolic stress, and thus improved running performance.

ISSN exercise & sport nutrition review: research & recommendations

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.

Effect of hydration state on resistance exercise-induced endocrine markers of anabolism, catabolism, and metabolism

Hypohydration (decreased total body water) exacerbates the catabolic hormonal response to endurance exercise with unclear effects on anabolic hormones. Limited research exists that evaluates the effect of hypohydration on endocrine responses to resistance exercise; this work merits attention as the acute postexercise hormonal environment potently modulates resistance training adaptations. The purpose of this study was to examine the effect of hydration state on the endocrine and metabolic responses to resistance exercise. Seven healthy resistance-trained men (age = 23 ± 4 yr, body mass = 87.8 ± 6.8 kg, body fat = 11.5 ± 5.2%) completed three identical resistance exercise bouts in different hydration states: euhydrated (EU), hypohydrated by ∼2.5% body mass (HY25), and hypohydrated by ∼5.0% body mass (HY50). Investigators manipulated hydration status via controlled water deprivation and exercise-heat stress. Cortisol, epinephrine, norepinephrine, testosterone, growth hormone, insulin-like growth factor-I, insulin, glucose, lactate, glycerol, and free fatty acids were measured during euhydrated rest, immediately preceding resistance exercise, immediately postexercise, and during 60 min of recovery. Body mass decreased 0.2 ± 0.4, 2.4 ± 0.4, and 4.8 ± 0.4% during EU, HY25, and HY50, respectively, supported by humoral and urinary changes that clearly indicated subjects achieved three distinct hydration states. Hypohydration significantly 1) increased circulating concentrations of cortisol and norepinephrine, 2) attenuated the testosterone response to exercise, and 3) altered carbohydrate and lipid metabolism. These results suggest that hypohydration can modify the hormonal and metabolic response to resistance exercise, influencing the postexercise circulatory milieu.

Androgen receptors and testosterone in men--effects of protein ingestion, resistance exercise and fiber type

The purpose of this study was to examine the impact of protein ingestion on circulating testosterone and muscle androgen receptor (AR) as well as on insulin-like growth factor-I (MGF and IGF-IEa) responses to a resistance exercise (RE) bout in (57-72 year) men. Protein (15 g whey) (n=9) or placebo (n=9) was consumed before and after a RE bout (5 sets of 10 repetition maximums), and vastus lateralis muscle biopsies were taken pre, 1 and 48 h post-RE. The protein ingestion blunted the RE-induced increase in serum free and total testosterone while the RE bout significantly increased muscle AR mRNA levels in older men (P<0.05). However, protein ingestion did not significantly affect AR mRNA or protein expression, or MGF and IGF-IEa mRNA expression at 1 and 48 h post-RE. Immunohistochemical staining of muscle cross-sections was done with antibodies specific to AR and MyHC I and II and showed that there seems to be within or near the type-I muscle fibers a greater staining of ARs than within or near the type-II fibres. In conclusion, the protein ingestion hinders RE-induced increase in serum testosterone in older men but may not significantly affect muscle AR, MGF or IGF-IEa gene expression. Furthermore, the present study shows that even older men are able to increase muscle AR mRNA expression in response to a RE bout.

Effects of ingesting protein with various forms of carbohydrate following resistance-exercise on substrate availability and markers of anabolism, catabolism, and immunity

Background

Ingestion of carbohydrate (CHO) and protein (PRO) following intense exercise has been reported to increase insulin levels, optimize glycogen resynthesis, enhance PRO synthesis, and lessen the immuno-suppressive effects of intense exercise. Since different forms of CHO have varying glycemic effects, the purpose of this study was to determine whether the type of CHO ingested with PRO following resistance-exercise affects blood glucose availability and insulin levels, markers of anabolism and catabolism, and/or general immune markers.

Methods

40 resistance-trained subjects performed a standardized resistance training workout and then ingested in a double blind and randomized manner 40 g of whey PRO with 120 g of sucrose (S), honey powder (H), or maltodextrin (M). A non-supplemented control group (C) was also evaluated. Blood samples were collected prior to and following exercise as well as 30, 60, 90, and 120 min after ingestion of the supplements. Data were analyzed by repeated measures ANOVA or ANCOVA using baseline values as a covariate if necessary.

Results

Glucose concentration 30 min following ingestion showed the H group (7.12 ± 0.2 mmol/L) to be greater than S (5.53 ± 0.6 mmol/L; p < 0.03); M (6.02 ± 0.8 mmol/L; p < 0.05), and C (5.44 ± 0.18 mmol/L; p < 0.0002) groups. No significant differences were observed among groups in glucose area under the curve (AUC) values, although the H group showed a trend versus control (p = 0.06). Insulin response for each treatment was significant by time (p < 0.0001), treatment (p < 0.0001) and AUC (p < 0.0001). 30-min peak post-feeding insulin for S (136.2 ± 15.6 uIU/mL), H (150.1 ± 25.39 uIU/mL), and M (154.8 ± 18.9 uIU/mL) were greater than C (8.7 ± 2.9 uIU/mL) as was AUC with no significant differences observed among types of CHO. No significant group × time effects were observed among groups in testosterone, cortisol, the ratio of testosterone to cortisol, muscle and liver enzymes, or general markers of immunity.

Conclusion

CHO and PRO ingestion following exercise significantly influences glucose and insulin concentrations. Although some trends were observed suggesting that H maintained blood glucose levels to a better degree, no significant differences were observed among types of CHO ingested on insulin levels. These findings suggest that each of these forms of CHO can serve as effective sources of CHO to ingest with PRO in and attempt to promote post-exercise anabolic responses.