bluuebunny/crossref_metadata_2025 huggingface dataset:
Hematological Status of Male Runners in Relation to the Extent of Physical Training
Authors: Robertson John D. , Maughan Ronald J. , Milne Ann C. , Davidson Ronald J.L.
Published: August 2016

Blood biochemical indices of iron status were measured in venous blood from 20 runners and 6 control subjects. All subjects were.male, ages 20 to 40 years, and stable with regard to body weight and degree of physical activity. Dietary analysis was undertaken using a 7-day weighed food intake. There was no evidence of iron deficiency: hemoglobin concentrations and serum femtin levels were within the normal population range for all individuals. However, serum ferritin was negatively correlated with the amount of training. Daily iron intake appeared to be adequate; iron intake was correlated with protein intake but not related to training or energy intake. Serum ferritin, an indicator of iron status, was significantly correlated with vitamin C intake but not iron intake. Serum transferrin concentration was higher in the group of athletes undertaking a high weekly training load compared with the control subjects, suggesting an alteration in iron metabolism although there was no evidence of increased erythropoiesis. The biological significance of this is unclear.
Prevalence of Eating Disorders in Elite Female Athletes
Authors: Sundgot-Borgen Jorunn
Published: August 2016

This study examined the prevalence of eating disorders (ED) and the possible difference between ED symptoms and true ED by using questionnaires as compared with an interview and clinical evaluation in Norwegian elite female athletes (n=522) from 35 sports and nonathletic controls (n=448). In addition to the 117 athletes classified as "at risk" to develop ED, 90 subjects were randomly chosen, comprising 30 athletic controls, 30 at-risk nonathletes, and 30 nonathletic controls. All weIe interviewed and clinically examined. A significantly higher number of athletes (18%) than controls (5%) were found to actually suffer from ED, particularly athletes competing in sports in which leanness or a specific weight were considered important. When results from the screening study were compared to those from the interviews and clinical examinations, a significant underreporting of ED among athletes was demonstrated. The athletes also reported the use of other pathogenic methods in the screening study compared to what they reported in the interview. Nonathletes more correctly reported the use of pathogenic methods but overreported the prevalence of ED. Thus the issue of using questionnaires alone or in combination with personal interview/clinical examination merits further investigation.
Diet and Weight Changes of Female Bodybuilders Before and After Competition
Authors: Walberg-Rankin Janet , Edmonds Cynthia Eckstein , Gwazdauskas Frank C.
Published: August 2016

This study assessed nutritional and body weight patterns in 6 female body- builders approximately a month before and after a competition. The women kept dietary and body weight records and two of them also agreed to collect morning urine samples to provide information about their menstrual cycle. All women lost weight before and gained weight after competition. Energy intake was modestly restricted and the subjects consumed a moderate-protein, low-fat, high-carbohydrate diet just prior to competition. Energy intake doubled, and total grams of fat increased approximately tenfold just after competition. Urinary data indicated that the cycle following competition was prolonged, with reduced reproductive hormone concentrations. In summary, the women practiced extreme dietary control while preparing for a competi- tion but followed the event with a higher energy and fat intake. These changes in diet and body weight may contribute to the disturbances previously observed in the menstrual cycle of these athletes.
Acute Changes in Vitamin B6, Status in Endurance Athletes before and after a Marathon
Authors: Rokitzki Lothar , Sagredos Andree N. , Reuß Friedrich , Büchner Michael , Keul Josef
Published: August 2016

The vitamin status of 13 endurance athletes was determined by whole blood (microbiological) and urine 4-pyridoxic acid (4-PA) (HPLC), serum vitamin (pyridoxal, pyridoxol, pyridoxamin) (HPLC), and erythrocyte α- EGOT measurements with the aid of 7-day records. In addition, blood and serum samples and urine were collected before (Time A), directly after (Time B), and 2 hr after a marathon race (Time C). The total energy intake was 12,303 ± 3,464 Wday (34% fat, 48% carbohydrates, 14% protein). The vitamin intake, serum concentrations, α-EGOT value, and 4-PA excretion were higher than the reference values at Time A. Only the vitamin whole blood levels were below the normal level at Time A. The vitamin B, status of the athletes corresponded essentially to reference values obtained for untrained individuals. There was a mean loss of about 1 mg vitamin as a result of the marathon race. Vitamin supplementation does not appear necessary if a balanced diet is consumed.
High School Athletes and Nutritional Supplements: A Study of Knowledge and Use
Authors: Massad Susan J. , Shier Nathan W. , Koceja David M. , Ellis Nancy T.
Published: August 2016

Factors influencing nutritional supplement use by high school students were assessed. Comparisons were made between various groups of sports participants and non-sports participants. The Nutritional Supplement Use and Knowledge Scale was administered to 509 students. Mean supplement use score was 10.87 (SEM = 0.50, range 0-57). Mean knowledge score was 13.56 (SEM = 0.16, range 1-21). Significant relationships (p < .01) were obtained for supplement knowledge with use, and supplement use with gender. ANOVA found significant differences between supplement use by gender (p < .01), supplement use by sports category (p < .05), and knowledge scores by sports category (p < .01). Discriminant function analysis indicated knowledge, supplement use, and subscores for protein, vitamins/minerals, and carbohydrates were best discriminators of sport group membership. Greater knowledge about supplements was associated with less use; hence, education about supplements can be a deterrent to use. This study may help coaches, athletic trainers, athletic directors, teachers, physicians, and parents identify nutritional misconceptions held by adolescents.
Body Weight Changes and Voluntary Fluid Intakes during Training and Competition Sessions in Team Sports
Authors: Broad Elizabeth M. , Burke Louise M. , Cox Greg R. , Heeley Prue , Riley Malcolm
Published: August 2016

Fluid losses (measured by body weight changes) and voluntary fluid intakes were measured in elite basketball, netball, and soccer teams during typical summer and winter exercise sessions to determine fluid requirements and the degree of fluid replacement. Each subject was weighed in minimal clothing before and immediately after training, weights, and competition sessions; fluid intake, duration of exercise, temperature and humidity, and opportunity to drink were recorded. Sweat rates were greatest during competition sessions and significantly lower during weights sessions for all sports. Seasonal variation in dehydration (%DH) was not as great as may have been expected, particularly in sports played indoors. Factors influencing fluid replacement during exercise included provision of an individual water bottle, proximity to water bottles during sessions, encouragement to drink, rules of the game, duration and number of breaks or substitutions, and awareness of personal sweat rates. Guidelines for optimizing fluid intakes in these three sports are provided.
Influence of Sodium Replacement on Fluid Ingestion Following Exercise-Induced Dehydration
Authors: Wemple Richard D. , Morocco Tamara S. , Mack Gary W.
Published: August 2016

This study investigated the hypothesis that addition of to a rehydration beverage would stimulate drinking and augment restoration of body water in individuals dehydrated during 90 min of continuous treadmill exercise in the heat. Following a 3.0 ± 0.2% decrease in body weight (BW), 6 subjects sat in a thermoneutral environment for 30 min to allow body fluid compartments to stabilize. Over the next 3 hr, subjects rehydrated ad libitum using either flavored/artificially sweetened water (H20-R) or a flavored, 6% sucrose drink containing either or 50 mmol/L NaCl. Results demonstrated that rapid removal of the osmotic stimulus, during 0-R, and the volume-dependent dipsogenic stimuli, during , are important factors in limiting fluid intake during rehydration, compared to . It was also found that the pattern of fluid replacement and restoration of fluid balance following dehydration is influenced by the dehydration protocol used to induce the loss in total body water and the sodium content of the rehydration beverage.
Effect of Low- and High-Carbohydrate Diets on the Plasma Glutamine and Circulating Leukocyte Responses to Exercise
Authors: Gleeson Michael , Blannin Andrew K. , Walsh Neil P. , Bishop Nicolette C. , Clark Anya M.
Published: August 2016

We examined the effects of a low-carbohydrate (CHO) diet on the plasma glutamine and circulating leukocyte responses to prolonged strenuous exercise. Twelve untrained male subjects cycled for 60 min at 70% of maximal oxygen uptake on two separate occasions, 3 days apart. All subjects performed the first exercise task after a normal diet: they completed the second exercise task after 3 days on either a high-CHO diet (75±8% CHO, n = 6) or a low-CHO diet (7±4% CHO, n = 6). The low-CHO diet was associated with a larger rise in plasma cortisol during exercise, a greater fall in the plasma glutamine concentration during recovery, and a larger neutrophilia during the postexercise period. Exercise on the high-CHO diet did not affect levels of plasma glutamine and circulating leukocytes. We conclude that CHO availability can influence the plasma glutamine andcirculaling leukocyte responses during recovery from intense prolonged exercise.
Influence of Diet and/or Exercise on Body Composition and Cardiorespiratory Fitness in Obese Women
Authors: Utter Alan C. , Nieman David C. , Shannonhouse Elizabeth M. , Butterworth Diane E. , Nieman Cathy N.
Published: August 2016

The purpose of this study was to measure the influence of diet, exercise, or both on body composition and cardiorespiratory fitness in obese women. Ninety-one obese subjects were randomized into one of four groups: diet (D) (4.19–5.44 MJ or 1,200–1,300 kcal/day), exercise (E) (five 45-min sessions at 78.5 ± 0.5% maximum heart rate), exercise and diet (ED), and controls (C). Maximal aerobic power and body composition were measured in all subjects before and after a 12-week diet intervention period. Subjects in D and ED lost 7.8 ± 0.7 and 8.1 ± 0.6 kg body mass, with no significant change for E relative to C. Losses of percent body fat and fat mass were significantly greater in D and ED but not in E relative to C. The change in VO2max was greater in ED and E but not D when compared to C. Results indicate that moderate aerobic exercise training during a 12-week period has no discernible effects on body composition but does improve cardiorespiratory fitness in dieting obese women.
Creatine Supplementation and Swimming Performance
Authors: Leenders Nicole , Sherman W. Michael , Lamb David R. , Nelson Timothy E.
Published: August 2016

The purpose of this study was to determine if oral creatine (CR) ingestion, compared to a placebo (PL), would enable swimmers to maintain a higher swimming velocity across repeated interval sets over 2 weeks of supplementation. Fourteen female and 18 male university swimmers consumed a PL during a 2-week baseline period. Using a randomized, double-blind design, during the next 2 weeks subjects consumed either CR or PL. Swimming velocity was assessed twice weekly during 6 × 50-m swims and once weekly during 10 × 25-yd swims. There was no effect ofCR on the 10 × 25-yd interval sets for men and women and no effect on the 6 × 50-m interval sets for women. In contrast, for men, CR significantly improved mean overall swimming velocity in the 6 × 50-m interval after 2 weeks of supplementation, whereas PL had no effect. Although ineffective in women, CR supplementation apparently enables men to maintain a faster mean overall swimming velocity during repeated swims each lasting about 30 s; however, CR was not effective for men in repeated swims each lasting about 10-15 s.
A Report of Vitamin and Mineral Supplement Use among University Athletes in a Division I Institution
Authors: Krumbach Chad J. , Ellis Dave R. , Driskell Judy A.
Published: August 2016

The influences of gender, ethnicity, and sport of varsity athletes on their vitamin/mineral supplementation habits were examined. Subjects included 145 females and 266 males from 22 varsity teams; 80% were Caucasian; 12% African American; and 8% Combined-Other. Over half of the subjects took supplements. Males were more likely than females to give "too expensive" as a reason for not taking supplements, and "improve athletic performance" and "build muscle" as reasons for taking supplements. The most common supplement was multivitamins plus minerals. Females were more likely to take calcium and iron, and males vitamins B 12 and A. African Americans were the most likely to take vitamin A. Males were more likely to get supplement information from nutritionists/dietitians and self, and females from family members or friends and physicians or pharmacists. Football players were more likely to get supplement information from nutritionists/dietitians, and males in other sports from coaches/trainers. There were some differences in vitamin/mineral supplement habits of the athletes by gender, ethnicity, and sport.
No Effect of Heavy Resistance Training and Creatine Supplementation on Blood Lipids
Authors: Volek Jeff S. , Duncan Noel D. , Mazzetti Scott A. , Putukian Margot , Gómez Ana L. , Kraemer William J.
Published: August 2016

In order to examine the effects of heavy resistance training and the influence of creatine supplementation on nonperformance measures of health status, 19 healthy resistance-trained men were matched and then randomly assigned in a double-blind fashion to either a creatine (n = 10) or placebo (n = 9) group. Periodized heavy resistance training was performed 3—4 times per week for 12 weeks. During the first week of training, creatine subjects consumed 25 g creatine monohydrate per day, while the placebo group ingested an equal number of placebo capsules. Five grams of supplement per day was consumed for the remainder of the study. Body composition, fasting serum creatinine, lipo-proteins and triglycerides, and reported changes in body function were determined prior to and after 12 weeks of training and supplementation. After training, significant increases in body mass and fat-free mass were greater in creatine (5.2 and 4.3 kg, respectively) than placebo (3.0 and 2.1 kg. respectively) subjects. There was no change in percent body fat. Dietary energy and macronutrient distribution was not significantly different during Weeks 1 and 12. Serum creatinine was significantly elevated in creatine subjects after 1(11.6%) and 12 weeks (13.8%); however, values were within normal limits for healthy men. There were no effects of training or supplementation on serum total cholesterol, HDL-cholesterol, LDL-cholesterol. or triglycerides. In healthy men, a 12-week heavy resistance training program, with or without creatine supplementation, did not significantly influence serum lipid profiles, subjective reports of body functioning, or serum creatinine concentrations.
Minimal Influence of Carbohydrate Ingestion on the Immune Response Following Acute Resistance Exercise
Authors: Koch Alexander J. , Potteiger Jeffrey A. , Chan Marcia A. , Benedict Stephen H. , Frey Bruce B.
Published: August 2016

The effect of carbohydrate supplementation (CHO) on the lymphocyte response to acute resistance exercise was examined in 10 resistance-trained males. Subjects completed a randomized double-blind protocol with sessions separated by 14 days. The exercise session consisted of a high intensity, short rest interval squat workout. Subjects consumed 1.0 g · kg body mass−1 CHO or an equal volume of placebo (PLC) 10 min prior to and 10 min following exercise. Blood was collected at rest (REST), immediately post exercise (POST), and at 1.5 hours and 4.0 hours of recovery, and analyzed for plasma glucose, serum cortisol, leukocyte subsets, and phytohemagglutinin (PHA)-stimulated lymphocyte proliferation. A significant Treatment × Time effect was observed for lymphocyte proliferation between CHO and PLC, but post hoc analyses revealed no between-treatment differences at any post-exercise time point. Lymphocyte proliferation was significantly depressed below REST at POST (−39.2% for PLC, −25.7% for CHO). Significant fluctuations in leukocyte subset trafficking were observed for both treatments at POST, 1.5 hours, and 4.0 hours. Plasma glucose was significantly increased POST in CHO compared to PLC. Cortisol was significantly increased from REST to POST in both treatments. These data support a minimal effect of carbohydrate ingestion on the lymphocyte response to high-intensity resistance exercise.
Nutrition Knowledge, Opinions, and Practices of Coaches and Athletic Trainers at a Division I University
Authors: Rockwell Michelle Smith , Nickols-Richardson Sharon M. , Thye Forrest W.
Published: August 2016

The purpose of this investigation was to assess nutrition knowledge, opinions, and practices of coaches and trainers at a Division I university. Participants (n = 53) completed questionnaires regarding nutrition knowledge, opinions, and practices. Descriptive statistics and analysis of variance were used to analyze data. Overall, participants responded correctly to 67% of nutrition knowledge questions. Participants who coached/trained female athletes tended to score better than respondents who coached/trained male athletes. Strength and conditioning coaches and participants with greater than 15 years of experience scored higher than other participants. Nutrition opinions/practices responses revealed that nutritional supplements were provided for all but 6% of participants’ athletes. Participants rated body weight as more important than body composition to athletes’ performances. Over 30% of participants perceived at least one case of disordered eating within the past year. Some participants (53%) felt that athletes may consume more nutritious meals on team-sponsored trips if given larger food allowances. Thirty percent of participants reported dietitians were available to them; the same percentage reported utilizing dietitians. Coaches and trainers are knowledgeable about some appropriate nutritional recommendations, but registered dietitians or qualified sports nutrition professionals may complement the nutrition-related education and counseling of athletes (23).
High-Fat Diet versus Habitual Diet Prior to Carbohydrate Loading: Effects on Exercise Metabolism and Cycling Performance
Authors: Lambert Estelle V. , Goedecke Julia H. , van Zyl Charl , Murphy Kim , Hawley John A. , Dennis Steven C. , Noakes Timothy D.
Published: August 2016

We examined the effects of a high-fat diet (HFD-CHO) versus a habitual diet, prior to carbohydrate (CHO)-loading on fuel metabolism and cycling time-trial (TT) performance. Five endurance-trained cyclists participated in two 14-day randomized cross-over trials during which subjects consumed either a HFD (>65% MJ from fat) or their habitual diet (CTL) (30 ± 5% MJ from fat) for 10 day, before ingesting a high-CHO diet (CHO-loading, CHO > 70% MJ) for 3 days. Trials consisted of a 150-min cycle at 70% of peak oxygen uptake (V̇O2peak), followed immediately by a 20-km TT. One hour before each trial, cyclists ingested 400 ml of a 3.44% medium-chain triacylglycerol (MCT) solution, and during the trial, ingested 600 ml/hour of a 10% 14C-glucose + 3.44% MCT solution. The dietary treatments did not alter the subjects’ weight, body fat, or lipid profile. There were also no changes in circulating glucose, lactate, free fatty acid (FFA), and β-hydroxybutyrate concentrations during exercise. However, mean serum glycerol concentrations were significantly higher (p < .01) in the HFD-CHO trial. The HFD-CHO diet increased total fat oxidation and reduced total CHO oxidation but did not alter plasma glucose oxidation during exercise. By contrast, the estimated rates of muscle glycogen and lactate oxidation were lower after the HFD-CHO diet. The HFD-CHO treatment was also associated with improved TT times (29.5 ± 2.9 min vs. 30.9 ± 3.4 min for HFD-CHO and CTL-CHO, p < .05). High-fat feeding for 10 days prior to CHO-loading was associated with an increased reliance on fat, a decreased reliance on muscle glycogen, and improved time trial performance after prolonged exercise.
The Effect of Whey Protein Supplementation with and Without Creatine Monohydrate Combined with Resistance Training on Lean Tissue Mass and Muscle Strength
Authors: Burke Darren G. , Chilibeck Philip D. , Davison K. Shawn , Candow Darren C. , Farthing Jon , Smith-Palmer Truis
Published: August 2016

Our purpose was to assess muscular adaptations during 6 weeks of resistance training in 36 males randomly assigned to supplementation with whey protein (W; 1.2 g/kg/day), whey protein and creatine monohydrate (WC; 0.1 g/kg/day), or placebo (P; 1.2 g/kg/day maltodextrin). Measures included lean tissue mass by dual energy x-ray absorptiometry, bench press and squat strength (1-repetition maximum), and knee extension/flexion peak torque. Lean tissue mass increased to a greater extent with training in WC compared to the other groups, and in the W compared to the P group (p < .05). Bench press strength increased to a greater extent for WC compared to W and P (p < .05). Knee extension peak torque increased with training for WC and W (p < .05), but not for P. All other measures increased to a similar extent across groups. Continued training without supplementation for an additional 6 weeks resulted in maintenance of strength and lean tissue mass in all groups. Males that supplemented with whey protein while resistance training demonstrated greater improvement in knee extension peak torque and lean tissue mass than males engaged in training alone. Males that supplemented with a combination of whey protein and creatine had greater increases in lean tissue mass and bench press than those who supplemented with only whey protein or placebo. However, not all strength measures were improved with supplementation, since subjects who supplemented with creatine and/or whey protein had similar increases in squat strength and knee flexion peak torque compared to subjects who received placebo.
Comparison of Carbohydrate and Milk-Based Beverages on Muscle Damage and Glycogen Following Exercise
Authors: Wojcik Janet R. , Walberg-Rankin Janet , Smith Lucille L. , Gwazdauskas F.C.
Published: August 2016

This study examined effects of carbohydrate (CHO), milk-based carbohydrate-protein (CHO-PRO), or placebo (P) beverages on glycogen resynthesis, muscle damage, inflammation, and muscle function following eccentric resistance exercise. Untrained males performed a cycling exercise to reduce muscle glycogen 12 hours prior to performance of 100 eccentric quadriceps contractions at 120% of 1-RM (day 1) and drank CHO (n = 8), CHO-PRO (n = 9; 5 kcal/kg), or P (n = 9) immediately and 2 hours post-exercise. At 3 hours post-eccentric exercise, serum insulin was four times higher for CHO-PRO and CHO than P (p < .05). Serum creatine kinase (CK) increased for all groups in the 6 hours post-eccentric exercise (p < .01), with the increase tending to be lowest for CHO-PRO (p < .08) during this period. Glycogen was low post-exercise (33 ± 3.7 mmol/kg ww), increased 225% at 24 hours, and tripled by 72 hours, with no group differences. The eccentric exercise increased muscle protein breakdown as indicated by urinary 3-methylhistidine and increased IL-6 with no effect of beverage. Quadriceps isokinetic peak torque was depressed similarly for all groups by 24% 24 hours post-exercise and remained 21 % lower at 72 hours (p < .01). In summary, there were no influences of any post-exercise beverage on muscle glycogen replacement, inflammation, or muscle function.
The Effect of Glycerol Hyperhydration on Olympic Distance Triathlon Performance in High Ambient Temperatures
Authors: Coutts Aaron , Reaburn Peter , Mummery Kerry , Holmes Mark
Published: August 2016

The purpose of this study was to examine the effect of prior glycerol loading on competitive Olympic distance triathlon performance (ODT) in high ambient temperatures. Ten (3 female and 7 male) well-trained triathletes (VO2max = 58.4 ±2.4 ml-kg−1 min−1; best ODT time = 131.5 ± 2.6 min) completed 2 ODTs (1.5-km swim, 40-km bicycle, 10-km run) in a randomly assigned (placebo/ glycerol) double-blind study conducted 2 weeks apart. The wet-bulb globe temperature (outdoors) was 30.5 + 0.5 °C (relative humidity: 46.3 ± 1.1%; hot) and 25.4 + 0.2 °C (relative humidity: 51.7 ± 2.4%; warm) for day 1 and day 2, respectively. The glycerol solution consisted of 1.2 g of glycerol per kilogram of body mass (BM) and 25 ml of a 0.75 g · kg−1 BM carbohydrate solution (Gatorade®) and was consumed over a 60-min period, 2 hours prior to each ODT. Measures of performance (ODT time), fluid retention, urine output, blood plasma volume changes, and sweat loss were obtained prior to and during the ODT in both the glycerol and placebo conditions. Following glycerol loading, the increase in ODT completion time between the hot and warm conditions was significantly less than the placebo group (placebo 11:40 min vs. glycerol 1:47 min; p < .05). The majority of the performance improvement occurred during the final 10-km run leg of ODT on the hot day. Hyperhydration occurred as a consequence of a reduced diuresis (p < .05) and a subsequent increase in fluid retention (p < .05). No significant differences were observed in sweat loss between the glycerol and placebo conditions. Plasma volume expansion during the loading period was significantly greater (p < .05) on the hot day when glycerol appeared to attenuate the performance decrement in the heat. The present results suggest that glycerol hyperhydration prior to ODT in high ambient temperatures may provide some protection against the negative performance effects of competing in the heat.
Reported Eating Behavior and Attitudes Improvement after a Nutrition Intervention Program in a Group of Young Female Dancers
Authors: Yannakoulia Mary , Sitara Marietta , Matalas Antonia-Leda
Published: August 2016

The aim of the study was to evaluate the effectiveness of an intervention program that combined nutrition education and prevention of disordered eating in a group of female professional dance students. Thirty-two dancers, aged 19-25 years, took part in the program. Evaluation was done by a series of questionnaires that participants were asked to complete on 3 occasions. Assessments of body composition and dietary intake were also performed. Significant improvements in nutrition knowledge as well as a decrease in abnormal eating behavior and dietary restraint were observed at post intervention. At 6-month follow-up, the positive effects were maintained and further benefits were recorded; only nutrition knowledge showed a minor decline. Participants who were at higher risk for adopting abnormal eating behavior benefited the most from the program. These findings encourage the implementation of intervention programs in groups of young women that experience particular pressures for controlling body weight.
Caffeine, Body Fluid-Electrolyte Balance, and Exercise Performance
Authors: Armstrong Lawrence E.
Published: August 2016

Recreational enthusiasts and athletes often are advised to abstain from consuming caffeinated beverages (CB). The dual purposes of this review are to (a) critique controlled investigations regarding the effects of caffeine on dehydration and exercise performance, and (b) ascertain whether abstaining from CB is scientifically and physiologically justifiable. The literature indicates that caffeine consumption stimulates a mild diuresis similar to water, but there is no evidence of a fluid-electrolyte imbalance that is detrimental to exercise performance or health. Investigations comparing caffeine (100-680 mg) to water or placebo seldom found a statistical difference in urine volume. In the 10 studies reviewed, consumption of a CB resulted in 0-84% retention of the initial volume ingested, whereas consumption of water resulted in 0-81% retention. Further, tolerance to caffeine reduces the likelihood that a detrimental fluid-electrolyte imbalance will occur. The scientific literature suggests that athletes and recreational enthusiasts will not incur detrimental fluid-electrolyte imbalances if they consume CB in moderation and eat a typical U.S. diet. Sedentary members of the general public should be at less risk than athletes because their fluid losses via sweating are smaller.
Effect of Creatine Supplementation and a Lacto-Ovo-Vegetarian Diet on Muscle Creatine Concentration
Authors: Lukaszuk Judith M. , Robertson Robert J. , Arch Judith E. , Moore Geoffrey E. , Yaw Kenneth M. , Kelley David E. , Rubin Joshua T. , Moyna Niall M.
Published: August 2016

The purpose of this investigation was to examine the effects of preceding oral creatine monohydrate with a lacto-ovo-vegetarian diet on muscle creatine concentration. Thirty-two healthy men, who regularly consumed an omnivorous diet, were randomly assigned to consume a weight maintaining, lacto-ovo-vegetarian (LOV; n = 16) or omnivorous (Omni; n = 16) diet for 26 days. In addition to their assigned diet, on day 22 of the study, subjects were assigned in a double-blind manner to receive either creatine monohydrate (CM; 0.3 g · kg · d−1 + 20 g Polycose) or an equivalent dose of placebo (PL) for 5 days. There were no significant differences between the LOV and Omni groups at baseline with respect to age, height, and weight. The results demonstrated that consuming a LOV diet for 21 days was an effective procedure to decrease muscle creatine concentration (p < .01) in individuals who normally consume meat and fish in their diet. However, muscle total creatine (TCr) following creatine supplementation did not differ statistically between LOV and Omni diet groups (148.6 ± 4.5 vs. 141.7 ± 4.5 mmol · kg−1 d.m.).
Policies on Screening Female Athletes for Iron Deficiency in NCAA Division I-A Institutions
Authors: Cowell Brandy S. , Rosenbloom Christine A. , Skinner Robert , Summers Stephanie H.
Published: August 2016

Iron deficiency is the most prevalent nutritional deficiency in the United States. This condition has been reported to affect 60% of female athletes. The Centers for Disease Control and Prevention emphasize screening for anemia in women of childbearing age. The purpose of this study was to determine the number of National Collegiate Athletic Association (NCAA) Division I-A schools that implement screening for iron deficiency in female athletes as well as the screening policies for those who do. A link to an online survey was sent to 94 NCAA Division I-A schools to determine current practices concerning screening and treating female athletes for iron deficiency. There was a 58% response rate. Frequencies for each response were computed. Forty-three percent of responding institutions report screening female athletes for iron deficiency. This study suggests that screening for iron deficiency in female athletes at NCAA Division I-A schools is not a routine procedure and, for those who do screen, variability exists in the criteria for diagnosis, as well as in treatment protocols. Standard protocols for assessment and treatment of iron deficiency in female athletes need to be developed and implemented.
Effect of a Carbohydrate-Protein Supplement on Endurance Performance during Exercise of Varying Intensity
Authors: Ivy John L. , Res Peter T. , Sprague Robert C. , Widzer Matthew O.
Published: August 2016

Increasing the plasma glucose and insulin concentrations during prolonged variable intensity exercise by supplementing with carbohydrate has been found to spare muscle glycogen and increase aerobic endurance. Furthermore, the addition of protein to a carbohydrate supplement will enhance the insulin response of a carbohydrate supplement. The purpose of the present study was to compare the effects of a carbohydrate and a carbohydrate-protein supplement on aerobic endurance performance. Nine trained cyclists exercised on 3 separate occasions at intensities that varied between 45% and 75% VO2max for 3 h and then at 85% VO2max until fatigued. Supplements (200 ml) were provided every 20 min and consisted of placebo, a 7.75% carbohydrate solution, and a 7.75% carbohydrate / 1.94% protein solution. Treatments were administered using a double-blind randomized design. Carbohydrate supplementation significantly increased time to exhaustion (carbohydrate 19.7 ± 4.6 min vs. placebo 12.7 ± 3.1 min), while the addition of protein enhanced the effect of the carbohydrate supplement (carbohydrate-protein 26.9 ± 4.5 min, p < .05). Blood glucose and plasma insulin levels were elevated above placebo during carbohydrate and carbohydrate-protein supplementation, but no differences were found between the carbohydrate and carbohydrate-protein treatments. In summary, we found that the addition of protein to a carbohydrate supplement enhanced aerobic endurance performance above that which occurred with carbohydrate alone, but the reason for this improvement in performance was not evident.
Effect of Pre-exercise Carbohydrate Ingestion on Plasma Cytokine, Stress Hormone, and Neutrophil Degranulation Responses to Continuous, High-Intensity Exercise
Authors: Lancaster Graeme I. , Jentjens Roy L.P.G. , Moseley Luke , Jeukendrup Asker E. , Gleeson Michael
Published: August 2016

The purpose of the present study was to examine the effect of pre-exercise carbohydrate (CHO) ingestion on circulating leukocyte numbers, plasma interleukin (IL)-6, plasma cortisol, and lipopolysaccharide (LPS)-stimulated neutrophil degranulation responses in moderately trained male cyclists who completed approximately 1-h of high-intensity cycling. The influence of the timing of pre-exercise CHO ingestion was investigated in 8 subjects who consumed 75 g CHO as a glucose solution at either 15 (–15 trial), or 75 (–75 trial) min before the onset of exercise. The influence of the amount of pre-exercise CHO ingestion was investigated in a further 10 subjects who consumed either 25 g or 200 g CHO as a glucose solution or a placebo 45 min before the onset of exercise. At the onset of exercise in the timing experiment, the plasma glucose concentration was significantly (p < .05) lower on the –75 trial compared with pre-drink values, and the plasma cortisol concentration and neutrophil to lymphocyte (N/L) ratio were significantly (p < .05) elevated in the post-exercise period. In the –15 trial, plasma glucose concentration was well maintained, and the plasma cortisol concentration and N/L ratio were not significantly elevated above resting levels. However, LPS-stimulated neutrophil degranulation was similar in the –15 and –75 trials. The amount of CHO ingested had no effect on the magnitude of the rise in the N/L ratio compared with placebo when consumed 45 min pre-exercise. Finally, although an exercise-induced increase in the plasma IL-6 concentration was observed, this effect was independent of pre-exercise CHO ingestion.
Fluid and Electrolyte Intake and Loss in Elite Soccer Players during Training
Authors: Maughan Ronald J. , Merson Stuart J. , Broad Nick P. , Shirreffs Susan M.
Published: August 2016

This study measured fluid balance during a 90-min preseason training session in the first team squad (24 players) of an English Premier League football team. Sweat loss was assessed from changes in body mass after correction for ingested fluids and urine passed. Sweat composition was measured by collection from patches attached to the skin at 4 sites. The weather was warm (24-29 °C), with moderate humidity (46–64%). The mean ± SD body mass loss over the training session was 1.10 ± 0.43 kg, equivalent to a level of dehydration of 1.37 ± 0.54% of the pre-training body mass. Mean fluid intake was 971 ± 303 ml. Estimated total mean sweat loss was 2033 ±413 ml. Mean sweat electrolyte concentrations (mmol/L) were: sodium,49± 12; potassium,6.0± 1.3;chloride, 43 ± 10. Total sweat sodium loss of 99 ± 24 mmol corresponds to a salt (sodium chloride) loss of 5.8 ± 1.4 g. Mean urine osmolality measured on pre-training samples provided by the players was 666 ±311 mosmol/kg (n=21). These data indicate that sweat losses of water and solute in football players in training can be substantial but vary greatly between players even with the same exercise and environmental conditions. Voluntary fluid intake also shows wide inter-individual variability and is generally insufficient to match fluid losses.
Prevalent Use of Dietary Supplements among People Who Exercise at a Commercial Gym
Authors: Morrison Laura J. , Gizis Frances , Shorter Barbara
Published: August 2016

Supplement use was surveyed in a convenience sample of persons who exercised regularly at a Long Island, NY gym. Participants, age at least 18 y, completed anonymous questionnaires. A majority (84.7%) took supplements. Many consumed multivitamin/minerals (MVM; 45%), protein shakes/bars (PRO; 42.3%), vitamin C (34.7%), and vitamin E (VE; 23.4%) at least 5 times per wk. Other dietary supplements were used less frequently or by fewer participants. Ephedra was consumed by 28% at least once per wk. Choices and reasons for dietary supplement use varied with age of the participant. More of the oldest consumed MVM or VE, while those 45 y or younger chose PRO. Those younger than 30 consumed creatine more frequently. The oldest participants took supplements to prevent future illness, while others took supplements to build muscle. The reason for committing to an exercise program influenced supplement use. Bodybuilders more frequently consumed PRO, creatine, and ephedra compared to those exercising for health reasons.
Increased Caloric Intake Soon after Exercise in Cold Water
Authors: White Lesley J. , Dressendorfer Rudolph H. , Holland Eric , McCoy Sean C. , Ferguson Michael A.
Published: August 2016

We examined the acute effect of cold-water temperature on post-exercise energy intake (EI) for 1 h. In a randomized, crossover design, 11 men (25.6 ± 5 y) exercised for 45 min on a submersed cycle ergometer at 60 ± 2% VO2max in 33°C (neutral) and 20° (cold) water temperatures, and also rested for 45 min (control). Energy expenditure (EE) was determined using indirect calorimetry before, during, and after each condition. Following exercise or rest, subjects had free access to a standard assortment of food items of known caloric value. EE was similar for the cold and neutral water conditions, averaging 505 ± 22 (± standard deviation) and 517 ± 42 kcal, respectively (P = NS). EI after the cold condition averaged 877 ± 457 kcal, 44% and 41% higher (P < 0.05) than for the neutral and resting conditions, respectively. Cold-water temperature thus stimulated post-exercise EI. Water temperature warrants consideration in aquatic programs designed for weight loss.
Improved Recovery from Prolonged Exercise Following the Consumption of Low Glycemic Index Carbohydrate Meals
Authors: Stevenson Emma , Williams Clyde , McComb Gareth , Oram Christopher
Published: August 2016

This study examined the effects of the glycemic index (GI) of post-exercise carbohydrate (CHO) intake on endurance capacity the following day. Nine active males participated in 2 trials. On day 1, subjects ran for 90 min at 70% VO2max (R1). Thereafter, they were supplied with either a high GI (HGI) or low GI (LGI) CHO diet which provided 8 g CHO/kg body mass (BM). On day 2, after an overnight fast, subjects ran to exhaustion at 70% VO2max (R2). Time to exhaustion during R2 was longer in the LGI trial (108.9 ± 7.4 min) than in the HGI trial (96.9 ± 4.8 min) (P < 0.05). Fat oxidation rates and free fatty acid concentrations were higher in the LGI trial than the HGI trial (P < 0.05). The results suggest that the increased endurance capacity was largely a consequence of the increased fat oxidation following the LGI recovery diet.
Supplementation with β-Hydroxy- β-Methylbutyrate (HMB) and α-Ketoisocaproic Acid (KIC) Reduces Signs and Symptoms of Exercise-Induced Muscle Damage in Man
Authors: van Someren Ken A. , Edwards Adam J. , Howatson Glyn
Published: August 2016

This study examined the effects of β-hydroxy-β-methylbutyrate (HMB) and α-ketoisocaproic acid (KIC) supplementation on signs and symptoms of exercise-induced muscle damage following a single bout of eccentrically biased resistance exercise. Six non-resistance trained male subjects performed an exercise protocol designed to induce muscle damage on two separate occasions, performed on the dominant or non-dominant arm in a counter-balanced crossover design. Subjects were assigned to an HMB/KIC (3 g HMB and 0.3 g α-ketoisocaproic acid, daily) or placebo treatment for 14 d prior to exercise in the counter-balanced crossover design. One repetition maximum (1RM), plasma creatine kinase activity (CK), delayed onset muscle soreness (DOMS), limb girth, and range of motion (ROM) were determined pre-exercise, at 1h, 24 h, 48 h, and 72 h post-exercise. DOMS and the percentage changes in 1RM, limb girth, and ROM all changed over the 72 h period (P < 0.05). HMB/KIC supplementation attenuated the CK response, the percentage decrement in 1RM, and the percentage increase in limb girth (P < 0.05). In addition, DOMS was reduced at 24 h post-exercise (P < 0.05) in the HMB/KIC treatment. In conclusion, 14 d of HMB and KIC supplementation reduced signs and symptoms of exercise-induced muscle damage in non-resistance trained males following a single bout of eccentrically biased resistance exercise.
Influence of Acute Vitamin C and/or Carbohydrate Ingestion on Hormonal, Cytokine, and Immune Responses to Prolonged Exercise
Authors: Davison Glen , Gleeson Michael
Published: August 2016

The aim of the present study was to investigate the effect of vitamin C with or without carbohydrate consumed acutely in beverages before and during prolonged cycling on immunoendocrine responses. In a single blind, randomized manner six healthy, moderately trained males exercised for 2.5 h at 60% VO2max and consumed either placebo (PLA), carbohydrate (CHO, 6% w/v), vitamin C (VC, 0.15% w/v) or CHO+VC beverages before and during the bouts; trials were separated by 1 wk. CHO and CHO+VC significantly blunted the post-exercise increase in plasma concentrations of cortisol, ACTH, total leukocyte, and neutrophil counts and limited the decrease in plasma glucose concentration and bacteria-stimulated neutrophil degranulation. VC increased plasma antioxidant capacity (PAC) during exercise (P < 0.05) but had no effect on any of the immunoendocrine responses (P > 0.05). CHO+VC increased PAC compared to CHO but had no greater effects, above those observed with CHO alone, on any of the immunoendocrine responses. In conclusion, acute supplementation with a high dose of VC has little or no effect on the hormonal, interleukin-6, or immune response to prolonged exercise and combined ingestion of VC with CHO provides no additional effects compared with CHO alone.
Evaluation of Sports Nutrition Knowledge of New Zealand Premier Club Rugby Coaches
Authors: Zinn Caryn , Schofield Grant , Wall Clare
Published: August 2016

Little is known about if and how team coaches disseminate nutrition information to athletes. In a census survey, New Zealand premier rugby coaches (n = 168) completed a psychometrically validated questionnaire, received by either Internet or standard mail (response rate, 46%), identifying their nutrition advice dissemination practices to players, their level of nutrition knowledge, and the factors determining this level of knowledge. The majority of coaches provided advice to their players (83.8%). Coaches responded correctly to 55.6% of all knowledge questions. An independent t-test showed coaches who imparted nutrition advice obtained a significantly greater score, 56.8%, than those not imparting advice, 48.4% (P = 0.008). One-way ANOVA showed significant relationships between total knowledge score of all coaches and qualifications [F(1,166) = 5.28, P = 0.001], own knowledge rating [F(3,164) = 6.88, P = 0.001] and nutrition training [F(1,166) = 9.83, P = 0.002]. We conclude that these rugby coaches were inadequately prepared to impart nutrition advice to athletes and could benefit from further nutrition training.
Effect of High Dose Vitamin C Supplementation on Muscle Soreness, Damage, Function, and Oxidative Stress to Eccentric Exercise
Authors: Bryer S.C. , Goldfarb A.H.
Published: August 2016

This study investigated if vitamin C supplementation before and after eccentric exercise could reduce muscle soreness (MS), oxidative stress, and muscle function. Eighteen healthy men randomly assigned to either a placebo (P) or vitamin C (VC) (3 g/d) treatment group took pills for 2 wk prior and 4 d after performing 70 eccentric elbow extensions with their non-dominant arm. MS increased in both groups with significantly reduced MS for the first 24 h with VC. Range of motion was reduced equally in both groups after the exercise (P ≥ 0.05). Muscle force declined equally and was unaffected by treatment. VC attenuated the creatine kinase (CK) increase at 48 h after exercise with similar CK after this time. Gluta-thione ratio (oxidized glutathione/total glutathione) was significantly increased at 4 and 24 h with P but VC prevented this change. These data suggest that vitamin C pretreatment can reduce MS, delay CK increase, and prevent blood glutathione oxidation with little influence on muscle function loss.
B-Vitamins and Exercise: Does Exercise Alter Requirements?
Authors: Woolf Kathleen , Manore Melinda M.
Published: August 2016

The B-vitamins (thiamin, ribofavin, vitamin B-6) are necessary in the energy-producing pathways of the body, while folate and vitamin B-12 are required for the synthesis of new cells, such as the red blood cells, and for the repair of damaged cells. Active individuals with poor or marginal nutritional status for a B-vitamin may have decreased ability to perform exercise at high intensities. This review focuses on the B-vitamins and their role in energy metabolism and cell regeneration. For each vitamin, function related to physical activity, requirement, and status measures are given. Research examining dietary intakes and nutritional status in active individuals is also presented. Current research suggests that exercise may increase the requirements for ribofavin and vitamin B-6, while data for folate and vitamin B-12 are limited. Athletes who have poor diets, especially those restricting energy intakes or eliminating food groups from the diet, should consider supplementing with a multivitamin/mineral supplement.
Positive and Negative Placebo Effects Resulting from the Deceptive Administration of an Ergogenic Aid
Authors: Beedie Christopher J. , Coleman Damian A. , Foad Abigail J.
Published: August 2016

The article describes a study examining placebo effects associated with the administration of a hypothetical ergogenic aid in sport. Forty-two team-sport athletes were randomly assigned to 2 groups. All subjects completed 3 × 30-m baseline sprint trials after which they were administered what was described to them as an ergogenic aid but was in fact 200 mg of cornstarch in a gelatin capsule. Group 1 was provided with positive information about the likely effects on performance of the substance, whereas Group 2 was provided with negative information about the same substance. The sprint protocol was repeated 20 min later. Although for Group 1 mean speed did not differ significantly between baseline and experimental trials, a significant linear trend of greater speed with successive experimental trials suggested that positive belief exerted a positive effect on performance (P < 0.01). Group 2 ran 1.57% slower than at baseline (P < 0.01, 95% confidence intervals 0.32–2.82%), suggesting that negative belief exerted a negative effect on performance. Collectively, data suggest that subjects’ belief in the efficacy or otherwise of a placebo treatment might significantly influence findings in experimental research.