bluuebunny/crossref_metadata_2025 huggingface dataset:
The Prevalence of Vitamin Supplementation in Ultraendurance Triathletes
Authors: Knez Wade L. , Peake Jonathan M.
Published: August 2016

Ultraendurance exercise training places large energy demands on athletes and causes a high turnover of vitamins through sweat losses, metabolism, and the musculoskeletal repair process. Ultraendurance athletes may not consume sufficient quantities or quality of food in their diet to meet these needs. Consequently, they may use oral vitamin and mineral supplements to maintain their health and performance. We assessed the vitamin and mineral intake of ultraendurance athletes in their regular diet, in addition to oral vitamin and mineral supplements. Thirty-seven ultraendurance triathletes (24 men and 13 women) completed a 7-day nutrition diary including a questionnaire to determine nutrition adequacy and supplement intake. Compared with dietary reference intakes for the general population, both male and female triathletes met or exceeded all except for vitamin D. In addition, female athletes consumed slightly less than the recommended daily intake for folate and potassium; however, the difference was trivial. Over 60% of the athletes reported using vitamin supplements, of which vitamin C (97.5%), vitamin E (78.3%), and multivitamins (52.2%) were the most commonly used supplements. Almost half (47.8%) the athletes who used supplements did so to prevent or reduce cold symptoms. Only 1 athlete used supplements on formal medical advice. Vitamin C and E supplementation was common in ultraendurance triathletes, despite no evidence of dietary deficiency in these 2 vitamins.
Effects of Oral Supplementation With Plant Superoxide Dismutase Extract on Selected Redox Parameters and an Inflammatory Marker in a 2,000-m Rowing-Ergometer Test
Authors: Skarpanska-Stejnborn Anna , Pilaczynska-Szczesniak Lucja , Basta Piotr , Deskur-Smielecka Ewa , Woitas-Slubowska Donata , Adach Zdzislaw
Published: August 2016

The aim of this study was to investigate the effect of plant superoxide dismutase extract (GliSODin) supplementation on the balance of oxidants and antioxidants in the serum and erythrocytes of competitive rowers. The double-blinded study included 19 members of the Polish rowing team who were participating in a preparatory camp. Subjects were randomly assigned to the supplemented group (n = 10), who received 2 capsules (500 mg) of GliSODin extract once daily for 6 weeks, or the placebo group (n = 9). At the beginning and end of the study, subjects performed a 2,000-m maximum-effort test on a rowing ergometer. Blood samples were taken from the antecubital vein before each exercise test, 1 min after completing the test, and after a 24-hr restitution period. The following redox parameters were assessed in erythrocytes: superoxide dismutase (SOD) activity, glutathione peroxidase activity, and concentrations of thiobarbituric-acid-reactive substances. In addition, creatine kinase activity and total antioxidant capacity were measured in plasma samples, lactate levels were determined in capillary blood samples, and C-reactive protein and lactate dehydrogenase concentrations were measured in serum. After supplementation, SOD activity was significantly higher (p = .0037) in the supplemented group than the placebo group, and C-reactive protein was significantly (p = .00001) lower in athletes receiving GliSODin than those in the placebo group. In conclusion, supplementation with an extract rich in SOD activity promoted antioxidant status and protected against increased inflammation in the serum of professional rowers but had no effect on oxidative damage induced by exhaustive exercise.
Dietary Thiamin and Riboflavin Intake and Blood Thiamin and Riboflavin Concentrations in College Swimmers Undergoing Intensive Training
Authors: Sato Akiko , Shimoyama Yoshimitsu , Ishikawa Tomoji , Murayama Nobuko
Published: August 2016

The purpose of this study was to examine the effect of high-intensity physical activity during training on the biochemical status of thiamin and riboflavin in athletes. Thiamin and riboflavin concentrations in whole blood of a group of 19 athletes (6 men and 13 women) were measured during a low-intensity preparatory period and compared with measurements taken during a high-intensity training period. Additional variables measured included anthropometric characteristics, estimated energy expenditure during swim training, distance covered, resting energy expenditure obtained by indirect calorimetry, estimated energy requirement per day, and dietary intake of energy, thiamin, and riboflavin estimated from 3-day food records. For both male and female subjects, no major changes were observed in anthropometric characteristics or dietary intake, but energy expenditure during swim training per day significantly increased in the intensive-training period (496 ± 0 kcal in the preparation period compared with 995 ± 96 kcal in the intensive-training period for male subjects [p < .001] and 361 ± 27 kcal vs. 819 ± 48 kcal, respectively, for female subjects [p < .001]). Blood thiamin concentration decreased significantly during the intensive-training period compared with the preparation period (41 ± 6 ng/ml decreased to 36 ± 3 ng/ml for male subjects [p = .048], and 38 ± 10 ng/ml decreased to 31 ± 5 ng/ml for female subjects [p = .004]); however, the concentration of riboflavin was unchanged. These results suggest that intense training affects thiamin concentration, but not riboflavin concentration, in the whole blood of college swimmers.
The Relationship Between Physical Fitness, Urine Iodine Status, and Body-Mass Index in 6- to 7-year-old Polish Children
Authors: Merkiel Sylwia , Chalcarz Wojciech
Published: August 2016

The aim of this study was to assess physical fitness in 6- to 7-yr-old children and determine if there is any relationship between children’s physical fitness, their urine iodine status, and their body-mass index (BMI). The studied population included 121 children from southern Poland. Physical fitness was measured using a physical fitness test for children age 3–7 yr. Urinary iodine concentrations were measured in the children’s first urine output on waking using the modified PAMM (Program Against Micronutrient Malnutrition) method. Body height and weight were measured and BMI was calculated. The subjects were characterized by low physical fitness. Boys obtained better results in agility, power, and strength exercises (p ≤ .05). In girls, 11 correlation coefficients between the scores obtained in the physical fitness test, urinary iodine, and anthropometric measures were statistically significant, and in boys, only 2. BMI correlated positively with agility in girls and with strength in girls and boys. Our study revealed low physical fitness in Polish 6- to 7-yr-old children, which shows the need to implement programs aimed at increasing their physical activity. The relationship found between physical fitness and urine iodine status in girls indicates that future research in this area is needed.
The Effect of Adding Caffeine to Postexercise Carbohydrate Feeding on Subsequent High-Intensity Interval-Running Capacity Compared With Carbohydrate Alone
Authors: Taylor Conor , Higham Daniel , Close Graeme L. , Morton James P.
Published: August 2016

The aim of this study was to test the hypothesis that adding caffeine to postexercise carbohydrate (CHO) feedings improves subsequent high-intensity interval-running capacity compared with CHO alone. In a repeated-measures design, 6 men performed a glycogen-depleting exercise protocol until volitional exhaustion in the morning. Immediately after and at 1, 2, and 3 hr postexercise, participants consumed 1.2 g/kg body mass CHO of a 15% CHO solution, a similar CHO solution but with addition of 8 mg/kg body mass of caffeine (CHO+CAFF), or an equivalent volume of flavored water only (WAT). After the 4-hr recovery period, participants performed the Loughborough Intermittent Shuttle Test (LIST) to volitional exhaustion as a measure of high-intensity interval-running capacity. Average blood glucose values during the 4-hr recovery period were higher in the CHO conditions (p < .005) than in the WAT trial (4.6 ± 0.3 mmol/L), although there was no difference (p = .46) between CHO (6.2 ± 0.8 mmol/L) and CHO+CAFF (6.7 ± 1.0 mmol/L). Exercise capacity during the LIST was significantly longer in the CHO+CAFF trial (48 ± 15 min) than in the CHO (32 ± 15 min, p = .04) and WAT conditions (19 ± 6 min, p = .001). All 6 participants improved performance in CHO+CAFF compared with CHO (95% CI for mean difference = 1–32 min). The study provides novel data by demonstrating that adding caffeine to postexercise CHO feeding improves subsequent high-intensity interval-running capacity, a finding that may be related to higher rates of postexercise muscle glycogen resynthesis previously observed under similar feeding conditions.
Long-Term Effect of Weight Loss on Body Composition and Performance in Elite Athletes
Authors: Garthe Ina , Raastad Truls , Sundgot-Borgen Jorunn
Published: August 2016

Context:

When weight loss (WL) is needed, it is recommended that athletes do it gradually by 0.5–1 kg/wk through moderate energy restriction. However, the effect of WL rate on long-term changes in body composition (BC) and performance has not been investigated in elite athletes.

Purpose:

To compare changes in body mass (BM), fat mass (FM), lean body mass (LBM), and performance 6 and 12 mo after 2 different WL interventions promoting loss of 0.7% vs. 1.4% of body weight per wk in elite athletes.

Methods:

Twenty-three athletes completed 6- and 12-mo postintervention testing (slow rate [SR] n = 14, 23.5 ± 3.3 yr, 72.2 ± 12.2 kg; fast rate [FR] n = 9, 21.4 ± 4.0 yr, 71.6 ± 12.0 kg). The athletes had individualized diet plans promoting the predetermined weekly WL during intervention, and 4 strength-training sessions per wk were included. BM, BC, and strength (1-repetition maximum) were tested at baseline, postintervention, and 6 and 12 mo after the intervention.

Results:

BM decreased by ~6% in both groups during the intervention but was not different from baseline values after 12 mo. FM decreased in SR and FR during the intervention by 31% ± 3% vs. 23% ± 4%, respectively, but was not different from baseline after 12 mo. LBM and upper body strength increased more in SR than in FR (2.0% ± 1.3% vs. 0.8% ± 1.1% and 12% ± 2% vs. 6% ± 2%) during the intervention, but after 12 mo there were no significant differences between groups in BC or performance.

Conclusion:

There were no significant differences between groups after 12 mo, suggesting that WL rate is not the most important factor in maintaining BC and performance after WL in elite athletes.
Effects of Fed- Versus Fasted-State Aerobic Training During Ramadan on Body Composition and Some Metabolic Parameters in Physically Active Men
Authors: Trabelsi Khaled , Abed Kais el , Stannard Stephen R. , Jammoussi Kamel , Zeghal Khaled M. , Hakim Ahmed
Published: August 2016

The aim of this study was to evaluate the effects of aerobic training in a fasted versus a fed state during Ramadan on body composition and metabolic parameters in physically active men. Nineteen men were allocated to 2 groups: 10 practicing aerobic training in a fasted state (FAST) and 9 training in an acutely fed state (FED) during Ramadan. All subjects visited the laboratory for a total of 4 sessions on the following occasions: 3 days before Ramadan (Bef-R), the 15th day of Ramadan; the 29th day of Ramadan (End-R), and 21 days after Ramadan. During each session, subjects underwent anthropometric measurement, completed a dietary questionnaire, and provided fasting blood and urine samples. Body weight decreased in FAST and FED by 1.9% (p < .001) and 2.6% (p = .046), respectively. Body fat percentage decreased only in FAST by 6.2% (p = .016). FAST experienced an increase in the following parameters from Bef-R to End-R: urine specific gravity (0.64%, p = .012), urea (8.7%, p < .001), creatinine (7.5%, p < .001), uric acid (12.7%, p < .001), sodium (1.9%, p = .003), chloride (2.6%, p < .001), and high-density lipoprotein cholesterol (27.3%, p < .001). Of these parameters, only creatinine increased (5.8%, p = .004) in FED. Creatinine clearance values of FAST decreased by 8.9% (p < .001) and by 7.6% in FED (p = .01) from Bef-R to End-R. The authors conclude that aerobic training in a fasted state lowers body weight and body fat percentage. In contrast, fed aerobic training decreases only body weight. In addition, Ramadan fasting induced change in some metabolic parameters in FAST, but these changes were absent in FED.
Nitrate Supplementation’s Improvement of 10-km Time-Trial Performance in Trained Cyclists
Authors: Cermak Naomi M. , Gibala Martin J. , van Loon Luc J.C.
Published: August 2016

Six days of dietary nitrate supplementation in the form of beetroot juice (~0.5 L/d) has been reported to reduce pulmonary oxygen uptake (VO2) during submaximal exercise and increase tolerance of high-intensity work rates, suggesting that nitrate can be a potent ergogenic aid. Limited data are available regarding the effect of nitrate ingestion on athletic performance, and no study has investigated the potential ergogenic effects of a small-volume, concentrated dose of beetroot juice. The authors tested the hypothesis that 6 d of nitrate ingestion would improve time-trial performance in trained cyclists. Using a double-blind, repeated-measures crossover design, 12 male cyclists (31 ± 3 yr, VO2peak = 58 ± 2 ml · kg−1 · min−1, maximal power [Wmax] = 342 ± 10 W) ingested 140 ml/d of concentrated beetroot (~8 mmol/d nitrate) juice (BEET) or a placebo (nitrate-depleted beetroot juice; PLAC) for 6 d, separated by a 14-d washout. After supplementation on Day 6, subjects performed 60 min of submaximal cycling (2 × 30 min at 45% and 65% Wmax, respectively), followed by a 10-km time trial. Time-trial performance (953 ± 18 vs. 965 ± 18 s, p < .005) and power output (294 ± 12 vs. 288 ± 12 W, p < .05) improved after BEET compared with PLAC supplementation. Submaximal VO2 was lower after BEET (45% Wmax = 1.92 ± 0.06 vs. 2.02 ± 0.09 L/min, 65% Wmax 2.94 ± 0.12 vs. 3.11 ± 0.12 L/min) than with PLAC (main effect, p < .05). Wholebody fuel selection and plasma lactate, glucose, and insulin concentrations did not differ between treatments. Six days of nitrate supplementation reduced VO2 during submaximal exercise and improved time-trial performance in trained cyclists.
The Effects of Postexercise Feeding on Saliva Antimicrobial Proteins
Authors: Costa Ricardo J.S. , Fortes Matthew B. , Richardson Katharine , Bilzon James L.J. , Walsh Neil P.
Published: August 2016

The purpose of this study was to determine the effects of a carbohydrate (CHO) and protein (PRO) drink consumed immediately after endurance exercise on saliva antimicrobial proteins known to be important for host defense. Eleven male runners ran for 2 hr at 75% VO2max on 2 occasions and immediately postexercise were provided, in randomized order, either a placebo solution (CON) or a CHO-PRO solution containing 1.2 g CHO/kg body mass (BM) and 0.4 g PRO/kg BM (CHO-PRO). The solutions were flavor and volume equivalent (12 ml/kg BM). Saliva flow rate, lysozyme, α-amylase, and secretory (S) IgA concentrations were determined from unstimulated saliva samples collected preexercise, immediately postexercise, and every 30 min until 180 min postexercise. CHO-PRO ingestion immediately postexercise resulted in a lower saliva flow rate than with CON at 30 and 60 min postexercise. Saliva lysozyme concentration increased immediately postexercise in both trials compared with preexercise (p< .05), and CHO-PRO ingestion immediately postexercise resulted in a higher saliva lysozyme concentration in the first hour of recovery than with CON (125% greater at 30 min, 94% greater at 60 min; p< .01). Saliva SIgA concentration decreased below preexercise concentrations 90–150 min postexercise (p< .001), with no effect of CHO-PRO. Saliva α-amylase activity was unaffected by exercise or CHO-PRO refeeding. CHO-PRO refeeding did not alter the secretion rates of any saliva variables during recovery. In conclusion, immediate refeeding with CHO-PRO evoked a greater saliva lysozyme concentration during the first hour of recovery after prolonged exercise than ingestion of placebo but had minimal impact on saliva α-amylase and SIgA responses.
Dietary Nitrate Supplementation Improves Rowing Performance in Well-Trained Rowers
Authors: Bond Hannah , Morton Lillian , Braakhuis Andrea J.
Published: August 2016

Increased plasma nitrate concentrations from dietary sources of nitrate have proven to benefit exercise performance. Beetroot (BR) contains relatively high levels of nitrate (NO3−), which increases nitric oxide stores. This study investigated whether dietary nitrate supplementation, in the form of a BR beverage, would improve rowing performance during ergometer repetitions. In a randomized crossover design, 14 well-trained junior male rowers consumed 500 ml of either BR or placebo (PL) daily for 6 d. After supplementation, rowers completed 6 maximal 500-m ergometer repetitions and times were recorded. A 7-d washout period separated the 2 trials. Blood pressure, oxygen saturation, maximum heart rate, urine (specific gravity, pH, and nitrites), and lactates were collected for analysis at baseline and pre- and postperformance. Changes in the mean with 95% confidence limits were calculated. There was a likely benefit to average repetition time in the BR condition, compared with PL (0.4%, 95% confidence limits, ± 1.0%). In particular, Repetitions 4–6 showed an almost certain benefit in rowing time on BR (1.7%, 95% CL, ± 1.0%). The underlying mechanism for the observed results remains unknown, as differences observed in rowers’ physiological measures between the 2 conditions were unclear. Conclusively, nitrate supplementation in the form of BR juice resulted in improved maximal rowing-ergometer repetitions, particularly in the later stages of exercise.
The Effect of 6 Days of Sodium Phosphate Supplementation on Appetite, Energy Intake, and Aerobic Capacity in Trained Men and Women
Authors: West Jessica S. , Ayton Tom , Wallman Karen E. , Guelfi Kym J.
Published: August 2016

Ingestion of an acute dose of phosphate has been shown to attenuate energy intake in the subsequent meal. This raises the question of whether the practice of phosphate supplementation over a number of days by athletes to enhance performance also influences energy intake. This study investigated the effect of 6 d of phosphate supplementation on appetite and energy intake, as well as aerobic capacity, in trained individuals. Twenty participants completed two 6-d phases of supplementation with either sodium phosphate (50 mg/kg of fat-free mass per day) or a placebo in a double-blinded, counterbalanced design. On Days 1, 2, and 6 of supplementation, a laboratory meal was provided to assess appetite and ad libitum energy intake. All other food and drink consumed during each supplementation phase were recorded in a food diary. After the 6 d of supplementation, peak aerobic capacity (VO2peak) was assessed. There was no difference in energy intake at the laboratory meal after an acute dose (i.e., on Day 1; placebo 2,471 ± 919 kJ, phosphate 2,353 ± 987 kJ; p = .385) or prolonged supplementation with sodium phosphate (p = .581) compared with placebo. Likewise, there was no difference in VO2peak with phosphate supplementation (placebo 52.6 ± 5.2 ml · kg−1 · min−1, phosphate 53.3 ± 6.1 ml · kg−1 · min−1; p = .483). In summary, 6 d of sodium phosphate supplementation does not appear to influence energy intake. Therefore, athletes supplementing with sodium phosphate can do so without hindering their nutritional status. However, given that phosphate supplementation failed to improve aerobic capacity, the ergogenic benefit of this supplement remains questionable.
Whey Protein Before and During Resistance Exercise Has No Effect on Muscle Mass and Strength in Untrained Young Adults
Authors: Weisgarber Krissy D. , Candow Darren G. , Vogt Emelie S. M.
Published: August 2016

Purpose:

To determine the effects of whey protein before and during resistance exercise (RE) on body composition and strength in young adults.

Methods:

Participants were randomized to ingest whey protein (PRO; 0.3 g/kg protein; n = 9, 24.58 ± 1.8 yr, 88.3 ± 17.1 kg, 172.5 ± 8.0 cm) or placebo (PLA; 0.2 g/kg cornstarch maltodextrin + 0.1 g/kg sucrose; n = 8, 23.6 ± 4.4 yr, 82.6 ± 16.1 kg, 169.4 ± 9.2 cm) during RE (3 sets of 6–10 repetitions for 9 whole-body exercises), which was performed 4 d/wk for 8 wk. PRO and PLA were mixed with water (600 ml); 50% of the solution containing 0.15 g/kg of PRO or PLA was consumed immediately before the start of exercise, and ~1.9% of the remaining solution containing ~0.006 g/kg of PRO or PLA was consumed immediately after each training set. Before and after the study, measures were taken for leantissue mass (dual-energy X-ray absorptiometry), muscle size of the elbow and knee flexors and extensors and ankle dorsiflexors and plantar flexors (ultrasound), and muscle strength (1-repetition-maximum chest press).

Results:

There was a significant increase (p < .05) in muscle size of the knee extensors (PRO 0.6 ± 0.4 cm, PLA 0.1 ± 0.5 cm), knee flexors (PRO 0.4 ± 0.6 cm, PLA 0.5 ± 0.7 cm) and ankle plantar flexors (PRO 0.6 ± 0.7 cm, PLA 0.8 ± 1.4 cm) and chest-press strength (PRO 16.6 ± 11.1 kg, PLA 9.1 ± 14.6 kg) over time, with no differences between groups.

Conclusion:

The ingestion of whey protein immediately before the start of exercise and again after each training set has no effect on muscle mass and strength in untrained young adults.
No Improvement in Endurance Performance after a Single Dose of Beetroot Juice
Authors: Cermak Naomi M. , Res Peter , Stinkens Rudi , Lundberg Jon O. , Gibala Martin J. , van Loon Luc J.C.
Published: August 2016

Introduction:

Dietary nitrate supplementation has received much attention in the literature due to its proposed ergogenic properties. Recently, the ingestion of a single bolus of nitrate-rich beetroot juice (500 ml, ~6.2 mmol NO3−) was reported to improve subsequent time-trial performance. However, this large volume of ingested beetroot juice does not represent a realistic dietary strategy for athletes to follow in a practical, performancebased setting. Therefore, we investigated the impact of ingesting a single bolus of concentrated nitrate-rich beetroot juice (140 ml, ~8.7 mmol NO3−) on subsequent 1-hr time-trial performance in well-trained cyclists.

Methods:

Using a double-blind, repeated-measures crossover design (1-wk washout period), 20 trained male cyclists (26 ± 1 yr, VO2peak 60 ± 1 ml · kg−1 · min−1, Wmax 398 ± 7.7 W) ingested 140 ml of concentrated beetroot juice (8.7 mmol NO3−; BEET) or a placebo (nitrate-depleted beetroot juice; PLAC) with breakfast 2.5 hr before an ~1-hr cycling time trial (1,073 ± 21 kJ). Resting blood samples were collected every 30 min after BEET or PLAC ingestion and immediately after the time trial.

Results:

Plasma nitrite concentration was higher in BEET than PLAC before the onset of the time trial (532 ± 32 vs. 271 ± 13 nM, respectively; p < .001), but subsequent time-trial performance (65.5 ± 1.1 vs. 65 ± 1.1 s), power output (275 ± 7 vs. 278 ± 7 W), and heart rate (170 ± 2 vs. 170 ± 2 beats/min) did not differ between BEET and PLAC treatments (all p > .05).

Conclusion:

Ingestion of a single bolus of concentrated (140 ml) beetroot juice (8.7 mmol NO3−) does not improve subsequent 1-hr time-trial performance in well-trained cyclists.
Physical Activity and Sedentary Behavior’s Association With Body Weight in Korean Adolescents
Authors: So Wi-Young
Published: August 2016

The purpose of this study was to examine whether physical activity (PA) and sedentary behavior were related to weight status in Korean adolescents. A total of 72,399 students in Grades 7–12 participated in the 5th Korea Youth Risk Behavior Web-Based Survey (KYRBWS-V) project in 2009. Body mass index, PA, and sedentary behavior were assessed by the KYRBWS-V. The study results show that boys had higher PA and less sedentary behavior than did girls (p < .01). The amounts of vigorous PA (p < .001), moderate PA (p < .001), moderate PA for at least 60 min (p < .001), exercise for muscle strength (p < .001), walking on a weekday (p < .001), and walking on a weekend (p = .012) were less in boys who were more obese than the other boys. The time spent sitting on a weekday (p < .001) and weekend (p < .001) was higher in more obese individuals in boys. Exercise for muscle strength (p = .011) was less in girls who were more obese. Time spent sitting on a weekday (p = .005) and weekend (p < .001) was higher in more obese individuals in girls. However, vigorous PA (p < .001), moderate PA (p < .001), moderate PA for at least 60 min (p = .003), and walking on a weekday (p < .001) were higher for the more obese girls. PA and sedentary behavior could be independent factors that reduce or prevent obesity in Korean adolescents.
Fluid and Sodium Balance of Elite Wheelchair Rugby Players
Authors: Black Katherine Elizabeth , Huxford Jody , Perry Tracy , Brown Rachel Clare
Published: August 2016

Blood sodium concentration of tetraplegics during exercise has not been investigated. This study aimed to measure blood sodium changes in relation to fluid intakes and thermal comfort in tetraplegics during wheelchair rugby training. Twelve international male wheelchair rugby players volunteered, and measures were taken during 2 training sessions. Body mass, blood sodium concentration, and subjective thermal comfort using a 10-point scale were recorded before and after both training sessions. Fluid intake and the distance covered were measured during both sessions. The mean (SD) percentage changes in body mass during the morning and afternoon training sessions were +0.4%1 (0.65%) and +0.69% (1.24%), respectively. There was a tendency for fluid intake rate to be correlated with the percentage change in blood sodium concentration (p = .072, r2 = .642) during the morning training session; this correlation reached significance during the afternoon session (p = .004, r2 = .717). Fluid intake was significantly correlated to change in thermal comfort in the morning session (p = .018, r2 = .533), with this correlation showing a tendency in the afternoon session (p = .066, r2 = .151). This is the first study to investigate blood sodium concentrations in a group of tetraplegics. Over the day, blood sodium concentrations significantly declined; 2 players recorded blood sodium concentrations of 135 mmol/L, and 5 recorded blood sodium concentrations of 136 mmol/L. Excessive fluid intake as a means of attenuating thermal discomfort seems to be the primary cause of low blood sodium concentrations in tetraplegic athletes. Findings from this study could aid in the design of fluid-intake strategies for tetraplegics.
Effects of a Flavonoid-Rich Juice on Inflammation, Oxidative Stress, and Immunity in Elite Swimmers: A Metabolomics-Based Approach
Authors: Knab Amy M. , Nieman David C. , Gillitt Nicholas D. , Shanely R. Andrew , Cialdella-Kam Lynn , Henson Dru A. , Sha Wei
Published: August 2016

The effects of a flavonoid-rich fresh fruit and vegetable juice (JUICE) on chronic resting and postexercise inflammation, oxidative stress, immune function, and metabolic profiles (metabolomics analysis, gas-chromatography mass-spectrometry platform) in elite sprint and middle-distance swimmers were studied. In a randomized, crossover design with a 3-wk washout period, swimmers (n = 9) completed 10-d training with or without 16 fl oz of JUICE (230 mg flavonoids) ingested pre- and postworkout. Blood samples were taken presupplementation, post–10-d supplementation, and immediately postexercise, with data analyzed using a 2 × 3 repeated-measures ANOVA. Prestudy blood samples were also acquired from nonathletic controls (n = 7, age- and weight-matched) and revealed higher levels of oxidative stress in the swimmers, no differences in inflammation or immune function, and a distinct separation in global metabolic scores (R2Y [cum] = .971). Swim workouts consisted of high-intensity intervals (1:1, 1:2 swim-to-rest ratio) and induced little inflammation, oxidative stress, or immune changes. A distinct separation in global metabolic scores was found pre- to postexercise (R2Y [cum] = .976), with shifts detected in a small number of metabolites related to substrate utilization. No effect of 10-d JUICE was found on chronic resting levels or postexercise inflammation, oxidative stress, immune function, and shifts in metabolites. In conclusion, sprint and middle-distance swimmers had a slight chronic elevation in oxidative stress compared with nonathletic controls, experienced a low magnitude of postworkout perturbations in the biomarkers included in this study, and received no apparent benefit other than added nutrient intake from ingesting JUICE pre- and postworkout for 10 days.
Contribution of Nonesterified Fatty Acids to Mitogen-Activated Protein Kinase Activation in Human Skeletal Muscle During Endurance Exercise
Authors: Zbinden-Foncea Hermann , van Loon Luc J. C. , Raymackers Jean-Marc , Francaux Marc , Deldicque Louise
Published: August 2016

Mitogen-activated protein kinase (MAPK) pathways are activated in skeletal muscle during endurance exercise, but the upstream molecular events are incompletely resolved. As an increase in plasma nonesterified fatty acids (NEFA) is a common feature of long-lasting exercise, the authors tested the hypothesis that NEFA contribute to the activation of MAPK during endurance exercise. Acipimox was used before and during endurance exercise to prevent the elevation of plasma NEFA levels in healthy subjects and patients with diabetes. In 2 separate studies, healthy subjects cycled for 2 hr and patients with diabetes for 1 hr at 50% Wmax. In control conditions, plasma NEFA concentrations increased from 0.35 to 0.90 mM during exercise in healthy subjects and from 0.55 to 0.70 mM in patients with diabetes (p < .05). Phosphorylation states of extracellularly regulated kinase 1 and 2 (ERK1/2), p38, and c-Jun NH2-terminal kinases (JNK) were significantly increased after exercise in the vastus lateralis in both groups. Acipimox blocked the increase in plasma NEFA concentrations and almost completely repressed any rise in ERK1/2 and p38 but not in JNK. In conclusion, the data support a role for plasma NEFA in the activation of p38 and ERK1/2 in skeletal-muscle tissue of healthy and diabetic subjects during endurance exercise. Further investigation will be required to determine the molecular link between NEFA and MAPK activation during exercise in human skeletal muscle.
Physical Activity, Fitness, and Metabolic Syndrome in Young Adults
Authors: López-Martínez Sara , Sánchez-López Mairena , Solera-Martinez Montserrat , Arias-Palencia Natalia , Fuentes-Chacón Rosa M. , Martínez-Vizcaíno Vicente
Published: August 2016

Purpose:

Our objective was to analyze the association between different intensities of physical activity (PA), physical fitness, and metabolic syndrome (MS) in young adults.

Methods:

Cross-sectional study including 275 university students, 18–30 years old, from Cuenca, Spain. We evaluated (a) physical activity using accelerometry, (b) aerobic capacity (VO2max), and (c) muscle strength, by a muscle strength index calculated as the sum of the standardized z score of handgrip dynamometry/weight and standing broad jump. An MS index was estimated by summing standardized z scores of waist circumference, ratio of triglycerides to high-density lipoprotein, mean arterial blood pressure, and HOMA-IR.

Results:

The mean scores of MS index and HOMAIR were significantly higher and the VO2max significantly lower for individuals who did not perform 20 min or more per week of vigorous physical activity. However, those who performed 250 min/week of moderate physical activity showed no significant differences in either VO2max or the MS index when compared with individuals who did not perform this level of activity. The MS index was lower in those with medium-high levels of aerobic capacity. In addition, individuals with medium-high levels of muscular fitness showed lower waist circumference and a lower MS index.

Conclusions:

VO2max and muscle strength are negatively associated with metabolic risk. 20-min/week of vigorous physical activity was associated with lower cardiometabolic risk in young adults; moderate physical activity did not show association with lower cardiometabolic risk.
The Effect of Sodium Acetate Ingestion on the Metabolic Response to Prolonged Moderate-Intensity Exercise in Humans
Authors: Smith Gordon I. , Jeukendrup Asker E. , Ball Derek
Published: August 2016

At rest, administration of the short-chain fatty acid acetate suppresses fat oxidation without affecting carbohydrate utilization. The combined effect of increased acetate availability and exercise on substrate utilization is, however, unclear. With local ethics approval, we studied the effect of ingesting either sodium acetate (NaAc) or sodium bicarbonate (NaHCO3) at a dose of 4 mmol·kg-1 body mass 90 min before completing 120 min of exercise at 50% VO2peak. Six healthy young men completed the trials after an overnight fast and ingested the sodium salts in randomized order. As expected NaAc ingestion decreased resting fat oxidation (mean ± SD; 0.09 ± 0.02 vs. 0.07 ± 0.02 g·min-1 pre- and post-ingestion respectively, p < .05) with no effect upon carbohydrate utilization. In contrast, NaHCO3 ingestion had no effect on substrate utilization at rest. In response to exercise, fat and CHO oxidation increased in both trials, but fat oxidation was lower (0.16 ± 0.10 vs. 0.29 ± 0.11 g·min-1, p < .05) and carbohydrate oxidation higher (1.67 ± 0.35 vs. 1.44 ± 0.22 g·min-1, p < .05) in the NaAc trial compared with the NaHCO3 trial during the first 15 min of exercise. Over the final 75 min of exercise an increase in fat oxidation and decrease in carbohydrate oxidation was observed only in the NaAc trial. These results demonstrate that increasing plasma acetate concentration suppresses fat oxidation both at rest and at the onset of moderate-intensity exercise.
Oral Creatine Supplementation Augments the Repeated Bout Effect
Authors: Veggi Kelle F. T. , Machado Marco , Koch Alexander J. , Santana Sandro C. , Oliveira Sedison S. , Stec Michael J.
Published: August 2016

Purpose:

We examined the effects of creatine supplementation on the response to repeated bouts of resistance exercise.

Methods:

Young men (24.1 ± 5.2 yr) were divided into Creatine (CM, n = 9) and Placebo (PL, n = 9) groups. On day (D) 1 and D15, subjects performed four sets of bicep curls at 75% 1-RM to concentric failure. On D8-D13, subjects consumed either 20g/d creatine monohydrate or placebo. Muscle soreness and elbow joint range of motion (ROM) were assessed on D1-D5 and D15-D19. Serum creatine kinase activity (CK) was assessed on D1, D3, D5, D15, D17, and D19.

Results:

The first exercise bout produced increases in muscle soreness and CK, and decreases in ROM in both groups (p < .001). The second bout produced lesser rises in serum CK, muscle soreness, and a lesser decrease in ROM (bout effect, p < .01 for all), with greater attenuation of these damage markers in CM than PL. CK levels on D17 were lower (+110% over D15 for CM vs. +343% for PL), muscle soreness from D15–19 was lower (–75% for CM vs. –56% for PL compared with first bout), and elbow ROM was decreased in PL, but not CM on D16 (p < .05 for all).

Conclusions:

Creatine supplementation provides an additive effect on blunting the rise of muscle damage markers following a repeated bout of resistance exercise. The mechanism by which creatine augments the repeated bout effect is unknown but is likely due to a combination of creatine’s multifaceted functions.
Alteration of IGFBP-1 in Soccer Players Due to Intensive Training
Authors: Lagundžin Dragana , Vučić Vesna , Glibetić Marija , Nedić Olgica
Published: August 2016

Physical activity is accompanied by the changes in Insulin-like Growth Factor I (IGF-I)/IGF-Binding Protein 1 (IGFBP-1) axis. Inconsistent results concerning IGF-I and IGFBP-1 levels were reported. In this study we have raised some questions on the events that occur at the molecular level of the exercise-related IGFBP-1 changes. We have examined the fragmentation pattern of IGFBP-1, IGFBP-1 protease activity, interaction between IGFBP-1 and alpha2-macroglobulin (α2M), and possible existence of minor structural changes of IGFBP-1 in professional soccer players. Athletes had significantly greater amounts of fragmented IGFBP- 1, whereas no difference was found in the amount of intact IGFBP-1 compared with controls. An increased activity of matrix metalloprotease-9 (MMP-9) was detected in athletes, causing IGFBP-1 degradation down to the fragment of 9 kDa as the major one. The amount of α2M, which protects IGFBP-1 from proteolysis, or the amount of IGFBP-1/α2M complexes was unaltered. Finally, we have examined whether IGFBP-1 isolated from soccer players exhibited altered reactivity with several chemical surfaces used in surface-enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS). Different reactivity was detected with anion and cation exchangers, suggesting existence of at least one sequence within IGFBP-1, whose ionization pattern was not equal in athletes and controls. Differences in spectra obtained with ion exchanges may reflect differences in IGFBP-1 phosphorylation. Physiological implications of the events described in this study on the IGF-I availability are, at this time, unknown. It can be hypothesized that IGFBP-1 proteolysis leads to altered distribution of IGF-I among IGFBPs, which may affect the final IGF-associated response.
A Comparison of Caffeine versus Pseudoephedrine on Cycling Time-Trial Performance
Authors: Spence Angela L. , Sim Marc , Landers Grant , Peeling Peter
Published: August 2016

Both caffeine (CAF) and pseudoephedrine (PSE) are proposed to be central nervous system stimulants. However, during competition, CAF is a permitted substance, whereas PSE is a banned substance at urinary levels >150 μg·ml−1. As a result, this study aimed to compare the effect of CAF versus PSE use on cycling time trial (TT) performance to explore whether the legal stimulant was any less ergogenic than the banned substance. Here, 10 well-trained male cyclists or triathletes were recruited for participation. All athletes were required to attend the laboratory on four separate occasions—including a familiarization trial and three experimental trials, which required participants to complete a simulated 40 km (1,200 kJ) cycling TT after the ingestion of either 200 mg CAF, 180 mg PSE or a nonnutritive placebo (PLA). The results showed that the total time taken and the mean power produced during each TT was not significantly different (p > .05) between trials, despite a 1.3% faster overall time (~57 s) after CAF consumption. Interestingly, the time taken to complete the second half of the TT was significantly faster (p < .05) in CAF as compared with PSE (by 99 s), with magnitude based inferences suggesting a 91% beneficial effect of CAF during the second half of the TT. This investigation further confirms the ergogenic benefits of CAF use during TT performances and further suggests this legal CNS stimulant has a better influence than a supra-therapeutic dose of PSE.
Fluid and Electrolyte Balance During 24-Hour Fluid and/or Energy Restriction
Authors: James Lewis J. , Shirreffs Susan M.
Published: August 2016

Weight categorized athletes use a variety of techniques to induce rapid weight loss (RWL) in the days leading up to weigh in. This study examined the fluid and electrolyte balance responses to 24-hr fluid restriction (FR), energy restriction (ER) and fluid and energy restriction (F+ER) compared with a control trial (C), which are commonly used techniques to induce RWL in weight category sports. Twelve subjects (six male, six female) received adequate energy and water (C) intake, adequate energy and restricted water (~10% of C; FR) intake, restricted energy (~25% of C) and adequate water (ER) intake or restricted energy (~25% of C) and restricted (~10% of C) water intake (F+ER) in a randomized counterbalanced order. Subjects visited the laboratory at 0 hr, 12 hr, and 24 hr for blood and urine sample collection. Total body mass loss was 0.33% (C), 1.88% (FR), 1.97% (ER), and 2.44% (F+ER). Plasma volume was reduced at 24 hr during FR, ER, and F+ER, while serum osmolality was increased at 24 hr for FR and F+ER and was greater at 24 hr for FR compared with all other trials. Negative balances of sodium, potassium, and chloride developed during ER and F+ER but not during C and FR. These results demonstrate that 24 hr fluid and/or energy restriction significantly reduces body mass and plasma volume, but has a disparate effect on serum osmolality, resulting in hypertonic hypohydration during FR and isotonic hypohydration during ER. These findings might be explained by the difference in electrolyte balance between the trials.
A Prediction Model for Peak Power Output From Different Incremental Exercise Tests
Authors: Luttikholt Hans , McNaughton Lars R. , Midgley Adrian W. , Bentley David J.
Published: August 2016

Context:

There is currently no model that predicts peak power output (PPO) thereby allowing comparison between different incremental exercise test (EXT) protocols. In this study we have used the critical power profile to develop a mathematical model for predicting PPO from the results of different EXTs.

Purpose:

The purpose of this study was to examine the level of agreement between actual PPO values and those predicted from the new model.

Methods:

Eleven male athletes (age 25 ± 5 years, VO2max 62 ± 8 mL · kg–1 · min–1) completed 3 laboratory tests on a cycle ergometer. Each test comprised an EXT consisting of 1-minute workload increments of 30 W (EXT30/1) and 3-minute (EXT25/3) and 5-minute workload increments (EXT25/5) of 25 W. The PPO determined from each test was used to predict the PPO from the remaining 2 EXTs.

Results:

The differences between actual and predicted PPO values were statistically insignificant (P > .05). The random error components of the limits of agreement of ≤30 W also indicated acceptable levels of agreement between actual and predicted PPO values.

Conclusions:

Further data collection is necessary to confirm whether the model is able to predict PPO over a wide range of EXT protocols in athletes of different aerobic and anaerobic capacities.
Acute Explosive-Force Movements Enhance Bench-Press Performance in Athletic Men
Authors: Wilcox Jim , Larson Rich , Brochu Kevin M. , Faigenbaum Avery D.
Published: August 2016

Purpose:

The purpose of this investigation was to determine whether the performance of explosive-force movements before bench-press exercise would improve 1-repetition-maximum (1RM) strength.

Methods:

Twelve male college athletes participated in 3 testing sessions separated by at least 5 days of rest. During each testing session, the 1RM was assessed on the bench-press exercise. After a general warm-up, subjects performed a specific warm-up that consisted of submaximal sets with increasing loads on the bench-press exercise before attempting a 1RM lift. During the first testing trial, subjects performed a series of 1RM attempts with increasing loads until their 1RM was determined. During the second and third testing trials, subjects performed in a counterbalanced randomized order either 2 plyometric push-ups or 2 medicine-ball (3 to 5 kg) chest passes 30 seconds before each 1RM attempt.

Results:

Analysis of the data revealed that 1RM bench-press strength was significantly greater after plyometric push-ups (P = .004) or chest passes (P = .025) in comparison with the first trial (123.8 ± 23.5 kg and 124.0 ± 24.1 kg vs 120.9 ± 23.2 kg, respectively).

Conclusions:

These data suggest that an acute bout of low-volume, explosive-force upper body movements performed 30 seconds before a 1RM attempt might enhance bench-press performance in athletic men.
Reliability and Validity of a Soccer-Specific Test of Prolonged Repeated-Sprint Ability
Authors: Oliver Jon L. , Armstrong Neil , Williams Craig A.
Published: August 2016

Purpose:

The purpose of the study was to assess the reliability and validity of a newly developed laboratory protocol to measure prolonged repeated-sprint ability (RSA) during soccer-specific exercise.

Methods:

To assess reliability, 12 youth soccer players age 15.2 ± 0.3 y performed 2 trials of a soccer-specific intermittent-exercise test (SSIET) separated by 3 months. The test was performed on a nonmotorized treadmill. A separate sample of 12 youth soccer players (15.2 ± 0.3 y) completed the SSIET while simultaneously HR, VO2, and blood lactate (BLa) were monitored. The SSIET was designed to replicate the demands of competing in one half of a soccer match while sprint performance was monitored. The test included a 5-s sprint every 2 min.

Results:

The mean coefficient of variation was 2.5% for the total distance covered during the SSIET and 3.8% for the total distance sprinted; measures of power output were less reliable (>5.9%). Participants covered 4851 ± 251 m during the SSIET, working at an average intensity of 87.5% ± 3.2% HRpeak and 70.2% ± 3.1% VO2peak, with ~7mmol/L BLa accumulation. A significant reduction (P < .05) in sprint performance was ob served over the course of the SSIET.

Conclusion:

The SSIET provided a reliable method of assessing prolonged RSA in the laboratory. The distance covered and the physiological responses during the SSIET successfully recreated the demands of competing in a soccer match.
Time Course of Changes in Vertical-Jumping Ability After Static Stretching
Authors: Brandenburg Jason , Pitney William A. , Luebbers Paul E. , Veera Arun , Czajka Alicja
Published: August 2016

Purpose:

To examine the acute effects of static stretching on countermovement vertical-jump (CMVJ) ability and monitor the time course of any stretch-induced changes.

Methods:

Once familiarized, 16 experienced jumpers completed 2 testing sessions in a randomized order. Each session consisted of a general warm-up, a pretreatment CMVJ assessment, a treatment, and multiple posttreatment CMVJ assessments. One treatment included lower-body static stretching, and the second treatment, involving no stretching, was the control. Posttreatment CMVJ measures occurred immediately, 3, 6, 12, and 24 minutes posttreatment. Stretching consisted of 3 static-stretching exercises, with each exercise repeated 3 times and each repetition held for 30 s.

Results:

Prestretch CMVJ height equaled 47.1 (± 9.7) cm. CMVJ height immediately poststretch was 45.7 (± 9.2) cm, and it remained depressed during the 24-min follow-up period. Pre-no-stretch CMVJ height was 48.4 (± 9.8) cm, whereas immediately post-no-stretch CMVJ height equaled 46.8 (± 9.5) cm, and as in the stretch treatment, post-no-stretch CMVJ height remained lower than pre-no-stretch values. Although there was a significant main effect of time (P = .005), indicating that CMVJ was lower and remained impaired after both treatments, no significant interaction effect (P = .749) was observed.

Conclusion:

In comparison with the no-activity control, static stretching resulted in similar reductions in CMVJ ability when examined over the same time course, so athletes preparing for CMVJ should avoid periods of inactivity, as well as static stretching.
Individualized Aerobic-Power Training in an Underperforming Youth Elite Association Football Player
Authors: Mujika Iñigo , Santisteban Juanma , Angulo Paco , Padilla Sabino
Published: August 2016

A 7-week, 10-session individual training program was implemented with a youth elite football (soccer) player who had been underperforming because of poor aerobic fitness. The intervention focused on developing aerobic power and high lactate production and contributed to a 32.3% improvement in a football-specific performance test. The player was able to return to play and exceed expected performance levels during competitive match play.