bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of an Amino Acid/Creatine Energy Supplement on the Acute Hormonal Response to Resistance Exercise
Authors: Ratamess Nicholas A. , Hoffman Jay R. , Ross Ryan , Shanklin Miles , Faigenbaum Avery D. , Kang Jie
Published: August 2016

The authors aimed to examine the acute hormonal and performance responses to resistance exercise with and without prior consumption of an amino acid/creatine/energy supplement. Eight men performed a resistance-exercise protocol at baseline (BL), 20 min after consuming a supplement (S) consisting of essential amino acids, creatine, taurine, caffeine, and glucuronolactone or a maltodextrin placebo (P). Venous blood samples were obtained before and immediately after (IP), 15 min (15P), and 30 min (30P) after each protocol. Area under the curve of resistance-exercise volume revealed that BL was significantly less than S (10%) and P (8.6%). For fatigue rate, only S (18.4% ± 12.0%) was significantly lower than BL (32.9% ± 8.4%). Total testosterone (TT) and growth hormone (GH) were significantly elevated at IP and 15P in all conditions. The GH response was significantly lower, however, in S and P than in BL. The TT and GH responses did not differ between S and P. These results indicated that a supplement consisting of amino acids, creatine, taurine, caffeine, and glucuronolactone can modestly improve high-intensity endurance; however, the anabolic-hormonal response was not augmented.
Absorption Kinetics of Amino Acids, Peptides, and Intact Proteins
Authors: Have Gabriella A.M. Ten , Engelen Marielle P.K.J. , Luiking Yvette C. , Deutz Nicolaas E.P.
Published: August 2016

The small intestine acts as interface and regulator between the gut lumen and the rest of the body and controls the degree and rate of transport of amino acids coming from dietary protein via the portal vein to the liver and the systemic circulation. To measure protein absorption, kinetics multicatheter animal (pig) models in combination with amino acid tracer technology are available. Dietary factors infuence the absorption rates from the lumen to the gut, metabolism of dietary component in the gut, and the release of amino acids to the portal circulation from digested protein. In a balanced-protein meal, the gut dietary amino acid utilization (30–50%) for gut protein synthesis will result in a labile protein pool in the gut that can be benefcial during the postabsorptive state. To enhance gut retention, amount and quality of protein and the presence of carbohydrate are major factors. Besides this the use of a slowly digestible protein or the presence of fber in the meal can increase retention further. During the absorption of low-quality protein meals, fewer amino acids are utilized by the gut, resulting in higher amounts of amino acid release to the portal circulation. Malnutrition or starvation, protein depletion, defciencies of specifc nutrients, or illness such as sepsis all inhibit the growth and change protein turnover of the intestinal mucosa and therefore affect absorption kinetics. Therefore, the kind of protein meal that has the most optimal absorption kinetics (the most benefcial) for gut and for the rest of the body depends on these (patho)physiological circumstances. Despite the absence of different absorption kinetics between protein, peptides, and amino acids, they could be benefcial in specifc circumstances.
Nutritional Intake during a Simulated Adventure Race
Authors: Zimberg Ioná Zalcman , Crispim Cibele Aparecida , Juzwiak Claudia Ridel , Antunes Hanna Karen Moreira , Edwards Ben , Waterhouse Jim , Tufik Sérgio , de Mello Marco Túlio
Published: August 2016

The objective of the study was to describe the food intake of adventure racers during a competition simulated in the laboratory. Ten male athletes with international experience in adventure races took part in the study. The experiment lasted 67 hr (total distance covered 477.3 km), but 3 athletes did not finish the race. Food intake was recorded throughout the simulation. Athletes’ total energy expenditure was greater than their total energy intake (24,516 vs. 14,738 kcal), and the athletes obtained significantly more energy from food than from supplements. Carbohydrate intake was below the recommendation of 0.5–1.0 g · kg−1 · hr−1. These results indicate that guidelines for multiday adventure races are needed.
Opuntia Ficus Indica Increases Heart-Rate Variability in High-Level Athletes
Authors: Schmitt Laurent , Fouillot Jean-Pierre , Nicolet Gérard , Midol Alain
Published: August 2016

Opuntia ficus indica (OFI) has many physiological effects, but a relationship between OFI and heart-rate variability (HRV) has never been established. The aim of this study was to describe the effects of a diet supplement of OFI on HRV in athletes. The first day, heart rate (HR) was measured at rest in supine (SU) and standing (ST) positions to analyze HRV in 10 athletes, followed by a randomized assignment to an OFI (5) or placebo (5) group. The next day, the athletes repeated the HRV test. One month later the crossover protocol was applied. In OFI, the high-frequency-activity HFSU (1,773 ± 2,927 vs. 5,856 ± 8,326 ms2, p < .05), HFST (295 ± 313 vs. 560 ± 515 ms2, p < .05), and low-frequency LFSU (1,621 ± 1,795 vs. 6,029 ± 9,007 ms2, p < .01) increased. HRSU (66 ± 13 vs. 57 ± 11 beats/min, p < .01) and HRST (87 ± 11 vs. 76 ± 9 beats/min, p < .01) decreased. A diet supplement of OFI increases HF and LF activities and decreases HR.
Dietary Intake and Body Composition of Prepubescent Female Aesthetic Athletes
Authors: Soric Maroje , Misigoj-Durakovic Marjeta , Pedisic Zeljko
Published: August 2016

The purpose of this study was to assess dietary intake and body composition of prepubescent girls competing in 3 aesthetic sports (artistic and rhythmic gymnastics and ballet). Because physiological demands of ballet training are similar to those in other aesthetic sports, ballet dancers were, for the purpose of this study, regarded as athletes. The sample consisted of 39 athletes (median age, 11 years, range 9–13) and 15 controls (median age, 11 years, range 10–12). Dietary intake was assessed using a quantitative food frequency questionnaire, and body composition, by means of anthropometry. There was no significant difference in total energy intake between groups, but there was a significant difference in energy substrate distribution. Artistic gymnasts reported significantly higher carbohydrate and lower fat contribution to total energy (57% ± 6% and 29% ± 5%, respectively) than rhythmic gymnasts (48% ± 6% and 36% ± 5%), ballet dancers (51% ± 4% and 34% ± 3%), or controls (51% ± 5% and 34% ± 4%). Relative to body weight, artistic gymnasts reported higher intake of carbohydrates (9.1 ± 4.2 g/kg) than rhythmic gymnasts (5.6 ± 3.1 g/kg), ballet dancers (6.6 ± 2.5 g/kg), or controls (5.4 ± 1.9 g/kg). Artistic gymnasts also had the lowest body-fat percentage among the groups. In all the groups mean reported daily intakes of most nutrients were higher than the current daily recommended intakes. The exceptions were dietary fiber and calcium. The proportion of athletes with an inadequate reported intake was highest for phosphorus (33%), followed by vitamin A and niacin (18%) and zinc (13%).
N-Acetylcysteine Supplementation and Oxidative Damage and Inflammatory Response after Eccentric Exercise
Authors: Silva Luciano A. , Silveira Paulo C.L , Pinho Cléber A. , Tuon Talita , Pizzol Felipe Dal , Pinho Ricardo A.
Published: August 2016

The objective of the study was to verify the effect of N-acetylcysteine (NAC) supplementation on parameters of oxidative damage and inflammatory response after high-intensity eccentric exercise (EE). 29 participants with a mean age of 21.3 ± 4 yr, weight of 74.5 ± 7.7 kg, and height of 177.2 ± 6.9 cm were selected and divided randomly into 3 groups: placebo (21 days; n = 8), NAC (21 days; n = 9), and NAC plus placebo (14 days; n = 8). Four participants withdrew from the study for personal reasons. 14 days after starting supplementation, the participants performed EE: 3 sets until exhaustion (elbow flexion and extension on the Scott bench, 80% 1RM). Blood samples were collected before and on the 2nd, 4th, and 7th day after EE. Muscle soreness (MS), lipoperoxidation, protein carbonylation, tumor-necrosis factor-cc(TNF-(), and interleukin 10 (IL-10) were determined. Results showed a significant increase in MS in all the groups on the 2nd day after EE and a decrease in the following days. A significant increase was observed in malondialdehyde and carbonyl levels on the 4th and 7th days after EE in all groups. TNF-EEincreased significantly on the 2nd day after eccentric exercise and decreased in the following days irrespective of NAC supplementation; concentration of IL-10 increased significantly on the 4th day in all groups. Only the supplemented groups maintained high levels of IL-10 on the 7th day after EE. The results suggest that treatment with NAC represents an important factor in the defense against muscle soreness and has different effects on oxidative damage and pro- and anti-inflammatory cytokines.
Nutritional Practices of Male Cyclists before and during an Ultraendurance Event
Authors: Havemann Lize , Goedecke Julia H.
Published: August 2016

The aim of the study was to investigate the pre- and during-race nutritional intake of cyclists competing in a 210-km 1-day ultraendurance cycle race. Forty-five endurancetrained male cyclists participated in this dietary survey and completed a 3-day dietary record. Mean reported carbohydrate (CHO) intake over the 3 days before the race (5.6 ± 1.7 g/kg) was below the recommended guidelines of 7–10 g/kg. Although 57% of participants indicated that they CHO loaded 1–3 days before the race, only 23% of these participants achieved CHO intakes of ≥7 g/kg over the 3-day period before the race, demonstrating a discrepancy between perceived and actual intakes of CHO. Most participants indicated the use of CHO supplements before (84%) and during (98%) the race and achieved a CHO intake of 63 ± 23 g/hr during the race. Although most cyclists failed to meet recommended prerace CHO intakes, most achieved the recommended CHO intakes during the race.
Oral Quercetin Supplementation and Blood Oxidative Capacity in Response to Ultramarathon Competition
Authors: Quindry John C. , McAnulty Steven R. , Hudson Matthew B. , Hosick Peter , Dumke Charles , McAnulty Lisa S. , Henson Dru , Morrow Jason D. , Nieman David
Published: August 2016

Previous research indicates that ultramarathon exercise can result in blood oxidative stress. The purpose of this investigation was to examine the efficacy of oral supplementation with quercetin, a naturally occurring compound with known antioxidant properties, as a potential countermeasure against blood oxidative stress during an ultramarathon competition. In double-blind fashion, 63 participants received either oral quercetin (250 mg, 4×/day; 1,000 mg/day total) or quercetin-free supplements 3 weeks before and during the 160-km Western States Endurance Run. Blood drawn before and immediately after (quercetin finishers n = 18, quercetin-free finishers n = 21) the event was analyzed for changes in blood redox status and oxidative damage. Results show that quercetin supplementation did not affect race performance. In response to the ultramarathon challenge, aqueous-phase antioxidant capacity (ferric-reducing ability of plasma) was similarly elevated in athletes in both quercetin and quercetin-free treatments and likely reflects significant increases in plasma urate levels. Alternatively, trolox-equivalent antioxidant capacity was not altered by exercise or quercetin. Accordingly, neither F2-isoprostances nor protein carbonyls were influenced by either exercise or quercetin supplementation. In the absence of postrace blood oxidative damage, these findings suggest that oral quercetin supplementation does not alter blood plasma lipid or aqueous-phase antioxidant capacity or oxidative damage during an ultramarathon challenge.
Carbohydrate Ingestion Improves Performance of a New Reliable Test of Soccer Performance
Authors: Currell Kevin , Conway Steve , Jeukendrup Asker E.
Published: August 2016

The aim of the study was to investigate the reliability of a new test of soccer performance and evaluate the effect of carbohydrate (CHO) on soccer performance. Eleven university footballers were recruited and underwent 3 trials in a randomized order. Two of the trials involved ingesting a placebo beverage, and the other, a 7.5% maltodextrin solution. The protocol comprised a series of ten 6-min exercise blocks on an outdoor Astroturf pitch, separated by the performance of 2 of the 4 soccer-specific tests, making the protocol 90 min in duration. The intensity of the exercise was designed to be similar to the typical activity pattern during soccer match play. Participants performed skill tests of dribbling, agility, heading, and shooting throughout the protocol. The coefficients of variation for dribbling, agility, heading, and shooting were 2.2%, 1.2%, 7.0%, and 2.8%, respectively. The mean combined placebo scores were 42.4 ± 2.7 s, 43.1 ± 3.7 s, 210 ± 34 cm, and 212 ± 17 points for agility, dribbling, heading, and kicking, respectively. CHO ingestion led to a combined agility time of 41.5 ± 0.8 s, for dribbling 41.7 ± 3.5 s, 213 ± 11 cm for heading, and 220 ± 5 points for kicking accuracy. There was a significant improvement in performance for dribbling, agility, and shooting (p < .05) when CHO was ingested compared with placebo. In conclusion, the protocol is a reliable test of soccer performance, and ingesting CHO leads to an improvement in soccer performance.
A Soccer Match’s Ability to Enhance Lymphocyte Capability to Produce ROS and Induce Oxidative Damage
Authors: Ferrer Miguel David , Tauler Pedro , Sureda Antoni , Pujol Pedro , Drobnic Franchec , Tur Josep Antoni , Pons Antoni
Published: August 2016

Soccer-associated oxidative stress has barely been studied. The aims of this study were to establish the effect of a soccer training match and the effect of a diet supplementation with a multivitamin complex and coenzyme Q during 3 months of soccer training on the pro-oxidant and antioxidant status of lymphocytes. In a randomized, double-blind trial, 19 male preprofessional soccer players were treated with either an antioxidant nutrient cocktail or placebo for 90 days. After this period the athletes played a soccer match lasting 60 min. All determinations were made under basal conditions before and after the training period and after the match. Basal lymphocyte hydrogen peroxide (H2O2) production did not change after the 3 months of training. Catalase activity decreased (about 50%) after the 3 months, whereas glutathione reductase increased its activity (150–200%) both with placebo and in the supplemented group. Basal ascorbate levels were maintained during the training period, whereas α-tocopherol and MDA decreased (about 40%) in both groups. The match increased H2O2 production (180%) in both groups when the lymphocytes were stimulated with phorbol myristate acetate, and it also increased MDA levels (150%). Antioxidant enzyme activities and antioxidant vitamin levels were maintained before and after the match. Regular soccer training modifies the lymphocyte strategy to eliminate ROS and increases protection against oxidative damage. A friendly soccer match raises lymphocyte capacity to produce ROS and oxidative damage, but it is not enough to induce a defensive response, thus leading to a situation of postexercise oxidative stress. Supplementation with low doses of antioxidant vitamins and coenzyme Q does not modify the endogenous antioxidant response to training.
Catering for the Athletes Village at the Sydney 2000 Olympic Games: The Role of Sports Dietitians
Authors: Pelly Fiona , O’Connor Helen , Denyer Gareth , Caterson Ian
Published: August 2016

This article describes the development, analysis, and implementation of the menu available to athletes and patrons in the main dining hall of the Athletes Village at the Sydney 2000 Olympic Games and the significant role of sports dietitians in this process. Menu design and development was informed by focus groups, literature reviews, and food-preference surveys of athletes. The final menu was also assessed by an expert panel of Australian sports dietitians. A custom-designed database (Foodweb) was developed to enable dietary analysis of food-production data and creation of point-of-choice nutrition labels. Dietitians assisted with quality assurance testing and training of catering staff. Athletes surveyed in the main dining hall (N = 414) agreed that the menu contained sufficient variety and adequate meat, pasta/rice, vegetable/salad, fruit, and snack items. Sports dietitians played a significant role in ensuring that the menu met the needs of athletes from a range of differing cultural and sporting backgrounds. Dining-hall patrons provided positive feedback and few complaints about the overall dining experience. The information presented in this report can help future caterers and dietitians with the planning and provision of suitable food for athletic performance at an Olympic Games.
Racial Differences in Postprandial Oxidative Stress with and Without Acute Exercise
Authors: Bloomer Richard J. , Cole Bradford , Fisher-Wellman Kelsey H.
Published: August 2016

High-kilocalorie feedings induce oxidative stress. Acute exercise has the potential to attenuate postprandial oxidative stress. No study has determined whether there are racial differences in postprandial oxidative stress with and without a preceding bout of acute exercise.

Purpose:

To investigate the impact of acute exercise on blood oxidative- stress biomarkers, triglycerides (TAG), and glucose in African American (AA) and White (W) women.

Methods:

10 AA (age 29 ± 3 yr, body-mass index [BMI] 31 ± 3 kg/m2) and 10 W (age 30 ± 2 yr, BMI 30 ± 3 kg/m2) women consumed a meal of 1.2 g of fat and carbohydrate and 0.25 g of protein per kilogram body mass, on 2 occasions—with and without a session of aerobic exercise 15 min preceding the meal (45 min cycling at 65% heart-rate reserve)—in a random-order crossover design. Blood samples were collected premeal (fasted), and at 1, 2, 4, and 6 hr postmeal and assayed for TAG, glucose, xanthine oxidase activity, hydrogen peroxide (H2O2), and malondialdehyde (MDA). Area under the curve (AUC) was calculated for each variable.

Results:

AUC was lower for AA compared with W for both the exercise and the no exercise conditions for H2O2, MDA, and TAG (p < .01). However, acute exercise had no effect on decreasing the AUC for any variable in either AA or W women (p > .05).

Conclusions:

Postprandial lipemia and oxidative stress are lower in AA than in W overweight/obese women. However, acute exercise, performed at the intensity and duration in the current study, does not influence postprandial lipemia or oxidative stress in AA or W women.
Heterogeneity of Dietary Profiles in Highly Sedentary Young Guadeloupean Women
Authors: Antoine-Jonville Sophie , Sinnapah Stéphane , Laviolle Bruno , Paillard François , Hue Olivier
Published: August 2016

Objective:

The aim was to examine the relationship between physical activity pattern and dietary profile. Although some clustering of the variables related to these major determinants of cardiovascular risk has been demonstrated, they have not been extensively studied together.

Participants, Design, and Setting:

Two hundred two female university students from the main Guadeloupe (French West Indies) campus participated. They self-administered a validated Food Frequency Questionnaire and the 1-yr recall Modifiable Activity Questionnaire. Principal-component analysis was performed on the scores and the variables related to the physical activity pattern and dietary profile.

Results:

A model including 10 variables explained 84.9% of the total variance. The physical activity pattern was not associated with the dietary profile, apart from fruit intake. The physical activity level was homogeneously low (median 1.58, first and last quartile cutoffs 1.54 and 1.66, respectively). There was no correlation between the physical activity level and the Food Frequency Questionnaire score (r = –.005).

Conclusions:

The absence of a strong relationship between the food and physical activity profiles is interpreted as a possible reflection of a dysregulation of the quality of food intake in this population with a sedentary lifestyle.
Conjugated Linoleic Acid’s Lack of Attenuation of Hyperpnea-Induced Bronchoconstriction in Asthmatic Individuals in the Short Term
Authors: Stickford Jonathon L. , Mickleborough Timothy D. , Fly Alyce D. , Stager Joel M.
Published: August 2016

Purpose:

Conjugated linoleic acid (CLA) has been reported to modify the inflammatory response associated with allergic airway disease, primarily in animal models. To extend these observations to humans, the effect of short-term CLA supplementation on the severity of exercise-induced bronchoconstriction (EIB) was investigated in asthmatics.

Methods:

Six subjects with physician-diagnosed asthma and EIB began the study on their usual diet, to which was added 4.8 g CLA/d for 8 wk. Pulmonary-function tests were administered before and after eucapnic voluntary hyperventilation (EVH) challenge at the commencement (Week 0) and conclusion of the treatment period (Week 8). Pre- and 90 min post-EVH challenge, urine was assayed for the presence of cysteinyl leukotrienes (LT) C4−E4 and 9α,11β-prostaglandin (PG) F2.

Results:

Pre- to post- EVH forced expiratory volume in 1 s (FEV1) did not significantly differ (p > .05) from Week 8 to Week 0. The pre- to post-EVH decline in FEV1 at Week 8 (–29.6% ± 6.6%) was not significantly different (p > .05) from that at Week 0 (–32.0% ± 5.5%). Area under the curve of FEV1 plotted against time from zero to 60 min (AUC0–60) was unaltered at Week 8 (–931% ± 350% change per minute) compared with Week 0 (−1,090% ± 270% change per minute). CLA supplementation did not alter forced midexpiratory flow, forced vital capacity (FVC), or FEV1/FVC. In addition, post-EVH urinary LTC4–E4 and 9α,11β-PGF2 were unchanged after CLA supplementation.

Conclusion:

Daily supplementation of 4.8 g CLA for 8 wk does not attenuate airway inflammation or hyperpnea-induced bronchoconstriction in asthmatic individuals.
Marginal Effects of a Large Caffeine Dose on Heat Balance During Exercise-Heat Stress
Authors: Ely Brett R. , Ely Matthew R. , Cheuvront Samuel N.
Published: August 2016

The use of caffeine supplements in athletic and military populations has increased in recent years. Excessive caffeine consumption in conjunction with exercise in a hot environment may predispose individuals to heat illness.

Purpose:

To examine heat balance induced by a large dose of caffeine during exercise in a hot environment.

Methods:

Ten men, not heat acclimated and not habitual caffeine users, consumed either caffeine (CAF; 9 mg/kg) or placebo (PLA) before performing cycle-ergometer exercise for 30 min at 50% VO2peak in a 40 °C, 25% relative humidity environment while body temperature (core and skin) and ratings of thermal comfort (TC) were monitored. Heat-exchange variables were calculated using partitional calorimetry and thermometry.

Results:

Mean body temperature (Tb) was higher (p < .05) with CAF (37.18 ± 0.15 °C) than with PLA (36.93 ± 0.15 °C) at the start of exercise. Heat production was slightly higher (~8 W, p < .05) with CAF. There were no differences in heat storage, dry heat gains, TC, or Tb during exercise.

Conclusions:

A caffeine dose of 9 mg/kg does not appreciably alter heat balance during work in a hot environment. The small increase in Tb observed with CAF was undetected by the participants and is unlikely to increase physiological strain sufficiently to affect endurance performance or risk of heat illness.
Effect of Quercetin Supplementation on Repeated-Sprint Performance, Xanthine Oxidase Activity, and Inflammation
Authors: Abbey Elizabeth L. , Rankin Janet Walberg
Published: August 2016

Maintenance of repeated-sprint performance is a goal during team-sport competition such as soccer. Quercetin has been shown to be an adenosine-receptor antagonist and may reduce oxidative stress via inhibition of the enzyme xanthine oxidase (XO). The purpose of the study was to determine the effect of quercetin consumption on performance of repeated sprints and, secondarily, the XO and inflammatory-marker response induced by repeated-sprint exercise. Fifteen recreationally active, young adult men completed 2 repeated-sprint tests (RST), 12 × 30-m maximal-effort sprints (S1–S12), each after 1 wk supplementation with a placebo, a 6% carbohydrate commercial sports drink, or that drink with 500 mg of quercetin-3-glucoside, consumed twice a day (1,000 mg/d). Blood samples were collected before supplementation (B0), at baseline before each RST (B1), immediately after RST (B2), and 1 hr after RST (B3). Mean sprint time increased progressively and was significantly higher by S9 for both treatments (5.9%); however, there were no significant differences between treatments. Percent fatigue decrement (%FD) for placebo (3.8% ± 2.3%) was significantly less than with quercetin (5.1% ± 2.7%). Changes in blood XO, IL-6, and uric acid from B1 to B2 were +47%, +77%, and +25%, respectively, with no difference by treatment. In conclusion, repeated-sprint performance was not improved by quercetin supplementation and was worse than with placebo when expressed as %FD. Quercetin did not attenuate indicators of XO activity or IL-6, a marker of the inflammatory response after sprint exercise.
Body-Density Measurement in Children: The BOD POD Versus Hydrodensitometry
Authors: Holmes Jason C. , Gibson Ann L. , Cremades J. Gualberto , Mier Constance M.
Published: August 2016

Objective:

To compare estimates of body density (Db) from air-displacement plethysmography (ADP) with measured and predicted thoracic-gas-volume (TGV) measurements and those from hydrodensitometry (HD) in children.

Methods:

Seventeen participants (13 male and 4 female; 10.1 ± 2.20 yr, 42.0 ± 15.03 kg, 145.6 ± 17.41 cm, 30.0 ± 8.66 kg/m2) were tested using ADP and HD, with ADP always preceding HD. Db estimates were compared between ADP with measured TGV, ADP with predicted TGV, and the reference measure, HD. Regression analyses were used to assess the accuracy of the ADP methods, and potential bias between the ADP procedures and HD were evaluated using Bland–Altman analyses. The cross-validation criteria described by Lohman for estimating Db relative to HD were used to interpret the results of the study.

Results:

A significant difference was found between Db estimates from ADP with measured TGV (1.0453 ± 0.01934 g/cm3) and ADP with predicted TGV (1.0415 ± 0.01858 g/cm3); however, neither was significantly different from Db obtained by the reference HD procedure (1.0417 ± 0.02391 g/cm3). For both ADP procedures, regression analyses produced an r = .737–.738, r2 = .543−.544, and SEE = 0.02 g/cm3, and the regression lines deviated significantly from the line of identity; however, no significant biases were indicated.

Conclusions:

Despite no significant mean differences between Db estimates from the ADP procedures and HD, more cross-validation research is needed before recommending the BOD POD for routine use with children in clinical and research settings.
Nutrition Knowledge in Athletes: A Systematic Review
Authors: Heaney Susan , O’Connor Helen , Michael Scott , Gifford Janelle , Naughton Geraldine
Published: August 2016

Context:

Nutrition education aims to enhance knowledge and improve dietary intake in athletes. Understanding athletes’ nutrition knowledge and its influence on dietary intake will inform nutrition-education programs in this population.

Purpose:

To systematically review the level of nutrition knowledge in athletes, benchmark this against nonathlete comparison groups, and determine the impact of nutrition knowledge on dietary intake.

Methods:

An extensive literature search from the earliest record to March 2010 using the terms nutrition knowledge or diet knowledge and athlete or sport was conducted. Included studies recruited able or physically disabled, male or female, competitive (recreational or elite) athletes over the age of 13 yr. Quantitative assessment of knowledge and, if available, diet intake was required. Because of variability in the assessment of nutrition knowledge and dietary intake, meta-analysis was not conducted.

Results:

Twenty-nine studies (17 published before 2000) measuring nutrition knowledge (7 including a nonathlete comparison group) met inclusion criteria. Athletes’ knowledge was equal to or better than that of nonathletes but lower than comparison groups including nutrition students. When found statistically significant, knowledge was greater in females than males. A weak (r < .44), positive association between knowledge and dietary intake was reported in 5 of 9 studies assessing this. Common flaws in articles included inadequate statistical reporting, instrument validation, and benchmarking.

Conclusion:

The nutrition knowledge of athletes and its impact on their dietary intake is equivocal. There is a need for high-quality, contemporary research using validated tools to measure nutrition knowledge and its impact on dietary intake.
Muscle-Fiber Type and Blood Oxidative Stress After Eccentric Exercise
Authors: Quindry John , Miller Lindsey , McGinnis Graham , Irwin Megan , Dumke Charles , Magal Meir , Triplett N. Travis , McBride Jeffrey , Urbiztondo Zea
Published: August 2016

Acute strength exercise elicits a transient oxidative stress, but the factors underlying the magnitude of this response remain unknown. The purpose of this investigation was to determine whether muscle-fiber type relates to the magnitude of blood oxidative stress after eccentric muscle activity. Eleven college-age men performed 3 sets of 50 eccentric knee-extensions. Blood samples taken pre-, post-, and 24, 48, 72, and 96 hr postexercise were assayed for comparison of muscle damage and oxidative-stress biomarkers including protein carbonyls (PCs). Vastus lateralis muscle biopsies were assayed for relative percentage of slow- and fast-twitch muscle fibers. There was a mixed fiber composition (Type I = 39.6% ± 4.5%, Type IIa = 35.7% ± 3.5%, Type IIx = 24.8% ± 3.8%; p = .366). PCs were elevated 24, 48, and 72 hr (p = .032) postexercise, with a peak response of 126% (p = .012) above baseline, whereas other oxidative-stress biomarkers were unchanged. There are correlations between Type II muscle-fiber type and postexercise PC. Further study is needed to understand the mechanisms responsible for the observed fast-twitch muscle-fiber oxidative-stress relationship.
Effects of Dynamic Exercise on Plasma Arachidonic Acid Epoxides and Diols in Human Volunteers
Authors: Giordano Rose M. , Newman John W. , Pedersen Theresa L. , Ramos Marisa I. , Stebbins Charles L.
Published: August 2016

Metabolites of the cytochrome P450 (CYP) pathway may contribute to vasodilation of the vasculature. However, it is not known whether exercise affects their circulating concentrations. The authors determined effects of exercise intensity and duration on plasma concentrations of epoxy and dihydroxy metabolites of arachidonic acid. Their goal was to delineate the threshold workload, optimal workload, and duration required to produce increases in plasma concentrations of these vasoactive substances. Healthy volunteers (N = 14) performed maximal exercise testing on a bicycle ergometer during Visit 1. On separate days, subjects cycled for 20 min at 30%, 60%, and 80% of their maximal exercise intensity. The last day consisted of 40 min of exercise at 60% of maximal exercise intensity. Venous blood was obtained before, during, and after exercise for analysis. Compared with rest, increases were observed during the 80% workload at 20 min postexercise —14,15-DHET (0.77 ± 0.21 vs. 0.93 ± 0.27 nM)—and at 2 min postexercise: 11,12-DHET (0.64 ± 0.22 vs. 0.71 ± 0.24 nM; p < .05). Also compared with rest, 40-min values during the 60% workload were 14,15-DHET 0.79 ± 0.22 vs. 0.91 ± 0.31 nM and at 2 min post 14,15 EET 0.12 ± 0.06 vs. 0.21 ± 0.16 nM (p < .05). Results suggest the CYP metabolites (i.e., DHETs) are released during short-term high-intensity and long-term moderateintensity exercise.
Case Study: Nutrition Challenges of a Marathon Runner With a Gastric Bypass
Authors: Clark Nancy
Published: August 2016

A new type of athlete is appearing in the offices of sports dietitians: formerly obese people who have undergone gastric bypass surgery and now aspire to be marathoners, triathletes, and other types of endurance athletes. The standard nutrition advice offered to bypass patients is contrary to the standard sports advice given to athletes. Bypass athletes need to limit carbohydrates, fluids, and energy intake and consume a protein-based diet. This case study describes the sport nutrition concerns of a woman who, after having gastric bypass surgery, trained to run a marathon (42 km). Because of her limited ability to consume food and fluids, she experienced difficulty preventing fatigue and dehydration during her long training runs and the marathon itself. She learned through trial and error how to survive the nutritional challenges and complete the marathon. Health professionals need to be aware of the potential medical risks associated with endurance exercise in gastric bypass patients. Research is needed to determine the best sports nutrition practices for bypass patients. Only then can sport dietitians better educate this small but growing contingent of endurance athletes so the athletes can meet their training and performance goals and reduce their risk of experiencing serious health consequences.
Energy Expenditure Estimate by Heart-Rate Monitor and a Portable Electromagnetic-Coil System
Authors: Gastinger Steven , Nicolas Guillaume , Sorel Anthony , Sefati Hamid , Prioux Jacques
Published: August 2016

The aim of this article was to compare 2 portable devices (a heart-rate monitor and an electromagnetic-coil system) that evaluate 2 different physiological parameters—heart rate (HR) and ventilation (VE)—with the objective of estimating energy expenditure (EE). The authors set out to prove that VE is a more pertinent setting than HR to estimate EE during light to moderate activities (sitting and standing at rest and walking at 4, 5, and 6 km/hr). Eleven healthy men were recruited to take part in this study (27.6 ± 5.4 yr, 73.7 ± 9.7 kg). The authors determined the relationships between HR and EE and between VE and EE during light to moderate activities. They compared EE measured by indirect calorimetry (EEREF) with EE estimated by HR monitor (EEHR) and EE estimated by electromagnetic coils (EEMAG) in upright sitting and standing positions and during walking exercises. They compared EEREF with EEHR and EEMAG. The results showed no significant difference between the values of EEREF and EEMAG. However, they showed several significant differences between the values of EEREF and EEHR (for standing at rest and walking at 5 and 6 km/hr). These results showed that the electromagnetic-coil system seems to be more accurate than the HR monitor to estimate EE at rest and during exercise. Taking into consideration these results, it would be interesting to associate the parameters VE and HR to estimate EE. Furthermore, a new version of the electromagnetic-coil device was recently developed and provides the possibility to perform measurement under daily life conditions.
The Development of Nutritional-Supplement Fact Sheets for Irish Athletes: A Case Study
Authors: Pumpa Kate L. , Madigan Sharon M. , Wood-Martin Ruth E. , Flanagan Richelle , Roche Noreen
Published: August 2016

The use of sport supplements presents a dilemma for many of those involved in supporting athletes, including coaches, families, support staff, and the athletes themselves. Often the information that they source can be incorrect and promote a biased view regarding the use of nutritional supplements. The aim of this case study was to describe the process that occurred around the development of a series of targeted educational fact sheets on a range of nutritional supplements for Irish athletes. It describes the initiation and support of the process by the Irish Sports Council; one of its subgroups, the Food and Food Supplements Committee; and the Irish Institute of Sport. A needs assessment through questionnaires was carried out to establish the most commonly used sport nutrition supplements by athletes age 16 or over in Ireland. Respondents completed 105 questionnaires over a 4-mo period in 2008–09 that led to the production of 20 supplement fact sheets. These supplement fact sheets will enable Irish athletes to access high-quality, up-to-date, scientific information about the supplements they have reported consuming. Since personal reading had a strong influence over athletes’ decision-making process for taking nutritional supplements, as did scientific research, fact sheets available on the Internet from a reliable source are an ideal way to educate Irish athletes.
Hydration Status of Arabic Adolescents and Young Men: Measurement, Evaluation, and a School-Based Initiative to Improve Drinking Behavior
Authors: Carter James M. , Loney Tom , Blacker Sam D. , Nicholson Graham F. , Wilkinson David M.
Published: August 2016

Background:

Despite the importance of hydration, limited research on the topic has been undertaken in Arabic populations.

Methods:

Study 1. Five sequential daily midmorning urine samples were provided by 88 adult military cadets and 32 school-based adolescents. Hydration thresholds were produced using percentiles of estimated urine osmolality (Uosm) and urine color (Ucol). Study 2. The authors assessed 1,077 midmorning urine samples from 120 military cadets and 52 adolescents for the Uosm:Ucol relationship using regression. Study 3. The authors conducted a 4-wk hydration campaign in which 21 adolescents participated, providing urine samples before (PreC), at the end of (EndC), and 2 wk after the campaign (PostC).

Results:

Study 1. Euhydration (41–60th percentile) was 881–970 mOsmol/kg in adults and 821–900 mOsmol/kg in adolescents. Study 2. In both cohorts, Uosm and Ucol were associated (p < .01): adults R2 = .33, adolescents R2 = .59. Study 3. Urine osmolality was significantly higher PreC than at EndC and PostC.

Conclusions:

Urinary output of Arabic adolescents and military cadets was more concentrated than frequently recommended for euhydration. Further work in similar populations is required to determine if these values represent hypohydration or merely reflect dietary and cultural differences. In male Arabic adolescents and adults, Ucol was an adequate indicator of hydration status. Favorable hydration changes were made after a school-based health campaign.
β-Alanine Improves Punch Force and Frequency in Amateur Boxers During a Simulated Contest
Authors: Donovan Tim , Ballam Tim , Morton James P. , Close Graeme L.
Published: August 2016

The aim of this study was to test the hypothesis that β-alanine supplementation improves punch power and frequency in amateur boxers during a simulated contest. Sixteen amateur boxers (each approximately 6 yr experience) were assigned to β-alanine (n = 8; 1.5 g 4 times/d for 4 wk) or placebo supplementation (n = 8) after initially being assessed for baseline punch performance. Before and after the supplementation period, all boxers completed a simulated contest consisting of 3 × 3-min rounds (interspersed with 60-s rests) on a punching bag (with a force transducer attached). Each round involved performing 2 min 50 s standardized punching (standardized jab, cross combination) based on notation analysis, whereas the last 10 s involved maximal-output punching (standardized jab, cross combination), during which time punch force and frequency were recorded. Postcontest blood lactate was significantly increased in the β-alanine group (presupplementation 9.5 ± 0.9 mmol/L, postsupplementation 12.6 ± 0.5 mmol/L, p < .05), whereas the placebo group showed no change (presupplementation 8 ± 2.8 mmol/L, postsupplementation 7.0 ± 2.7 mmol/L; p > .05). During the 10-s maximal-output punching, changes in mean punch force (β-alanine 20 ± 1.01 kg, placebo 1 ± 1 kg) and punch frequency (β-alanine 5 ± 4, placebo –2 ± 3) were greater (p < .05) in the β-alanine-supplemented group. The authors conclude that β-alanine supplementation improves punching performance in amateur boxers and suggest that this supplementation protocol may also prove ergogenic for other combat-related sports.
Fluid Balance of Elite Female Basketball Players Before and During Game Play
Authors: Brandenburg Jason P. , Gaetz Michael
Published: August 2016

This study determined the fluid balance of elite female basketball players before and during competition. Before and during 2 international games, 17 national-level players (age 24.2 ± 3 yr, height 180.5 ± 6 cm, mass 78.8 ± 8 kg) were assessed. Fluid-balance assessment included pregame hydration level as determined by urine specific gravity (USG), change in body mass during the game, ad libitum intake of water or sports drink, and estimated sweat losses. Mean (± SD) USG before Game 1 was 1.005 ± 0.002 and before Game 2 USG equaled 1.010 ± 0.005. Players lost an average of 0.7% ± 0.8% and 0.6% ± 0.6% of their body mass during Games 1 and 2, respectively. In each game, 3 players experienced a fluid deficit >1% of body mass, and 1 other, a fluid deficit >2%. Sweat losses in both games, from the beginning of the warm-up to the conclusion of the game (~125 min with average playing time 16–17 min), were approximately 1.99 ± 0.75 L. Fluid intake in Game 1 and Game 2 equaled 77.8% ± 32% and 78.0% ± 21% of sweat losses, respectively. Most players were hydrated before each game and did not become meaningfully dehydrated during the game. It is possible that the players who experienced the highest levels of dehydration also experienced some degree of playing impairment, and the negative relationship between change in body mass and shooting percentage in Game 2 provides some support for this notion.
Tyrosine Supplementation Does Not Influence the Capacity to Perform Prolonged Exercise in a Warm Environment
Authors: Watson Phillip , Enever Sophie , Page Andrew , Stockwell Jenna , Maughan Ronald J.
Published: August 2016

Eight young men were recruited to a study designed to examine the effect of tyrosine (TYR) supplementation on the capacity to perform prolonged exercise in a warm environment. Subjects entered the laboratory in the morning and remained seated for 1 hr before cycling to exhaustion at 70% VO2peak. Two 250-ml aliquots of a placebo (PLA ) or a TYR solution were ingested at 30-min intervals before exercise, with an additional 150 ml consumed every 15 min throughout exercise (total TYR dose: 150 mg/kg BM). Cognitive function was assessed before drink ingestion, at the end of the rest period, and at exhaustion. TYR ingestion had no effect on exercise capacity (PLA 61.4 ± 13.7 min, TYR 60.2 ± 15.4 min; p = .505). No differences in heart rate (p = .380), core temperature (p = .554), or weighted mean skin temperature (p = .167) were apparent between trials. Ingestion of TYR produced a marked increase in serum TYR concentrations (+236 ± 46 μmol/L; p < .001), with this difference maintained throughout exercise. No change was apparent during the PLA trial (p = .924). Exercise caused an increase in error rate during the complex component of the Stroop test (p = .034), but this response was not influenced by the drink ingested. No other component of cognitive function was altered by the protocol (all p > .05). Ingestion of a TYR solution did not influence time to exhaustion or several aspects of cognitive function when exercise was undertaken in a warm environment.
Effect of a Single Dose of Green Tea Polyphenols on the Blood Markers of Exercise-Induced Oxidative Stress in Soccer Players
Authors: Jówko Ewa , Sacharuk Jaroslaw , Balasinska Bozena , Wilczak Jacek , Charmas Malgorzata , Ostaszewski Piotr , Charmas Robert
Published: August 2016

Purpose:

To evaluate the effect of acute ingestion of green tea polyphenols (GTP) on blood markers of oxidative stress and muscle damage in soccer players exposed to intense exercise.

Methods:

This randomized, double-blinded study was conducted on 16 players during a general preparation period, when all athletes participated in a strength-training program focused on the development of strength endurance. After ingestion of a single dose of GTP (640 mg) or placebo, all athletes performed an intense muscle-endurance test consisting of 3 sets of 2 strength exercises (bench press, back squat) performed to exhaustion, with a load at 60% 1-repetition maximum and 1-min rests between sets. Blood samples were collected preexercise, 5 min after the muscle-endurance test, and after 24 hr of recovery. Blood plasma was analyzed for the concentrations of thiobarbituric acid–reacting substances (TBARS), uric acid (UA), total catechins, total antioxidant status (TAS), and activity of creatine kinase (CK); at the same time, erythrocytes were assayed for the activity of superoxide dismutase (SOD).

Results:

In both groups, plasma TBARS, UA, and TAS increased significantly postexercise and remained elevated after a 24-hr recovery period. SOD activity in erythrocytes did not change significantly in response to the muscle-endurance test, whereas in both groups plasma CK activity increased significantly after 24 hr of recovery. Acute intake of GTP cased a slight but significant increase in total plasma catechins. However, GTP was found not to exert a significant effect on measured parameters.

Conclusions:

Acute ingestion of GTP (640 mg) does not attenuate exercise-induced oxidative stress and muscle damage.
Athletes’ Opinions of Food Provision at the 2010 Delhi Commonwealth Games: The Influence of Culture and Sport
Authors: Burkhart Sarah J. , Pelly Fiona E.
Published: August 2016

The aim of this study was to investigate whether athletes’ opinion of food provision in the main dining hall of the athletes’ village at the Delhi 2010 Commonwealth Games varied according to cultural background, sport, stage of competition, and previous experience at similar events. A previously developed questionnaire was distributed over 3 meal periods to 351 athletes dining in the main dining hall during the course of the games (Sept. 23 to Oct. 4, 2010). Despite the challenges of food provision in a non-Western region, the availability of food and beverage items was rated highly. However, athletes from Western regions tended to rate food provision qualities lower than athletes from non-Western regions. Most athletes found it easy to find items to meet their nutrition needs; however, requests for sports foods, snacks, and culturally specific items were received. Power/sprint athletes were more critical of the food provision, whereas athletes from aesthetic sports tended to rate it more highly. Athletes farther from competition gave higher ratings for taste, while athletes who had more experience in this type of environment also tended to be more critical of the food provision. Overall daily mean opinion scores for taste and menu variety decreased over the games period. The results of this study can help organizers and caterers ensure that appropriate food and beverage are provided for athletes at major competition events.