Background: Pre-exercise carbohydrate intake is known to influence performance; however, data describing their effect on cardiorespiratory parameters is scarce. This study aimed to assess the effects of isotonic drink consumption on cardiopulmonary exercise test (CPET) parameters in elitemale youth basketball players.
Methods: The athletes were randomized into a fasting (400 ml mineral water) and an isotonic drink (400 ml 7% isotonic solution) group respectively, and consumed the drinks 30 minutes before the CPET. Pre-, peak- and post-CPET glucose levels were measured. Borg and lactate were assessed every 2 minutes during the test.
Results: Seventy-one athletes (age: 15.9 ± 1.8 years) were included in the study. The isotonic drink group had higher pre- and post-CPET glucose levels (p < 0.05). They reported a lower Borg scale at the 2nd, 6th, and 10th minutes (p < 0.05), while their lactate levels were lower at the 14th minute (p < 0.05). Regression analysis showed that fasting was associated with higher Borg scale ratings (β-coefficient: 0.72, p < 0.001) and increased lactate accumulation over time (β-coefficient: 0.13, p = 0.01). No difference was found in exercise duration or maximal aerobic capacity.
Conclusions: Single-dose isotonic drink consumption before CPET reduces perceived exertion and moderates lactate accumulation, which may suggest a beneficial effect during the exercise test.
Background: Pre-competition weight loss (WL) is a widely adopted strategy in weight-sensitive sports, particularly among combat sport. This strategy enables athletes to compete at a weight or weight classes below their habitual body mass (BM). Although research on WL for weight-sensitive sports has steadily grown, it mostly employs the term "RWL". However, there is no compelling or universally accepted definition of RWL.
Objective: In this current opinion, we discussed the deficiencies and misuse of the current definition of RWL and proposed a new theoretical framework to provide a basis for better defining RWL in the future.
Discussion: A most commonly used definition describes RWL as losing 5% of body mass within 7 days. However, this definition is somewhat arbitrary and lacks empirical justification. This definition is based on two parameters: magnitude (5% BM) and duration (7 days), yet its cut-off remains rigid and lacks empirical support. Several studies on combat athletes have found that a relatively faster rate of WL can lead to significant negative impacts on performance and health variables. We argue that using WL rate as the core criterion is more robust, as the term "rapid" emphasizes the speed of WL. However, at what rate does WL become classified as RWL? The limited research in this area underscores the need for studies to establish a solid foundation for defining RWL. In many studies, authors use the term "RWL," especially in quantitative research. However, using the current definition, some practices reported by participants (e.g., losing 2% BM over 30 days) do not qualify as RWL. Finally, we propose that WL (not RWL) practices be classified along two dimensions: WL rate and WL magnitude. Based on rate, practices can be categorized as slow, moderate, or rapid WL. Based on magnitude, they can be classified as low, moderate, or high WL.
Background and objective: Nordic skiers represent a low-impact, weight-sensitive sport and may be inclined to engage in weight-controlling behavior, hence increasing their risk for low energy availability and impairment in health and performance. Jarlsberg cheese (J) is rich in vitamin K₂ from fermentation by Propionibacterium freudenreichii subsp. shermanii LMGT 2951 (Pf) and lactic acid bacteria and increases the osteocalcin (OC) level. Vitamin K is essential for activating OC, which is described to be associated positively with muscle strength, whereas propionic acid bacteria are found to enhance endurance. Except for Pf and its by-products, J and Norvegia (N) cheeses have almost identical nutrient content. The objective of this study was to compare the effects of Jarlsberg and N as potential supplements to training on muscle strength (MS), lean body mass (LBM) and VO2 max.
Methods: Thirty female and 30 male Nordic skiers were block randomized 1:1 to either J or N and studied during a 24-week offseason training schedule. The Norvegia group served as a control group. Females and males were treated with 75 and 90 grams/day, respectively. MS by seated pulldown and half-squat, LBM by DXA, and VO2 max were measured at baseline and after the 24 weeks off-season period. Dietary intake and training hours were registered and monitored at baseline and every eight weeks during the study.
Results: MS significantly increased in both groups after 24 weeks (p < 0.01). The mean increase difference in MS-upper body favored Jarlsberg by 0.95 kg (95% CI: -0.02-1.46), approaching significance (p = 0.06). No significant difference was found between groups in MS-lower body. LBM and VO2-max both increased significantly in each group (p ≤ 0.05), with no notable differences between groups. Correlation analysis identified LBM as the dominant outcome variable at both baseline and 24 weeks. Endurance training was the dominant input variable and correlated significantly positively both multiply and partially to LBM, (p = 0.04, p = 0.02), respectively. At baseline and 24-weeks sex, endurance training along with OC-level explained 65% and 68% of the LBM variations, respectively.
Conclusion: Both Jarlsberg cheese, characterized by its unique Propionibacterium freudenreichii content, and Norvegia cheese, when combined with off-season training, led to increases in LBM, VO₂ max, and MS, with no significant differences observed between groups. However, there was a trend toward greater improvements in MS in the Jarlsberg group. Overall, increases in LBM through structured training appear to be a key driver of gains in both muscle strength and aerobic capacity.
Protocol number: XCS-Jarlsberg/IIA.
Clinicaltrial.gov: NCT06688032.
Purpose: The purpose of this study was to examine caffeine consumption and the factors that affect caffeine use in high school athletes.
Methods: Three hundred and ninety-four Rhode Island high school athletes (age: 16.8 ± 1.27 years) completed a cross-sectional online survey to assess caffeine consumption. A multivariate logistic regression analysis and binary logistic regression were performed to characterize associations between use and nonuse and the independent variables of ethnicity, grade, sex, and sport played. 95% confidence intervals (CI) were calculated for all models. Statistical significance was set to p ≤ 0.05 for all analysis.
Results: Fifteen point five percent of the variance in caffeine use was related to ethnicity, grade, and sex(R2 = 0.155), with significant results for each variable. A majority of female athletes consumed caffeine (67.4%), compared to male athletes (37.8%) (p < 0.001). Athletes identifying as Caucasian reported significantly more caffeine use (55.9%), compared to athletes from underrepresented backgrounds (32.6%) (p < 0.001). Caffeine use was significantly different across grades, where 30.6% of 9th graders, 49.2% of 10th graders, 55.2% of 11th graders, and 49.2% of 12th graders reported caffeine use (p = 0.049). Coffee (51%) and energy drinks (43%) were the primary sources of caffeine consumption. Dance, cheerleading, and gymnastics participants were more than ten times as likely to consume caffeine compared to other sports (95% CI [2.28, 48.94], Exp (β) = 10.57).
Conclusion: Caffeine use in young athletes is related to factors including sex and ethnicity. Given the prevalence of use, young athletes, coaches, and parents/guardians should be educated on the risks and benefits of caffeine use. Future research should focus on the potential benefits of caffeine use to athletic performance verses possible side effects in this population.
Supported by: The Clean Competition Grant from the Rhode Island Foundation.
Background: Pre-workout multi-ingredients are designed to enhance energy levels and acutely increase exercise performance. This study compared the effectiveness of ingesting an admixture providing caffeinated ingredients and plant-based protein enriched with amino acids versus carbohydrates alone on body composition, hypertrophy and physical performance.
Methods: Forty-three middle-aged physically active individuals (26 peri- and post-menopausal females and 17 males) completed the study after being randomly assigned to one of the following intervention groups: pre-workout (PREW n = 24, 54 ± 4 years, body mass 77.6 ± 16.0 kg) or a carbohydrate-only comparator (COMP n = 19, 52 ± 4 years, body mass 80.6 ± 16.0 kg). Measurement of fat and fat-free mass (via plethysmography), waist and hip circumferences, muscle thickness (via ultrasound), strength, power output and muscle endurance performance were collected before and after a 6-week resistance training programme performed 3 times per week. Treatment consisted of ingesting 30g of the assigned supplement, mixed with 400mL of plain water, 15min before each workout session.
Results: Both groups significantly (p < 0.05) reduced fat mass (mean ± SD) (PREW -1.4 ± 1.6 kg; COMP -1.0 ± 1.5 kg), increased fat-free mass (PREW +0.9 ± 1.1 kg; COMP + 0.8 ± 0.9 kg); vastus lateralis (PREW +0.2 ± 0.2 cm; COMP + 0.1 ± 0.6 cm), and elbow flexors (PREW +0.5 ± 0.3 cm; COMP + 0.4 ± 0.2 cm) muscle thickness. Only the PREW group showed a significant reduction in the waist circumference (-1.8 ± 1.8 cm, p < 0.01). However, no significant differences between groups (PREW vs. COMP) were identified at post-intervention. Isometric force, countermovement jump, medicine ball throw, and upper and lower body muscle endurance performance improved (p < 0.05) for both treatments, with no difference between groups.
Conclusion: Except for waist circumference reduction, ingesting a pre-workout vegan protein-based caffeinated supplement promotes no further resistance training benefits in middle-aged individuals.
Background: Caffeine is commonly used to combat fatigue and enhance both cognitive and physical performance. However, its effects on neurophysiological responses and sport-specific performance following fatigue induction remain unclear, particularly in combat sports such as Taekwondo. This study investigated the effects of a 200 mg caffeine dose on physiological markers, electroencephalographic (EEG) brainwave activity, auditory P300 event-related potentials (ERPs), and Taekwondo-specific performance following combined mental and physical fatigue.
Methods: Thirteen male Taekwondo athletes participated in a randomized, double-blind, crossover study with caffeine (CAF) and placebo (PLA) conditions. Measurements were taken at baseline (pre-supplementation), 30 minutes post-supplementation (post-Sup), and after fatigue induction (post-I). Physiological parameters (heart rate, blood glucose, blood lactate, and ratings of perceived exertion), EEG brainwave activity during resting eyes-open conditions, auditory P300 ERPs, and Taekwondo-specific agility (TSAT) were assessed at all time points.
Results: Caffeine significantly reduced delta wave power at frontal and parieto-occipital sites at post-Sup (p < 0.05), indicating decreased cortical drowsiness; however, this effect was not sustained at post-I (p > 0.05). P300 amplitude significantly increased in the CAF condition compared to PLA from post-Sup to post-I at the central and parietal electrode sites (p < 0.05), while P300 latency remained unchanged (p > 0.05). No significant differences were observed in reaction time, accuracy, or error rate in the auditory oddball task or TSAT performance across conditions (p > 0.05). Similarly, physiological parameters remained unchanged between groups (p > 0.05).
Conclusion: A single 200 mg dose of caffeine reduced central fatigue and enhanced cognitive processing, as reflected by suppressed delta wave activity at post-Sup and increased P300 amplitude at post-I. However, caffeine did not influence physiological responses or Taekwondo-specific performance. These findings suggest that low-dose caffeine primarily benefits cognitive function rather than physical performance in combat sports. Future studies should explore dose-response relationships and individual variability in caffeine metabolism to optimize its application in competitive settings.
Background: This study aimed to investigate the effects of a high-dose beta-alanine (BA) supplementation on physical performance, blood lactate concentration, and ratings of perceived exertion (RPE) in trained futsal players.
Methods: Sixteen trained futsal players participated in a randomized, parallel, double-blind experiment, completing a two-week supplementation period with either 12 g/day of BA (n = 8; age: 19 ± 2 years; height: 1.78 ± 0.03 m; body mass: 68.5 ± 5.4 kg) or a placebo (PLA) (n = 8; age: 18 ± 1 years; height: 1.74 ± 0.08 m; body mass: 65.6 ± 6.4 kg). Athletes completed the futsal intermittent endurance test (FIET) and a 30-m speed test before and after supplementation. Plasma lactate levels were measured before, immediately after, and three minutes post-FIET, while RPE was assessed during each FIET stage.
Results: There was a significant main effect of time for distance covered in the FIET (Pre-BA: 1618.13 ± 268.14 m; Post-BA: 1857.50 ± 277.81 m; Pre-PLA: 1519.13 ± 243.19 m; Post-PLA: 1621.88 ± 323.65 m; p = 0.003; ηp2 = 0.73), while no significant interaction effect was revealed for FIET (p = 0.147; ηp2 = 0.27). Furthermore, no significant interaction effects were found in the 30-m sprint test (p = 0.149; ηp2 = 0.27, Pre-BA: 4.33 ± 0.25 s; Post-BA: 4.22 ± 0.124 s; Pre-PLA: 4.33 ± 0.26 s; Post-PLA: 4.37 ± 0.22 s). Neither plasma lactate levels nor RPE showed significant main effects of treatment or timepoint (all p > 0.5). Conclusion: Two weeks of high-dose BA supplementation did not have an ergogenic impact on the distance covered during the intermittent endurance test, sprint performance, blood lactate, or RPE in trained futsal players.
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