Darryn S. Willoughby

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.

International society of sports nutrition position stand: caffeine and performance

Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (≥ 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance.

The Antioxidant Role of Glutathione and N-Acetyl-Cysteine Supplements and Exercise-Induced Oxidative Stress

An increase in exercise intensity is one of the many ways in which oxidative stress and free radical production has been shown to increase inside our cells. Effective regulation of the cellular balance between oxidation and antioxidation is important when considering cellular function and DNA integrity as well as the signal transduction of gene expression. Many pathological states, such as cancer, Parkinsons disease, and Alzheimers disease have been shown to be related to the redox state of cells. In an attempt to minimize the onset of oxidative stress, supplementation with various known antioxidants has been suggested. Glutathione and N-acetyl-cysteine (NAC) are antioxidants which are quite popular for their ability to minimize oxidative stress and the downstream negative effects thought to be associated with oxidative stress. Glutathione is largely known to minimize the lipid peroxidation of cellular membranes and other such targets that is known to occur with oxidative stress. N-acetyl-cysteine is a by-product of glutathione and is popular due to its cysteine residues and the role it has on glutathione maintenance and metabolism. The process of oxidative stress is a complicated, inter-twined series of events which quite possibly is related to many other cellular processes. Exercise enthusiasts and researchers have become interested in recent years to identify any means to help minimize the detrimental effects of oxidative stress that are commonly associated with intense and unaccustomed exercise. It is possible that a decrease in the amount of oxidative stress a cell is exposed to could increase health and performance.

Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength

Summary.This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6–8 repetitions at 85–90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance.

Effects of heavy resistance training on myostatin mRNA and protein expression.

PURPOSE Myostatin is a negative regulator of muscle mass and its effects seem to be exacerbated by glucocorticoids; however, its response to resistance training is not well known. This study examined 12 wk of resistance training on the mRNA and protein expression of myostatin, follistatin-like related gene (FLRG), activin IIb receptor, cortisol, glucocorticoid receptor, myofibrillar protein, as well as the effects on muscle strength and mass and body composition. METHODS Twenty-two untrained males were randomly assigned to either a resistance-training [RTR (N = 12)] or control group [CON (N = 10)]. Muscle biopsies and blood samples were obtained before and after 6 and 12 wk of resistance training. RTR trained 3 x wk(-1) using three sets of six to eight repetitions at 85-90% 1-RM on lower-body exercises, whereas CON performed no resistance training. Data were analyzed with two- and three-way ANOVA. RESULTS After 12 wk of training, RTR increased total body mass, fat-free mass, strength, and thigh volume and mass; however, they increased myostatin mRNA, myostatin, FLRG, cortisol, glucocorticoid receptor, and myofibrillar protein after 6 and 12 wk of training (P < 0.05). CONCLUSIONS Resistance training and/or increased glucocorticoid receptor expression appears to up-regulate myostatin mRNA expression. Furthermore, it is possible that any plausible decreases in skeletal muscle function from the observed increase in serum myostatin were attenuated by increased serum FLRG levels and the concomitant down-regulation of the activin IIb receptor. It is therefore concluded that the increased myostatin in response to cortisol and/or resistance training appears to have no effects on training-induced increases in muscle strength and mass.

Effects of acute and 14-day coenzyme Q10 supplementation on exercise performance in both trained and untrained individuals

BackgroundTo determine whether acute (single dose) and/or chronic (14-days) supplementation of CoQ10 will improve anaerobic and/or aerobic exercise performance by increasing plasma and muscle CoQ10 concentrations within trained and untrained individuals.MethodsTwenty-two aerobically trained and nineteen untrained male and female subjects (26.1 ± 7.6 yrs, 172 ± 8.7 cm, 73.5 ± 17 kg, and 21.2 ± 7.0%) were randomized to ingest in a double-blind manner either 100 mg of a dextrose placebo (CON) or a fast-melt CoQ10 supplement (CoQ10) twice a day for 14-days. On the first day of supplementation, subjects donated fasting blood samples and a muscle biopsy. Subjects were then given 200 mg of the placebo or the CoQ10 supplement. Sixty minutes following supplement ingestion, subjects completed an isokinetic knee extension endurance test, a 30-second wingate anaerobic capacity test, and a maximal cardiopulmonary graded exercise test interspersed with 30-minutes of recovery. Additional blood samples were taken immediately following each exercise test and a second muscle biopsy sample was taken following the final exercise test. Subjects consumed twice daily (morning and night), 100 mg of either supplement for a period of 14-days, and then returned to the lab to complete the same battery of tests. Data was analyzed using repeated measures ANOVA with an alpha of 0.05.ResultsPlasma CoQ10 levels were significantly increased following 2 weeks of CoQ10 supplementation (p < 0.001); while a trend for higher muscle CoQ10 levels was observed after acute CoQ10 ingestion (p = 0.098). A trend for lower serum superoxide dismutase (SOD) was observed following acute supplementation with CoQ10 (p = 0.06), whereas serum malondialdehyde (MDA) tended to be significantly higher (p < 0.05). Following acute ingestion of CoQ10, plasma CoQ10 levels were significantly correlated to muscle CoQ10 levels; maximal oxygen consumption; and treadmill time to exhaustion. A trend for increased time to exhaustion was observed following 2 weeks of CoQ10 supplementation (p = 0.06).ConclusionAcute supplementation with CoQ10 resulted in higher muscle CoQ10 concentration, lower serum SOD oxidative stress, and higher MDA levels during and following exercise. Chronic CoQ10 supplementation increased plasma CoQ10 concentrations and tended to increase time to exhaustion. Results indicate that acute and chronic supplementation of CoQ10 may affect acute and/or chronic responses to various types of exercise.

Position stand on androgen and human growth hormone use.

Hoffman, JR, Kraemer, WJ, Bhasin, S, Storer, T, Ratamess, NA, Haff, GG, Willoughby, DS, and Rogol, AD. Position stand on Androgen and human growth hormone use. J Strength Cond Res 23(5): S1-S59, 2009-Perceived yet often misunderstood demands of a sport, overt benefits of anabolic drugs, and the inability to be offered any effective alternatives has fueled anabolic drug abuse despite any consequences. Motivational interactions with many situational demands including the desire for improved body image, sport performance, physical function, and body size influence and fuel such negative decisions. Positive countermeasures to deter the abuse of anabolic drugs are complex and yet unclear. Furthermore, anabolic drugs work and the optimized training and nutritional programs needed to cut into the magnitude of improvement mediated by drug abuse require more work, dedication, and preparation on the part of both athletes and coaches alike. Few shortcuts are available to the athlete who desires to train naturally. Historically, the NSCA has placed an emphasis on education to help athletes, coaches, and strength and conditioning professionals become more knowledgeable, highly skilled, and technically trained in their approach to exercise program design and implementation. Optimizing nutritional strategies are a vital interface to help cope with exercise and sport demands (516-518). In addition, research-based supplements will also have to be acknowledged as a strategic set of tools (e.g., protein supplements before and after resistance exercise workout) that can be used in conjunction with optimized nutrition to allow more effective adaptation and recovery from exercise. Resistance exercise is the most effective anabolic form of exercise, and over the past 20 years, the research base for resistance exercise has just started to develop to a significant volume of work to help in the decision-making process in program design (187,248,305). The interface with nutritional strategies has been less studied, yet may yield even greater benefits to the individual athlete in their attempt to train naturally. Nevertheless, these are the 2 domains that require the most attention when trying to optimize the physical adaptations to exercise training without drug use. Recent surveys indicate that the prevalence of androgen use among adolescents has decreased over the past 10-15 years (154,159,246,253,370,441,493). The decrease in androgen use among these students may be attributed to several factors related to education and viable alternatives (i.e., sport supplements) to substitute for illegal drug use. Although success has been achieved in using peer pressure to educate high school athletes on behaviors designed to reduce the intent to use androgens (206), it has not had the far-reaching effect desired. It would appear that using the people who have the greatest influence on adolescents (coaches and teachers) be the primary focus of the educational program. It becomes imperative that coaches provide realistic training goals for their athletes and understand the difference between normal physiological adaptation to training or that is pharmaceutically enhanced. Only through a stringent coaching certification program will academic institutions be ensured that coaches that they hire will have the minimal knowledge to provide support to their athletes in helping them make the correct choices regarding sport supplements and performance-enhancing drugs. The NSCA rejects the use of androgens and hGH or any performance-enhancing drugs on the basis of ethics, the ideals of fair play in competition, and concerns for the athletes health. The NSCA has based this position stand on a critical analysis of the scientific literature evaluating the effects of androgens and human growth hormone on human physiology and performance. The use of anabolic drugs to enhance athletic performance has become a major concern for professional sport organizations, sport governing bodies, and the federal government. It is the belief of the NSCA that through education and research we can mitigate the abuse of androgens and hGH by athletes. Due to the diversity of testosterone-related drugs and molecules, the term androgens is believed to be a more appropriate term for anabolic steroids.Androgen administration in a concentration-dependent manner increases lean body mass, muscle mass, and maximal voluntary strength in men. However, the upper concentration for maximum effects remains unknown.Combined administration of androgens and resistance exercise training is associated with greater gains in lean body mass, muscle size, and maximal voluntary strength in men than either intervention alone.Testosterone therapy is approved only for the treatment of hypogonadism in adolescent and adult men. However, the anabolic applications of androgens and selective AR modulators are being explored for the functional limitations associated with aging and some types of chronic illness.The magnitude and frequency of adverse effects among androgen users have not been systematically studied. Potential adverse effects of androgen use in men include suppression of the hypothalamic-pituitary-gonadal axis, mood and behavior disorders, increased risk of cardiovascular disease, hepatic dysfunction with oral androgens, insulin resistance, glucose intolerance, acne, gynecomastia, and withdrawal after discontinuation. In addition, the polypharmacy of many androgen users (psychoactive and accessory drugs) may have serious adverse effects of their own.The adverse effects of androgen administration in women are similar to those noted in men. In addition, women using androgens may also experience virilizing side effects such as enlargement of the clitoris, deepening of the voice, hirsutism, and changes in body habitus. These changes may not be reversible on cessation of androgen use.In pre- and peripubertal children, androgen use may lead to virilization, premature epiphyseal closure, and resultant adult short stature.Since 1990, the use of androgens for a nonmedical purpose is illegal. Androgens are labeled as a schedule III drug. Possession of any schedule III substance including androgens is punishable by fine, prison time, or both. Prescribing androgens for bodybuilding or enhanced athletic performance is also punishable as noted above.Human growth hormone increases lean body mass within weeks of administration; however, the majority of the change is within the water compartment and not in body cell mass.Human growth hormone is unlikely to be administered as a single agent but often in combination with androgens.Combined administration of hGH and resistance exercise training is associated with minimal gains in lean body mass, muscle size, and maximal voluntary strength in men compared with resistance exercise alone.Human growth hormone is approved for the therapy of children and adolescents with growth hormone deficiency, Turner syndrome, small for gestational age with failure to catch-up to the normal growth curves, chronic kidney disease, Prader-Willi syndrome, idiopathic short stature, Noonan syndrome, and SHOX gene deletion. For adults, hGH is approved for the treatment of GH deficiency, AIDS/HIV with muscle wasting, and short bowel syndrome.The magnitude and frequency of adverse events associated with hGH use are clearly dose related. Potential adverse events include suppression of the hypothalamic-pituitary GH/IGF-1 axis, water retention, edema, increased intracranial pressure, joint and muscle aches, and those of needle injection (hepatitis and HIV/AIDS). These should be the same in women as well as in men.Continued effort should be made to educate athletes, coaches, parents, physicians, and athletic trainers along with the general public on androgen and hGH use and abuse. Educational programs should focus on potential medical risks of these illegal performance-enhancing drugs use, optimizing training programs and concurrent nutritional strategies to enhance physiological adaptation and performance. In addition, educating coaches on setting realistic training goals and expectations for their athletes will help reduce the pressures to use illegal PED and assist in potentially identifying potential users of illegal PED.The NSCA supports and promotes additional research funding to be directed toward effective educational programs, documentation of both acute and long-term adverse effects of androgen and hGH abuse, strategies for optimizing athletic performance through training and nutritional interventions, strategies to help athletes discontinue androgen and hGH use, and strategies for the detection of abuse of androgens and hGH.

Effects of sequential bouts of resistance exercise on androgen receptor expression.

PURPOSE Increased serum testosterone (TST) occurs in response to resistance exercise and is associated with increased muscle mass. However, the effects of elevated TST and sequential resistance exercise bouts on androgen receptor (AR) expression in humans are not well known. This study examined three sequential bouts of heavy-resistance exercise on serum total TST, sex hormone-binding globulin (SHBG) and free androgen index (FAI), skeletal muscle AR mRNA and protein expression, and myofibrillar protein content. METHODS Eighteen untrained males were randomly assigned to either a resistance-training [RST (N = 9)] or control group [CON (N = 9)]. RST performed three lower-body resistance exercise bouts, each separated by 48 h. At each exercise bout, RST performed three sets of 8-10 repetitions at 75-80% one-repetition maximum using the squat, leg press, and leg extension exercises, respectively, whereas CON performed no resistance exercise. Muscle biopsies were obtained immediately before the first exercise bout and 48 h after each of the three bouts, whereas blood samples were obtained immediately before, immediately after, and 30 min after each bout. Data were analyzed with two-way ANOVA and bivariate correlations. RESULTS Serum TST and FAI were significantly increased after each exercise bout (P < 0.05); however, there were no significant changes for SHBG. AR mRNA and protein were significantly increased (P < 0.05) after the second and third exercise bouts, respectively, and were significantly correlated to TST and FAI (P < 0.05). Myofibrillar protein increased after the third bout (P < 0.05). CONCLUSIONS Three sequential bouts of heavy resistance exercise increases serum TST and are effective at up-regulating AR mRNA and protein expression that appears to correspond to subsequent increases in myofibrillar protein.

Impact of DHEA(S) and cortisol on immune function in aging : a brief review

A decline in the human immune system that occurs with aging is known as immunosenescence. Several factors are involved in the process, including reduced neutrophil function and cytotoxic capacity of natural killer (NK) cells, thymus atrophy and reduced naïve T cell number, and lowered B cell antibody production in response to antigen. The endocrine system, specifically the hypothalamus-pituitary-adrenal axis, plays an important role in modulating immune function. With aging an imbalance occurs between two adrenal hormones, cortisol and DHEA, that have opposing actions on immune function. This brief review explores the interactions between cortisol and DHEA and their effects on immune function in aging, as well as potential methods to combat the endocrine-related contribution to immunosenescence, including DHEA supplementation and exercise.

Glucocorticoid receptor and ubiquitin expression after repeated eccentric exercise.

INTRODUCTION/PURPOSE Eccentric exercise causes muscle proteolysis that may be attenuated with repeated exercise. Therefore, this study determined the effect of repeated bouts of eccentric exercise on ubiquitin (UBI), ubiquitin conjugating enzyme (E2), and 20S proteasome (20S) and glucocorticoid receptor (GR) mRNA and protein expression, myofibrillar protein content, DNA content, caspase-3 activity, serum skeletal muscle troponin-I (sTnI) and cortisol (CORT), and muscle strength. METHODS Nine males underwent two identical eccentric exercise bouts (BT1 and BT2) 3 wk apart involving seven sets of 10 repetitions at 150% one-repetition maximum of the dominant knee extensors. Blood and muscle biopsy samples were obtained before and at 6 and 24 h postexercise whereas muscle strength was assessed before and at 24, 48, and 72 h postexercise. Data were analyzed with separate 2 x 3 and 2 x 4 factorial ANOVA (P < 0.05). RESULTS Decrements in strength and increased soreness occurred at 24 and 48 h postexercise for both bouts (P < 0.05); however, the changes for BT1 were greater than BT2. Serum CORT and sTnI were greater immediately after and at 6, 24, and 48 h postexercise for both bouts; however, the differences in BT1 were greater than BT2 (P < 0.05). Caspase-3 activity and the mRNA and protein levels of UBI, E2, 20S, and GR were increased at 6 and 24 h postexercise, and these differences were greater for BT1 than BT2 (P < 0.05). For BT1, DNA and myofibrillar protein content decreases were apparent at 24 h postexercise (P < 0.05) but not in BT2. CONCLUSION These results indicate that muscle injury occurring from an initial bout of eccentric exercise seems to decrease muscle strength and myofibrillar protein, possibly due to apoptosis and up-regulation of glucocorticoid receptor mediated increases in UBI-proteolytic pathway activity, all of which appear to be tempered with a repeated eccentric exercise bout.