This study aimed to analyze the effect of caffeine (CAF) intake on pulmonary oxygen uptake (V˙O2) kinetics, muscle fatigue, and physiological and perceptual parameters during severe-intensity cycling exercise.

Hypoxia (HY) and sleep deprivation have opposite effects on appetite. As HY may alter sleep, it may be informative to assess the accumulative effects of these two stressors on hunger, energy intake (EI), and food reward. Seventeen young, active, healthy males completed four 5-hr sessions in normoxia (NO) or normobaric HY (FIO2 = 13.6%, ∼3,500 m) after a night of habitual sleep (HS; total sleep time >6 hr) or sleep restriction (SR; total sleep time <3 hr). Subjective appetite was assessed regularly using visual analogic scales and EI during an ad libitum lunch after 3.5 hr of exposure. Food reward was assessed using the Leeds Food Preference Questionnaire just before the lunch. As expected, EI was lower for the HY-HS (4.32 ± 0.71 MJ; p = .048) and HY-SR (4.16 ± 0.68 MJ, p = .013) sessions than the NO-HS (4.90 ± 0.84 MJ) session without acute mountain sickness-related gastrointestinal symptoms. No significant effect of SR alone was observed (NO-SR: 4.40 ± 0.68 MJ). Subjective appetite was not affected. Explicit liking for high-fat foods was higher with SR than HS (main effect: p = .002) and implicit wanting for high-fat foods was higher for the NO-SR, HY-HS, and HY-SR sessions than the NO-HS session (p < .006). Thus, acute SR did not modify subjective appetite or EI despite the increasing food reward for high-fat foods and did not alter the HY-induced changes of appetite or food reward.

Marine-derived proteins, such as blue whiting-derived protein hydrolysates (BWPH), represent high-quality sources of dietary protein, but their ability to support postexercise anabolism is not established. The impact of BWPH on whole-body anabolism was compared with an isonitrogenous whey protein isolate (WPI) and nonessential amino acid (NEAA) control in 10 trained young males (31 ± 4 years) who, on three separate visits, performed a session of whole-body resistance exercise and then consumed, in randomized crossover fashion, BWPH, WPI, or NEAA (0.33 g/kg; 19, 33, and 0 mg/kg leucine, respectively) with L-[1-13C]leucine. Breath, blood, and urine samples were collected for 6-hr postprandial to assess dietary leucine oxidation, amino acid (AA) concentrations, and 3-methylhistidine: creatinine ratio. Peak and area under the curve concentrations for leucine, branched-chain amino acids, and essential amino acids were greater in WPI compared with BWPH (all p < .05) but with no differences in time to peak concentration. Total oxidation reflected leucine intake (WPI > BWPH > NEAA; p < .01), whereas relative oxidation was greater (p < .01) in WPI (28.6 ± 3.6%) compared with NEAA (21.3 ± 4.2%), but not BWPH (28.6 ± 8.8%). Leucine retention, a proxy for whole-body protein synthesis, was greater in WPI (185.6 ± 9.5 μmol/kg) compared with BWPH (109.3 ± 14.1 μmol/kg) and NEAA (5.74 ± 0.30 μmol/kg; both p < .01), with BWPH being greater than NEAA (p < .01). Urinary 3-methylhistidine: creatinine ratio did not differ between conditions. Both WPI and BWPH produced essential aminoacidemia and supported whole-body anabolism after resistance exercise, but a higher intake of BWPH to better approximate the leucine and EAA content of WPI may be needed to produce an equivalent anabolic response.

This article provides a recap of the 10 Questions/10 Experts session at the 2024 American College of Sports Medicine Annual Meeting. Each of the speakers considered the validity of common "myths," while providing evidence-based opinions to support, or, bust, myths addressing the following questions: (1) Would 100 g/hr of carbohydrate be advisable for the Olympic Cycling Road race? (2) Is there an advantage in the marathon of ingesting bicarbonate as a hydrogel product? (3) Can genotyping be used to individualize caffeine supplementation in football? (4) Should low fluid consumers drink more to improve 1,500-m track performance? (5) Do urinary markers of dehydration predict poor basketball performance? (6) Do placebo effects influence 10-km track performance? (7) Should combat athletes make weight using glucagon-like peptide-1 receptor agonists? (8) Would crushed ice ingestion help tennis umpires make better decisions in the heat? (9) Are collagen supplements useful to reduce tendon and ligament injuries in volleyball? and (10) Should female athletes plan their training and diet according to their menstrual cycle? This article describes the content of each of the presentations including the most important outcomes and conclusions drawn by the presenters.

Enhanced buffering capacity following sodium citrate (SC) ingestion may be optimized when subsequent exercise commences at individual time-to-peak (TTP) alkalosis (blood pH or bicarbonate concentration [HCO3-]). While accounting for considerable interindividual variation in TTP (188-300 min), a reliable blood alkalotic response is required for practical use. This study evaluated the reliability of blood pH, HCO3-, and sodium (Na+) following acute SC ingestion. Fourteen recreationally active males ingested 0.4 or 0.5 g/kg body mass (BM) of SC on two occasions each and 0.07 g/kg BM of sodium chloride (control) once. Blood pH and HCO3- were measured for 4 hr postingestion. Blood pH and HCO3- displayed good reliability following 0.5 g/kg BM SC (r = .819, p = .002, standardized technical error [sTE] = 0.67 and r = .840, p < .001, sTE = 0.63, respectively). Following 0.4 g/kg BM SC, blood HCO3- retained good reliability (r = .771, p = .006, sTE = 0.78) versus moderate for blood pH (r = .520, p = .099, sTE = 1.36). TTP pH was moderately reliable following 0.5 (r = .676, p = .026, sTE = 1.05) and 0.4 g/kg BM SC (r = .679, p = .025, sTE = 0.91) versus poor for HCO3- following 0.5 (r = .183, p = .361, sTE = 5.38) and 0.4 g/kg BM SC (r = .290, p = .273, sTE = 2.50). Although the magnitude of (and displacement in) blood alkalosis, particularly HCO3-, appears reliable following potentially ergogenic doses of SC, strategies based on individual TTP cannot be recommended.

Carbohydrate (CHO) gels are a staple among endurance athletes. When ingested during competition, CHO gels can improve endurance performance by acting as an external energy substrate, sparing endogenous glycogen, mitigating the risk of hypoglycemia, and engaging the central nervous system via receptors in the mouth and gastrointestinal tract. However, published studies and a growing number of anecdotal reports have raised concerns about possible energy and macronutrient deficiencies in several products. We therefore performed a content analysis on CHO gels from Gu Energy, Honey Stinger, Hüma, Maurten, Näak, Precision Fuel, Science in Sport, and Spring Energy. On average, products contained significantly less energy than stated on the labels (n = 8, p = .109, large effect) but with no discrepancy in CHO content (n = 8, p = .219, medium effect). Bland-Altman analyses revealed a systematic bias toward less energy and CHO in measured samples relative to the label-derived nutritional information. Moreover, the Spring Energy product fell outside the 95% limits of agreement for both energy and CHO, containing ∼71% less energy (53 vs. 180 kcal) and ∼72% less CHO (12.5 vs. 45 g) than stated on the label. A follow-up analysis revealed similar discrepancies in several Spring Energy products from multiple lots. These findings have performance, clinical, and legal implications.

The aim of this study was to examine the effects of multiday beetroot juice ingestion on neuromuscular performance in semi-professional, male handball players. Twelve handball players competing in the second Spanish national division received 70 ml of beetroot juice (6.4 mmol of nitrate [NO3-]) or 70 ml of a placebo beetroot juice (0.04 mmol NO3-) for three consecutive days in a randomized, double-blind, crossover manner with a 1-week washout between conditions. Following supplementation in each condition, players completed a neuromuscular test battery involving handball throwing, isometric handgrip strength, countermovement jump, change-of-direction speed, and repeated-sprint assessments, with side effects also measured. Countermovement jump (4.7%; p = .038; Hedge's gav = 0.29) and isometric handgrip strength (7.8%; p = .021; gav = 0.59) were significantly superior with beetroot juice ingestion compared to the placebo. In contrast, nonsignificant differences were evident between conditions for all other neuromuscular performance variables (p > .05; gav = 0.00-0.27). Red urine production was the only side effect, demonstrating a significantly higher prevalence (p = .046) with beetroot juice ingestion. Three days of beetroot juice supplementation may be a useful nutritional strategy in semi-professional, male handball players given its ergogenic benefit to some aspects of neuromuscular performance.

This study investigated the effect of sodium hyperhydration on thermal and cardiovascular strain and exercise performance in unacclimatized endurance-trained females exercising in the heat and whether effects differ between menstrual cycle (MC) Phase 1 (low estrogen and progesterone) and MC Phase 4 (moderate estrogen and high progesterone). Twelve female cyclists/triathletes completed four trials in a randomized, double-blinded, crossover design. Participants consumed 30 ml·kg-1 fat-free mass fluid with either sodium chloride (7.5 g·kg-1) or placebo (sucrose) 2 hr prior to 75 min of steady-state cycling (60% V˙O2peak) followed by a 200-kJ time trial (TT) in 34 °C and 60% relative humidity, with both interventions completed during MC Phase 1 and Phase 4. Rectal temperature and heart rate were measured at baseline, every 5 min during steady state, every 50 kJ of TT, and TT completion. Body mass was measured every 30 min preexercise and pre and post steady state and TT to assess hydration status. Linear mixed models were fitted to estimate intervention and MC phase effect. There were no significant sodium hyperhydration or MC phase effects on rectal temperature or heart rate (p > .05). Body mass increased with sodium versus placebo (0.38 [0.02, 0.74] kg; p = .04), with a greater increase in MC Phase 4 (0.69 [0.17, 1.2] kg; p < .001). TT performance improved with sodium versus placebo (-1.55 [-2.46, -0.64] min; p = .001), with a greater improvement in MC Phase 4 (-1.85 [-3.16, -0.55] min; p = .005). Sodium hyperhydration is a promising heat mitigation strategy for females undertaking prolonged exercise in the heat, especially during MC Phase 4 and when fluid access is limited.

We characterized daily dietary protein intakes, focusing on protein source (animal and nonanimal) and form (whole-foods and supplemental) in young (18-40 years) resistance trained (training ≥ 3×/week for ≥ 6 months; TRA; male, n = 30; female, n = 14) and recreationally active (no structured training; REC; male, n = 30; female, n = 30) individuals. Using 3-day weighed food diaries from 10 previous studies, we assessed macronutrient intakes using dietary analysis software. Energy intakes trended greater in TRA compared with REC (p = .056) and were greater in males than females (p = .006). TRA consumed greater (p = .002) proportions of daily energy intake as protein than REC (23 ± 6 vs. 19 ± 5%Energy), which also trended greater in males compared with females (22 ± 3 vs. 20 ± 2%Energy; p = .060). Absolute (p < .001) and relative (to body mass [BM]; p < .001) protein intakes were greater in TRA (males, 159 ± 54 g/day or 1.6 ± 0.7 g·kg-1 BM·day-1; females, 105 ± 40 g/day or 2.0 ± 0.6 g·kg-1 BM·day-1; p < .001) than REC (males, 103 ± 37 g/day or 1.3 ± 0.5 g·kg-1 BM·day-1; females, 85 ± 23 g/day or 1.3 ± 0.4 g·kg-1 BM·day-1; p < .001), with absolute (p = .025), but not relative (p = .129) intakes greater in males. A greater proportion of total protein was consumed from animal compared with nonanimal in TRA (68% vs. 32%, respectively; p < .001) and REC (64% vs. 36%, respectively; p < .001); the skew driven exclusively by males (72% vs. 28%, respectively; p < .001). A greater proportion (∼92%) of total protein was consumed as whole-foods compared with supplemental, irrespective of training status or sex (p < .001). We show animal and whole-food-derived proteins contribute the majority to daily dietary protein intakes in TRA and REC young males and females.

This study aimed to determine energy availability (EA) and within-day energy balance (WDEB) in female soccer players during preseason and also explored eating disorder risk and athlete food choice. We hypothesized commonly used indicators of low energy availability (LEA) risk would correlate with measured EA and WDEB variables, and that food choice determinants would differ according to EA. Eleven National Premier League female soccer players participated in this observational cross-sectional study over 3 weeks. Assessment of resting metabolic rate and physique traits, including bone mineral density, was conducted during Weeks 1 or 3. During Week 2, dietary intake, energy expenditure, and continuous monitor-derived glucose were measured for 5 days. EA was calculated daily and WDEB calculated hourly with deficits/surpluses carried continuously. Questionnaires were administered throughout the 3 weeks, including the Athlete Food Choice Questionnaire, the Eating Disorders Screen for Athletes, and the Low Energy Availability in Females Questionnaire. Resting metabolic rate ratio, bone mineral density, Low Energy Availability in Females Questionnaire, and Eating Disorders Screen for Athletes scores were used as indicators of LEA risk. EA averaged 30.7 ± 7.5 kcals·kg fat-free mass-1·day-1. Approximately one-third (36%) of athletes were at risk of an eating disorder, while approximately half (45%) were identified at risk of the female athlete triad via Low Energy Availability in Females Questionnaire, compared with approximately one-third (36%) of athletes identified with EA < 30 kcal·kg fat-free mass-1·day-1. No athlete achieved EA >45 kcal·kg fat-free mass-1·day-1, and no indicator of LEA risk was associated with calculated EA or WDEB. However, overnight glycemic variability was positively correlated with measured EA (r = .722, p = .012).

This study investigated the effect of oral and topical sodium bicarbonate (SB) on soccer-specific performance during simulated soccer exercise. In a block randomized, double-blind, crossover design, 10 collegiate male soccer players (stature: 181.7 ± 3.2 cm, body mass: 81.7 ± 10.5 kg) performed soccer-specific performance tests (countermovement jumps, Illinois agility, 8 × 25 m repeated sprints) throughout a 90-min soccer-specific aerobic field test (SAFT90) following 0.3 g/kg body mass SB in capsules (SB-ORAL), 0.9036 g/kg body mass PR Lotion (SB-LOTION), or placebo capsules and lotion (PLA). Soccer-specific performance tests were conducted pre-SAFT90, during half-time and post-SAFT90. Blood samples were analyzed for acid-base balance (pH; bicarbonate, HCO3-) and strong ions (sodium, Na+; potassium, K+). Average sprint times were quicker for SB-ORAL than PLA during half-time (3.7%; p = .049; g = .57) and post-SAFT90 (4.9%; p = .041; g = .66). SB-ORAL increased pH and HCO3- prewarm-up and during half-time (p < .05), and lowered K+ during half-time (p = .035) compared with PLA. SB-LOTION increased pH (p = .019) and lowered K+ (p = .012) during half-time compared with PLA. SB-LOTION increased Na+ postexercise compared with PLA (p = .008). Repeated sprint times during simulated soccer exercise improved for SB-ORAL, which might have been mechanistically underpinned by elevated blood buffering capacity and greater regulation of strong ion concentration. Consuming SB in capsules is a more effective strategy than topical SB application for improving blood buffering capacity and repeated sprint performance throughout competitive soccer matches.

This study explored the body mass (BM) management practices among competitive male and female Olympic weightlifting athletes, hypothesizing that athletes compete in lighter weight categories than their habitual training weight (i.e., making weight). Utilizing a validated, anonymous survey, data were collected from 149 Olympic weightlifting athletes (>18 years; female = 94). The survey comprised five sections: demographics, training/competition history, weight history, source of influence, and BM management practices. The prevalence, magnitude, and methods employed for BM management were analyzed with subgroup analysis using one-way analysis of variance. Post hoc testing including Spearman's rho and chi-square analysis was completed when a significant effect was found. Three quarters (76%) of athletes acknowledged using chronic weight loss and/or acute weight loss strategies to make weight. Usual BM loss (2%-3%) in the week before competition was within recommended guidelines. Gradual dieting, fluid restriction, and low food weight, high-calorie options were the most commonly used BM management strategies. Female athletes were more likely to use gradual dieting (p = .043; r = .104) and were less likely to increase their exercise (p = .046; r = -.105) and utilize fasting (p = .038; r = .05) compared with their male counterparts. Women further identified dietitians/nutritionists (p = .006; r = .022) as a highly influential source of information. This research offers new insights into the BM management practices of Olympic weightlifting athletes, identifying that the majority of athletes compete at a BM lighter than their habitual training weight, achieved using a range of chronic weight loss and acute weight loss strategies.

Taurine (TAU) has been shown to improve time to exhaustion (TTE) and fat oxidation during exercise; however, no studies have examined the effect of acute TAU supplementation on maximal fat oxidation (MFO) and related intensity to MFO (FATmax). Our study aimed to investigate the effect of acute TAU supplementation on MFO, FATmax, VO2peak, and TTE. Eleven recreationally trained male endurance runners performed three incremental running tests. The first visit included a familiarization to the test, followed by two subsequent visits in which exercise was performed 90 min after ingestion of either 6-g TAU or placebo (PLA) using a triple-blind randomized crossover design. There was no effect of TAU on MFO (p = .89, d = -0.07, TAU: 0.48 ± 0.22 g/min; PLA: 0.49 ± 0.15 g/min or FATmax (p = .26, d = -0.66; TAU: 49.17 ± 15.86 %V˙O2peak; PLA: 56.00 ± 13.27 %V˙O2peak). TTE was not significantly altered (TAU: 1,444.8 ± 88.6 s; PLA: 1,447.6 ± 87.34 s; p = .65, d = -0.04). TAU did not show any effect on V˙O2peak in comparison with PLA (TAU: 58.9 ± 8.4 ml·kg-1·min-1; PLA: 56.5 ± 5.7 ml·kg-1·min-1, p = .47, d = 0.48). However, V˙O2 was increased with TAU at most stages of exercise with large effect sizes. The acute ingestion of 6 g of TAU before exercise did not enhance MFO, FATmax, or TTE. However, it did increase the oxygen cost of running fixed intensities in recreationally trained endurance runners.

Preexercise caffeine intake has proven to exert ergogenic effects on cycling performance. However, whether these benefits are also observed under fatigue conditions remains largely unexplored. We aimed to assess the effect of caffeine ingested during prolonged cycling on subsequent time-trial performance in trained cyclists.

Numerous studies have revealed the role of low dietary calcium-to-phosphorous ratio and low bone health. However, its possible role in visceral adiposity, skeletal muscle mass (SMM), and metabolic parameters has not been investigated before. Therefore, the aim of the current cross-sectional study was to evaluate the relation between dietary calcium-to-phosphorous ratio, metabolic risk factors, SMM, and visceral fat area (VFA) among physically active young individuals.

There is little evidence that body size alters exogenous glucose oxidation rates during exercise. This study assessed whether larger people oxidize more exogenous glucose during exercise than smaller people. Fifteen cyclists were allocated into two groups based on body mass (SMALL, <70 kg body mass, n = 9, two females) or (LARGE, >70 kg body mass, n = 6) matched for lactate threshold (SMALL: 2.3 ± 0.4 W/kg, LARGE: 2.3 ± 0.3 W/kg). SMALL completed 120 min of cycling at 95% of lactate threshold1. LARGE completed two trials in a random order, one at 95% of lactate threshold1 (thereby exercising at the same relative intensity [RELATIVE]) and one at an absolute intensity matched to SMALL (ABSOLUTE). In all trials, cyclists ingested 90 g/hr of 13C-enriched glucose. Total exogenous glucose oxidation was (mean ± SD) 33 ± 8 g/hr in SMALL versus 45 ± 13 g/hr in LARGE-RELATIVE (mean difference: 13 g/hr, 95% confidence interval [2, 24] g/hr, p = .03). Large positive correlations were observed for measures of exogenous carbohydrate oxidation versus body size (body mass, height, and body surface area; e.g., body surface area vs. peak exogenous glucose oxidation, r = .85, 95% confidence interval [.51, .95], p < .01). When larger athletes reduced the intensity from RELATIVE to ABSOLUTE, total exogenous glucose oxidation was 39 ± 7 g/hr (p = .43 vs. LARGE-RELATIVE). In conclusion, the capacity for exogenous glucose oxidation is, on average, higher in larger athletes than smaller athletes during exercise. The extent to which this is due to higher absolute exercise intensity requires further research, but body size may be a consideration in tailoring sports nutrition guidelines for carbohydrate intake during exercise.

This study investigated the effect of menthol (MEN) mouth rinsing (MR) on cycling performance during a modified variable cycle test (M-VCT) in adolescent athletes under hot conditions (31.4 ± 0.9 °C, 23.4 ± 3.7% relative humidity).