Showing papers in "International Journal of Sport Nutrition and Exercise Metabolism in 2004"
TL;DR: Female athletes were more likely to take supplements for their health or because of an inadequate diet, while men reported taking supplements to improve speed and agility, strength and power, or for weight/muscle gain.
Abstract: A survey was conducted to examine the source of information and usage of nutritional supplements in 115 male and 88 female varsity athletes at a Division I university. The survey asked each athlete to define supplement, and report supplement use and type, source of information, and reasons for use. Supplement use frequencies were determined, and comparisons were made between gender and sport. Eighty-nine percent of the subjects had or were currently using nutritional supplements. Many athletes did not consider sports drinks and calorie replacement products as supplements. Females were more likely to take calcium and multivitamins, and males had significant intake for ginseng, amino acids, glutamine, hydroxy-methyl-buterate (HMB), weight gainers, whey protein, and Juven. The most frequently used supplements overall were energy drinks (73%), calorie replacement products of all types (61.4%), multivitamin (47.3%), creatine (37.2%), and vitamin C (32.4%). There was also significant supplement use noted per sp...
359 citations
TL;DR: The results from this meta-analysis confirm the ergogenic effects of caffeine, particularly for endurance testing that use Tlim protocols, particularly in studies that use time-to-exhaustion protocols.
Abstract: This study used the meta-analytic approach to examine the effects of caffeine ingestion on exercise testing. Forty double-blind studies with 76 effect sizes (ES) met the inclusion criteria. The type of exercise test was classified as endurance, graded, or short-term. In comparison with placebo, caffeine improved test outcome by 12.3 % (95 % CI, 9.1 to 15.4), which was equivalent to an overall ES of 0.41 (95 % CI, 0.31 to 0.51). Endurance exercise significantly improved test outcome (P < 0.05) more than either graded or short-term exercise. When exercise protocol was examined, time-to-exhaustion (Tlim) protocols had a significantly greater (P < 0.05) ES than either the graded or the non-Tlim protocol(s). The results from this meta-analysis confirm the ergogenic effects of caffeine, particularly for endurance testing that use Tlim protocols.
244 citations
TL;DR: 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, and voluntary fluid intake also shows wide inter-individual variability and is generally insufficient to match fluid losses.
Abstract: 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 ...
191 citations
TL;DR: 3 consecutive BM measurements provide an accurate assessment of daily BM variability, which is less than 1% for active men when replacing 100% of sweat losses during exercise, and suggest that daily BM is a sufficiently stable physiological parameter for potential daily fluid balance monitoring.
Abstract: The purpose of this study was to quantify the variability and stability of 1st morning body mass (BM) fluctuations during daily exercise in the heat while following traditional fluid intake guidance. Data from 65 men were examined retrospectively. BM fluctuations were monitored over 4 to 15 consecutive days. Group daily variation in BM was 0.51+/-0.20 kg. Group coefficient of variation was 0.66+/-0.24%, normally distributed, and not related to either absolute BM (r = 0.04) or number of measurements (r = 0.34). Three days resulted in a similar variability estimate compared to 6 or 9 d, although precision was improved with 9 d. In conclusion, 3 consecutive BM measurements provide an accurate assessment of daily BM variability, which is less than 1% for active men when replacing 100% of sweat losses during exercise. The data also suggest that daily BM is a sufficiently stable physiological parameter for potential daily fluid balance monitoring.
141 citations
TL;DR: The desire to lose weight was associated with decreased energy and macronutrients consumption, but not with inadequate micronutrient intakes, while males were more likely to exceed the Dietary Guidelines for fat, saturated fat, cholesterol, and sodium than females.
Abstract: The purpose of this study was to assess the dietary intakes and behaviors of male and female collegiate athletes. Athletes (n =345) at a NCAA Division I university completed an anonymous questionnaire. T-tests, chi(2) statistic, and ANOVA were used to assess gender and sport differences. Multiple linear regression was used to assess gender differences in nutrient intakes, controlling for energy intake and to examine the relationships between desired weight change, dietary behaviors, and nutrient intakes. Only 15 % and 26 % of athletes had adequate intakes of carbohydrate and protein, respectively, based on recommendations for athletes. Males were more likely to exceed the Dietary Guidelines for fat, saturated fat, cholesterol, and sodium than females. Sixty-two percent of female athletes wanted to lose at least 5 lbs compared to 23 % of males. The desire to lose weight was associated with decreased energy and macronutrient consumption, but not with inadequate micronutrient intakes.
140 citations
TL;DR: It is concluded that after resistance exercise, a mixture of whey protein, AA, and CHO stimulated muscle protein synthesis to a greater extent than isoenergetic CHO alone and the addition of protein to an AA+ CHO mixture seems to extend the anabolic effect.
Abstract: This study tests the hypotheses that (a) a mixture of whey protein, amino acids (AA), and carbohydrates (CHO) stimulates net muscle protein synthesis to a greater extent than isoenergetic CHO alone after resistance exercise; and (b) that the stimulatory effect of a protein, AA, and CHO mixture will last beyond the 1st hour after intake. Eight subjects participated in 2 trials. In one (PAAC), they ingested 77.4 g CHO, 17.5 g whey protein, and 4.9 g AA 1 hr after resistance exercise. In the other (CON), 100 g CHO was ingested instead. They received a primed constant infusion of L-[2H5]-phenylalanine, and samples from femoral artery and vein, and biopsies from vastus lateralis were obtained. The area under the curve for net uptake of phenylalanine into muscle above pre-drink value was 128+/- 42 mg x leg(- 1) (PAAC) versus 32+/- 10 mg x leg (-1) (CON) for the 3 hr after the drink (p =.04). The net protein balance response to the mixture consisted of two components, one rapid immediate response, and a smaller delayed response about 90 min after drink, whereas in CON only a small delayed response was seen. We conclude that after resistance exercise, a mixture of whey protein, AA, and CHO stimulated muscle protein synthesis to a greater extent than isoenergetic CHO alone. Further, compared to previously reported findings, the addition of protein to an AA+ CHO mixture seems to extend the anabolic effect.
123 citations
TL;DR: In this paper, supplement use was surveyed in a convenience sample of persons who exercised regularly at a Long Island, NY gym and a majority (84.7%) of the participants took supplements.
Abstract: 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.
123 citations
TL;DR: Acute Rhodiola rosea intake can improve endurance exercise capacity in young healthy volunteers and this response was not altered by prior daily 4-week Rhodiola intake.
Abstract: Purpose: The purpose of this study was to investigate the effect of acute and 4-week Rhodiola rosea intake on physical capacity, muscle strength, speed of limb movement, reaction time, and attention. Methods: PHASE I: A double blind placebo-controlled randomized study (n = 24) was performed, consisting of 2 sessions (2 days per session). Day 1: One hour after acute Rhodiola rosea intake (R, 200-mg Rhodiola rosea extract containing 3% rosavin + 1% salidroside plus 500 mg starch) or placebo (P, 700 mg starch) speed of limb movement (plate tapping test), aural and visual reaction time, and the ability to sustain attention (Fepsy Vigilance test) were assessed. Day 2: Following the same intake procedure as on day 1, maximal isometric knee-extension torque and endurance exercise capacity were tested. Following a 5-day washout period, the experimental procedure was repeated, with the treatment regimens being switched between groups (session 2). PHASE II: A double blind placebo-controlled study (n = 12) was perfo...
119 citations
TL;DR: A high prevalence of iron depletion, anemia, and iron deficiency anemia was found among basketball players of both genders and it is recommended to recommend screening ballgame players for blood count and iron store status, and providing nutritional counseling and iron supplementation when necessary.
Abstract: Iron depletion, with or without anemia, may have a negative effect on physical and mental performance. Even with current recognition of the problem, its incidence among athletes remains high. Most studies describe iron status in endurance athletes. This study examined the prevalence of iron depletion and anemia among male and female top-level basketball players. Adolescents and adults (N = 103) from 8 national basketball teams were screened for anemia and iron stores status, which included a complete blood count and levels of plasma ferritin, transferrin, and serum iron. Iron depletion, defined by a ferritin level below 20 microg/L, was found among 22% of study participants (15% in males vs. 35% in females, p = .019). Anemia was found among 25% of athletes (18% in males vs. 38% in females, p = .028). Iron deficiency anemia, defined by the presence of anemia, ferritin levels below 12 microg/L, and transferrin saturation below 16%, was found among 7% of players (3% in males vs. 14% in females, p = .043). In summary, a high prevalence of iron depletion, anemia, and iron deficiency anemia was found among basketball players of both genders. We recommend screening ballgame players for blood count and iron store status, and providing nutritional counseling and iron supplementation when necessary.
104 citations
TL;DR: Although the diet met most recommendations for endurance athletes for macronutrient intake, it remains to be determined if modifying energy balance and fluid intake will enhance the performance of elite Kenyan runners.
Abstract: The food and macronutrient intake of elite Kenyan runners was compared to recommendations for endurance athletes Estimated energy intake (EI: 2987 +/- 293 kcal; mean +/- standard deviation) was lower than energy expenditure (EE: 3605 +/- 119 kcal; P < 0001) and body mass (BM: 589 +/- 27 kg vs 583 +/- 26 kg; P < 0001) was reduced over the 7-d intense training period Diet was high in carbohydrate (765%, 04 g/kg BM per day) and low in fat (134 %) Protein intake (101 %; 13 g/kg BM per day) matched recommendations for protein intake Fluid intake was modest and mainly in the form of water (1113 +/- 269 mL; 034 +/- 016 mL/kcal) and tea (1243 +/- 348 mL) Although the diet met most recommendations for endurance athletes for macronutrient intake, it remains to be determined if modifying energy balance and fluid intake will enhance the performance of elite Kenyan runners
99 citations
TL;DR: The objectives of this study were to describe the dietary practices recommended by coaches working with adolescent athletes and to assess their nutritional knowledge, and to indicate the importance of developing strategies that will enhance the nutritional training of coaches.
Abstract: The objectives of this study were to describe the dietary practices recommended by coaches working with adolescent athletes and to assess their nutritional knowledge. During a regional competition in the state of Sao Paulo, Brazil, 55 coaches were interviewed. These coaches represented 22 cities with athletes enrolled in Olympic gymnastics, tennis, swimming, and judo events. A 3-section questionnaire was used to obtain data on demographic characteristics, dietary recommendations, and nutrition knowledge. Results showed that all coaches recommended general dietary practices during training, with no specific strategies for pre-, during-, and post-training periods. The main objectives of the recommendations for the training period were weight control and muscle mass gain. Deleterious weight control practices were recommended by 27% of the coaches. Specific dietary practices pre and post competition were recommended by 93% and 46% of the coaches, respectively. Participants responded correctly to 70% (SD = 3.2) of the nutrition knowledge questions, with no significant differences (p =.61) between sports. The knowledge test identified a tendency to over-value proteins, excessively low-fat diets, and food myths. These findings indicate the importance of developing strategies that will enhance the nutritional training of coaches.
TL;DR: It is suggested that antioxidant supplementation was helpful in reducing the elevations in plasma CK activity and MS, with little impact on MIF and ROM loss.
Abstract: The purpose of this study was to determine the effects of antioxidant therapy on indirect markers of muscle damage following eccentric exercise (EE). Eighteen women were randomized to an antioxidant supplement or a placebo before a bout of EE. Plasma creatine kinase (CK) activity, muscle soreness (MS), maximal isometric force (MIF), and range of motion (ROM) were assessed before and through 14 d postexercise. Eccentric exercise resulted in an increase in CK activity and MS, and a drop in MIF and ROM during the days following EE, which returned to baseline values 14 d after EE in both groups. Antioxidants attenuated the CK activity and MS response to the EE, while little difference was noted between groups in MIF or ROM. These findings suggest that antioxidant supplementation was helpful in reducing the elevations in plasma CK activity and MS, with little impact on MIF and ROM loss.
TL;DR: In this paper, the effects of acute creatine-monohydrate supplementation on soccer-specific performance in young soccer players were examined and the main finding was that supplementation with creatine improved soccer specific skill performance compared with ingestion of placebo.
Abstract: The purpose of this study was to examine the effects of acute creatine-monohydrate supplementation on soccer-specific performance in young soccer players. Twenty young male soccer players (16.6 +/- 1.9 years) participated in the study and were matched and allocated to 2 randomly assigned trials: ingesting creatine-monohydrate supplement (3 x 10-g doses) or placebo for 7 days. Before and after the supplementation protocol, each subject underwent a series of soccer-specific skill tests: dribble test, sprint-power test, endurance test, and vertical jump test. Specific dribble test times improved significantly in the creatine group (13.0 +/- 1.5 vs. 10.2 +/- 1.8 s; p .05). There were no between-trial differences in the placebo trial (p > .05). The main finding of the present study indicates that supplementation with creatine in young soccer players improved soccer-specific skill performance compared with ingestion of placebo.
TL;DR: It was concluded that CHO-E consumption throughout a 1-h time trial, following a pre-exercise dietary regimen designed to optimize glucose availability, did not improve time or power output to a greater degree than P in well-trained cyclists.
Abstract: The effects of a commercial sports drink on performance in high-intensity cycling was investigated. Nine well-trained subjects were asked to complete a set amount of work as fast as possible (time trial) following 24 h of dietary (subjects were provided with food, energy 57.4 ± 2.4 kcal/kg and carbohydrate 9.1 ± 0.4 g/kg) and exercise control. During exercise, subjects were provided with 14 mL/kg of either 6% carbohydrate-electrolyte (CHO-E) solution or carbohydrate-free placebo (P). Results showed that subjects’ performances did not greatly improve (time, 62:34 ± 6:44 min:sec (CHO-E) vs. 62:40 ± 5:35 min:sec (P); average power output, 283.0 ± 25.0 W (CHO-E) vs. 282.9 ± 29.3 W (P), P > 0.05) while consuming the sports drink. It was concluded that CHO-E consumption throughout a 1-h time trial, following a pre-exercise dietary regimen designed to optimize glucose availability, did not improve time or power output to a greater degree than P in well-trained cyclists.
TL;DR: Time to exhaustion was increased significantly in subjects whose estimated intramuscular Cr levels were substantially increased, suggesting that Cr-induced hyperhydration can result in a more efficient thermoregulatory response during prolonged exercise in the heat.
Abstract: The effects of creatine (Cr) supplementation on cardiovascular, metabolic, and thermoregulatory responses, and on the capacity of trained humans to perform prolonged exercise in the heat was examined. Endurance-trained males (n = 21) performed 2 constant-load exercise tests to exhaustion at 63 +/- 5 % VO(2max) in the heat (ambient temperature: 30.3 +/- 0.5 C) before and after 7 d of Cr (20 g x d (-1 ) Cr + 140 g x d (-1 ) glucose polymer) or placebo. Cr increased intracellular water and reduced thermoregulatory and cardiovascular responses (e.g., heart rate, rectal temperature, sweat rate) but did not significantly increase time to exhaustion (47.0 +/-4.7 min vs. 49.7 +/- 7.5 min, P =0.095). Time to exhaustion was increased significantly in subjects whose estimated intramuscular Cr levels were substantially increased ("responders" : 47.3 +/- 4.9 min vs. 51.7 +/- 7.4 min, P = 0.031). Cr-induced hyperhydration can result in a more efficient thermoregulatory response during prolonged exercise in the heat.
TL;DR: Significant correlations were observed in all athletes between erythrocyte zinc, superoxide dismutase activity, and metallothionein consistent with the importance of an adequate zinc status in the response of antioxidant mechanisms to intense exercise.
Abstract: The purpose of this study was lo compare zinc and copper biochemical indices of antioxidant status and their relationship in elite athletes of different modalities: aerobic with high-impact (triathletes, n = 10 and long-distance runners, n = 12), anaerobic with high-impact (short-distance runners, n = 9), and anaerobic with low-impact (short-distance swimmers, n = 13). The influence of recent dietary intake and body composition was also evaluated. A venous blood sample was drawn 16-20 hr after competition for the following measurements: packed-cell volume and hemoglobin in blood; copper and zinc in plasma and erythrocytes; ceruloplasmin in plasma; superoxide dismutase activity and metal-lothionein in erythrocyles; and erythrocyte osmotic fragility. Zinc and copper intakes were not different in the athlete groups and did not affect the biochemical indices measured. Athletes of the long-distance high-impact aerobic modalities had higher indices of antioxidant protection (erythrocyte zinc, superoxide dismuta...
TL;DR: Prior consumption of COF did not decrease the ergogenic effect of the subsequent ingestion of anhydrous CAF, and times to exhaustion were significantly greater for all trials with CAF versus placebo.
Abstract: This study examined whether the prior consumption of coffee (COF) decreased the ergogenic effect of the subsequent ingestion of anhydrous caffeine (CAF). Thirteen subjects performed 6 rides to exhaustion at 80 % VO2max 1.5 h after ingesting combinations of COF, decaffeinated coffee (DECOF), CAF, or placebo. The conditions were DECOF + placebo (A), DECOF + CAF (5 mg/kg) (B), COF (1.1 mg/kg caffeine) + CAF (5 mg/kg) (C), COF + CAF (3 mg/kg) (D), COF + CAF (7 mg/kg) (E), and colored water + CAF (5 mg/kg) (F). Times to exhaustion were significantly greater for all trials with CAF versus placebo (trial A). Exercise times (in minutes) were: 21.7 +/- 8.1, 29.0 +/- 7.4, 27.8 +/- 10.8, 25.1 +/-7.9, 26.4 +/- 8.0 and 26.8 +/- 8.1 for trials A through F, respectively. In conclusion, the prior consumption of COF did not decrease the ergogenic effect of the subsequent ingestion of anhydrous CAF.
TL;DR: The results suggest the importance of nutritional education to promote a balanced intake, provide all nutrients in optimal amounts, inhibit unnecessary ingestion of nutritional supplements, maintain ideal performance, and improve the swimmers' health status.
Abstract: The purpose of this study was to evaluate the body composition, dietary intake, use of nutritional supplements, and biochemical status of 8 Brazilian male elite swimmers, aged 18-21 years, participants at a national swimming competition. Data from the athletes were obtained through a 4-day food record, a fasting blood sample, and anthropometric measurements. The anthropometric results showed that body composition was compatible with sport category. The dietary assessment showed an adequate ingestion of calories, vitamins, and mineral, with the exception of calcium, for which only half of the sample reached the recommendation. The results also indicated low carbohydrate and high protein and cholesterol intakes. Of the swimmers, 62.5% and 25% consumed synthetic aminoacids and antioxidants supplements, respectively. The biochemical indices of the nutritional status were within normal limits in all swimmers, with the exception of creatine-kinase, which was above the recommended level, indicating muscle degradation probably due to poor carbohydrate intake. In conclusion, the results suggest the importance of nutritional education to promote a balanced intake, provide all nutrients in optimal amounts, inhibit unnecessary ingestion of nutritional supplements, maintain ideal performance, and improve the swimmers' health status.
TL;DR: The data suggest that athletes of both genders consumed too much fat and too little carbohydrate, which was related to low intake of antioxidants.
Abstract: To investigate whether aquatic athletes follow optimal dietary intake, 58 athletes, all members of the Greek national swimming and water polo teams, were tested. Dietary intake was assessed at the nutrient, food, and food group level using the 24-h recall method and a food frequency questionnaire. Mean energy intake for males and females was 14.3 and 8.5 MJ, respectively. Mean carbohydrate consumption for male and female athletes was 4.5 g/kg and 3.8 g/kg of body weight, respectively. Fat intake was 153 g for males and 79 g for females. A significant number of the athletes (71% of the males, 93% of the females) did not meet the Dietary Reference Intakes for at least one of the antioxidant vitamins. The data suggest that athletes of both genders consumed too much fat and too little carbohydrate. Insufficient fruit and vegetable intake was related to low intake of antioxidants.
TL;DR: Based on this study, athletes need help to achieve their sports-related nutrition goals, especially during intense training, with inadequate intake of carbohydrate and some micronutrients.
Abstract: The objectives of this study were to determine the dietary habits, energy balance, and macro- and micronutrient dietary adequacy of triathletes, and to provide an athletes’ food pyramid. Thirty-eight Brazilian triathletes, had anthropometric measurements taken. Mean (± standard deviation) body weight, height, and percentage body fat were 71.2 kg (± 9.4), 176.7 cm (± 5.5), and 12.3% (± 3.6) for men and 55.8 kg (± 5.2), 161.6 cm (± 4.5), and 24.3% (± 4.2) for women, respectively. A 24-h recall and a food-frequency questionnaire showed that mean total intakes of energy (MJ), carbohydrate, protein, and fat (g · kg–1 · d–1) were, respectively, 15.4, 7.3, 2.0, and 1.6 for men and 9.9, 5.9, 1.6, and 1.3 for women. The number of meals and intake of some food groups were insufficient, resulting in inadequate intake of carbohydrate and some micronutrients. Based on this study, athletes need help to achieve their sports-related nutrition goals, especially during intense training.
TL;DR: Data do not support the benefit of AR when compared to PR in the maintenance of subsequent intense aerobic exercise performance, and plasma lactate concentration was higher in PR versus AR during the recovery period.
Abstract: This study tested the hypothesis that active recovery between bouts of intense aerobic exercise would lead to better maintenance of exercise performance in the second bout of exercise. Seven trained men on 2 separate occasions (VO(2peak) = 58.3+/- 9.4 ml x kg(-1) x min(-1)) performed as much work as possible during two 20-min cycling exercise bouts, separated by a 15-min recovery period. During passive recovery (PR), subjects rested supine, while during active recovery (AR) subjects continued to cycle at 40% VO(2peak). Muscle biopsies and blood samples were obtained. Neither muscle glycogen or lactate was different when comparing AR with PR at any point. In contrast, plasma lactate concentration was higher (p<.05) in PR versus AR during the recovery period, such that subjects commenced the second bout of intense exercise with a lower (p <.05) plasma lactate concentration in AR (4.4 +/- 0.7 vs. 7.7 +/- 1.4 mmol. L(-1) following AR and PR, respectively). Work performed in Bout 2 was less than that performed in Bout 1 in both trials (p<.01), with no difference in work performed between trials. These data do not support the benefit of AR when compared to PR in the maintenance of subsequent intense aerobic exercise performance.
TL;DR: More than half of all female varsity athletes used some type of supplement at least once a month (65.4%) as mentioned in this paper and the most frequently cited reason for supplement use was good health.
Abstract: This study examined the traditional (single and multivitamin/mineral supplements) and nontraditional supplement (herbals, botanicals, and other biologic and nutrient supplements) use by female athletes. Frequency, reasons for use, and sources of supplement information were assessed with a self-report questionnaire. Participants were 162 collegiate female varsity athletes. More than half of all athletes used some type of supplement at least once a month (65.4%). Thirty-six percent (n = 58) of the sample used a multivitamin and mineral with iron. Twelve percent (n = 19) reported amino acid/protein supplement use and 17% (n = 29) used an herbal/botanical supplement. The most frequently cited reason for supplement use was “good health” (60.1%). A major source of information on supplements reported was family (53%). With the general rise in supplement use, nutrition education on the use of traditional and non-traditional supplements is warranted.
TL;DR: In conclusion, higher CHO concentration and osmolality in an ingested beverage provokes stomach upset and side ache during intermittent, high-intensity exercise.
Abstract: This study investigated whether different beverage carbohydrate concentration and osmolality would provoke gastrointestinal (GI) discomfort during intermittent, high-intensity exercise. Thirty-six adult and adolescent athletes were tested on separate days in a double-blind, randomized trial of 6 % and 8 % carbohydrate-electrolytes (CHO-E) beverages during four 12-min quarters (Q) of circuit training that included intermittent sprints, lateral hops, shuttle runs, and vertical jumps. GI discomfort and fatigue surveys were completed before the first Q and immediately after each Q. All ratings of GI discomfort were modest throughout the study. The cumulative index for GI discomfort, however, was greater for the 8 % CHO-E beverage than for the 6 % CHO-E beverage at Q3 and Q4 (P < 0.05). Averaging across all 4 quarters, the 8 % CHO-E treatment produced significantly higher mean ratings of stomach upset and side ache. In conclusion, higher CHO concentration and osmolality in an ingested beverage provokes stomach upset and side ache.
TL;DR: Results suggest that these behaviors and attitudes need to be assessed and addressed among figure skaters, given their impact on dietary intakes and overall well-being.
Abstract: The objectives of this study were to determine food preferences, body image perceptions, dieting behaviors, and nutrient intakes of elite male and female figure skaters. Male (n = 23) and female (n = 26) figure skaters completed a food preference checklist, a questionnaire examining their demographics, dieting behaviors and body image perceptions, and 3-d food records. Male skaters had a higher preference (score ≥ 6) for grains, fruit, meat, dairy, fats, and sweets. Female skaters had higher preference for grains and fruits. Of the female skaters, 30% considered themselves overweight and indicated a preference for a thinner body contour. Both male and female skaters expressed a preference for leaner body contours for members of the opposite gender. Total energy intake, total fat (females) and dietary fiber were below the dietary recommendations. Vitamin E, vitamin D, folate (females), pantothenic acid (females), calcium (females), magnesium, potassium, and phosphorus (females) were less than two-thirds of...
TL;DR: The results indicate that VEG have a lower muscle TCr content and an increased capacity to load Cr into muscle following CrS, and Muscle CreaT gene expression does not appear to be affected by vegetarianism.
Abstract: This study examined the effect of vegetarianism on skeletal muscle total creatine (TCr) content and creatine transporter (CreaT) gene expression, prior to and during 5 d of Cr supplementation (CrS). In a double-blind, crossover design, 7 vegetarians (VEG) and nonvegetarians (NVEG) were assigned Cr or placebo supplements for 5 d and after 5 wk, received the alternative treatment. Muscle sampling occurred before, and after 1 and 5 d of treatment ingestion. Basal muscle TCr content was lower (P < 0.05) in VEG compared with NVEG. Muscle TCr increased (P < 0.05) throughout the Cr trial in both groups but was greater (P < 0.05) in VEG compared with NVEG, at days 1 and 5. CreaT gene expression was not different between VEG and NVEG. The results indicate that VEG have a lower muscle TCr content and an increased capacity to load Cr into muscle following CrS. Muscle CreaT gene expression does not appear to be affected by vegetarianism.
TL;DR: The palatability and voluntary intake of 4 beverages commonly available to athletes were compared in a laboratory exercise protocol designed to mimic aerobic training or competitive conditions in which limited time is available for drinking.
Abstract: Palatability and voluntary intake of 4 beverages commonly available to athletes were compared in a laboratory exercise protocol designed to mimic aerobic training or competitive conditions in which limited time is available for drinking. Diluted orange juice (DOJ), homemade 6% carbohydrate-electrolyte sports beverage (HCE), commercially available 6% carbohydrate-electrolyte sports beverage (CCE), and water (W) were tested. Fifty adult triathletes and runners (34 males, 16 females) exercised for 75 min at 80-85% of age-predicted heart rate, during which time they were given brief access (60 s) to one of the beverages after 30 min and 60 min of exercise. Results indicated that for overall palatability, CCE > W, HCE, DOJ; W > DOJ, and for amount of beverage consumed, CCE > W, HCE, DOJ; HCE > W, DOJ. The palatability of these beverages varied substantially, as did their voluntary intakes during exercise.
TL;DR: It is concluded that 5 weeks of CordyMax Cs-4 supplementation has no effect on aerobic capacity or endurance exercise performance in endurance-trained male cyclists.
Abstract: It is purported that supplementation with Cordyceps Sinensis (CordyMax Cs-4) will improve oxidative capacity and endurance performance. The intent of this investigation was to examine the effects of CordyMax Cs-4 supplementation on VO<(2peak,) ventilatory threshold, and endurance performance in endurance-trained cyclists. Twenty-two male cyclists participated in 5 weeks of supplementation with CordyMax Cs-4 tablets (3 g/d). Training intensity was maintained by weekly documentation and reporting throughout the 5-week period. Subjects completed a VO(2peak) test and work-based time trial prior to and following the supplementation period. VO(2peak) was similar within and between placebo (PLA) and treatment (CS) groups prior to (59.9 +/- 5.9 vs. 59.1 +/- 5.4 ml/kg/min, respectively) and following (60.1 +/- 5.5 vs. 57.1 +/- 5.8 ml/kg/min, respectively) the supplementation period. Ventilatory threshold (VT) was measured at 72 +/- 10% of VO(2peak) in P and T prior to supplementation and did not change in either group following the supplementation. PLA completed the time trial in 61.4+/- 2.4 min compared to 62.1+/- 4.0 min in T. Time trial measurements did not differ between groups, nor did they change in response to supplementation. It is concluded that 5 weeks of CordyMax Cs-4 supplementation has no effect on aerobic capacity or endurance exercise performance in endurance-trained male cyclists.
TL;DR: Vitamin-mineral supplementation was found to attenuate cardiac and muscle damage markers while also enhancing antioxidant levels and reducing membrane LPO levels in response to 1 month of swim training.
Abstract: The relationship among the enzyme activities of cardiac markers, the antioxidant defense system, and erythrocyte membrane malonyldialdehyde (MDA) levels related to vitamin-mineral supplementation in swim exercise was investigated. Swimmers aged 11–13 years were divided into 2 separate groups as control and vitamin-mineral supplemented. Swimmers participated in a monthly swimming program (4 times/wk) and swam approximately 2–2.5 km/d. Cardiac markers such as creatine kinase (CK), creatine kinase-MB (CK-MB), glutamic oxaloacetic transaminase [GOT (AST)], lactate dehydrogenase (LDH), and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities in post-training samples were found to be significantly (p < .05) higher than in pre-training samples. Except for GOT (AST), the activity increases in CK, CK-MB, and LDH in female and male supplemented groups were significantly (p < .05) lower than those of control groups during the 1-month period of swim tr...
TL;DR: There is little evidence to suggest that the use of beverages containing caffeine during nonexercise might hinder hydration status, and a significant difference was found for urine color for the post-AM time point.
Abstract: The purpose of this study was to assess the influence of rehydration with a caffeinated beverage during nonexercise periods on hydration status throughout consecutive practices in the heat. Ten (7 women, 3 men) partially heat- acclimated athletes (age 24 +/-1y, body fat 19.2 +/- 2 %, weight 68.4 +/- 4.0 kg, height 170 +/- 3 cm) completed 3 successive days of 2-a-day practices (2 h/practice, 4 h/d) in mild heat (WBGT = 23 C). The 2 trials (double-blind, random, cross-over design) included; 1) caffeine (CAF) rehydrated with Coca-Cola and 2) caffeine-free (CF) rehydrated with Caffeine-Free Coca-Cola. Urine and psychological measures were determined before and after each 2-h practice. A significant difference was found for urine color for the post-AM time point, F = 5.526, P = 0.031. No differences were found among other variables (P > 0.05). In summary, there is little evidence to suggest that the use of beverages containing caffeine during nonexercise might hinder hydration status.
TL;DR: The single bout of prolonged exercise performed in the afternoon induced a larger neutrophilia and monocytosis than the identical bout of morning exercise, possibly the result of reduced carbohydrate availability and the circadian rhythm in cortisol levels.
Abstract: This study compared immunoendocrine responses to a single bout of prolonged cycling at different times of day and to a 2nd bout of cycling at the same intensity on the same day. In a counterbalanced design, 8 men participated in 3 experimental trials separated by at least 4 d. In the afternoon exercise-only trial, subjects cycled for 2 h at 60% VO2max starting at 14:00. In the other 2 trials, subjects performed either 2 bouts of cycling at 60% VO2max for 2 h (starting at 09:00 and 14:00) or a separate resting trial. The single bout of prolonged exercise performed in the afternoon induced a larger neutrophilia and monocytosis than the identical bout of morning exercise, possibly the result of reduced carbohydrate availability and the circadian rhythm in cortisol levels. The 2nd prolonged exercise bout caused greater immunoendocrine responses but lower plasma glucose levels and neutrophil function compared with the 1st bout.