bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Preexercise Glycemic-Index Meal on Running When CHO-Electrolyte Solution Is Consumed during Exercise
Authors: Wong Stephen H.S , Chan Oi Won , Chen Ya Jun , Hu Heng Long , Lam Ching Wan , Chung Pak Kwong 
Published: August 2016

Purpose:This study examined the effect of consuming carbohydrate- (CHO) electrolyte solution on running performance after different-glycemic-index (GI) meals.Methods:Nine men completed 3 trials in a randomized counterbalanced order, with trials separated by at least 7 days. Two hours before the run after an overnight fast, each participant consumed a high-GI (GI = 83) or low-GI (GI = 36) CHO meal or low-energy sugar-free Jell-O (GI = 0, control). The 2 isocaloric GI meals provided 1.5 g available CHO/kg body mass. During each trial, 2 ml/kg body mass of a 6.6% CHO-electrolyte solution was provided immediately before exercise and every 2.5 km after the start of running. Each trial consisted of a 21-km performance run on a level treadmill. The participants were required to run at 70% VO2max during the first 5 km of the run. They then completed the remaining 16 km as fast as possible.Results:There was no difference in the time to complete the 21-km run (high-GI vs. low-GI vs. control: 91.1 ± 2.0 vs. 91.8 ± 2.2 vs. 92.9 ± 2.0 min, n.s.). There were no differences in total CHO and fat oxidation throughout the trials, despite differences in preexercise blood glucose, serum insulin, and serum free-fatty-acid concentrations.Conclusion:When a CHO-electrolyte solution is consumed during a 21-km run, the GI of the preexercise CHO meal makes no difference in running performance.
Effect of Ingesting a Honey-Sweetened Beverage on Soccer Performance and Exercise-Induced Cytokine Response
Authors: Abbey Elizabeth L. , Rankin Janet Walberg 
Published: August 2016

Purpose:This study compared the effect of a honey-sweetened beverage with those of a commercial sports drink and a placebo on performance and inflammatory response to a 90-min soccer simulation.Methods:Ten experienced male soccer players randomly performed 3 trials (honey [H], sports drink [S], and placebo [P]), consuming the beverage before and during halftime for a total of 1.0 g/kg carbohydrate for H and S. Performance measures included 5 sets (T1–T5) of a high-intensity run and agility and ball-shooting tests followed by a final progressive shuttle-run (PSR) test to exhaustion. Blood samples were drawn pretest, posttest (B2), and 1 hr posttest (B3) for markers of inflammation, oxygen radical absorbance capacity (ORAC), and hormone response.Results:T2–T5 were significantly slower than T1 (p < .05), and a decrease in PSR time was observed from baseline (–22.9%) for all treatments. No significant effect of the interventions was observed for any performance measures. Plasma IL-1ra levels increased posttest for all treatments (65.5% S, 63.9% P, and 25.8% H), but H was significantly less than S at posttest and P at B3. Other cytokines and ORAC increased at B2 (548% IL-6, 514% IL-10, 15% ORAC) with no difference by treatment.Conclusion:Acute ingestion of honey and a carbohydrate sports drink before and during a soccer-simulation test did not improve performance, although honey attenuated a rise in IL-1ra. Ingestion of carbohydrate and/or antioxidant-containing beverages at frequencies typical of a regulation match may not be beneficial for trained soccer players.
12 Weeks of Combined Exercise Is Better Than Aerobic Exercise for Increasing Growth Hormone in Middle-Aged Women
Authors: Seo Dong-Il , Jun Tae-Won , Park Kae-Soon , Chang Hyukki , So Wi-Young , Song Wook 
Published: August 2016

Background:The purpose of this study was to examine the effects of combined exercise training on growth hormone (GH), insulin-like growth factor-1 (IGF-1), and metabolic-syndrome factors and determine whether the changes in GH and/or IGF-1 induced by exercise correlate to the metabolic-syndrome factors in healthy middle-aged women (50–65 years of age).Methods:The participants were randomly assigned into an aerobic-exercise training (walking + aerobics) group (AEG; n = 7), a combined-exercise training (walking + resistance training) group (CEG; n = 8), or a control group (CG; n = 7). Exercise sessions were performed 3 times per wk for 12 wk. The aerobic-exercise training consisted of walking and aerobics at 60–80% of heart-rate reserve, and the combined-exercise training consisted of walking and resistance exercise at 50–70% of 1-repetition maximum.Results:GH, percentage body fat, fasting glucose, systolic blood pressure, and waist circumference were significantly improved in CEG (p < .05). However, GH induced by exercise training showed no correlation with metabolic-syndrome factors. IGF-1 was not significantly increased in either AEG or CEG compared with CG.Conclusion:These results indicate that the combined-exercise training produced more enhancement of GH, body composition, and metabolic-syndrome factors than did aerobic-exercise training.
Comparison of Strategies for Assessing Nutritional Adequacy in Elite Female Athletes’ Dietary Intake
Authors: Heaney Susan , O’Connor Helen , Gifford Janelle , Naughton Geraldine 
Published: August 2016

Purpose:This study aimed to compare strategies for assessing nutritional adequacy in the dietary intake of elite female athletes.Methods:Dietary intake was assessed using an adapted food-frequency questionnaire in 72 elite female athletes from a variety of sports. Nutritional adequacy was evaluated and compared using mean intake; the proportion of participants with intakes below Australian nutrient reference values (NRV), U.S. military dietary reference intakes (MDRI), and current sports nutrition recommendations; and probability estimates of nutrient inadequacy.Results:Mean energy intake was 10,551 ± 3,836 kJ/day with macronutrient distribution 18% protein, 31% fat, and 46% carbohydrate, consistent with Australian acceptable macronutrient distribution ranges. Mean protein intake (1.6 g · kg−1 · d−1) was consistent with (>1.2 g · kg−1 · d−1), and carbohydrate intake (4.5 g · kg−1 · d−1), below, current sports nutrition recommendations (>5 g · kg−1 · d−1), with 30% and 65% of individuals not meeting these levels, respectively. Mean micronutrient intake met the relevant NRV and MDRI except for vitamin D and folate. A proportion of participants failed to meet the estimated average requirement for folate (48%), calcium (24%), magnesium (19%), and iron (4%). Probability estimates of inadequacy identified intake of folate (44%), calcium (22%), iron (19%), and magnesium (15%) as inadequate.Conclusion:Interpretation of dietary adequacy is complex and varies depending on whether the mean, proportion of participants below the relevant NRV, or statistical probability estimate of inadequacy is used. Further research on methods to determine dietary adequacy in athlete populations is required.
Increased Blood pH but Not Performance With Sodium Bicarbonate Supplementation in Elite Rugby Union Players
Authors: Cameron Sonya L. , McLay-Cooke Rebecca T. , Brown Rachel C. , Gray Andrew R. , Fairbairn Kirsty A. 
Published: August 2016

Purpose:This study investigated the effect of ingesting 0.3 g/kg body weight (BW) of sodium bicarbonate (NaHCO3) on physiological responses, gastrointestinal (GI) tolerability, and sprint performance in elite rugby union players.Methods:Twenty-five male rugby players, age 21.6 (2.6) yr, participated in a randomized, double-blind, placebo-controlled crossover trial. Sixty-five minutes after consuming 0.3 g/kg BW of either NaHCO3 or placebo, participants completed a 25-min warm-up followed by 9 min of high-intensity rugby-specific training followed by a rugby-specific repeated-sprint test (RSRST). Whole-blood samples were collected to determine lactate and bicarbonate concentrations and pH at baseline, after supplement ingestion, and immediately after the RSRST. Acute GI discomfort was assessed by questionnaire throughout the trials, and chronic GI discomfort was assessed during the 24 hr postingestion.Results:After supplement ingestion and immediately after the RSRST, blood HCO3 − concentration and pH were higher for the NaHCO3 condition than for the placebo condition (p < .001). After the RSRST, blood lactate concentrations were significantly higher for the NaHCO3 than for the placebo condition (p < .001). There was no difference in performance on the RSRST between the 2 conditions. The incidence of belching, stomachache, diarrhea, stomach bloating, and nausea was higher after ingestion of NaHCO3 than with placebo (all p < .050). The severity of stomach cramps, belching, stomachache, bowel urgency, diarrhea, vomiting, stomach bloating, and flatulence was rated worse after ingestion of NaHCO3 than with placebo (p < .050).Conclusions:NaHCO3 supplementation increased blood HCO3 − concentration and attenuated the decline in blood pH compared with placebo during high-intensity exercise in well-trained rugby players but did not significantly improve exercise performance. The higher incidence and greater severity of GI symptoms after ingestion of NaHCO3 may negatively affect physical performance, and the authors strongly recommend testing this supplement during training before use in competitive situations.
Does Caffeine Added to Carbohydrate Provide Additional Ergogenic Benefit for Endurance?
Authors: Conger Scott A. , Warren Gordon L. , Hardy Michelle A. , Millard-Stafford Mindy L. 
Published: August 2016

Context:Carbohydrate (CHO) and caffeine (CAF) both improve endurance performance.Purpose:To determine by systematic literature review coupled with meta-analysis whether CAF ingested with CHO (CHO+CAF) improves endurance performance more than CHO alone.Methods:Databases were searched using the keywords caffeine, endurance, exercise, carbohydrate, and performance. Criteria for inclusion were studies that used human subjects performing an endurance-exercise performance task and included both a CHO and CHO+CAF condition. Effect sizes (ESs) were calculated as the standardized mean difference.Results:Twenty-one studies met the criteria for analysis. ESs for individual studies ranged from –0.08 (trivial effect favoring CHO) to 1.01 (large effect favoring CHO+CAF). The overall ES equaled 0.26 (95% CI 0.15–0.38, p < .001), indicating that CHO+CAF provides a small but significant performance benefit over CHO. ES was not significantly (p > .05) related to CAF dose, exercise duration, or performance-assessment method. To determine whether ES of CHO+CAF vs. CHO was different than CAF compared with water (placebo), a subgroup meta-analysis compared 36 CAF vs. placebo studies against the 21 CHO+CAF vs. CHO studies. The overall ES for the former group of studies (ES = 0.51, 95% CI 0.40–0.61) was nearly 2-fold greater than in CHO+CAF vs. CHO studies (p = .006).Conclusions:CHO+CAF ingestion provides a significant but small effect to improve endurance performance compared with CHO alone. However, the magnitude of the performance benefit that CAF provides is less when added to CHO than when added to placebo.
A Comparative Analysis Between the Effects of Galactose and Glucose Supplementation on Endurance Performance
Authors: Macdermid Paul W. , Stannard Stephen , Rankin Dean , Shillington David 
Published: August 2016

Purpose:To determine beneficial effects of short-term galactose (GAL) supplementation over a 50:50 glucose–maltodextrin (GLUC) equivalent on self-paced endurance cycling performance.Methods:On 2 separate occasions, subjects performed a 100-km self-paced time trial (randomized and balanced order). This was interspersed with four 1-km and four 4-km maximal efforts reflecting the physical requirements of racing. Before each trial 38 ± 3 g of GAL or GLUC was ingested in a 6% concentrate fluid form 1 hr preexercise and then during exercise at a rate of 37 ± 3 g/hr. Performance variables were recorded for all 1- and 4-km efforts, all interspersed intervals, and the total 100-km distance. Noninvasive indicators of work intensity (heart rate [HR] and rating of perceived exertion) were also recorded.Results:Times taken to complete the 100-km performance trial were 8,298 ± 502 and 8,509 ± 578 s (p = .132), with mean power outputs of 271 ± 37 and 256 ± 45 W (p = .200), for GAL and GLUC, respectively. Mean HR did not differ (GAL 157 ± 7 and GLUC 157 ± 7 beats/min, p = .886). A main effect of carbohydrate (CHO) type on time to complete 4-km efforts occurred, with no CHO Type × Effort Order interaction observed. No main effect of CHO type or interaction of CHO Type × Sequential Order occurred for 1-km efforts.Conclusion:A 6% GAL drink does not enhance performance time during a self-paced cycling performance trial in highly trained endurance cyclists compared with a formula typically used by endurance athletes but may improve the ability to produce intermediate self-paced efforts.
Acute Caffeine Ingestion’s Increase of Voluntarily Chosen Resistance-Training Load After Limited Sleep
Authors: Cook Christian , Beaven C. Martyn , Kilduff Liam P. , Drawer Scott 
Published: August 2016

Introduction:This study aimed to determine whether caffeine ingestion would increase the workload voluntarily chosen by athletes in a limited-sleep state.Methods:In a double-blind, crossover study, 16 professional rugby players ingested either a placebo or 4 mg/kg caffeine 1 hr before exercise. Athletes classified themselves into nondeprived (8 hr+) or sleep-deprived states (6 hr or less). Exercise comprised 4 sets of bench press, squats, and bent rows at 85% 1-repetition maximum. Athletes were asked to perform as many repetitions on each set as possible without failure. Saliva was collected before administration of placebo or caffeine and again before and immediately after exercise and assayed for testosterone and cortisol.Results:Sleep deprivation produced a very large decrease in total load (p = 1.98 × 10−7). Caffeine ingestion in the nondeprived state resulted in a moderate increase in total load, with a larger effect in the sleep-deprived state, resulting in total load similar to those observed in the nondeprived placebo condition. Eight of the 16 athletes were identified as caffeine responders. Baseline testosterone was higher (p < .05) and cortisol trended lower in non-sleep-deprived athletes. Changes in hormones from predose to preexercise correlated to individual workload responses to caffeine. Testosterone response to exercise increased with caffeine compared with placebo, as did cortisol response.Conclusions:Caffeine increased voluntary workload in professional athletes, even more so under conditions of self-reported limited sleep. Caffeine may prove worthwhile when athletes are tired, especially in those identified as responders.
Chemical Composition of Three Polysaccharides From Gynostemma pentaphyllum and Their Antioxidant Activity in Skeletal Muscle of Exercised Mice
Authors: Chi Aiping , Tang Liang , Zhang Jing , Zhang Kunru 
Published: August 2016

Purpose:To investigate the effects of polysaccharide from Gynostemma pentaphyllum on antioxidant activity in skeletal muscle of mice exercised to exhaustion.Methods:Three polysaccharide fractions were obtained from G. pentaphyllum polysaccharide (GPP) and termed GPP1-a, GPP2-b, and GPP3-a. Gas chromatography (GC) and infrared spectrum of the polysaccharides were determined. The fractions were orally administrated to mice once daily for 1 wk. The exercise time to exhaustion was assessed using a forced swim test of mice after a week. The glucose, creatine phosphokinase, and lactic dehydrogenase in serum; the activity of superoxide dismutase and glutathione peroxidase; and the levels of malondialdehyde (MDA) and glycogen in muscle were determined.Results:The results of GC demonstrated that GPP1-a, GPP2-b, and GPP3-a were composed of different monosaccharides with distinct molar ratios. Infrared spectrum showed that the main typicals of GPP1-a and GPP2-b were β-configuration and the main typical of GPP3-a was α-configuration. Among the 3 fractions of GPP, GPP1-a administration significantly prolonged exercise time to exhaustion of mice, increased glycogen level and some of antioxidant enzyme activities, and decreased MDA level in muscle.Conclusions:The mechanism by which GPP1-a prolonged exercise time to exhaustion in mice may be associated with scavenging reactive oxygen species excessively produced and further increasing glycogen levels in skeletal muscle.
Association of Gastrointestinal Distress in Ultramarathoners With Race Diet
Authors: Stuempfle Kristin J. , Hoffman Martin D. , Hew-Butler Tamara 
Published: August 2016

Context:Gastrointestinal (GI) distress is common during ultrarunning.Purpose:To determine if race diet is related to GI distress in a 161-km ultramarathon.Methods:Fifteen (10 male, 5 female) consenting runners in the Javelina Jundred (6.5 loops on a desert trail) participated. Body mass was measured immediately prerace and after each loop. Runners reported if they had nausea, vomiting, abdominal cramps, and/or diarrhea after each loop. Subjects were interviewed after each loop to record food, fluid, and electrolyte consumption. Race diets were analyzed using Nutritionist Pro.Results:Nine (8 male, 1 female) of 15 runners experienced GI distress including nausea (89%), abdominal cramps (44%), diarrhea (44%), and vomiting (22%). Fluid consumption rate was higher (p = .001) in runners without GI distress (10.9 ± 3.2 ml · kg−1 · hr−1) than in those with GI distress (5.9 ± 1.6 ml · kg−1 · hr−1). Runners without GI distress consumed a higher percentage fat (p = .03) than runners with GI distress (16.5 ± 2.6 vs. 11.1 ± 5.0). In addition, fat intake rate was higher (p = .01) in runners without GI distress (0.06 ± 0.03 g · kg−1 · hr−1) than in runners with GI distress (0.03 ± 0.01 g · kg−1 · hr−1). Lower fluid and fat intake rates were evident in those developing GI distress before the onset of symptoms.Conclusions:A race diet with higher percentage fat and higher intake rates of fat and fluid may protect ultramarathoners from GI distress. However, these associations do not indicate cause and effect, and factors other than race diet may have contributed to GI distress.
Dietary Tendencies as Predictors of Marathon Time in Novice Marathoners
Authors: Wilson Patrick B. , Ingraham Stacy J. , Lundstrom Chris , Rhodes Gregory 
Published: August 2016

Background:The effects of dietary factors such as carbohydrate (CHO) on endurance-running performance have been extensively studied under laboratory-based and simulated field conditions. Evidence from “reallife” events, however, is poorly characterized. The purpose of this observational study was to examine the associations between prerace and in-race nutrition tendencies and performance in a sample of novice marathoners.Methods:Forty-six college students (36 women and 10 men) age 21.3 ± 3.3 yr recorded diet for 3 d before, the morning of, and during a 26.2-mile marathon. Anthropometric, physiological, and performance measurements were assessed before the marathon so the associations between diet and marathon time could be included as part of a stepwise-regression model.Results:Mean marathon time was 266 ± 42 min. A premarathon 2-mile time trial explained 73% of the variability in marathon time (adjusted R2 = .73, p < .001). Day-before + morning-of CHO (DBMC) was the only other significant predictor of marathon time, explaining an additional 4% of the variability in marathon time (adjusted R2 = .77, p = .006). Other factors such as age, body-mass index, gender, day-before + morning-of energy, and in-race CHO were not significant independent predictors of marathon time.Conclusions:In this sample of primarily novice marathoners, DBMC intake was associated with faster marathon time, independent of other known predictors. These results suggest that novice and recreational marathoners should consider consuming a moderate to high amount of CHO in the 24–36 hr before a marathon.
Effect of Preexercise Soup Ingestion on Water Intake and Fluid Balance During Exercise in the Heat
Authors: Johannsen Neil M. , Sullivan Zebblin M. , Warnke Nicole R. , Smiley-Oyen Ann L. , King Douglas S. , Sharp Rick L. 
Published: August 2016

Purpose:To determine whether chicken noodle soup before exercise increases ad libitum water intake, fluid balance, and physical and cognitive performance compared with water.Methods:Nine trained men (age 25 ± 3 yr, VO2peak 54.2 ± 5.1 ml · kg−1 · min−1; M ± SD) performed cycle exercise in the heat (wet bulb globe temperature = 25.9 ± 0.4 °C) for 90 min at 50% VO2peak, 45 min after ingesting 355 ml of either commercially available bottled water (WATER) or chicken noodle soup (SOUP). The same bottled water was allowed ad libitum throughout both trials. Participants then completed a time trial to finish a given amount of work (10 min at 90% VO2peak; n = 8). Cognitive performance was evaluated by the Stroop color–word task before, every 30 min during, and immediately after the time trial.Results:Ad libitum water intake throughout steady-state exercise was greater in SOUP than with WATER (1,435 ± 593 vs. 1,163 ± 427 g, respectively; p < .03). Total urine volume was similar in both trials (p = .13), resulting in a trend for greater water retention in SOUP than in WATER (87.7% ± 7.6% vs. 74.9% ± 21.7%, respectively; p = .09), possibly due to a change in free water clearance (–0.32 ± 1.22 vs. 0.51 ± 1.06 ml/min, respectively; p = .07). Fluid balance tended to be improved with SOUP (–106 ± 603 vs. –478 ± 594 g, p = .05). Likewise, change in plasma volume tended to be reduced in SOUP compared with WATER (p = .06). Only mild dehydration was achieved (<1%), and physical performance was not different between treatments (p = .77). The number of errors in the Stroop color–word task was lower in SOUP throughout the entire trial (treatment effect; p = .04).Conclusion:SOUP before exercise increased ad libitum water intake and may alter kidney function.
An Aggregate Urine Analysis Tool to Detect Acute Dehydration
Authors: Hahn Robert G. , Waldréus Nana 
Published: August 2016

Purpose:Urine sampling has previously been evaluated for detecting dehydration in young male athletes. The present study investigated whether urine analysis can serve as a measure of dehydration in men and women of a wide age span.Methods:Urine sampling and body weight measurement were undertaken before and after recreational physical exercise (median time: 90 min) in 57 volunteers age 17–69 years (mean age: 42). Urine analysis included urine color, osmolality, specific gravity, and creatinine.Results:The volunteers’ body weight decreased 1.1% (mean) while they exercised. There were strong correlations between all 4 urinary markers of dehydration (r = .73–.84, p < .001). Researchers constructed a composite dehydration index graded from 1 to 6 based on these markers. This index changed from 2.70 before exercising to 3.55 after exercising, which corresponded to dehydration of 1.0% as given by a preliminary reference curve based on 7 previous studies in athletes. Men were slightly dehydrated at baseline (mean: 1.9%) compared with women (mean: 0.7%; p < .001), though age had no influence on the results. A final reference curve that considered both the present results and the 7 previous studies was constructed in which exercise-induced weight loss (x) was predicted by the exponential equation x = 0.20 dehydration index1.86.Conclusion:Urine sampling can be used to estimate weight loss due to dehydration in adults up to age 70. A robust dehydration index based on four indicators reduces the influence of confounders.