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Journal of the International Society of Sports Nutrition

Jozo Grgic, Eric T Trexler, Bruno Lazinica, Zeljko Pedisic
Background: Caffeine is commonly used as an ergogenic aid. Literature about the effects of caffeine ingestion on muscle strength and power is equivocal. The aim of this systematic review and meta-analysis was to summarize results from individual studies on the effects of caffeine intake on muscle strength and power. Methods: A search through eight databases was performed to find studies on the effects of caffeine on: (i) maximal muscle strength measured using 1 repetition maximum tests; and (ii) muscle power assessed by tests of vertical jump...
2018: Journal of the International Society of Sports Nutrition
Brad Jon Schoenfeld, Alan Albert Aragon
Controversy exists about the maximum amount of protein that can be utilized for lean tissue-building purposes in a single meal for those involved in regimented resistance training. It has been proposed that muscle protein synthesis is maximized in young adults with an intake of ~ 20-25 g of a high-quality protein; anything above this amount is believed to be oxidized for energy or transaminated to form urea and other organic acids. However, these findings are specific to the provision of fast-digesting proteins without the addition of other macronutrients...
2018: Journal of the International Society of Sports Nutrition
Artur Juszkiewicz, Piotr Basta, Elżbieta Petriczko, Bogusław Machaliński, Jerzy Trzeciak, Karolina Łuczkowska, Anna Skarpańska-Stejnborn
Background: The aim of this study was to analyze the response of selected components of the immune system in rowers to maximal physical exercise, and to verify if this response can be modulated by supplementation with spirulina (cyanobacterium Spirulina platensis ) . Method: The double-blind study included 19 members of the Polish Rowing Team. The subjects were randomly assigned to the supplemented group ( n  = 10), receiving 1500 mg of spirulina extract for 6 weeks, or to the placebo group ( n  = 9)...
2018: Journal of the International Society of Sports Nutrition
Marcos Maynar, Francisco Llerena, Ignacio Bartolomé, Javier Alves, María-Concepción Robles, Francisco-Javier Grijota, Diego Muñoz
Background: The aim of the present study was to determine changes in serum concentrations of trace elements Cooper (Cu), Chromiun (Cr), Manganesum (Mn), Nickel (Ni) and Selenium (Se) in high-level sportsmen. Methods: Eighty professional athletes of different metabolic modalities, were recruited before the start of their training period. Thirty one sedentary participants of the same geographic area constituted the control group. Cu, Cr, Mn, Ni and Se analysis was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS)...
2018: Journal of the International Society of Sports Nutrition
Cassie M Williamson, Brett S Nickerson, Emily E Bechke, Cherilyn N McLester, Brian M Kliszczewicz
Background: Bioelectrical impedance analysis (BIA) is often used to estimate total body water (TBW), intracellular body water (ICW), extracellular body water (ECW), and body fat percentage (BF%). A common restriction for BIA analysis is abstinence from caffeine 12-h prior to testing. However, research has yet to determine whether the consumption of caffeine influences BIA testing results. The purpose of this study was to determine if the consumption of caffeine influences BIA-derived BF% and body water values in habitual caffeine users...
2018: Journal of the International Society of Sports Nutrition
Jose Antonio, Anya Ellerbroek, Cassandra Evans, Tobin Silver, Corey A Peacock
Background: It has been posited that the consumption of extra protein (> 0.8 g/kg/d) may be deleterious to bone mineral content. However, there is no direct evidence to show that consuming a high-protein diet results in a demineralization of the skeleton. Thus, the primary endpoint of this randomized controlled trial was to determine if a high-protein diet affected various parameters of whole body and lumbar bone mineral content in exercise-trained women. Methods: Twenty-four women volunteered for this 6-month investigation ( n  = 12 control, n = 12 high-protein)...
2018: Journal of the International Society of Sports Nutrition
Sybille Buchwald-Werner, Ioanna Naka, Manfred Wilhelm, Elivra Schütz, Christiane Schoen, Claudia Reule
Background: Exhaustive exercise causes muscle damage accompanied by oxidative stress and inflammation leading to muscle fatigue and muscle soreness. Lemon verbena leaves, commonly used as tea and refreshing beverage, demonstrated antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effects of a proprietary lemon verbena extract (Recoverben®) on muscle strength and recovery after exhaustive exercise in comparison to a placebo product. Methods: The study was performed as a randomized, placebo-controlled, double-blind study with parallel design...
2018: Journal of the International Society of Sports Nutrition
A J Chappell, T Simper, M E Barker
Background: Competitive bodybuilders employ a combination of resistance training, cardiovascular exercise, calorie reduction, supplementation regimes and peaking strategies in order to lose fat mass and maintain fat free mass. Although recommendations exist for contest preparation, applied research is limited and data on the contest preparation regimes of bodybuilders are restricted to case studies or small cohorts. Moreover, the influence of different nutritional strategies on competitive outcome is unknown...
2018: Journal of the International Society of Sports Nutrition
Troy Purdom, Len Kravitz, Karol Dokladny, Christine Mermier
Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO2max , is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox)...
2018: Journal of the International Society of Sports Nutrition
Raúl Domínguez, José Luis Maté-Muñoz, Eduardo Cuenca, Pablo García-Fernández, Fernando Mata-Ordoñez, María Carmen Lozano-Estevan, Pablo Veiga-Herreros, Sandro Fernandes da Silva, Manuel Vicente Garnacho-Castaño
Beetroot juice contains high levels of inorganic nitrate (NO3 - ) and its intake has proved effective at increasing blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of investigations have sought to assess the effects of this supplement on performance at high-intensity exercise...
2018: Journal of the International Society of Sports Nutrition
Michael Cameron, Clayton L Camic, Scott Doberstein, Jacob L Erickson, Andrew R Jagim
Background: The use of dietary supplements to improve performance is becoming increasingly popular among athletes and fitness enthusiasts. Unfortunately, there is a tremendous lack of research being done regarding female athletes and the use of sport supplements. The purpose of this study was to examine the acute effects of multi-ingredient pre-workout supplement (MIPS) ingestion on resting metabolism and exercise performance in recreationally-active females. Methods: Fifteen recreationally-active females participated in a randomized, double-blind, placebo controlled study...
2018: Journal of the International Society of Sports Nutrition
John G Seifert, Allison Brumet, John A St Cyr
Background: Skeletal muscle adenosine triphosphate (ATP) levels are severely depleted during and following prolonged high intensity exercise. Recovery from these lower ATP levels can take days, which can affect performance on subsequent days of exercise. Untrained individuals often suffer the stress and consequences of acute, repeated bouts of exercise by not having the ability to perform or recovery sufficiently to exercise on subsequent days. Conversely, trained individuals may be able to recover more quickly due to their enhanced metabolic systems...
2017: Journal of the International Society of Sports Nutrition
Grant M Tinsley, Matthew A Hamm, Amy K Hurtado, Austin G Cross, Jose G Pineda, Austin Y Martin, Victor A Uribe, Ty B Palmer
Background: Pre-workout supplements purportedly enhance feelings of energy, reduce fatigue and improve exercise performance. The purpose of this study was to examine the performance effects of caffeinated and non-caffeinated multi-ingredient pre-workout supplements. Methods: In a counterbalanced, double-blind, placebo-controlled design, eccentric and concentric force production during lower body resistance exercise on a mechanized squat device were assessed after supplement ingestion...
2017: Journal of the International Society of Sports Nutrition
Kana Konishi, Tetsuya Kimura, Atsushi Yuhaku, Toshiyuki Kurihara, Masahiro Fujimoto, Takafumi Hamaoka, Kiyoshi Sanada
Background: A decline in executive function could have a negative influence on the control of actions in dynamic situations, such as sports activities. Mouth rinsing with a carbohydrate solution could serve as an effective treatment for preserving the executive function in exercise. The purpose of this study was to examine the effects of mouth rinsing with a carbohydrate solution on executive function after sustained moderately high-intensity exercise. Methods: Eight young healthy participants completed 65 min of running at 75% V̇O2 max with two mouth-rinsing conditions: with a carbohydrate solution (CHO) or with water (CON)...
2017: Journal of the International Society of Sports Nutrition
Justin Roberts, Anastasia Zinchenko, Craig Suckling, Lee Smith, James Johnstone, Menno Henselmans
Background: Dietary protein intakes up to 2.9 .d-1 and protein consumption before and after resistance training may enhance recovery, resulting in hypertrophy and strength gains. However, it remains unclear whether protein quantity or nutrient timing is central to positive adaptations. This study investigated the effect of total dietary protein content, whilst controlling for protein timing, on recovery in resistance trainees. Methods: Fourteen resistance-trained individuals underwent two 10-day isocaloric dietary regimes with a protein content of 1...
2017: Journal of the International Society of Sports Nutrition
Håvard Hamarsland, Anne Lene Nordengen, Sigve Nyvik Aas, Kristin Holte, Ina Garthe, Gøran Paulsen, Matthew Cotter, Elisabet Børsheim, Haakon B Benestad, Truls Raastad
Background: Protein intake is essential to maximally stimulate muscle protein synthesis, and the amino acid leucine seems to possess a superior effect on muscle protein synthesis compared to other amino acids. Native whey has higher leucine content and thus a potentially greater anabolic effect on muscle than regular whey (WPC-80). This study compared the acute anabolic effects of ingesting 2 × 20 g of native whey protein, WPC-80 or milk protein after a resistance exercise session...
2017: Journal of the International Society of Sports Nutrition
Robert A DiSilvestro, Staci Hart, Trisha Marshall, Elizabeth Joseph, Alyssa Reau, Carmen B Swain, Jason Diehl
Background: Certain essential and conditionally essential nutrients (CENs) perform functions involved in aerobic exercise performance. However, increased intake of such nutrient combinations has not actually been shown to improve such performance. Methods: For 1 mo, aerobically fit, young adult women took either a combination of 3 mineral glycinate complexes (daily dose: 36 mg iron, 15 mg zinc, and 2 mg copper) + 2 CENs (daily dose: 2 g carnitine and 400 mg phosphatidylserine), or the same combination with generic mineral complexes, or placebo (n = 14/group)...
2017: Journal of the International Society of Sports Nutrition
Haruna Muwonge, Robert Zavuga, Peninnah Aligawesa Kabenge, Timothy Makubuya
Background: The use of nutritional supplements (NS) places athletes at great risk for inadvertent doping. Due to the paucity of data on supplement use, this study aimed to determine the proportion of Ugandan athletes using nutritional supplements and to investigate the athletes' motivation to use these supplements. Methods: A cross-sectional study was conducted in which an interviewer-administered questionnaire was used to collect data from 359 professional athletes participating in individual (boxing, cycling, athletics) and team (basketball, rugby, football, netball, and volleyball) sports...
2017: Journal of the International Society of Sports Nutrition
Mayur K Ranchordas, Nicholas B Tiller, Girish Ramchandani, Raj Jutley, Andrew Blow, Jonny Tye, Ben Drury
Background: The purpose of this paper was to report normative data on regional sweat sweat-sodium concentrations of various professional male team-sport athletes, and to compare sweat-sodium concentrations among sports. Data to this effect would inform our understanding of athlete sodium requirements, thus allowing for the individualisation of sodium replacement strategies. Accordingly, data from 696 athletes (Soccer, n = 270; Rugby, n = 181; Baseball, n = 133; American Football, n = 60; Basketball, n = 52) were compiled for a retrospective analysis...
2017: Journal of the International Society of Sports Nutrition
Lena Marcus, Jason Soileau, Lawrence W Judge, David Bellar
BACKGROUND: Recent studies have suggested that alpha glycerylphosphorylcholine (A-GPC) may be an effective ergogenic aid. The present study was designed to assess the efficacy of two doses of A-GPC in comparison to placebo and caffeine for increasing countermovement jump performance, isometric strength, and psychomotor function. METHODS: Forty-eight healthy, college aged males volunteered for the present study and underwent baseline assessment of countermovement jump (CMJ), isometric mid thigh pull (IMTP), upper body isometric strength test (UBIST), and psychomotor vigilance (PVT)...
2017: Journal of the International Society of Sports Nutrition
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