Showing papers in "International Journal of Sport Nutrition and Exercise Metabolism in 2018"

International Olympic Committee (IOC) Consensus Statement on Relative Energy Deficiency in Sport (RED-S): 2018 Update

Abstract: In 2014, the International Olympic Committee (IOC) published a consensus statement entitled “Beyond the Female Athlete Triad: Relative Energy Deficiency in Sport (RED-S)”. The syndrome of RED-S refers to: “impaired physiological functioning caused by relative energy deficiency, and includes but is not limited to impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health.”

Athletes and Supplements: Prevalence and Perspectives

Abstract: In elite sport, where opponents are evenly matched, small factors can determine the outcome of sporting contests. Not all athletes know the value of making wise nutrition choices, but anything that might give a competitive edge, including dietary supplements, can seem attractive. Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements. However, unless the athlete has a nutrient deficiency, supplementation may not improve performance and may have a detrimental effect on both performance and health. Dietary supplements are classified as a subcategory of food, so manufacturers are not required to provide evidence of product safety and efficacy, nor obtain approval from regulatory bodies before marketing supplements. This creates the potential for health risks, and serious adverse effects have been reported from the use of some dietary supplements. Athletes who compete in sports under an anti-doping code must also realize that supplement use exposes them to a risk of ingesting banned substances or precursors of prohibited substances. Government systems of regulations do not include specific laboratory testing for banned substances according to the WADA list, so a separate regulatory framework to evaluate supplements for their risk of provoking a failed doping test is needed. In the high-performance culture typical of elite sport, athletes may use supplements regardless of possible risks. A discussion around medical, physiological, cultural, and ethical questions may be warranted to ensure that the athlete has the information needed to make an informed choice.

Endocrine Effects of Relative Energy Deficiency in Sport

Abstract: The term Relative Energy Deficiency in Sport was introduced by the International Olympic Committee in 2014. It refers to the potential health and performance consequences of inadequate energy for s...

Pitfalls of Conducting and Interpreting Estimates of Energy Availability in Free-Living Athletes

Abstract: The human body requires energy for numerous functions including, growth, thermogenesis, reproduction, cellular maintenance, and movement In sports nutrition, energy availability (EA) is defined as the energy available to support these basic physiological functions and good health once the energy cost of exercise is deducted from energy intake (EI), relative to an athlete’s fat-free mass (FFM) Low EA provides a unifying theory to link numerous disorders seen in both female and male athletes, described by the syndrome Relative Energy Deficiency in Sport, and related to restricted energy intake, excessive exercise or a combination of both These outcomes are incurred in different dose–response patterns relative to the reduction in EA below a “healthy” level of ∼45 kcal·kg FFM−1·day−1 Although EA estimates are being used to guide and monitor athletic practices, as well as support a diagnosis of Relative Energy Deficiency in Sport, problems associated with the measurement and interpretation of EA in the field should be explored These include the lack of a universal protocol for the calculation of EA, the resources needed to achieve estimates of each of the components of the equation, and the residual errors in these estimates The lack of a clear definition of the value for EA that is considered “low” reflects problems around its measurement, as well as differences between individuals and individual components of “normal”/“healthy” function Finally, further investigation of nutrition and exercise behavior including within- and between-day energy spread and dietary characteristics is warranted since it may directly contribute to low EA or its secondary problems

Evidence-Based Supplements for the Enhancement of Athletic Performance

Abstract: A strong foundation in physical conditioning and sport-specific experience, in addition to a bespoke and periodized training and nutrition program, are essential for athlete development. Once these underpinning factors are accounted for, and the athlete reaches a training maturity and competition level where marginal gains determine success, a role may exist for the use of evidence-based performance supplements. However, it is important that any decisions surrounding performance supplements are made in consideration of robust information that suggests the use of a product is safe, legal, and effective. The following review focuses on the current evidence-base for a number of common (and emerging) performance supplements used in sport. The supplements discussed here are separated into three categories based on the level of evidence supporting their use for enhancing sports performance: (1) established (caffeine, creatine, nitrate, beta-alanine, bicarbonate); (2) equivocal (citrate, phosphate, carnitine); and (3) developing. Within each section, the relevant performance type, the potential mechanisms of action, and the most common protocols used in the supplement dosing schedule are summarized.

Dietary Supplements for Health, Adaptation, and Recovery in Athletes

Abstract: Some dietary supplements are recommended to athletes based on data that supports improved exercise performance. Other dietary supplements are not ergogenic per se, but may improve health, adaptation to exercise, or recovery from injury, and so could help athletes to train and/or compete more effectively. In this review, we describe several dietary supplements that may improve health, exercise adaptation, or recovery. Creatine monohydrate may improve recovery from and adaptation to intense training, recovery from periods of injury with extreme inactivity, cognitive processing, and reduce severity of or enhance recovery from mild traumatic brain injury (mTBI). Omega 3-fatty acid supplementation may also reduce severity of or enhance recovery from mTBI. Replenishment of vitamin D insufficiency or deficiency will likely improve some aspects of immune, bone, and muscle health. Probiotic supplementation can reduce the incidence, duration, and severity of upper respiratory tract infection, which may indirectly improve training or competitive performance. Preliminary data show that gelatin and/or collagen may improve connective tissue health. Some anti-inflammatory supplements, such as curcumin or tart cherry juice, may reduce inflammation and possibly delayed onset muscle soreness (DOMS). Beta-hydroxy beta-methylbutyrate (HMB) does not consistently increase strength and/or lean mass or reduce markers of muscle damage, but more research on recovery from injury that includes periods of extreme inactivity is needed. Several dietary supplements, including creatine monohydrate, omega 3-fatty acids, vitamin D, probiotics, gelatin, and curcumin/tart cherry juice could help athletes train and/or compete more effectively.

Toward a Common Understanding of Diet-Exercise Strategies to Manipulate Fuel Availability for Training and Competition Preparation in Endurance Sport.

Abstract: From the breakthrough studies of dietary carbohydrate and exercise capacity in the 1960s through to the more recent studies of cellular signaling and the adaptive response to exercise in muscle, it has become apparent that manipulations of dietary fat and carbohydrate within training phases, or in the immediate preparation for competition, can profoundly alter the availability and utilization of these major fuels and, subsequently, the performance of endurance sport (events >30 min up to ∼24 hr). A variety of terms have emerged to describe new or nuanced versions of such exercise–diet strategies (e.g., train low, train high, low-carbohydrate high-fat diet, periodized carbohydrate diet). However, the nonuniform meanings of these terms have caused confusion and miscommunication, both in the popular press and among the scientific community. Sports scientists will continue to hold different views on optimal protocols of fuel support for training and competition in different endurance events. However, to promote collaboration and shared discussions, a commonly accepted and consistent terminology will help to strengthen hypotheses and experimental/experiential data around various strategies. We propose a series of definitions and explanations as a starting point for a more unified dialogue around acute and chronic manipulations of fat and carbohydrate in the athlete’s diet, noting philosophies of approaches rather than a single/definitive macronutrient prescription. We also summarize some of the key questions that need to be tackled to help produce greater insight into this exciting area of sports nutrition research and practice.

Relative Energy Deficiency in Sport in Male Athletes: A Commentary on Its Presentation Among Selected Groups of Male Athletes

Abstract: Low energy availability (LEA) is a key element of the Female Athlete Triad. Causes of LEA include failure to match high exercise energy expenditure (unintentional) or pathological behaviors of disordered eating (compulsive) and overzealous weight control programs (misguided but intentional). Recognition of such scenarios in male athletes contributed to the pronouncement of the more inclusive Relative Energy Deficiency in Sport (RED-S) syndrome. This commentary describes the insights and experience of the current group of authors around the apparently heightened risk of LEA in some populations of male athletes: road cyclists, rowers (lightweight and open weight), athletes in combat sports, distance runners, and jockeys. The frequency, duration, and magnitude of the LEA state appear to vary between populations. Common risk factors include cyclical management of challenging body mass and composition targets (including “making weight”) and the high energy cost of some training programs or events that is not easily matched by energy intake. However, additional factors such as food insecurity and lack of finances may also contribute to impaired nutrition in some populations. Collectively, these insights substantiate the concept of RED-S in male athletes and suggest that a specific understanding of a sport, subpopulation, or culture may identify a complex series of factors that can contribute to LEA and the type and severity of its outcomes. This commentary provides a perspective on the range of risk factors that should be addressed in future surveys of RED-S in athletic populations and targeted for specific investigation and modification.

Within-Day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes

Abstract: Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health We aimed to estimate and compare within-day energy balance (WDEB) in male athletes with suppressed and normal resting metabolic rate (RMR) and explore if within-day energy deficiency (WDED) is associated with endocrine markers of energy deficiency Thirty-one male cyclists, triathletes, and long-distance runners recruited from regional competitive sports clubs were included The protocol comprised measurements of RMR by ventilated hood, and energy intake and energy expenditure to predict RMRratio (measured RMR/predicted RMR), energy availability (EA), 24-hour energy balance (EB) and WDEB in 1-hour intervals, assessment of body-composition by dual-energy X-ray absorptiometry, and blood plasma analysis Subjects were categorized as having suppressed (RMRratio 090, n=11) Despite no observed differences in 24-hour EB or EA between the grou

Making Decisions About Supplement Use

Abstract: The use of dietary supplements is widespread among athletes in all sports and at all levels of competition, as it is in the general population. For the athlete training at the limits of what is sustainable, or for those seeking a shortcut to achieving their aims, supplements offer the prospect of bridging the gap between success and failure. Surveys show, however, that this is often not an informed choice and that the knowledge level among consumers is often low and that they are often influenced in their decisions by individuals with an equally inadequate understanding of the issues at stake. Supplement use may do more harm than good, unless it is based on a sound analysis of the evidence. Where a deficiency of an essential nutrient has been established by appropriate investigations, supplementation can provide a rapid and effective correction of the problem. Supplements can also provide a convenient and time-efficient solution to achieving the necessary intake of key nutrients such as protein and carbohydrate. Athletes contemplating the use of supplements should consider the potential for both positive and negative outcomes. Some ergogenic supplements may be of benefit to some athletes in some specific contexts, but many are less effective than is claimed. Some may be harmful to health of performance and some may contain agents prohibited by anti-doping regulations. Athletes should make informed choices that maximize the benefits while minimizing the risks.

Low RMRratio as a Surrogate Marker for Energy Deficiency, the Choice of Predictive Equation Vital for Correctly Identifying Male and Female Ballet Dancers at Risk

Abstract: Ballet dancers are reported to have an increased risk for energy deficiency with or without disordered eating behavior A low ratio between measured (m) and predicted (p) resting metabolic rate (RMRratio < 090) is a recognized surrogate marker for energy deficiency We aimed to evaluate the prevalence of suppressed RMR using different methods to calculate pRMR and to explore associations with additional markers of energy deficiency Female (n = 20) and male (n = 20) professional ballet dancers, 19-35 years of age, were enrolled mRMR was assessed by respiratory calorimetry (ventilated open hood) pRMR was determined using the Cunningham and Harris-Benedict equations, and different tissue compartments derived from whole-body dual-energy X-ray absorptiometry assessment The protocol further included assessment of body composition and bone mineral density, blood pressure, disordered eating (Eating Disorder Inventory-3), and for females, the Low Energy Availability in Females Questionnaire The prevalence of suppressed RMR was generally high but also clearly dependent on the method used to calculate pRMR, ranging from 25% to 80% in males and 35% to 100% in females Five percent had low bone mineral density, whereas 10% had disordered eating and 25% had hypotension Forty percent of females had elevated Low Energy Availability in Females Questionnaire score and 50% were underweight Suppressed RMR was associated with elevated Low Energy Availability in Females Questionnaire score in females and with higher training volume in males In conclusion, professional ballet dancers are at risk for energy deficiency The number of identified dancers at risk varies greatly depending on the method used to predict RMR when using RMRratio as a marker for energy deficiency

No difference between the effects of supplementing with soy protein versus animal protein on gains in muscle mass and strength in response to resistance exercise

Abstract: Much attention has been given to determining the influence of total protein intake and protein source on gains in lean body mass (LBM) and strength in response to resistance exercise training (RET). Acute studies indicate that whey protein, likely related to its higher leucine content, stimulates muscle protein synthesis (MPS) to a greater extent than proteins such as soy and casein. Less clear is the extent to which the type of protein supplemented impacts strength and LBM in longer term studies (≥6 weeks). Therefore, a meta-analysis was conducted to compare the effect of supplementation with soy protein to animal protein supplementation on strength and LBM in response to RET. Nine studies involving 266 participants suitable for inclusion in the meta-analysis were identified. Five studies compared whey with soy protein and four compared soy protein with other proteins (beef, milk or dairy protein). Meta-analysis showed that supplementing RET with whey or soy protein resulted in significant increases in s...

Prevalence of Indicators of Low Energy Availability in Elite Female Sprinters

Abstract: Low energy availability (LEA), and subsequent relative energy deficiency in sport (RED-S), has been observed in endurance, aesthetic, and team sport athletes, with limited data on prevalence in athletes in short-burst activities such as sprinting. We examined prevalence of signs and symptoms of LEA in elite female sprinters at the start of the training season (PRE), and at the end of a 5-month indoor training period (POST). Four of 13 female sprinters (31%) presented at PRE testing with at least one primary (amenorrhea, low BMD, low FSH, LH, or estradiol, RMR ≤ 29kcal/kg FFM, Low Energy Availability in Females Questionnaire (LEAF-Q) score ≥8) and one secondary indicator of LEA (fasting blood glucose 3.0mmol/L, fasting insulin < 20pmol/L, low insulin-like growth factor-1 (IGF-1), SBP < 90 and/or DBP < 60mm Hg). At POST, 7/13 athletes (54%) presented with at least one primary and one secondary indicator of LEA, three of whom ...

Methodologies for Investigating Performance Changes With Supplement Use

Abstract: Many expert sporting bodies now support a pragmatic acceptance of the use of performance supplements which have passed a risk:benefit analysis of being safe, effective, and permitted for use, while also being appropriate to the athlete’s age and maturation in their sport. However, gaining evidence of the performance benefits of these supplements is a process challenged by the scarcity of research in relation to the number of available products, and the limitations of the poor quality of some studies. While meta-analyses and systematic reviews can help to provide information about the general use of performance supplements, the controlled scientific trial provides the basis on which these reviews are undertaken, as well as an opportunity to address more specific questions about supplement applications. Guidelines for the design of studies include the choice of well-trained athletes who are familiarized with performance tasks that have been chosen on their basis of their known reliability and validity. Supplement protocols should be chosen to maximize the likely benefits, and researchers should also make efforts to control confounding variables, while keeping conditions similar to real-life practices. Performance changes should be interpreted in light of what is meaningful to the outcomes of sporting competition. Issues that have been poorly addressed to date include the use of several supplements in combination and the use of the same supplement over successive events, both within a single, and across multiple competition days. Strategies to isolate and explain the variability of benefits to individuals are also a topic for future investigation.

Effects of Caffeinated Gum on a Battery of Soccer-Specific Tests in Trained University-Standard Male Soccer Players.

Abstract: The purpose of this study was to determine whether caffeinated gum influenced performance in a battery of soccer-specific tests used in the assessment of performance in soccer players. In a double-blind, randomized, crossover design, 10 male university-standard soccer players (age: 19 ± 1 years, stature: 1.80 ± 0.10 m, body mass: 75.5 ± 4.8 kg) masticated a caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum on two separate occasions. After a standardized warm-up, gum was chewed for 5 min and subsequently expectorated 5 min before players performed a maximal countermovement jump, a 20-m sprint test, and the Yo-Yo Intermittent Recovery Test Level 1. Performance on 20-m sprints was not different between trials (caffeine: 3.2 ± 0.3 s, placebo: 3.1 ± 0.3 s; p = .567; small effect size: d = 0.33), but caffeine did allow players to cover 2.0% more distance during Yo-Yo Intermittent Recovery Test Level 1 (caffeine: 1,754 ± 156 m, placebo: 1,719 ± 139 m; p = .016; small effect size: d = 0.24) and increase maximal countermovement jump height by 2.2% (caffeine: 47.1 ± 3.4 cm, placebo: 46.1 ± 3.2 cm; p = .008; small effect size: d = 0.30). Performance on selected physical tests (Yo-Yo Intermittent Recovery Test Level 1 and countermovement jump) was improved by the chewing of caffeinated gum in the immediate period before testing in university-standard soccer players, but the sizes of such effects were small. Such findings may have implications for the recommendations made to soccer players about to engage with subsequent exercise performance.

Effects of High Versus Low Protein Intake on Body Composition and Maximal Strength in Aspiring Female Physique Athletes Engaging in an 8-Week Resistance Training Program

Abstract: Aspiring female physique athletes are often encouraged to ingest relatively high levels of dietary protein in conjunction with their resistance training programs. However, there is little to no res...

Correcting Vitamin D Insufficiency Improves Some But Not All Aspects of Physical Performance During Winter Training in Taekwondo Athletes.

Abstract: We investigated the effects of vitamin D3 supplementation on physical performance during winter training in vitamin D insufficient taekwondo athletes. Thirty-five collegiate male and female taekwondo athletes, aged 19-22 years with low serum 25(OH)D concentration (28.8 ± 1.10 nmol/L), were randomly assigned to a vitamin D group (n = 20) or a placebo group (n = 15). Subjects received either a vitamin D3 capsule (5,000 IU/day) or a placebo during 4 weeks of winter training. Blood samples were collected for analyzing serum 25(OH)D concentration. Physical performance tests included Wingate anaerobic test, isokinetic muscle strength and endurance, a countermovement jump test, sit-ups, agility test, and 20-m pacer. Serum 25(OH)D concentrations increased significantly in the vitamin D group (96.0 ± 3.77 nmol/L) after 4 weeks of supplementation, but no changes were found in the placebo group (F = 242.44, p = .000). There were significant interaction effects for anaerobic peak power (F = 7.49, p = .010) and isokinetic knee extension at 180 deg/s (F = 6.08, p = .019). Changes in serum 25(OH)D concentration were positively associated with changes in peak power and isokinetic knee extension at 180 deg/s. However, no significant interaction effects were observed in other performance variables. This study suggests that 4 weeks of vitamin D supplementation elevates serum 25(OH)D concentration to sufficient levels. Correcting vitamin D insufficiency improves some but not all aspects of performance. Thus, efficacy of vitamin D supplementation to enhance performance remains unclear.

Caffeine Improves Triathlon Performance: A Field Study in Males and Females.

Abstract: The ergogenic effect of caffeine on endurance exercise is commonly accepted. We aimed to elucidate realistically the effect of caffeine on triathlon event performance using a field study design, wh...

A Review of Prevention, Diagnosis, and Treatment of Relative Energy Deficiency in Sport in Artistic (Synchronized) Swimming

Abstract: The syndrome of relative energy deficiency in sport (RED-S) is a clinical entity characterized by low energy availability, which can negatively affect the health and performance of both male and female athletes. The underlying mechanism of RED-S is an inadequacy of dietary energy to support optimal health and performance. This syndrome refers to impaired physiological function, including metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health, with psychological consequences that can either precede (through restrictive dietary habits) or result from RED-S. The term RED-S extends beyond the condition termed the "Female Athlete Triad." Formerly known as synchronized swimming, artistic swimming is an Olympic sport requiring a high level of fitness as well as technical skill and artistry. The risk of RED-S is high in artistic swimming as it is an aesthetic, judged sport with an emphasis on a lean physique. RED-S is of significant concern in the sport of artistic swimming because of the potential negative effects on physical and mental health as well as consequences on athletic performance. This paper reviews health and performance consequences associated with low energy availability resulting in RED-S in artistic swimming. Medical and nutritional considerations specific to artistic swimming are reviewed, and methods to help detect and manage RED-S are discussed. Prevention and management of RED-S in this athlete population should be a priority for coaches, and the sport medicine professionals working with artistic swimming athletes should utilize the RED-S CAT, a Clinical Assessment Tool for screening and managing RED-S.

Effects of Three-Day Serial Sodium Bicarbonate Loading on Performance and Physiological Parameters During a Simulated Basketball Test in Female University Players.

Abstract: The aim of this study was to investigate the effect of 3-day serial sodium bicarbonate ingestion on repeated sprint and jump performance. Fifteen female university basketball players (23.3 ± 3.4 years; 173.1 ± 5.8 cm; 65.8 ± 6.3 kg; 23.6 ± 4.9% body fat) ingested 0.4 g/kg body mass of sodium bicarbonate or placebo for 3 days (split in three equal daily doses), before completing a simulated basketball exercise. Sprint and circuit times, jump heights, performance decrements, and gastrointestinal side effects were recorded during the test, and blood lactate concentration was measured pre- and posttest. Sodium bicarbonate supplementation led to significant decreases in mean sprint times (1.34 ± 0.23 vs. 1.70 ± 0.41 s, p = .008, 95% confidence intervals [-0.54, -0.10 s]) and mean circuit times (30.6 ± 2.0 vs. 31.3 ± 2.0 s, p = .044) and significantly greater mean jump height (26.8 [range 25.2-34.2] vs. 26.0 [range 25.6-33.6] cm, p = .013) compared with placebo. Performance decrement was significantly less for sprints with sodium bicarbonate compared with placebo (9.9 [range 3.4-37.0]% vs. 24.7 [range 4.1-61.3]%, p = .013), but not different for jumps (13.1 ± 4.5% vs. 12.5 ± 3.1%, p = .321) between conditions. No differences in gastrointestinal side effects were noted between conditions. Significantly greater postexercise blood lactate concentrations were measured in the sodium bicarbonate condition compared with the placebo condition (8.2 ± 2.8 vs. 6.6 ± 2.4 mmol/L, p = .010). This study is the first to show that serial loading of sodium bicarbonate is effective for basketball players to improve repeated sprint and jump performance during competition, or withstand greater training load during practice sessions without any gastrointestinal side effects.

Organization of Dietary Control for Nutrition-Training Intervention Involving Periodized Carbohydrate Availability and Ketogenic Low-Carbohydrate High-Fat Diet.

Abstract: The authors describe the implementation of a 3-week dietary intervention in elite race walkers at the Australian Institute of Sport, with a focus on the resources and strategies needed to accomplish a complex study of this scale Interventions involved: traditional guidelines of high carbohydrate (CHO) availability for all training sessions; a periodized CHO diet which integrated sessions with low and high CHO availability within the same total CHO intake; and a ketogenic low-CHO high-fat diet Seven-day menus and recipes were constructed for a communal eating setting to meet nutritional goals as well as individualized food preferences and special needs Menus also included nutrition support before, during, and after exercise Daily monitoring, via observation and food checklists, showed that energy and macronutrient targets were achieved Diets were matched for energy (∼148 MJ/d) and protein (∼21 g·kg-1·day-1) and achieved desired differences for fat and CHO, with high CHO availability and periodized CHO availability: CHO = 85 g·kg-1·day-1, 60% energy, fat = 20% of energy and low-CHO high-fat diet: 05 g·kg-1·day-1 CHO, fat = 78% energy There were no differences in micronutrient intake or density between the high CHO availability and periodized CHO availability diets; however, the micronutrient density of the low-CHO high-fat diet was significantly lower Daily food costs per athlete were similar for each diet (∼AU$ 27 ± 10) Successful implementation and monitoring of dietary interventions in sports nutrition research of the scale of the present study require meticulous planning and the expertise of chefs and sports dietitians Different approaches to sports nutrition support raise practical challenges around cost, micronutrient density, accommodation of special needs, and sustainability

Effects of Coffee Components on Muscle Glycogen Recovery: A Systematic Review.

Abstract: Coffee is one of the most consumed beverages in the world, and it can improve insulin sensitivity, stimulating glucose uptake in skeletal muscle when adequate carbohydrate intake is observed. The aim of this review is to analyze the effects of coffee and coffee components on muscle glycogen metabolism. A literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis, and seven studies were included, that explored the effects of coffee components on various substances and signaling proteins. In one of the studies with humans, caffeine was shown to increase glucose levels, Ca2+/calmodulin-dependent protein kinase phosphorylation, glycogen resynthesis rates, and glycogen accumulation after exercise. After intravenous injection of caffeine in rats, caffeine increased adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation, and glucose transport. In in vitro studies, caffeine raised AMPK and ACC phosphorylation, increasing glucose transport activity and reducing energy status in rat muscle cells. Cafestol and caffeic acid increased insulin secretion in rat beta cells and glucose uptake into human muscle cells. Caffeic acid also increased AMPK and ACC phosphorylation, reducing the energy status and increasing glucose uptake in rat muscle cells. Chlorogenic acid did not show any positive or negative effect. The findings from this review must be taken with caution due to the limited number of studies on the subject. In conclusion, various coffee components had a neutral or positive role in the metabolism of glucose and muscle glycogen, whereas no detrimental effect was described. Coffee beverages should be tested as an option for athletes' glycogen recovery.

Australian Football Athletes Lack Awareness of Current Sport Nutrition Guidelines

Abstract: Sports nutrition is an evolving field, but there is a lack of data on Australian athletes’ knowledge of current sports nutrition guidelines. Additionally, several tools used to assess nutrition knowledge (NK) have not undergone adequate validation. The purpose of this study was to assess and compare the sports NK of elite and non-elite Australian Football (AF) athletes using a newly validated questionnaire—The Nutrition for Sport Knowledge Questionnaire (NSKQ). Elite AF players (n=46) were recruited directly from their club dietitian and non-elite AF players (n =53) were invited to participate via email from their club president or secretary. The mean NK score of elite and non-elite AF players was 46±16% and 51±11%, respectively (p = 0.041). In both groups, knowledge of macronutrients, weight management, and alcohol was better than knowledge of supplements, micronutrients, and sports nutrition. Non-elite athletes achieved statistically significantly higher scores on the questionnaire sub-sections testing ...

Matcha Green Tea Drinks Enhance Fat Oxidation During Brisk Walking in Females.

Abstract: Intake of the catechin epigallocatechin gallate and caffeine has been shown to enhance exercise-induced fat oxidation. Matcha green tea powder contains catechins and caffeine and is consumed as a drink. We examined the effect of Matcha green tea drinks on metabolic, physiological, and perceived intensity responses during brisk walking. A total of 13 females (age: 27 ± 8 years, body mass: 65 ± 7 kg, height: 166 ± 6 cm) volunteered to participate in the study. Resting metabolic equivalent (1-MET) was measured using Douglas bags (1-MET: 3.4 ± 0.3 ml·kg-1·min-1). Participants completed an incremental walking protocol to establish the relationship between walking speed and oxygen uptake and individualize the walking speed at 5- or 6-MET. A randomized, crossover design was used with participants tested between Days 9 and 11 of the menstrual cycle (follicular phase). Participants consumed three drinks (each drink made with 1 g of Matcha premium grade; OMGTea Ltd., Brighton, UK) the day before and one drink 2 hr before the 30-min walk at 5- (n = 10) or 6-MET (walking speed: 5.8 ± 0.4 km/hr) with responses measured at 8-10, 18-20, and 28-30 min. Matcha had no effect on physiological and perceived intensity responses. Matcha resulted in lower respiratory exchange ratio (control: 0.84 ± 0.04; Matcha: 0.82 ± 0.04; p < .01) and enhanced fat oxidation during a 30-min brisk walk (control: 0.31 ± 0.10; Matcha: 0.35 ± 0.11 g/min; p < .01). Matcha green tea drinking can enhance exercise-induced fat oxidation in females. However, when regular brisk walking with 30-min bouts is being undertaken as part of a weight loss program, the metabolic effects of Matcha should not be overstated.

Effect of Exercise Duration on Subsequent Appetite and Energy Intake in Obese Adolescent Girls

Abstract: There is a growing interest regarding the effect of exercise on appetite and energy intake in youth While the role of exercise intensity has been a primary focus of study, the effect of exercise duration on subsequent food intake has not been fully examined in obese adolescents On three separate mornings in a randomly assigned order, obese adolescent girls (n = 20) aged 12-15 years old were asked to perform a rest session (control, CON) or two cycling sessions for 20 (EX20) or 40 min (EX40) set at their ventilatory threshold Absolute and relative energy intake were measured from an ad libitum lunch meal 30 min after rest or exercise and appetite feelings assessed using visual analogue scales throughout the day Hunger, satiety, and prospective food consumption were not significantly different between conditions Absolute energy intake (kcal) did not differ between conditions, while relative energy intake on EX40 (571 ± 381 kcal) was significantly lower than during CON (702 ± 320 kcal; p < 05) and EX20 (736 ± 457 kcal; p < 05) Fat ingestion (in grams) was significantly lower on CON (78 ± 32 g) compared with EX20 (103 ± 46 g; p < 01) Protein intake (in grams) was higher on EX20 (370 ± 166 g) compared with both CON (295 ± 117 g; p < 01) and EX40 (331 ± 109 g; p < 05) However, the percentage of total energy derived from each macronutrient was not different between conditions Obese adolescent girls do not compensate for an acute bout of exercise set at their ventilatory threshold by increasing energy intake, regardless of the exercise duration

Protein Supplementation During a 6-Month Concurrent Training Program: Effect on Body Composition and Muscular Strength in Sedentary Individuals

Abstract: We examined the effect of a protein supplement on muscular strength and body composition during 6 months of a 5 days/week concurrent strength and endurance training program. Sedentary males (n = 26) and females (n = 25), 18–25 years, were randomly assigned to receive a protein (PRO, 42 g/serving) or carbohydrate (CON) supplement twice daily. Strength and body composition (dual-energy X-ray absorptiometry) were assessed at baseline, 3 (3M), and 6 (6M) months. Protein intake was higher in PRO (PRO: 2.2 g/kg; CON: 1.1 g/kg; p < .001). Females in both groups gained similar strength at 3M and 6M in bench press and hip sled. Males in PRO gained more bench press strength at 3M (PRO: 24.6 ± 3.2 kg; CON: 14.3 ± 3.8 kg; p = .06) and 6M (PRO: 34.4 ± 4.3 kg; CON: 18.7 ± 5.1 kg; p = .03) and hip sled strength at 3M (PRO: 67.7 ± 9.2 kg; CON: 40.8 ± 10.8 kg, p = .07) and 6M (PRO: 94.0 ± 10.6 kg; CON: 65.1 ± 12.4 kg; p = .09) compared with CON. Females in PRO experienced a greater reduction in fat mass over the course of...

Using Contemporary Behavior Change Science to Design and Implement an Effective Nutritional Intervention Within Professional Rugby League

Abstract: Designing and implementing successful dietary intervention is integral to the role of sport nutrition professionals as they attempt to positively change the dietary behavior of athletes. High-performance sport is a time-pressured environment where immediate results can often supersede pursuit of the most effective evidence-based practice. However, efficacious dietary intervention necessitates comprehensive, systematic, and theoretical behavioral design and implementation, if the habitual dietary behaviors of athletes are to be positively changed. Therefore, this case study demonstrates how the Behaviour Change Wheel was used to design and implement an effective nutritional intervention within a professional rugby league. The eight-step intervention targeted athlete consumption of a high-quality dietary intake of 25.1 MJ each day to achieve an overall body mass increase of 5 kg across a 12-week intervention period. The capability, opportunity, motivation, and behavior model and affordability, practicability, effectiveness/cost-effectiveness, acceptability, safety, and equity criteria were used to identify population-specific intervention functions, policy categories, behavior change techniques, and modes of intervention delivery. The resulting intervention was successful, increasing the average daily energy intake of the athlete to 24.5 MJ, which corresponded in a 6.2 kg body mass gain. Despite consuming 0.6 MJ less per day than targeted, secondary outcome measures of diet quality, strength, body composition, and immune function all substantially improved, supporting sufficient energy intake and the overall efficacy of a behavioral approach. Ultimately, the Behaviour Change Wheel provides sport nutrition professionals with an effective and practical stepwise method to design and implement effective nutritional interventions for use within high-performance sport.

Social Media as a Nutrition Resource for Athletes: A Cross-Sectional Survey.

Abstract: Social media contains a wealth of nutrition information and proposes a cost-effective, highly engaging platform to deliver nutrition information to athletes This study used an online questionnaire