bluuebunny/crossref_metadata_2025 huggingface dataset:
Branched-Chain Amino Acid Supplementation and Indicators of Muscle Damage after Endurance Exercise
Authors: Greer Beau Kjerulf , Woodard John L. , White Jim P. , Arguello Eric M. , Haymes Emily M.
Published: August 2016

The purpose of this study was to determine whether branched-chain amino acid (BCAA) supplementation attenuates indirect indicators of muscle damage during endurance exercise as compared with an isocaloric, carbohydrate (CHO) beverage or a noncaloric placebo (PLAC) beverage. Nine untrained men performed three 90-min cycling bouts at 55% VO2peak. Subjects, blinded to beverage selection, ingested a total of 200 kcal of energy via the CHO or BCAA beverage before and at 60 min of exercise, or they drank the PLAC beverage. Creatine kinase (CK), lactate dehydrogenase (LDH), isokinetic leg-extension and fexion torque, and muscle soreness were assessed before and immediately, 4 h, 24 h, and 48 h post exercise. The trials were separated by 8 wk. CK activities were significantly lower after the BCAA trial than in the PLAC trial at 4, 24, and 48 h post exercise, as well as lower than the CHO beverage at 24 h post exercise. CK was lower in the CHO trial at the 24- and 48-h time points than in the PLAC trial. LDH activities were lower in the BCAA trial at 4 h than in the PLAC trial. As compared with the CHO and PLAC trials, ratings of perceived soreness were lower at 24 h post exercise, and leg-fexion torque was higher at the 48-h time point after the BCAA trial. The present data suggest that BCAA supplementation attenuates muscle damage during prolonged endurance exercise in untrained college-age men. CHO ingestion attenuates CK activities at 24 and 48 h post exercise as compared with a placebo beverage.
Coingestion of Carbohydrate-Protein during Endurance Exercise: Influence on Performance and Recovery
Authors: Saunders Michael J.
Published: August 2016

Endurance athletes commonly consume carbohydrate-electrolyte sports beverages during prolonged events. The benefits of this strategy are numerous—sports-beverage consumption during exercise can delay dehydration, maintain blood glucose levels, and potentially attenuate muscle glycogen depletion and central fatigue. Thus, it is generally agreed that carbohydrate-electrolyte beverages can improve endurance performance. A controversy has recently emerged regarding the potential role of protein in sports beverages. At least 3 recent studies have reported that carbohydrate-protein ingestion improves endurance performance to a greater extent than carbohydrate alone. In addition, carbohydrate-protein ingestion has been associated with reductions in markers of muscle damage and improved post exercise recovery. Although many of these muscle damage and recovery studies examined post exercise nutritional intake, recent evidence suggests that these benefits may be elicited with carbohydrate-protein consumption during exercise. These findings are intriguing and suggest that the importance of protein for endurance athletes has been underappreciated. However, 2 studies recently reported no differences in endurance performance between carbohydrate and carbohydrate-protein beverages. The varied outcomes may have been influenced by a number of methodological differences, including the amounts and types of carbohydrate or protein in the beverages, the exercise protocols, and the relative statistical power of the studies. In addition, although there are plausible mechanisms that could explain the ergogenic effects of carbohydrate-protein beverages, they remain relatively untested. This review examines the existing research regarding the efficacy of carbohydrate-protein consumption during endurance exercise. Limitations of the existing research are addressed, as well as potential areas for future study.
Moderate Exercise, Postprandial Energy Expenditure, and Substrate Use in Varying Meals in Lean and Obese Men
Authors: Stiegler Petra , Sparks S. Andrew , Cunliffe Adam
Published: August 2016

Maximizing postprandial energy expenditure and fat oxidation could be of clinical relevance for the treatment of obesity. This study investigated the effect of prior exercise on energy expenditure and substrate utilization after meals containing varying amounts of macronutrients. Eight lean (11.6% ± 4.0% body fat, M ± SD) and 12 obese (35.9% ± 5.3% body fat) men were randomly assigned to a protein (43% protein, 30% carbohydrate) or a carbohydrate (10% protein, 63% carbohydrate) meal. The metabolic responses to the meals were investigated during 2 trials, when meals were ingested after a resting period (D) or cycling exercise (Ex+D; 65% of oxygen consumption reserve, 200 kcal). Energy expenditure, substrate utilization, and glucose and insulin responses were measured for 4 hr during the postprandial phase. Although postprandial energy expenditure was not affected by prior exercise, the total amount of fat oxidized was higher during Ex+D than during D (170.8 ± 60.1 g vs. 137.8 ± 50.8 g, p < .05), and, accordingly, the use of carbohydrate as substrate was decreased (136.4 ± 45.2 g vs. 164.0 ± 42.9 g, p < .05). After the protein meal fat-oxidation rates were higher than after carbohydrate intake (p < .05), an effect independent of prior exercise. Plasma insulin tended to be lower during Ex+D (p = .072) and after the protein meal (p = .066). No statistically significant change in postprandial blood glucose was induced by prior exercise. Exercising before meal consumption can result in a marked increase in fat oxidation, which is independent of the type of meal consumed.
The Influence of Carbohydrate Mouth Rinse on Self-Selected Speeds during a 30-min Treadmill Run
Authors: Rollo Ian , Williams Clyde , Gant Nicholas , Nute Maria
Published: August 2016

The purpose of this study was to examine the influences of a carbohydrate (CHO) mouth rinse on self-selected running speeds during a 30-min treadmill run. Ten endurance-trained men performed 2 trials, each involving a 10-min warm-up at 60% VO2max followed by a 30-min run. The run was performed on an automated treadmill that allowed the spontaneous selection of speeds without manual input. Participants were asked to run at speeds that equated to a rating of perceived exertion of 15, mouth rinsing with either a 6% CHO or taste-matched placebo (PLA) solution. In addition to recording self-selected speeds and total distance covered the authors assessed the runners’ subjective feelings. The total distance covered was greater during the CHO than during the PLA trial (p < .05). Faster speeds selected during the first 5 min of exercise corresponded with enhanced feelings of pleasure when mouth rinsing with the CHO solution. Mouth rinsing with a CHO solution increased total distance covered during a self-selected 30-min run in comparison with mouth rinsing with a color- and tastematched placebo.
Body Image and Body Composition: Comparisons of Young Male Elite Soccer Players and Controls
Authors: Arroyo Marta , González-de-Suso José Manue , Sanchez Celia , Ansotegui Laura , Rocandio Ana M.
Published: August 2016

The purpose of this study was to evaluate body composition and body image (perception and satisfaction) in a group of young elite soccer players and to compare the data with those of a control group (age and BMI matched). Participants were 56 volunteer males whose mean age and BMI were 19.6 (SD 1.3) years and 23.3 (SD 1.1) kg/m2, respectively. Results showed that soccer players have a higher lean mass and lower fat mass than controls. Moreover, body perception (difference between current and actual image) was more accurate in controls than in soccer players, and the results suggest a tendency for soccer players to aspire to have more muscle mass and body fat. Soccer players perceived an ideal image with significantly higher body-fat percentage than their current and actual images. There were no body-dissatisfaction differences between groups, however. Although the results are necessarily limited by the small sample size, the findings should be of interest to coaches of young elite soccer teams.
Effect of Protein-Supplement Timing on Strength, Power, and Body-Composition Changes in Resistance-Trained Men
Authors: Hoffman Jay R. , Ratamess Nicholas A. , Tranchina Christopher P. , Rashti Stefanie L. , Kang Jie , Faigenbaum Avery D.
Published: August 2016

The effect of 10 wk of protein-supplement timing on strength, power, and body composition was examined in 33 resistance-trained men. Participants were randomly assigned to a protein supplement either provided in the morning and evening (n = 13) or provided immediately before and immediately after workouts (n = 13). In addition, 7 participants agreed to serve as a control group and did not use any protein or other nutritional supplement. During each testing session participants were assessed for strength (one-repetition-maximum [1RM] bench press and squat), power (5 repetitions performed at 80% of 1RM in both the bench press and the squat), and body composition. A significant main effect for all 3 groups in strength improvement was seen in 1RM bench press (120.6 ± 20.5 kg vs. 125.4 ± 16.7 at Week 0 and Week 10 testing, respectively) and 1RM squat (154.5 ± 28.4 kg vs. 169.0 ± 25.5 at Week 0 and Week 10 testing, respectively). However, no significant between-groups interactions were seen in 1RM squat or 1RM bench press. Significant main effects were also seen in both upper and lower body peak and mean power, but no significant differences were seen between groups. No changes in body mass or percent body fat were seen in any of the groups. Results indicate that the time of protein-supplement ingestion in resistance-trained athletes during a 10-wk training program does not provide any added benefit to strength, power, or body-composition changes.
The Effect of Carbohydrate Gels on Gastrointestinal Tolerance during a 16-km Run
Authors: Pfeiffer Beate , Cotterill Alexandra , Grathwohl Dominik , Stellingwerff Trent , Jeukendrup Asker E.
Published: August 2016

Two studies were conducted to investigate gastrointestinal (GI) tolerance of high carbohydrate (CHO) intakes during intense running. The first study investigated tolerance of a CHO gel delivering glucose plus fructose (GLU+FRC) at different rates. The second study investigated tolerance of high intakes of glucose (GLU) vs. GLU+FRC gel. Both studies used a randomized, 2-treatment, 2-period crossover design: Endurance-trained men and women (Study 1: 26 men, 8 women; 37 ± 11 yr; 73 ± 9 kg; 1.76 ± 0.07 m. Study 2: 34 men, 14 women; 35 ± 10 yr; 70 ± 9 kg; 1.75 ± 0.09 m) completed two 16-km outdoor-runs. In Study 1 gels were administered to provide 1.0 or 1.4 g CHO/min with ad libitum water intake every 3.2 km. In Study 2 GLU or GLU+FRC gels were given in a double-blind manner to provide 1.4 g CHO/min. In both studies a postexercise questionnaire assessed 17 symptoms on a 10-point scale (from 0 to 9). For all treatments, GI complaints were mainly scored at the low end of the scale. In Study 1 mean scores ranged from 0.00 ± 0.00 to 1.12 ± 1.90, and in Study 2, from 0.00 ± 0.0 to 1.27 ± 1.78. GI symptoms were grouped into upper abdominal, lower abdominal, and systemic problems. There were no significant treatment differences in these categories in either study. In conclusion, despite high CHOgel intake, and regardless of the blend (GLU vs. GLU+FRC), average scores for GI symptoms were at the low end of the scale, indicating predominantly good tolerance during a 16-km run. Nevertheless, some runners (~10–20%) experienced serious problems, and individualized feeding strategies might be required.
Effects of Exercise on Hepcidin Response and Iron Metabolism during Recovery
Authors: Peeling Peter , Dawson Brian , Goodman Carmel , Landers Grant , Wiegerinck Erwin T. , Swinkels Dorine W. , Trinder Debbie
Published: August 2016

Urinary hepcidin, inflammation, and iron metabolism were examined during the 24 hr after exercise. Eight moderately trained athletes (6 men, 2 women) completed a 60-min running trial (15-min warm-up at 75–80% HRpeak + 45 min at 85–90% HRpeak) and a 60-min trial of seated rest in a randomized, crossover design. Venous blood and urine samples were collected pretrial, immediately posttrial, and at 3, 6, and 24 hr posttrial. Samples were analyzed for interleukin-6 (IL-6), C-reactive protein (CRP), serum iron, serum ferritin, and urinary hepcidin. The immediate postrun levels of IL-6 and 24-hr postrun levels of CRP were significantly increased from baseline (6.9 and 2.6 times greater, respectively) and when compared with the rest trial (p ≤ .05). Hepcidin levels in the run trial after 3, 6, and 24 hr of recovery were significantly greater (1.7–3.1 times) than the pre- and immediate postrun levels (p ≤ .05). This outcome was consistent in all participants, despite marked variation in the magnitude of rise. In addition, the 3-hr postrun levels of hepcidin were significantly greater than at 3 hr in the rest trial (3.0 times greater, p ≤ .05). Hepcidin levels continued to increase at 6 hr postrun but failed to significantly differ from the rest trial (p = .071), possibly because of diurnal influence. Finally, serum iron levels were significantly increased immediately postrun (1.3 times, p ≤ .05). The authors concluded that high-intensity exercise was responsible for a significant increase in hepcidin levels subsequent to a significant increase in IL-6 and serum iron.
The Influence of Caffeine and Carbohydrate Coingestion on Simulated Soccer Performance
Authors: Gant Nicholas , Ali Ajmol , Foskett Andrew
Published: August 2016

Carbohydrate and caffeine are known to independently improve certain aspects of athletic performance. However, less is understood about physiological and performance outcomes when these compounds are coingested in a rehydration and carbohydrate-replacement strategy. The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials. They ingested a carbohydrate-electrolyte solution (CON) providing a total of 1.8 g/kg body mass (BM) of carbohydrate or a similar solution with added caffeine (CAF; 3.7 mg/kg BM). Solutions were ingested 1 hr before exercise and every 15 min during the protocol. Soccer passing skill and countermovement-jump height (CMJ) were quantified before exercise and regularly during exercise. Sprinting performance, heart rate, blood lactate concentration (La) and the subjective experiences of participants were measured routinely. Mean 15-m sprint time was faster during CAF (p = .04); over the final 15 min of exercise mean sprint times were CAF 2.48 ± 0.15 s vs. CON 2.59 ± 0.2 s. Explosive leg power (CMJ) was improved during CAF (52.9 ± 5.8 vs. CON 51.7 ± 5.7 cm, p = .03). Heart rate was elevated throughout CAF, and ratings of pleasure were significantly enhanced. There were no significant differences in passing skill, rating of perceived exertion, La, or body-mass losses between trials. The addition of caffeine to the carbohydrate-electrolyte solution improved sprinting performance, countermovement jumping, and the subjective experiences of players. Caffeine appeared to offset the fatigue-induced decline in self-selected components of performance.
Effects of Induced Alkalosis on Simulated Match Performance in Elite Female Water Polo Players
Authors: Tan Frankie , Polglaze Ted , Cox Gregory , Dawson Brian , Mujika Iñigo , Clark Sally
Published: August 2016

This study investigated the effects of sodium bicarbonate (NaHCO3) ingestion on simulated water polo match performance. Twelve elite players from the Australian National Women’s Water Polo Squad (age 23.7 ± 3.0 yr, height 1.73 ± 0.05 m, body mass 75.7 ± 8.0 kg) participated in the study. In a randomized cross-over double-blind design, players ingested 0.3 g/kg of NaHCO3 or placebo 90 min before performing a 59-min match-simulation test (MST) that included 56 × 10-m maximal-sprint swims as the performance measure. Capillary blood samples were obtained preingestion, pre- and post-warm-up, and after each quarter of the MST. Preexercise ingestion of NaHCO3 was effective in enhancing extracellular pH from baseline levels of 7.41; ±0.01 (M; ±90% confidence limits) to 7.49; ±0.01 and bicarbonate levels from 24.4; ±0.3 to 28.5; ±0.5 mmol/L. The percentage difference in mean sprint times between trials showed no substantial effects of NaHCO3 (0.4; ±1.0, effect size = 0.09; ±0.23; p = .51). These findings are contrary to those of previous NaHCO3 studies on simulated team-sport performance, but this investigation is unique in that it examined highly trained athletes performing sport-specific tasks. In conclusion, water polo players should not expect substantial enhancement in intermittent-sprint performance from NaHCO3 supplementation.
Branched-Chain Amino Acid Supplementation Before Squat Exercise and Delayed-Onset Muscle Soreness
Authors: Shimomura Yoshiharu , Inaguma Asami , Watanabe Satoko , Yamamoto Yuko , Muramatsu Yuji , Bajotto Gustavo , Sato Juichi , Shimomura Noriko , Kobayashi Hisamine , Mawatari Kazunori
Published: August 2016

The authors examined the effect of branched-chain amino acid (BCAA) supplementation on squat-exercise-induced delayed-onset muscle soreness (DOMS) using 12 young, healthy, untrained female participants. The experiment was conducted with a crossover double-blind design. In the morning on the exercise-session day, the participants ingested either BCAA (isoleucine:leucine:valine = 1:2.3:1.2) or dextrin at 100 mg/kg body weight before the squat exercise, which consisted of 7 sets of 20 squats/set with 3-min intervals between sets. DOMS showed a peak on Days 2 and 3 in both trials, but the level of soreness was significantly lower in the BCAA trial than in the placebo. Leg-muscle force during maximal voluntary isometric contractions was measured 2 d after exercise (Day 3), and the BCAA supplementation suppressed the muscle-force decrease (to ~80% of the value recorded under the control conditions) observed in the placebo trial. Plasma BCAA concentrations, which decreased after exercise in the placebo trial, were markedly elevated during the 2 hr postexercise in the BCAA trial. Serum myoglobin concentration was increased by exercise in the placebo but not in the BCAA trial. The concentration of plasma elastase as an index of neutrophil activation appeared to increase after the squat exercise in both trials, but the change in the elastase level was significant only in the placebo trial. These results suggest that muscle damage may be suppressed by BCAA supplementation.
The Effect of Acute Taurine Ingestion on Endurance Performance and Metabolism in Well-Trained Cyclists
Authors: Rutherford Jane A. , Spriet Lawrence L. , Stellingwerff Trent
Published: August 2016

This study examined whether acute taurine (T) ingestion before prolonged cycling would improve time-trial (TT) performance and alter whole-body fuel utilization compared with a control (CON) trial and a placebo (PL) trial in which participants were told they received taurine but did not. Eleven endurance-trained male cyclists (27.2 ± 1.5 yr, 74.3 ± 2.3 kg, 59.9 ± 2.3 ml · kg−1 · min−1; M ± SEM) completed 3 trials in a randomized, crossover, blinded design in which they consumed a noncaloric sweetened beverage with either 1.66 g of T or nothing added (CON, PL) 1 hr before exercise. Participants then cycled at 66.5% ± 1.9% VO2max for 90 min followed immediately by a TT (doing 5 kJ of work/kg body mass as fast as possible). Data on fluid administration, expired gas, heart rate, and ratings of perceived exertion were collected at 15-min intervals during the 90-min cycling ride, but there were no differences recorded between trials. There was no difference in TT performance between any of the 3 trials (1,500 ± 87 s). Average carbohydrate (T 2.73 ± 0.21, CON 2.88 ± 0.19, PL 2.89 ± 0.20 g/min) and fat (T 0.45 ± 0.05, CON 0.39 ± 0.04, PL 0.39 ± 0.05 g/min) oxidation rates were unaffected by T supplementation. T ingestion resulted in a 16% increase (5 g, ~84 kJ; p < .05) in total fat oxidation over the 90-min exercise period compared with CON and PL. The acute ingestion of 1.66 g of T before exercise did not enhance TT performance but did result in a small but significant increase in fat oxidation during submaximal cycling in endurance-trained cyclists.
Excess Postexercise Oxygen Consumption After Aerobic Exercise Training
Authors: Sedlock Darlene A. , Lee Man-Gyoon , Flynn Michael G. , Park Kyung-Shin , Kamimori Gary H.
Published: August 2016

Literature examining the effects of aerobic exercise training on excess postexercise oxygen consumption (EPOC) is sparse. In this study, 9 male participants (19–32 yr) trained (EX) for 12 wk, and 10 in a control group (CON) maintained normal activity. VO2max, rectal temperature (Tre), epinephrine, norepinephrine, free fatty acids (FFA), insulin, glucose, blood lactate (BLA), and EPOC were measured before (PRE) and after (POST) the intervention. EPOC at PRE was measured for 120 min after 30 min of treadmill running at 70% VO2max. EX completed 2 EPOC trials at POST, i.e., at the same absolute (ABS) and relative (REL) intensity; 1 EPOC test for CON served as both the ABS and REL trial because no significant change in VO2max was noted. During the ABS trial, total EPOC decreased significantly (p < .01) from PRE (39.4 ± 3.6 kcal) to POST (31.7 ± 2.2 kcal). Tre, epinephrine, insulin, glucose, and BLA at end-exercise or during recovery were significantly lower and FFA significantly higher after training. Training did not significantly affect EPOC during the REL trial; however, epinephrine was significantly lower, and norepinephrine and FFA, significantly higher, at endexercise after training. Results indicate that EPOC varies as a function of relative rather than absolute metabolic stress and that training improves the efficiency of metabolic regulation during recovery from exercise. Mechanisms for the decreased magnitude of EPOC in the ABS trial include decreases in BLA, Tre, and perhaps epinephrine-mediated hepatic glucose production and insulin-mediated glucose uptake.
Bone-Mineral Density and Other Features of the Female Athlete Triad in Elite Endurance Runners: A Longitudinal and Cross-Sectional Observational Study
Authors: Pollock Noel , Grogan Claire , Perry Mark , Pedlar Charles , Cooke Karl , Morrissey Dylan , Dimitriou Lygeri
Published: August 2016

Low bone-mineral density (BMD) is associated with menstrual dysfunction and negative energy balance in the female athlete triad. This study determines BMD in elite female endurance runners and the associations between BMD, menstrual status, disordered eating, and training volume. Forty-four elite endurance runners participated in the cross-sectional study, and 7 provided longitudinal data. Low BMD was noted in 34.2% of the athletes at the lumbar spine, and osteoporosis in 33% at the radius. In cross-sectional analysis, there were no significant relationships between BMD and the possible associations. Menstrual dysfunction, disordered eating, and low BMD were coexistent in 15.9% of athletes. Longitudinal analysis identified a positive association between the BMD reduction at the lumbar spine and training volume (p = .026). This study confirms the presence of aspects of the female athlete triad in elite female endurance athletes and notes a substantial prevalence of low BMD and osteoporosis. Normal menstrual status was not significantly associated with normal BMD, and it is the authors’ practice that all elite female endurance athletes undergo dual-X-ray absorptiometry screening. The association between increased training volume, trend for menstrual dysfunction, and increased loss of lumbar BMD may support the concept that negative energy balance contributes to bone loss in athletes.
Effect of Caffeine Intake on Pain Perception During High-Intensity Exercise
Authors: Astorino Todd A. , Terzi Michael N. , Roberson Daniel W. , Burnett Timothy R.
Published: August 2016

Caffeine has been shown to reduce leg-muscle pain during submaximal cycle ergometry, as well as in response to eccentric exercise. However, less is known about its analgesic properties during non-steadystate, high-intensity exercise. The primary aim of this study was to examine the effect of 2 doses of caffeine on leg pain and rating of perceived exertion (RPE) during repeated bouts of high-intensity exercise. Fifteen active men (age 26.4 ± 3.9 yr) completed 2 bouts of 40 repetitions of “all-out” knee extension and flexion of the dominant leg at a contraction velocity equal to 180°/s. Before each trial, subjects abstained from caffeine intake and intense exercise for 48 hr. Over 3 days separated by 48 hr, subjects ingested 1 of 3 treatments (5 mg/kg or 2 mg/kg of anhydrous caffeine or placebo) in a randomized, single-blind, counterbalanced, crossover design. Leg-muscle pain and RPE were assessed during and after exercise using established categorical scales. Across all treatments, pain perception was significantly increased (p < .05) during exercise, as well as from Bout 1 to 2, yet there was no effect (p > .05) of caffeine on pain perception or RPE. Various measures of muscle function were improved (p < .05) with a 5-mg/kg caffeine dose vs. the other treatments. In the 5-mg/kg trial, it is plausible that subjects were able to perform better with similar levels of pain perception and exertion.
Dietary Supplementation Patterns of Korean Olympic Athletes Participating in the Beijing 2008 Summer Olympic Games
Authors: Kim Jongkyu , Kang Seung-ki , Jung Han-sang , Chun Yoon-suck , Trilk Jennifer , Jung Seung Ho
Published: August 2016

Athletes report frequent use of various dietary supplements (DSs). However, no study has examined DS use and antidoping knowledge in Korean Olympians. The objectives of this study were to obtain information about Korean Olympians’ DS use during the training period for the Beijing 2008 Summer Olympic Games and immediately before their Olympic events, to obtain DS-intake reasons and DS providers, and to obtain information on athletes’ doping education, knowledge, and educators. Korean Olympians completed 2 questionnaires 1 wk before the opening and within 1 wk after the closing of the Beijing 2008 Summer Olympic Games. Results showed that 79% of male and 82% of female Olympians take more than 1 DS during the training period and that vitamins and Oriental supplements are the 2 top-ranked DSs. Reasons for DS use were to improve recovery ability (66%) and muscle performance (22%), and sources of obtaining DSs were parents (36%) and coaches (35%). Furthermore, 79% of Korean Olympians reported receiving regular education on antidoping regulations from Olympic-sponsored education classes (64%) and coaches (15%). In conclusion, this study was the first to examine DS use and antidoping-related information in Korean Olympians. Because some herbal products contain substances banned by the World Anti-Doping Agency, athletes should be cautious in using mixed Oriental supplements.
Effects of a Dairy Supplement and Resistance Training on Lean Mass and Insulin-Like Growth Factor in Women
Authors: Thomas David Travis , Wideman Laurie , Lovelady Cheryl A.
Published: August 2016

Purpose:

To examine the effect of yogurt supplementation pre- and postexercise on changes in body composition in overweight women engaged in a resistance-training program.

Methods:

Participants (age = 36.8 ± 4.8 yr) with a body-mass index of 29.1±2.1 kg/m2 were randomized to yogurt supplement (YOG; n = 15) or isoenergetic sucrose beverage (CONT; n = 14) consumed before and after exercise for 16 wk. Participants were also instructed to reduce energy intake daily (–1,046 kJ) during the study. Body composition was assessed by dual-energy X-ray absorptiometry, waist circumference, and sagittal diameter. Strength was measured with 1-repetition maximum. Dietary recalls were obtained by a multipass approach using Nutrition Data System software. Insulin-like growth factor-1 and insulin-like growth-factor-binding protein-3 were measured with ELISA.

Results:

Significant weight losses of 2.6 ± 4.5 kg (YOG) and 1.2 ± 2.5 kg (CONT) were observed. Total lean weight increased significantly over time in both YOG (0.8 ± 1.2 kg) and CONT (1.1 ± 0.9 kg). Significant reductions in total fat (YOG = 3.4 ± 4.1 kg vs. CONT = 2.3 ± 2.4 kg) were observed over time. Waist circumference, sagittal diameter, and trunk fat decreased significantly over time without group differences. Both groups significantly decreased energy intake while maintaining protein intake. Strength significantly increased over time in both groups. No changes over time or between groups were observed in hormone levels.

Conclusions:

These data suggest that yogurt supplementation offered no added benefit for increasing lean mass when combined with resistance training and modest energy restriction.
Impact of Fluid Restriction and ad Libitum Water Intake or an 8% Carbohydrate-Electrolyte Beverage on Skill Performance of Elite Adolescent Basketball Players
Authors: Carvalho Pedro , Oliveira Bruno , Barros Renata , Padrão Patrícia , Moreira Pedro , Teixeira Vítor Hugo
Published: August 2016

Twelve adolescent athletes underwent, in a crossover-design study, 3 separate 90-min training sessions in the following conditions: no fluid ingestion allowed (NF), ad libitum ingestion of water (W), and ad libitum ingestion of a commercial 8% carbohydrate-electrolyte sports beverage (CSB). After each session athletes performed a set of basketball drills (2-point, 3-point, and free-throw shootout, suicide sprints, and defensive zigzags). Body weight (before and after sessions), rating of perceived exertion (RPE), urine color, and beverage acceptability were determined in each session. Athletes also completed a survey about their knowledge and behaviors regarding hydration and fluid replacement. The percentage of weight loss was significantly higher in NF (2.46% ± 0.87%) than in the other 2 conditions (W, 1.08% ± 0.67%, p = .006; CSB, 0.65% ± 0.62%, p = .001) but also higher in W than CSB (p = .012). RPE was higher in NF (16.8 ± 1.96) than in the W (14.2 ± 1.99, p = .004) and CSB (13.3 ± 2.06, p = .002) trials. Athletes’ fluid intake was positively correlated with proper self-reported behaviors (r = .75, p = .005) and knowledge (r = .76, p = .004) about fluid and hydration. In conclusion, fluid restriction during exercise was associated with a greater level of dehydration and increased perceived exertion but had no impact on basketball performance compared with ad libitum drinking of water or a CSB. Athletes with more knowledge about hydration and better self-reported hydration behaviors ingested more fluids during training sessions.
The Association of a High Drive for Thinness With Energy Deficiency and Severe Menstrual Disturbances: Confirmation in a Large Population of Exercising Women
Authors: Gibbs Jenna C. , Williams Nancy I. , Scheid Jennifer L. , Toombs Rebecca J. , De Souza Mary Jane
Published: August 2016

A high drive-for-thinness (DT) score obtained from the Eating Disorder Inventory-2 is associated with surrogate markers of energy deficiency in exercising women. The purposes of this study were to confirm the association between DT and energy deficiency in a larger population of exercising women that was previously published and to compare the distribution of menstrual status in exercising women when categorized as high vs. normal DT. A high DT was defined as a score ≥7, corresponding to the 75th percentile for college-age women. Exercising women age 22.9 ± 4.3 yr with a BMI of 21.2±2.2 kg/m2 were retrospectively grouped as high DT (n = 27) or normal DT (n = 90) to compare psychometric, energetic, and reproductive characteristics. Chi-square analyses were performed to compare the distribution of menstrual disturbances between groups. Measures of resting energy expenditure (REE) (4,949 ± 494 kJ/day vs. 5,406 ± 560 kJ/day, p < .001) and adjusted REE (123 ± 16 kJ/LBM vs. 130 ± 9 kJ/LBM, p = .027) were suppressed in exercising women with high DT vs. normal DT, respectively. Ratio of measured REE to predicted REE (pREE) in the high-DT group was 0.85 ± 0.10, meeting the authors’ operational definition for an energy deficiency (REE:pREE <0.90). A greater prevalence of severe menstrual disturbances such as amenorrhea and oligomenorrhea was observed in the high-DT group (χ2 = 9.3, p = .003) than in the normal-DT group. The current study confirms the association between a high DT score and energy deficiency in exercising women and demonstrates a greater prevalence of severe menstrual disturbances in exercising women with high DT.
Effect of Mixed Flavonoids, n-3 Fatty Acids, and Vitamin C on Oxidative Stress and Antioxidant Capacity Before and After Intense Cycling
Authors: McAnulty Steven R. , Nieman David C. , McAnulty Lisa S. , Lynch Worley S. , Jin Fuxia , Henson Dru A.
Published: August 2016

Consumption of plant flavonoids, antioxidants, and n-3 fatty acids is proposed to have many potential health benefits derived primarily through antioxidant and anti-inflammatory activities. This study examined the effects of 1,000 mg quercetin + 1,000 mg vitamin C (QC); 1,000 mg quercetin, 1,000 mg vitamin C, 400 mg isoquercetin, 30 mg epigallocatechin gallate, and 400 mg n-3 fatty acids (QFO); or placebo (P), taken each day for 2 wk before and during 3 d of cycling at 57% Wmax for 3 hr, on plasma antioxidant capacity (ferricreducing ability of plasma [FRAP], oxygen-radical absorbance capacity [ORAC]), plasma oxidative stress (F2-isoprostanes), and plasma quercetin and vitamin C levels. Thirty-nine athletes were recruited and randomized to QC, QFO, or P. Blood was collected at baseline, after 2 wk supplementation, immediately postexercise, and 14 hr postexercise. Statistical design used a 3 (groups) × 4 (times) repeated-measures ANOVA with post hoc analyses. Plasma quercetin was significantly elevated in QC and QFO compared with P. Plasma F2-isoprostanes, FRAP, and vitamin C were significantly elevated and ORAC significantly decreased immediately postexercise, but no difference was noted in the overall pattern of change. Post hoc analyses revealed that the QC and QFO groups did not exhibit a significant increase in F2-isoprostanes from baseline to immediately postexercise compared with P. This study indicates that combining flavonoids and antioxidants with n-3 fatty acids is effective in reducing the immediate postexercise increase in F2-isoprostanes. Moreover, this effect occurs independently of changes in plasma antioxidant capacity.
The Effects of 8 Weeks of Endurance Running on Hepcidin Concentrations, Inflammatory Parameters, and Iron Status in Female Runners
Authors: Auersperger Irena , Knap Bojan , Jerin Ales , Blagus Rok , Lainscak Mitja , Skitek Milan , Skof Branko
Published: August 2016

Exercise-associated iron deficiency is a common disorder in endurance athletes. The authors investigated the effects of long-term endurance exercise on hepcidin concentrations, inflammatory parameters, and iron status in moderately trained female long-distance runners. Eighteen runners were assigned to either an interval- or a continuous-training exercise group. The physical training consisted of two 3-week progressive overload periods, each followed by a week’s recovery, and concluded with a 10- or 21-km competitive run. Samples were taken 6 times during the 8-wk training program, first at baseline (BPre), then after the first and second 3-wk training loads (TPost1, TPost2), after each recovery week (Recovery1 and Recovery2), and poststudy (BPost). Soluble transferrin receptor (sTfR) concentrations were increased in Recovery2 and BPost compared with BPre (p = .02), hemoglobin decreased in TPost1 and TPost2 (p < .001), and red blood cells decreased in TPost2 (p = .01). Hepcidin decreased with time in TPost1 and in BPost compared with BPre (p < .001) and increased in TPost2 compared with TPost1 (p < .001). No differences over time were found for high-sensitivity C-reactive protein. The main findings of the current study indicate that serum hepcidin and sTfR were affected after 8 weeks of endurance running in women. No positive relation was found with inflammation.
Acute Effects of a Caffeine-Taurine Energy Drink on Repeated Sprint Performance of American College Football Players
Authors: Gwacham Nnamdi , Wagner Dale R.
Published: August 2016

Consumption of energy drinks is common among athletes; however, there is a lack of research on the efficacy of these beverages for short-duration, intense exercise. The purpose of this research was to investigate the acute effects of a low-calorie caffeine-taurine energy drink (AdvoCare Spark) on repeated sprint performance and anaerobic power in National Collegiate Athletic Association Division I football players. Twenty football players (age 19.7 ± 1.8 yr, height 184.9 ± 5.3 cm, weight 100.3 ± 21.7 kg) participated in a double-blind, randomized crossover study in which they received the energy drink or an isoenergetic, isovolumetric, noncaffeinated placebo in 2 trials separated by 7 days. The Running Based Anaerobic Sprint Test, consisting of six 35-m sprints with 10 s of rest between sprints, was used to assess anaerobic power. Sprint times were recorded with an automatic electronic timer. The beverage treatment did not significantly affect power (F = 3.84, p = .066) or sprint time (F = 3.06, p = .097). However, there was a significant interaction effect between caffeine use and the beverage for sprint times (F = 4.62, p = .045), as well as for anaerobic power (F = 5.40, p = .032), indicating a confounding effect. In conclusion, a caffeine-taurine energy drink did not improve the sprint performance or anaerobic power of college football players, but the level of caffeine use by the athletes likely influenced the effect of the drink.
Effect of Resistance Training During Ramadan on Body Composition and Markers of Renal Function, Metabolism, Inflammation, and Immunity in Recreational Bodybuilders
Authors: Trabelsi Khaled , Stannard Stephen R. , Maughan Ronald J. , Jammoussi Kamel , Zeghal Khaled , Hakim Ahmed
Published: August 2016

The aim of this study was to evaluate the effects of a hypertrophic training program during Ramadan on body composition and selected metabolic markers in trained bodybuilders. Sixteen male recreational bodybuilders (9 Ramadan fasters and 7 nonfasters) participated in the study. All visited the laboratory 2 d before the start of Ramadan (Bef-R) and on the 29th day of Ramadan (End-R). In the morning of each session, subjects underwent anthropometric measurement, completed a dietary questionnaire, and provided fasting blood and urine samples. Body mass and body-mass index in nonfasters increased by 2.4% (p = .05 and p = .04, respectively) from Bef-R to End-R but remained unchanged in fasters over the period of the investigation. Fasters experienced an increase in the following parameters from Bef-R to End-R: urine specific gravity (1%, p = .022) and serum concentrations of urea (5%, p = .008), creatinine (5%, p = .007), uric acid (17%, p < .001), sodium (2%, p = .019), potassium (6%, p = .006), chloride (2%, p = .028), and high-density lipoprotein cholesterol (10%, p = .005). However, only serum creatinine and low-density lipoprotein cholesterol increased in nonfasters (3%, p < .001 and 14%, p = .007, respectively) during the same period. Creatinine clearance values of fasters decreased by 3% (p = .03) from Bef-R to End-R. Continuance of hypertrophic training through Ramadan had no effect on body mass and body composition of bodybuilders, but a state of dehydration and reduced renal function were apparent, perhaps because of the restricted opportunity for fluid intake imposed by the study design.
Techniques for Undertaking Dual-Energy X-Ray Absorptiometry Whole-Body Scans to Estimate Body Composition in Tall and/or Broad Subjects
Authors: Nana Alisa , Slater Gary J. , Hopkins Will G. , Burke Louise M.
Published: August 2016

Dual-energy X-ray absorptiometry (DXA) is becoming a popular tool to measure body composition, owing to its ease of operation and comprehensive analysis. However, some people, especially athletes, are taller and/or broader than the active scanning area of the DXA bed and must be scanned in sections. The aim of this study was to investigate the reliability of DXA measures of whole-body composition summed from 2 or 3 partial scans. Physically active young adults (15 women, 15 men) underwent 1 whole-body and 4 partial DXA scans in a single testing session under standardized conditions. The partial scanning areas were head, whole body from the bottom of the chin down, and right and left sides of the body. Body-composition estimates from whole body were compared with estimates from summed partial scans to simulate different techniques to accommodate tall and/or broad subjects relative to the whole-body scan. Magnitudes of differences in the estimates were assessed by standardization. In simulating tall subjects, summation of partial scans that included the head scan overestimated whole-body composition by ~3 kg of lean mass and ~1 kg of fat mass, with substantial technical error of measurement. In simulating broad subjects, summation of right and left body scans produced no substantial differences in body composition than those of the whole-body scan. Summing partial DXA scans provides accurate body-composition estimates for broad subjects, but other strategies are needed to accommodate tall subjects.
Differences in Sociodemographic, Health-Related, and Psychological Factors in Users and Nonusers of Nutritional Supplements in Fitness Club Participants in Tehran, Iran
Authors: Saeedi Pouya , Taib Mohd Nasir Mohd , Saad Hazizi Abu
Published: August 2016

Nutritional supplement (NS) use has increased among the general population, athletes, and fitness club participants and has become a widespread and acceptable behavior. The objective of this study was to determine the differences in sociodemographic, health-related, and psychological factors between NS users and nonusers. A case-control study design was used, whereby participants included 147 NS users (cases) and 147 nonusers (controls) age 18 yr and above who exercised at least 3 d/wk in 24 fitness clubs in Tehran. A self-administered pretested and validated questionnaire was used to collect data. The results showed that on average, NS users were younger (29.8 ± 9.5 yr) than nonusers (35.5 ± 12.2 yr). Logistic-regression analysis showed that NS use was significantly associated with moderate or high physical activity level (PAL), smoking, gender, eating attitude, and age. In conclusion, NS users were more likely to be female, younger, and smokers; to have moderate or high PAL; and to be more prone to eating disorders than nonusers.
Dietary and Training Predictors of Stress Fractures in Female Runners
Authors: Wentz Laurel , Liu Pei-Yang , Ilich Jasminka Z. , Haymes Emily M.
Published: August 2016

Purpose:

To compare female runners with and without a history of stress fractures to determine possible predictors of such fractures.

Methods:

27 female runners (age 18–40 yr) who had had at least 1 stress fracture were matched to a control sample of 32 female runners without a history of stress fractures. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (iDXA). Subjects answered questionnaires on stress-fracture history, training, menstrual status, and diet.

Results:

No significant differences were found in menstrual characteristics, diet and dairy intake, or bone measurements. Weekly servings of milk during middle school significantly predicted BMD at the femur (p = .010), femoral neck (p = .002), Ward’s triangle (p = .014), and femoral shaft (p = .005). Number of menstrual cycles in the previous year predicted femoral-neck BMD (p = .004). Caffeine intake was negatively associated with BMD of the femur (p = .010), femoral neck (p = .003), trochanter (p = .038), and femoral shaft (p = .035). Weekly hours of training were negatively associated with total-body BMD (p = .021), total-body bone mineral content (p = .028), and lumbar-spine BMD (p = .011). Predictors for stress fractures included the number of years running, predominantly running on hard ground, irregular menstrual history, low total-body BMD, and low current dietary calcium intake when controlling for body-mass index (Nagelkerke R2 = .364).

Conclusions:

Servings of milk during middle-school years were positively correlated with hip BMD, although current calcium intake, low BMD, irregular menstrual history, hard training surface, and long history of training duration were the most important predictors of stress fractures.
Relationship Between Eating-Behavior Disorders and Psychological Parameters in Male First-Year Physical Education Students
Authors: Filaire Edith , Treuvelot Patrick , Toumi Hechmi
Published: August 2016

This study explores the prevalence of disordered eating attitudes in a sample of male first-year university students engaged in a physical education program and examines the relationships between emotional intelligence, coping, and emotional eating in relation to disordered-eating (DE) attitudes. A total of 140 students completed the following questionnaires: the Eating Attitudes Test, the Bar-On Emotional Intelligence Questionnaire, the Coping Inventory Stress Scale, and the Dutch Eating Behavior Questionnaire. The number of participants represented 80% of the male students registered in this discipline at the authors’ university. Twenty percent of students presented DE attitudes even though they were of normal weight. The Bar-On EQ-I results indicated that students with DE attitudes had lower levels of emotional intelligence (EI) scores than students without DE attitudes (control group). Moreover, they scored higher than the control group on coping styles such as avoidance-oriented coping, emotion-oriented coping, and emotional eating. The DE group presented a positive correlation between DE attitudes symptoms and both avoidance- and emotion-oriented coping but a negative correlation between DE attitudes and task-oriented coping. There was also a significant negative correlation between DE attitudes and EI score. Another result from this group indicated an association between EI score and emotional-eating score (p < .05, r = –.44) and also a positive correlation between emotion-oriented coping and emotional eating (p < .01, r = .47). The findings highlight future research potential on the role of emotions and EI in DE symptoms, which may be beneficial in the context of collaborative care management intervention.
Case Study: Nutrition and Training Periodization in Three Elite Marathon Runners
Authors: Stellingwerff Trent
Published: August 2016

Laboratory-based studies demonstrate that fueling (carbohydrate; CHO) and fluid strategies can enhance training adaptations and race-day performance in endurance athletes. Thus, the aim of this case study was to characterize several periodized training and nutrition approaches leading to individualized race-day fluid and fueling plans for 3 elite male marathoners. The athletes kept detailed training logs on training volume, pace, and subjective ratings of perceived exertion (RPE) for each training session over 16 wk before race day. Training impulse/load calculations (TRIMP; min × RPE = load [arbitrary units; AU]) and 2 central nutritional techniques were implemented: periodic low-CHO-availability training and individualized CHO- and fluidintake assessments. Athletes averaged ~13 training sessions per week for a total average training volume of 182 km/wk and peak volume of 231 km/wk. Weekly TRIMP peaked at 4,437 AU (Wk 9), with a low of 1,887 AU (Wk 16) and an average of 3,082 ± 646 AU. Of the 606 total training sessions, ~74%, 11%, and 15% were completed at an intensity in Zone 1 (very easy to somewhat hard), Zone 2 (at lactate threshold) and Zone 3 (very hard to maximal), respectively. There were 2.5 ± 2.3 low-CHO-availability training bouts per week. On race day athletes consumed 61 ± 15 g CHO in 604 ± 156 ml/hr (10.1% ± 0.3% CHO solution) in the following format: ~15 g CHO in ~150 ml every ~15 min of racing. Their resultant marathon times were 2:11:23, 2:12:39 (both personal bests), and 2:16:17 (a marathon debut). Taken together, these periodized training and nutrition approaches were successfully applied to elite marathoners in training and competition.