bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Post-exercise Macronutrient Intake on Energy Balance and Protein Metabolism in Active Females Participating in Endurance Training
Authors: Roy Brian D. , Luttmer Katherine , Bosman Michael J. , Tarnopolsky Mark A.
Published: August 2016

The purpose of this investigation was to determine the influence of post-exercise macronutrient intake on weight loss, protein metabolism, and endurance exercise performance during a period of increased training volume. Ten healthy young female endurance athletes performed 4 60-min bouts of cycle ergometry at ~65% of V̇O2peak on 4 days (day 1, 3, 4, and 6) during 2 separate 1-week periods. On day 7. participants performed a ride to exhaustion at ~75% of V̇O2peak. One of the 7-day periods served as a control condition, where a placebo beverage was consumed following the exercise bouts on days 1, 3, 4, and 6 (CON). During the other 7-day protocol (POST), participants consumed a predefined formula beverage with added carbohydrate following the exercise bouts on days 1. 3,4, and 6. Energy intake and macronutrient proportions were the same between the 2 trials; the only difference was the timing at which the macronutrients were consumed. Calculated fat oxidation was greater during exercise on day 6 during POST as compared to CON (p < .05). Glucose and insulin concentrations were significantly higher (p < .05) following exercise during POST as compared to CON. There was a trend (p = .06) for nitrogen balance to be greater on days 5 and 6 with POST as compared to CON. Time to exhaustion during exercise on day 7 was longer during POST as compared to CON (p < .05). POST resulted in a maintenance of body weight during the 7-day protocol, while there was a significant (p < .05) reduction with CON. It was concluded that post-exercise macronutrient intake following endurance exercise can attenuate reductions in body weight and improve nitrogen balance during 7 days of increased energy expenditure. Importantly, post-exercise supplementation improved time to exhaustion during a subsequent bout of endurance exercise.
New Zealand Jockeys’ Dietary Habits and Their Potential Impact on Health
Authors: Leydon Mark A. , Wall Clare
Published: August 2016

The purpose of this study was to determine the nutritional status, eating behaviors, and body composition of 20 jockeys working in the New Zealand Racing Industry. Seven-day weighed food records showed the mean daily energy intake for male and female jockeys was 6769 ± 1339 kJ and 6213 ± 1797 kJ, respectively. Energy and carbohydrate intakes were below the recommendations for athletes, and the jockeys did not meet the RDI for a number of micronu-trients. Of the jockeys, 67% used a variety of methods to "make weight". including: diuretics, saunas, hot baths, exercise, and the restriction of food and fluids. A number of jockeys (20%) showed signs of disordered eating. Forty-four percent of jockeys were classified as osteopenic, and a number of factors may have contributed to this outcome, namely: reduced calcium intake, delayed menarche (14.5 years) in female jockeys, alcohol intake, and smoking. Percent body fat of male and female jockeys was 11.7 ± 2.9 and 23.6 ± 3.8, respectively. Current weight restrictions imposed on jockeys by the horseracing industry impacts on their nutritional status, which may compromise their sporting performance and both their short- and long-term health.
Voluntary Food Intake by Elite Female Cyclists during Training and Racing: Influence of Daily Energy Expenditure and Body Composition
Authors: Martin Mary K. , Martin David T. , Collier Gregory R. , Burke Louise M.
Published: August 2016

We estimated self-reported energy intake (EI) and cycling energy expenditure (CEE) during racing and training over 26 days (9 days recovery [REC], 9 days training [TRN], and 8 days racing [RACE], which included a 5-day stage race) for 8 members of the Australian National Training Squad [mean ± SD; 25.1 ± 4.0 years, 59.2 ± 4.4 kg, 3.74 ± 0.24 L · min−1 V̇O2peak, 13.6 ± 4.5 % Body fat (%Bfat)]. After 70 days of training and racing, average body mass increased by 1.1 kg (95%CI 0.5 to 1.7 kg; p < .01) and average %Bfat decreased by 0.9% (95%CI –1.7 to –0.1%; p < .05). These minor changes, however, were not considered clinically significant. CEE was different between RACE, TRN, and REC (2.15 ± 0.18 vs. 1.73 ± 0.25 vs. 0.72 ± 0.15 MJ · d−1, p < .05). Reported EI for RACE and TRN were higher than REC (14.87 ± 3.03, 13.70 ± 4.04 vs.11.98 ± 3.57 MJ · d−1, p < .05). Reported intake of carbohydrate for RACE and TRN were also higher than REC (588 ± 122, 536 ± 130 vs. 448 ± 138 g · d−1, p < .05). Reported intake of fat (59 ± 21–68 ± 21 g · d−1) was similar during RACE, TRN, and REC, whereas protein intake tended to be higher during TRN (158 ± 49 g · d−1) compared to RACE and REC (136 ± 33; 130 ± 33 g · d−1). There was a relationship between average CEE and average EI over the 26 days (r = 0.77, p < .05), but correlations between CEE and EI for each of the women varied (r =–0.02 to 0.67). There was a strong trend for an inverse relationship between average EI and %Bfat (r = –.68, p = .06, n = 8). In this study, increases in reported EI during heavy training and racing were the result of an increase in carbohydrate intake. Most but not all cyclists modulated EI based on CEE. Research is required to determine whether physiological or psychological factors are primarily responsible for the observed relationship between CEE and EI and also the inverse correlation between %Bfat and EI.
Effect of Carbohydrate Ingestion during Exercise on Post-exercise Substrate Oxidation and Energy Intake
Authors: Melby Christopher L. , Osterberg Kristen L. , Resch Alyssa , Davy Brenda , Johnson Susan , Davy Kevin
Published: August 2016

Thirteen physically active, eumenorrheic, normal-weight (BMI ≤ 25 kg/m2) females, aged 18–30 years, completed 4 experimental conditions, with the order based on a Latin Square Design: (a) CHO/Ex: moderate-intensity exer-· cise (65% V̇O2peak) with a net energy cost of ~500 kcals, during which time the subject consumed a carbohydrate beverage (45 g CHO) at specific time intervals; (b) CHO/NoEx: a period of time identical to (a) but with subjects consuming the carbohydrate while sitting quietly rather than exercising; (c) NoCHO/ Ex: same exercise protocol as condition (a) during which time subjects consumed a non-caloric placebo beverage; and (d) NoCHO/NoEx: same as the no-exercise condition (b) but with subjects consuming a non-caloric placebo beverage. Energy expenditure, and fat and carbohydrate oxidation rates for the entire exercise/sitting period plus a 90-min recovery period were determined by continuous indirect calorimetry. Following recovery, subjects ate ad libitum amounts of food from a buffet and were asked to record dietary intake during the remainder of the day. Total fat oxidation (exercise plus recovery) was attenuated by carbohydrate compared to placebo ingestion by only ~4.5 g. There was a trend (p = .08) for a carbohydrate effect on buffet energy intake such that the CHO/Ex and CHO/NoEx energy intakes were lower than the NoCHO/Ex and NoCHO/NoEx energy intakes, respectively (mean for CHO conditions: 683 kcal; NoCHO conditions: 777 kcal). Average total energy intake (buffet plus remainder of the day) was significantly lower (p < .05) following the conditions when carbohydrate was consumed (CHO/Ex = 1470 kcal; CHO/NoEx = 1285 kcal) compared to the noncaloric placebo (NoCHO/Ex =1767 kcal; NoCHO/ NoEx = 1660 kcal). In conclusion, in young women engaging in regular exercise, ingestion of 45 g of carbohydrate during exercise only modestly suppresses total fat oxidation during exercise. Furthermore, the ingestion of carbohydrate with or without exercise resulted in a lower energy intake for the remainder of the day
Oral Bovine Colostrum Supplementation Enhances Buffer Capacity but Not Rowing Performance in Elite Female Rowers
Authors: Brinkworth Grant David , Buckley Jonathan David , Bourdon Pitre Collier , Gulbin Jason Paul , David Adrian Zachei
Published: August 2016

A randomized, double-blind, placebo controlled design was used in which 13 elite female rowers, all of whom had competed at World Championships, were supplemented with 60 g · day−1 of either bovine colostrum (BC; n = 6) or concentrated whey protein powder (WP; n = 7) during 9 weeks of pre-competition training. All subjects undertook the study as a group and completed the same training program. Prior to, and after 9 weeks of supplementation and training, subjects completed an incremental rowing test (ROW1) on a rowing ergometer consisting of 3 3 4-min submaximal workloads and a 4-min maximal effort (4max), each separated by a 1-min recovery period. The rowing test was repeated after a 15-min period of passive recovery (ROW2). The 4max for ROW1 provided a measure of performance, and the difference between the 4max efforts of ROW1 and ROW2 provided an index of recovery. Blood lactate concentrations and pH measured prior to exercise and at the end of each workload were used to estimate blood buffer capacity (b). Food intake was recorded daily for dietary analysis. There were no differences in macronutrient intakes (p > .56) or training volumes (p > .99) between BC and WP during the study period. Rowing performance (distance rowed and work done) during 4max of ROW2 was less than ROW1 at baseline (p < .05) but not different between groups (p > .05). Performance increased in both rows by Week 9 (p < .001), with no difference between groups (p > .75). However, the increase was greatest in ROW2 (p < .05), such that by Week 9 there was no longer a difference in performance between the two rows in either group (p > .05). b was not different between groups for ROW1 at baseline (BC 38.3 ± 5.0, WP 38.2 ± 7.2 slykes; p > .05) but was higher in BC by Week 9 (BC 40.8 ± 5.9, WP 33.4 ± 5.3 slykes; p < .05). b for ROW2 followed the same pattern of change as for ROW1. We conclude that supplementation with BC improves b, but not performance, in elite female rowers. It was not possible to determine whether b had any effect on recovery.
Muscle Blood Flow and Mitochondrial Function: Influence of Aging
Authors: Terjung Ronald L. , Zarzeczny Ryszard , Yang H.T.
Published: August 2016

Skeletal muscle mitochondrial capacity (mito), tissue blood flow (BF) capacity, and oxygen exchange capacity (e.g., DO2) appear to be well matched. The different skeletal muscle fiber types and muscle remodeled, due to inactivity >(e.g., related to aging or disease) or exercise training, exhibit widely differing aerobics capacities (V̇O2max). Yet, there are remarkably coordinated alterations in these 3 parameters in each of these conditions. With such a balance, there is likely shared control among these parameters in limiting (V̇O2max) of muscle, although this is a matter of considerable debate. The reduction in aerobic capacity in elderly can be improved by submaximal aerobic exercise training; this is related to increases in muscle mitochondria concentration and capillarity, but probably not BF capacity, as this is limited by central cardiovascular function. Thus, exercise-induced biochemical adaptations and angiogenesis occur in the elderly. The increase in muscle capillarity likely contributes to the increased oxygen exchange capacity, typical of endurance type training. The increase in [mito] appears essential to realize the increased in muscle V̇O2max with training and amplifies the rate-limiting influence of the muscle’s oxygen exchange capacity. Further, vascular remodeling induced by exercise in the elderly could be effective at improving flow capacity, if limited by peripheral obstruction. Thus, the limits to aerobic function specific to aged muscle appear most influenced by inactivity, whereas central cardiovascular changes impact whole body performance. Some may consider the aged myocyte as a small, inactive, normal myocyte in need of activity!
Prevalence of Hypoglycemia Following Pre-exercise Carbohydrate Ingestion Is Not Accompanied by Higher Insulin Sensitivity
Authors: Jentjens Roy L.P.G. , Jeukendrup Asker E.
Published: August 2016

Pre-exercise carbohydrate feeding may result in rebound hypoglycemia in some but not all athletes. The aim of the present study was to examine whether insulin sensitivity in athletes who develop rebound hypoglycemia is higher compared with those who do not show rebound hypoglycemia. Twenty trained athletes (V̇O2max of 61.8 ± 1.4 ml · kg−1 · min−1) performed an exercise trial on a cycle ergometer. Forty-five minutes before the start of exercise, subjects consumed 500 ml of a beverage containing 75 g of glucose. The exercise trial consisted of · 20 min of submaximal exercise at 74 ± 1% V̇O2max immediately followed by a time trial. Based upon the plasma glucose nadir reached during submaximal exercise, subjects were assigned to a Hypo group (<3.5 mmol/L) and a Non-hypo group (≥3.5 mmol/L). An oral glucose tolerance test was performed to obtain an index of insulin sensitivity (ISI). The plasma glucose nadir during submaximal exercise was significantly lower (p < .01) in the Hypo-group (n = 10) compared with the Non-hypo group (n = 10) (2.7 ± 0.1 vs. 4.1 ± 0.2 mmol/L, respectively). No difference was found in ISI between the Hypo and the Non-hypo group (3.7 ± 0.4 vs. 3.8 ± 0.5, respectively). The present results suggest that insulin sensitivity does not play an important role in the occurrence of rebound hypoglycemia.
Caffeine Ingestion Does Not Alter Performance during a 100-km Cycling Time-Trial Performance
Authors: Hunter Angus M. , St Allan , Gibson Clair , Collins Malcolm , Lambert Mike , Noakes Timothy D.
Published: August 2016

This study analyzed the effect of caffeine ingestion on performance during a repeated-measures, 100-km, laboratory cycling time trial that included bouts of 1- and 4-km high intensity epochs (HIE). Eight highly trained cyclists participated in 3 separate trials—placebo ingestion before exercise with a placebo carbohydrate solution and placebo tablets during exercise (Pl), or placebo ingestion before exercise with a 7% carbohydrate drink and placebo tablets during exercise (Cho), or caffeine tablet ingestion before and during exercise with 7% carbohydrate (Caf). Placebo (twice) or 6 mg · kg−1 caffeine was ingested 60 min prior to starting 1 of the 3 cycling trials, during which subjects ingested either additional placebos or a caffeine maintenance dose of 0.33 mg · kg−1 every 15 min to trial completion. The 100-km time trial consisted of five 1-km HIE after 10, 32, 52, 72, and 99 km, as well as four 4-km HIE after 20, 40, 60, and 80 km. Subjects were instructed to complete the time trial and all HIE as fast as possible. Plasma (caffeine) was significantly higher during Caf (0.43 ± 0.56 and 1.11 ± 1.78 mM pre vs. post Pl; and 47.32 ± 12.01 and 72.43 ± 29.08 mM pre vs. post Caf). Average power, HIE time to completion, and 100-km time to completion were not different between trials. Mean heart rates during both the 1-km HIE (184.0 ± 9.8 Caf; 177.0 ± 5.8 Pl; 177.4 ± 8.9 Cho) and 4-km HIE (181.7 ± 5.7 Caf; 174.3 ± 7.2 Pl; 175.6 ± 7.6 Cho; p < .05) was higher in Caf than in the other groups. No significant differences were found between groups for either EMG amplitude (IEMG) or mean power frequency spectrum (MPFS). IEMG activity and performance were not different between groups but were both higher in the 1-km HIE, indicating the absence of peripheral fatigue and the presence of a centrally-regulated pacing strategy that is not altered by caffeine ingestion. Caffeine may be without ergogenic benefit during endurance exercise in which the athlete begins exercise with a defined, predetermined goal measured as speed or distance.
The Effect of Diet Manipulations on Aerobic Performance
Authors: Roltsch Mark H. , Flohr Judith A. , Brevard Patricia B.
Published: August 2016

The purpose of this study was to examine the metabolic consequences of a moderate variation in dietary fat content of male endurance athletes during submaximal exercise. Six males (age, 29.8 ± 11 years; weight, 72.3 ± 10 kg) · with an average maximum oxygen uptake (V̇O2max) of 66 ± 10 ml/kg/min were tested on their normal diet and 3 experimental diets. The energy contributions from protein, carbohydrates, and fats were 16/59/22 (3% alcohol), 14/53/33, 13/72/15, and 16/61/23% for the normal diet (N), fat supplemented diet (F), high carbohydrate diet (C), and adjusted normal diet (AN), respectively. The F diet was designed to significantly increase fat content compared to the normal diet and be easily maintained by the athletes. Caloric content of the F, C, and AN diets were adjusted to meet estimated total daily energy expenditure. The difference between the N and AN diets is that the AN has been adjusted to meet estimated total daily energy expenditure. The diets were randomly assigned after substrate utilization testing on the N diet and were consumed for 7 days prior to testing. Substrate utilization was recorded at steady state (73 ± 1.4% of V̇O2max) while running on a treadmill for 40 min. There were no significant differences in respiratory exchange ratio between any of the dietary manipulations. No significant differences were observed for lactate, V̇O2, or HR during submaximal testing on the N, F, C, and AN diets. These data indicate that a fat supplemented diet did not affect substrate utilization during 40 min of steady-state submaximal exercise when compared to a high carbohydrate diet or the participant’s normal and adjusted normal diets.
A Report of Hypothyroidism Induced by an Over-the-Counter Fat Loss Supplement (Tiratricol)
Authors: Scally Michael C. , Hodge Andrew
Published: August 2016

Prior to presentation, two physically fit adults, a 39-year-old male and 40-year-old female, began supplementation with an over-the-counter thyroid preparation marketed as a metabolic accelerator and fat loss aid, tiratricol. Both participants took the supplement for 5 weeks (3000–4000 mcg/d) and 3 weeks (6000 mcg/d), respectively. At presentation, both complained of lethargy, loss of appetite, and muscle weakness. Upon initial laboratory evaluation, results revealed low thyroid stimulating hormone with profoundly elevated T3 values in both patients. After an extensive review of the literature, the cause of the problem was found to be the nutritional supplement they consumed contained tiratricol. After discontinuation of the supplement, thyroid levels slowly returned to baseline 40 days and 5 months later, respectively.
Weight Loss Practices of College Wrestlers
Authors: Oppliger Robert A. , Steen Suzanne A. Nelson , Scott James R.
Published: August 2016

Purpose: The purpose of this investigation was to examine the weight management (WM) behaviors of collegiate wrestlers after the implementation of the NCAA’s new weight control rules. Methods: In the fall of 1999, a survey was distributed to 47 college wrestling teams stratified by collegiate division (i.e., I, II, III) and competitive quality. Forty-three teams returned surveys for a total of 741 responses. Comparisons were made using the collegiate division, weight class, and the wrestler’s competitive winning percentage. Results: The most weight lost during the season was 5.3 kg ± 2.8 kg (mean ± SD) or 6.9% ± 4.7% of the wrestler’s weight; weekly weight lost averaged 2.9 kg ± 1.3 kg or 4.3% ± 2.3% of the wrestler’s weight; post-season, the average wrestler regained 5.5 kg ± 3.6 kg or 8.6% ± 5.4% of their weight. Coaches and fellow wrestlers were the primary influence on weight loss methods; however, 40.2% indicated that the new NCAA rules deterred extreme weight loss behaviors. The primary methods of weight loss reported were gradual dieting (79.4%) and increased exercise (75.2%). However, 54.8% fasted, 27.6% used saunas, and 26.7% used rubber/ plastic suits at least once a month. Cathartics and vomiting were seldom used to lose weight, and only 5 met three or more of the criteria for bulimia nervosa. WM behaviors were more extreme among freshmen, lighter weight classes, and Division II wrestlers. Compared to previous surveys of high school wrestlers, this cohort of wrestlers reported more extreme WM behaviors. However, compared to college wrestlers in the 1980s, weight loss behaviors were less extreme. Conclusions: The WM practices of college wrestlers appeared to have improved compared to wrestlers sampled previously. Forty percent of the wrestlers were influenced by the new NCAA rules and curbed their weight loss practices. Education is still needed, as some wrestlers are still engaging in dangerous WM methods.
Dietary Intake and Supplement Use in Female Master Cyclists and Runners
Authors: Beshgetoor Donna , Nichols Jeanne F.
Published: August 2016

This study compared the dietary intakes of supplementing (SA) and non-supplementing athletes (NSA). Twenty-five female master athletes (mean age = 50.4 yr) participated in the study (SA = 16, NSA = 9). Four-day diet records were analyzed using Nutritionist V. Statistical significance (p < .005) was determined by independent t tests. No significant differences were observed in intakes of kilocalories (SA = 2079 ± 628 kcals, NSA = 2001 ± 435 kcals), protein (SA = 104 ± 75 g, NSA = 84 ± 35 g), fat (SA = 65 ± 39 g, NSA = 61 ± 22 g), or carbohydrates (SA = 269 ± 112 g, NSA = 277 ± 43 g). Mean intakes exceeded Dietary Reference Intake (DRI) guidelines for all micro-nutrients except calcium and vitamin E (NSA = 79% and 87% of DRI, respectively). SA had significantly greater total intakes than NSA for calcium (p = .0001), magnesium (p = .004), vitamin C (p = .003), and vitamin E (p = .001). Results suggest that female master athletes may rely on dietary supplements rather than nutrient-dense food choices to provide daily nutritional needs.
Effect of Creatine Supplementation on Body Composition and Performance: A Meta-analysis
Authors: Branch J. David
Published: August 2016

Background: Creatine supplementation (CS) has been reported to increase body mass and improve performance in high-intensity, short-duration exercise tasks. Research on CS, most of which has come into existence since 1994, has been the focus of several qualitative reviews, but only one meta-analysis, which was conducted with a limited number of studies. Purpose: This study compared the effects of CS on effect size (ES) for body composition (BC) variables (mass and lean body mass), duration and intensity (≤30 s, [ATP-PCr = A]; 30–150 s [glycolysis = G]; >150 s, [oxidative phosphorylation = O]) of the exercise task, type of exercise task (single, repetitive, laboratory, field, upper-body, lower-body), CS duration (loading, maintenance), and subject characteristics (gender, training status). Methods: A search of MEDLINE and SPORTDiscus using the phrase “creatine supplementation” revealed 96 English-language, peer-reviewed papers (100 studies), which included randomized group formation, a placebo control, and human subjects who were blinded to treatments. ES was calculated for each body composition and performance variable. Results: Small, but significant (ES > 0, p ≤ .05) ES were reported for BC (n = 163, mean ± SE = 0.17 ± 0.03), ATP-PCr (n = 17, 0.24 ± 0.02), G (n = 135, 0.19 ± 0.05), and O (n = 69, 0.20 ± 0.07). ES was greater for change in BC following a loading-only CS regimen (0.26 ± 0.03, p = .0003) compared to a maintenance regimen (0.04 ± 0.05), for repetitive-bout (0.25 ± 0.03, p = .028) compared to single-bout (0.18 ± 0.02) exercise, and for upper-body exercise (0.42 ± 0.07, p < .0001) compared to lower (0.21 ± 0.02) and total body (0.13 ± 0.04) exercise. ES for laboratory-based tasks (e.g., isometric/isotonic/isokinetic exercise, 0.25 ± 0.02) were greater (p = .014) than those observed for field-based tasks (e.g., running, swimming, 0.14 ± 0.04). There were no differences in BC or performance ES between males and females or between trained and untrained subjects. Conclusion: ES was greater for changes in lean body mass following short-term CS, repetitive-bout laboratory-based exercise tasks ≤ 30 s (e.g., isometric, isokinetic, and isotonic resistance exercise), and upper-body exercise. CS does not appear to be effective in improving running and swimming performance. There is no evidence in the literature of an effect of gender or training status on ES following CS.
Case Study of Training, Fitness, and Nourishment of a Dog Driver during the Iditarod 1049-Mile Dogsled Race
Authors: Cox Carla , Gaskill Steven , Ruby Brent , Uhlig Sharon
Published: August 2016

The purpose of the present case study was threefold: (a) to estimate intake and expenditure of a dog driver (musher) while participating in the Iditarod, (b) to determine the hydration status of the musher at the completion of the event, and (c) to evaluate training related changes in aerobic capacity and body composition of a long-distance dog sled driver in preparation for and following completion of a 1049-mile (1692-km) sled dog race. Actual energy intake during the Iditarod Sled Dog Race was estimated at 8,921 kilojoules (kJ) per day. Nutrient intake expressed as percentage kJ of total energy (14%, 44% and 42% for protein, carbohydrates, and fat, respectively). Weight loss of .72 kg of body weight indicated an energy deficit of 1819 kJ per day during the race. Total energy needs per day were calculated to be 10,740 kJ/day. An increase in hematocrit and hemoglobin during the race may indicate dehydration during the event. There was an improvement in aerobic fitness during on-snow training as determined by ventilatory threshold and VO2peak data. Fat-free mass was maintained during training (46.4 kg), with a concomitant decrease in fat (2.4 kg). Fat-free mass was also maintained during the 12-day race.
Pre- and Post-season Dietary Intake, Body Composition, and Performance Indices of NCAA Division I Female Soccer Players
Authors: Clark Mandy , Reed Debra B. , Crouse Stephen F. , Armstrong Robert B.
Published: August 2016

Little published data describe the dietary and physiological profiles of intercollegiate female soccer players; therefore, the purpose of this investigation was to report baseline dietary data, anthropometrics, and performance indices of soccer women during rigorous pre-season training (2 sessions/day) and then during the post-competitive season. Members of a NCAA Division I women’s soccer squad completed 3-day diet records, anthropometrics, and physical tests, including VO2peak. Average body mass was 62 kg with 16% body fat, and no significant pre to post differences were observed. Total energy, carbohydrate (CHO), protein, and fat intakes were significantly greater during the pre-sea-son. Pre-season energy intake met the DRI for females with an “active” lifestyle (37 kcal/kg). While CHO intake failed to meet minimum recommendations to promote glycogen repletion (7–10 g/kg), protein and fat intakes were above minimum recommendations. Pre- and post-season intakes of several micronu-trients were marginal (<75% of the DRI) including vitamin E, folate, copper, and magnesium. VO2peak significantly improved from pre- to post-season (42 and 50 ml/kg/min). In this study female soccer players appeared to meet caloric needs during periods of training but failed to meet minimum CHO and micronu-trient recommendations. Foods higher in protein and fat displaced more CHOrich and nutrient-dense foods within athletes’ energy requirements and satiety limits.
Accuracy of Three Dry-Chemistry Methods for Lipid Profiling and Risk Factor Classification
Authors: Rubin Daniela A. , McMurray Robert G. , Harrell Joanne S. , Carlson Barbara W. , Bangdiwala Shrikant
Published: August 2016

The purpose of this project was to determine the accuracy in lipids measurement and risk factor classification using Reflotron, Cholestech, and Ektachem DT-60 dry-chemistry analyzers. Plasma and capillary venous blood from fasting subjects (n = 47) were analyzed for total cholesterol (TC), high density lipoprotein (HDL-C), and triglycerides (TG) using these analyzers and a CDC certified laboratory. Accuracy was evaluated by comparing the results of each portable analyzer against the CDC reference method. One-way ANOVAs were performed for TC, HDL-C, and TG between all portable analyzers and the reference method. Chi-square was used for risk classification (2001 NIH Guidelines). Compared to the reference method, the Ektachem and Reflotron provided significantly lower values for TC (p < .05). In addition, the Cholestech and Ektachem values for HDL-C were higher than the CDC (p < .05). The Reflotron and Cholestech provided higher values of TG than the CDC (p < .05). Chi-squares analyses for risk classification were not significant (p > .45) between analyzers. According to these results, the Ektachem and Cholestech analyzers met the current NCEP III guidelines for accuracy in measurement of TC, while only Ektachem met guidelines for TG. All 3 analyzers provided a good overall risk classification; however, values of HDL-C should be only used for screening purposes.
Substrate Utilization during Exercise Performed with and Without Glucose Ingestion in Female and Male Endurance-Trained Athletes
Authors: Riddell Michael C. , Partington Sara L. , Stupka Nicole , Armstrong David , Rennie C. , Tarnopolsky Mark A.
Published: August 2016

Compared to males, females oxidize proportionately more fat and less carbohydrate during endurance exercise performed in the fasted state. This study was designed to test the hypothesis that there may also be gender differences in exogenous carbohydrate (CHOexo) oxidation during exercise. Healthy, young males (n = 7) and females (n = 7) each completed 2 exercise trials (90 min cycle ergometry at 60% VO2peak), 1 week apart. Females were eumenorrheic and were tested in the midfollicular phase of their menstrual cycle. Subjects drank intermittently either 8% CHOexo (1 g glucose · kg · h−1) enriched with U-13C glucose or an artificially sweetened placebo during the trial. Whole-body substrate oxidation was determined from RER, urinary urea excretion, and the ratio of 13C:12C in expired gas during the final 60 min of exercise. During the placebo trial, fat oxidation was higher in females than in males (0.42 · 0.07 vs. 0.32 · 0.09 g · min−1 · kg LBM–1 × 10–2) at 30 min of exercise (p < .05). When averaged over the final 60 min of exercise, the relative proportions of fat, total carbohydrate, and protein were similar between groups. During CHOexo ingestion, both the ratio of 13C:12C in expired gas (p < .05) and the proportion of energy derived from CHOexo relative to LBM (p < .05) were higher in females compared to males at 75- and 90-min exercise. When averaged over the final 60 min of exercise, the percentage of CHOexo to the total energy contribution tended to be higher in females (14.3 · 1.2%) than in males (11.2 · 1.2%; p = .09). The reduction in endogenous CHO oxidation with CHOexo intake was also greater in females (12.9 · 3.1%) than in males (5.1 · 2.0%; p = .05). Compared to males, females may oxidize a greater relative proportion of CHOexo during endurance exercise which, in turn, may spare more endogenous fuel. Based on these observations, ingested carbohydrate may be a particularly beneficial source of fuel during endurance exercise for females.
Effect of Variable Carbohydrate Intake on Exercise Performance in Female Endurance Cyclists
Authors: Dolins Karen Reznik , Boozer Carol N. , Stoler Felicia , Bartels Matthew , DeMeersman Ronald , Contento Isobel
Published: August 2016

This study measured the effect of variable carbohydrate intake on time to exhaustion, variations in heart rate (HR), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) in female endurance cyclists during an exercise trial. Subjects were 11 eumenorrheic women with maximal oxygen consumption (VO2max) 60.1 ± 5.1 ml/kg who habitually cycled at least 100 miles per week. In a crossover design, each woman was randomly assigned to a eucaloric diet providing 8, 5, or 3 g of CHO/kg of body weight. Subjects cycled at least 100 miles while adhering to the diet for 6 days. The exercise trial was performed on the 7th day, consisting of a 60 min cycle at 70% VO2max, followed by an increase in intensity to 90% VO2max until that intensity could no longer be maintained. Results indicated no difference in mean time to exhaustion, heart rate, or RPE. RER increased over time-elapsed (F = 40.4, p < .001) and across diets (F = 6.1, p = .015). Conclusions: Female endurance cyclists did not experience a difference in time to exhaustion, HR, or RPE with different levels of CHO intake during an endurance trial. RER varied with diet at submaximal intensities. Further research is needed to determine the optimal level of CHO intake for this population.
Endurance Capacity and High-Intensity Exercise Performance Responses to a High-Fat Diet
Authors: Fleming Jesse , Sharman Matthew J. , Avery Neva G. , Love Dawn M. , Gómez Ana L. , Scheett Timothy P. , Kraemer William J. , Volek Jeff S.
Published: August 2016

The effects of adaptation to a high-fat diet on endurance performance are equivocal, and there is little data regarding the effects on high-intensity exercise performance. This study examined the effects of a high-fat/moderate protein diet on submaximal, maximal, and supramaximal performance. Twenty non-highly trained men were assigned to either a high-fat/moderate-protein (HFMP; 61% fat) diet (n = 12) or a control (C; 25% fat) group (n = 8). A maximal oxygen consumption test, two 30-s Wingate anaerobic tests, and a 45-min timed ride were performed before and after 6 weeks of diet and training. Body mass decreased significantly (–2.2 kg; p ≤ .05) in HFMP subjects. Maximal oxygen consumption significantly decreased in the HFMP group (3.5 ± 0.14 to 3.27 ± 0.09 L · min−1) but was unaffected when corrected for body mass. Perceived exertion was significantly higher during this test in the HFMP group. Main time effects indicated that peak and mean power decreased significantly during bout 1 of the Wingate sprints in the HFMP (–10 and –20%, respectively) group but not the C (–8 and –16%, respectively) group. Only peak power was lower during bout 1 in the HFMP group when corrected for body mass. Despite significantly reduced RER values in the HFMP group during the 45-min cycling bout, work output was significantly decreased (–18%). Adaptation to a 6-week HFMP diet in non-highly trained men resulted in increased fat oxidation during exercise and small decrements in peak power output and endurance performance. These deleterious effects on exercise performance may be accounted for in part by a reduction in body mass and/or increased ratings of perceived exertion.
Comparison of 24-Hour Whole Body versus Patch Tests for Estimating Body Surface Electrolyte Losses
Authors: Palacios Cristina , Wigertz Karin , Weaver Connie M.
Published: August 2016

Purpose:

To compare dermal electrolyte loss between whole body and regional patch methods in women during 24-h.

Methods:

Dermal loss was collected in 6 healthy women mean age 27 ± 4 years, while consuming 936 mg/d sodium, 1764 mg/d potassium, 696 mg/d calcium, and 152 mg/d magnesium. Twenty-four hour whole body dermal loss was collected using cotton suits by a washdown procedure. Twenty-four hour patch loss was collected from 8 patches placed on the legs, arms, and back.

Results:

Dermal loss from whole body was 108 ± 110 mg/d sodium, 133 ± 87 mg/d potassium, 103 ± 22 mg/d calcium, and 35 ± 13 mg/d magnesium. Electrolyte content from the 8 patches was similar among sites and ranged from 1.01–1.41 mg/d sodium, 0.35–0.83 mg/d potassium, 1.0– 1.45 mg/d calcium, and 0.43–0.49 mg/d magnesium. Projections from patches to whole body by the ratio of body surface area appear to overestimate actual whole body losses by 3.2X for sodium and calcium, 3.6X for magnesium, and 1.3X for potassium.

Conclusions:

Regional patch methods are more appropriate for relative comparisons than for accurately determining total daily dermal electrolyte losses.
No Effect of Pre-exercise Meal on Substrate Metabolism and Time Trial Performance during Intense Endurance Exercise
Authors: Paul David , Jacobs Kevin A. , Geor Raymond J. , Hinchcliff Kenneth W.
Published: August 2016

To determine the effect of macronutrient composition of pre-exercise meals on exercise metabolism and performance, 8 trained men exercised for 30 min above lactate threshold (30LT), followed by a 20-km time trial (TT). Approximately 3.5 h before exercise, subjects consumed a carbohydrate meal (C; 3 g carbohydrate/kg), an isoenergetic fat meal (F; 1.3 g fat/kg), or a placebo meal (P; no energy content) on 3 separate occasions in randomized order. Treatments had no effect on carbohydrate oxidation during exercise, but C decreased whole-body fat oxidation during the last 5 min of 30LT and TT, respectively (3.2 ± 1.6 and 4.8 ± 2.1 mmol · kg−1 · min−1, p < .05) when compared to F (13.3 ± 1.6 and 16.5 ± 2.7 mmol · kg−1 · min−1) and P (15.9 ± 2.7 and 17.0 ± 3.2 mmol · kg−1 · min−1). Glucose rate of appearance (Ra) and disappearance (Rd), and muscle glycogen utilization were not significantly different among treatments during exercise. TT performances were similar for C, F, and P (32.7 ± 0.5 vs. 33.1 ± 1.1 and 33.0 ± 0.8 min, p > .05). We conclude that the consumption of a pre-exercise meal has minor effects on fat oxidation during high-intensity exercise, and no effect on carbohydrate oxidation or TT performance.
Eating Patterns and Meal Frequency of Elite Australian Athletes
Authors: Burke Louise M. , Slater Gary , Broad Elizabeth M. , Haukka Jasmina , Modulon Sofie , Hopkins William G.
Published: August 2016

We undertook a dietary survey of 167 Australian Olympic team athletes (80 females and 87 males) competing in endurance sports (n = 41), team sports (n = 31), sprint- or skill-based sports (n = 67), and sports in which athletes are weight-conscious (n = 28). Analysis of their 7-day food diaries provided mean energy intakes, nutrient intakes, and eating patterns. Higher energy intakes relative to body mass were reported by male athletes compared with females, and by endurance athletes compared with other athletes. Endurance athletes reported substantially higher intakes of carbohydrate (CHO) than other athletes, and were among the athletes most likely to consume CHO during and after training sessions. Athletes undertaking weight-conscious sports reported relatively low energy intakes and were least likely to consume CHO during a training session or in the first hour of recovery. On average, athletes reported eating on ~5 separate occasions each day, with a moderate relationship between the number of daily eating occasions and total energy intake. Snacks, defined as food or drink consumed between main meals, provided 23% of daily energy intake and were chosen from sources higher in CHO and lower in fat and protein than foods chosen at meals. The dietary behaviors of these elite athletes were generally consistent with guidelines for sports nutrition, but intakes during and after training sessions were often sub-optimal. Although it is of interest to study the periodicity of fluid and food intake by athletes, it is difficult to compare across studies due to a lack of standardized terminology.
A Pilot Intervention to Increase Calcium Intake in Female Collegiate Athletes
Authors: Mehlenbeck Robyn S. , Ward Kenneth D. , Klesges Robert C. , Vukadinovich Christopher M.
Published: August 2016

Calcium intake in adolescent and young adult female athletes often is inadequate to optimize peak bone mass, an important determinant of osteoporosis risk. The purpose of this study was to determine if calcium supplementation in eumenorrheic female collegiate athletes increases intake to recommended levels and promotes increases in bone mineral density (BMD). Forty-eight eumenorrheic female athletes from several college teams (15 soccer, 7 crosscountry, 8 indoor track, and 18 basketball) were randomized at the beginning of a competitive season to receive either an oral calcium supplement (1000 mg calcium citrate/400 I.U. Vitamin D) or placebo daily throughout the training season (16 weeks). Self-reported daily pill intake was obtained every 2 weeks to assess adherence. Calcium intake was evaluated using the Rapid Assessment Method, and total body and leg BMD was measured at pre-, mid-, and postseason using dual energy x-ray absorptiometry (DEXA; Hologic QDR-2000). Pre-season calcium intake was lower than national recommendations for this age group (12), averaging 842 mg/d (SD = 719) and was lower in the placebo group compared to the supplemented group (649 ± 268 vs. 1071 ± 986 mg/d, respectively; p = .064). Adherence to supplementation was good, averaging 70% across the training season. Supplementation boosted total calcium intake to a mean of 1397 ± 411 mg/d, which is consistent with recommended levels for this group (37). Supplementation did not influence BMD change during this 16-week intervention. Across teams, a small increase of 0.8% was observed in leg BMD. Change in total body BMD was modified by team, with a significant increase of 1.5% observed in basketball players. These results indicate that providing calcium supplements of 1000 mg/d is adequate to boost total intake to recommended levels during athletic training. Longer intervention trials are required to determine whether calcium supplementation has a positive effect on BMD.
Moderate Intensity Resistance Exercise, Plus or Minus Soy Intake: Effects on Serum Lipid Peroxides in Young Adult Males
Authors: Hill Stephen , Box Wesley , DiSilvestro Robert A.
Published: August 2016

Lipid peroxides can be both a product and an initiator of oxidant stress. Conceivably, exercise can either increase concentrations of lipid peroxides (by causing oxidant stress), or decrease them (by accelerating peroxide breakdown). The net effect could depend on exercise intensity and nutritional intake of antioxidants. The present study examined the response of serum lipid peroxides to the combination of moderate intensity, weight resistance exercise plus intake of soy protein, a source of antioxidant phytochemicals. Recreationally trained, young adult men (N = 18) consumed soy protein or antioxidant-poor whey protein for 4 weeks (40 g protein/d) before a session of moderate intensity, weight resistance exercise. In the soy group, exercise decreased values for serum lipid peroxides at 5 min, 3 h, and 24 h post-exercise. The whey group showed the depression only at 24 h. In both the soy and whey groups, a small rise was seen for interleukin-8, which is consistent with the idea that the exercise session induced a moderate muscle stress. In summary, a moderate intensity, weight resistance exercise session, despite inducing mild inflammation, depressed plasma serum peroxide values, especially when combined with 4 weeks of soy consumption.
Effects of Vitamin-Mineral Supplementation on Cardiac Marker and Radical Scavenging Enzymes, and MDA Levels in Young Swimmers
Authors: Cavas Levent , Tarhan Leman
Published: August 2016

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 training. Antioxidant enzyme activity increases in the male vitamin-mineral group were significantly (p < .05) higher when compared with the other groups. Post-training MDA levels were significantly (p < .001) higher than pre-training MDA levels in the control groups, whereas no significant (p > .05) differences were found between the vitamin-mineral supplemented groups. 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.
Reduced Neuromuscular Activity with Carbohydrate Ingestion during Constant Load Cycling
Authors: Nikolopoulos Vasilis , Arkinstall Melissa J. , Hawley John A.
Published: August 2016

The purpose of this study was to determine the effect of carbohydrate ingestion before and during intense constant load cycling to volitional fatigue on surface electromyographic (sEMG) activity from the vastus lateralis (VL) and vastus medialis (VM) muscles. After 24-h diet and training control, 8 well-trained subjects [maximal O2 uptake (VO2max) 66 ± 2 ml · kg–1· min–1; mean ± SD] ingested 8 ml · kg–1 of either a 6.4% carbohydrate-electrolyte (CHO) or a placebo (PLA) solution immediately before, followed by 2 ml · kg–1 of the same solution every 15 min while cycling to exhaustion at 84 ± 1% of VO2max. Exercise time to fatigue was 13% longer with CHO ingestion compared to PLA (58:54 ± 8:48 vs. 51:18 ± 5:54 min:s, NS). VO2 (4.22 ± 0.11 vs. 4.20 ± 0.14 L · min–1), heart rate (172 ± 4 vs. 176 ± 4 beats · min–1), ratings of perceived effort (18 ± 0.1 vs. 19 ± 0.1), and rates of carbohydrate oxidation (314 ± 28 vs. 324 ± 26 μmol · kg–1 · min–1) were similar for both PLA and CHO at exhaustion. There was no main treatment effect of CHO ingestion on blood glucose or lactate concentrations, nor plasma prolactin levels either during exercise or at fatigue. However, CHO ingestion attenuated the rise in EMG root mean square (RMS) activity during the latter stages (>45 min) of exercise and at the point of exhaustion for both VM (0.325 ± 0.010 vs. 0.403 ± 0.020 mV; p = .006) and VL (0.298 ± 0.011 vs. 0.370 ± 0.007 mV; p = .0004). We conclude that in well-trained subjects, the ingestion of carbohydrate attenuated the increase in surface electromyographic activity during intense, constant load cycling leading to exhaustion in ~1 h. The precise mechanism(s) underlying this effect cannot be attributed to alterations in CHO availability but, instead, may be linked to changes in afferent sensory input.
Effect of Ingested Fluid Composition on Exercise-Related Transient Abdominal Pain
Authors: Morton Darren Peter , Aragón-Vargas Luis Fernando , Callister Robin
Published: August 2016

The present study investigated the effect of ingested fluid composition on the experience of exercise-related transient abdominal pain (ETAP). Forty subjects, susceptible to ETAP, completed 4 treadmill exercise trials: a no-fluid trial and flavored water (FW, no carbohydrate, osmolality = 48 mosmol/L, pH = 3.3), sports drink (SD, freshly mixed Gatorade®, 6% total carbohydrate, 295 mosmol/L, pH = 3.3), and reconstituted fruit juice (FJ, BERRI® orange, 10.4% total carbohydrate, 489 mosmol/L, pH = 3.2) trials. Measures of the experience of ETAP and gastrointestinal disturbances, particularly bloating, were quantified. The FJ was significantly (p < .01) more provocative of both ETAP and bloating than all other trials. There was no difference among the no-fluid, FW, and SD in the severity of ETAP experienced, although the difference between the no-fluid and SD approached significance at the .05 level (p = .056). There was a significant relationship between both the mean (r = 0.40, p < .01) and peak (r = 0.44, p < .01) levels of ETAP and bloating. When the level of bloating was controlled for, the FJ remained significantly (p < .01) more provocative of ETAP than the other conditions, with no difference between the FW and SD (p = .37). The results indicate that in order to avoid ETAP, susceptible individuals should refrain from consuming reconstituted fruit juices and beverages similarly high in carbohydrate content and osmolality, shortly before and during exercise. Further, the mechanism responsible for the heightened experience of ETAP in the FJ trial extends beyond a gastric mass explanation.