Journal of the International Society of Sports Nutrition最新文献

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.

Aim: This study investigated the effect of the combining Tabata training and cinnamon supplementation on metabolic changes and body composition in overweight and obese soldiers.

Materials and methods: 40 overweight and obese soldiers were divided into Tabata (T), Tabata training+supplement (T+S), supplement (S) and control (C) groups. The intervention completed during eight weeks with three sessions per week. Pre- and post-intervention assessments included body composition (body mass index [BMI], body fat percentage [BFP], performance parameters) push-up, squat, plank and vertical jump), metabolic markers (fasting blood sugar [FBS], insulin and [HOMA], liver enzymes (Serum Glutamic-Oxaloacetic Transaminase [SGOT], Serum Glutamic-Pyruvic Transaminase [SGPT], and Gamma-Glutamyl Transferase [GGT] (and inflammatory markers (C-Reactive Protein [CRP], Tumor Necrosis Factor-alpha [TNF-α], Adiponectin and Irisin). Cinnamon supplement was taken in 500 mg capsules three times a day.

Results: Body mass, BMI, and body fat percentage significantly decreased in all intervention groups (p < 0.001), with the greatest fat loss in T + S (-7.86%, p < 0.001), significantly more than T (p = 0.013). Performance (push-up, squat, plank, jump) improved in T and T + S (all p < 0.001), with no difference between them (p > 0.05). Fasting blood sugar, insulin, HOMA-IR, and liver enzymes (SGOT, SGPT, GGT) decreased across all interventions (p < 0.05), with the greatest reductions in T + S. Inflammatory markers (CRP, TNF-α) declined, while adiponectin and irisin increased in all interventions (p < 0.001), with superior changes in T + S versus all groups (p < 0.05). The control group showed no significant changes (p > 0.05).

Conclusion: Tabata training resulted in synergistically effect on performance, body composition, metabolic-inflammation markers, and liver enzyme function in overweight and obese individuals. Moreover, the cinnamon supplementation as an ergogenic potentiated the observed beneficial effects.

Introduction: Exercise-induced muscle damage (EIMD) results from intense or unaccustomed exercise, leading to inflammation, oxidative stress, and reduced muscle function due to excessive reactive oxygen species. Propolis, a natural bee-derived substance rich in bioactive coumpounds such as artepillin-c, exhibits anti-inflammatory and antioxidant properties, suggesting its potential to mitigate EIMD. This study investigated the effect of a standardized Brazilian green propolis extract (EPP-AF) on recovery from EIMD, which is characterized by muscle soreness, reduced function, and lower muscle quality.

Methods: Twenty-two trained female participants were randomly assigned to consume eight capsules of EPP-AF (containing approximately 54 mg artepillin C) or a placebo (PLA) for seven days. On day four, participants performed 10 sets of 10 maximal eccentric contractions of the knee extensor muscles. Maximal voluntary isokinetic torque (MVIT), muscle thickness (MT), muscle ultrasound echo intensity (EI), and delayed onset muscle soreness (DOMS) were assessed before and at 2 h, 24 h, 48 h, and 72 h post-EIMD.

Results: The EIMD protocol significantly increased MT (p = 0.031), EI (p = 0.013), and DOMS (p < 0.001) while reducing MVIT (p < 0.001). Compared to placebo, EPP-AF supplementation attenuated DOMS (p < 0.001), mitigated increases in MT (p = 0.025) and EI (p = 0.043), and accelerated MVIT recovery (p = 0.037) in the days following days of eccentric exercise compared to placebo.

Conclusion: EPP-AF may alleviate the symptoms and attenuate markers of muscle damage in the knee extensor muscles of resistance-trained females. These findings highlight the potential of propolis as a natural intervention to enhance recovery from EIMD.

Objective: The aim of this study was to identify the key regulatory mechanisms of cartilage injury and osteoporosis through bioinformatics methods, and to provide a new theoretical basis and molecular targets for the diagnosis and treatment of the disease.

Methods: Microarray data for cartilage injury (GSE129147) and osteoporosis (GSE230665) were first downloaded from the GEO database. Differential expression analysis was applied to identify genes that were significantly up-or down-regulated in the cartilage injury and osteoporosis samples. These genes were subjected to GO enrichment analysis and KEGG pathway analysis. In addition, we employed SVA and RRA methods to merge the two sets of data, eliminating batch effects and enhancing the statistical power of the analysis. Through WGCNA, we identified gene modules that were closely associated with disease phenotypes and then screened for key genes that intersected with differentially expressed genes. The diagnostic value of these genes as potential biomarkers was evaluated by ROC analysis. Moreover, we performed an immune infiltration analysis to explore the correlation between these core genes and immune cell infiltration.

Results: We performed GO enrichment analysis and KEGG pathway analysis of genes significantly up-or down-regulated in cartilage injury and osteoporosis samples. Important biological processes, cellular components and molecular functions, and key metabolic or signaling pathways associated with osteoporosis and cartilage injury were identified. Through WGCNA, we identified gene modules that were closely associated with the disease phenotype, from which we then screened for key genes that intersected with differentially expressed genes. Ultimately, we focused on two identified core genes, COL1A1 and TNFRSF12A, and assessed the diagnostic value of these genes as potential biomarkers by ROC analysis. Meanwhile, GSVA provided an in-depth view of the role of these genes in disease-specific biological pathways. Immune infiltration analysis further revealed the possible key role of COL1A1 and TNFRSF12A in regulating immune cell infiltration in osteoporosis and cartilage injury.

Conclusion: COL1A1 and TNFRSF12A as key regulatory molecules in osteoporosis and cartilage injury.

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of the literature surrounding the effects of long-chain omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplementation on exercise performance, recovery, and brain health. This position stand is intended to provide a scientific foundation for athletes, dietitians, trainers, and other practitioners regarding the effects of supplemental ω-3 PUFA in healthy and athletic populations. The following conclusions represent the official position of the ISSN: Athletes may be at a higher risk for ω-3 PUFA insufficiency.Diets rich in ω-3 PUFA, including supplements, are effective strategies for increasing ω-3 PUFA levels.ω-3 PUFA supplementation, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been shown to enhance endurance capacity and cardiovascular function during aerobic-type exercise.ω-3 PUFA supplementation may not confer a muscle hypertrophic benefit in young adults.ω-3 PUFA supplementation in combination with resistance training may improve strength in a dose- and duration-dependent manner.ω-3 PUFA supplementation may decrease subjective measures of muscle soreness following intense exercise.ω-3 PUFA supplementation can positively affect various immune cell responses in athletic populations.Prophylactic ω-3 PUFA supplementation may offer neuroprotective benefits in athletes exposed to repeated head impacts.ω-3 PUFA supplementation is associated with improved sleep quality.ω-3 PUFA are classified as prebiotics; however, studies on the gut microbiome and gut health in athletes are currently lacking.

Background: Caffeine, identified as a central nervous system stimulant in foods, beverages (coffee, tea, chocolate), and medications, has been focused on its ergogenic properties, enhancing physical performance. The aim of this study was to investigate the association between the caffeine intake (from coffee) and fat-free mass index (FFMI).

Materials and methods: We carried out a cohort study that included 3,466 women and 3,145 men aged ≥20 years who were intaking caffeine. Caffeine intake from coffee were obtained from two 24-hour dietary recall interviews. The FFMI was calculated as FFM (kg) divided by height in m². The caffeine intake was classified into quartiles and combined into 4 groups. Multiple linear regression model analysis and multiple logistic regression model analysis were used to assess associations between the caffeine and FFMI adjusted for potential confounders.

Results: Among the 2,427 participants, males accounted for 52.4%, and females 47.6%. In multiple linear regression model, Model 1 (unadjusted Model (p = 0.041)) and Model 2 (adjusted for age, race, and BMI (p = 0.006)) in women showed a significant relationship between caffeine intake and FFMI. In multivariable models, caffeine intake and FFMI were significantly different (p < 0.05). In sex subgroups, among females, each quartile of caffeine intake was positively correlated with FFMI levels in the average FFMI group in Model 3 (p < 0.001). In age subgroups, each quartile of caffeine intake was positively correlated with FFMI levels in the average FFMI group in Model 3 for individuals aged 20-40 (p = 0.039) and those aged above 40 (p = 0.016). In drinking status subgroups, if they drunk alcohol, each quartile was positively correlated with FFMI levels in the average FFMI group in Model 3 (p < 0.001).

Conclusion: Caffeine intake was mainly positively associated with FFMI, especially in women with above levels of FFMI. Longitudinal studies and randomized controlled trials are needed to establish causality and provide evidence-based recommendations regarding caffeine intake to optimize muscle health.

Background: Relative Energy Deficiency in Sports (REDs) is defined as a multifactorial syndrome of impaired physiological and/or psychological functioning was previously named as the Female Athlete Triad. REDs was proposed to be an expansion of the Female Athlete Triad model (Triad), corresponding to a combination of Low Energy Availability (LEA), alteration of the menstrual cycle and bone health. could be made possible by a screening tool to determine the risk of LEA. The Low Energy Availability in Female-Questionnaire (LEAF-Q) is a screening tool originally developed to identify individuals at risk of Triad based on self-reported symptoms in three primary categories: injuries, gastrointestinal function, and reproductive function - to identify individuals at risk of Triad. To date, LEAF-Q is recommended in the International Olympic Committee REDs Clinical Assessment Tool-Version 2 as a screening tool for studying various health and performance outcomes of REDs. This study aims to validate the Italian version (LEAFQ-ITA) among physically active women while adapting it to their culture in order to enhance the diagnosis and facilitate access to treatment of REDs.

Methods: The validation process was carried out in multiple stages: (i) translation and cultural adaptation of the content from the original questionnaire (LEAF-Q) into the Italian culture; (ii) expert validation of the content using the Delphi technique; (iii) reliability test-retest in a sample of Italian physical active women; and (iv) internal consistency checking using exploratory and confirmatory factorial analysis. A consensus rate of more than 90% for every item was considered sufficient agreement. The test-retest reliability was evaluated using the intraclass correlation coefficient estimates and their 95% confidence intervals based on a mean-rating, absolute agreement, 2-way mixed-effects model. Exploratory and confirmatory factorial analyses were performed with the Factor software. The analysis was implemented using a matrix dispersion through Pearson correlations and the Robust Diagonally Weighted Least Squares (RDWLS) extraction method. The Parallel Analysis technique suggested the number of factors to be retained. McDonald's Omega and Cronbach's alpha were performed to test internal consistency.

Results: After two rounds, the LEAFQ-ITA maintained the same amount of items and gained the consensus of content validation specialists. From the sample of 215 questionnaires answered, a sub-sample of 105 participants answered the LEAFQ-ITA twice (mean age: 26.1 ± 4.7 years old; mean body mass index: 21.3 ± 2.6 kg/m²; physical activity of 3.9 ± 1.3 days/week on average). Among them, 56 women (37.6%) obtained a were classified at risk of LEA by the final score of LEAFQ-ITA ≥8. The single measurement intraclass correlation coefficient resulted in 0.832 (F = 10.849, df = 105, p < 0.00