Journal of the International Society of Sports Nutrition最新文献

Background: This study aimed to examine the effect of a commercially available multi-ingredient powder (AG1^Ⓡ) on the gut microbiome and assess the impact of AG1^Ⓡ on GI tolerability and other clinical safety markers in healthy men and women.

Methods: Using a double-blind, randomized, two-arm, placebo-controlled, parallel design, we examined a 4-week daily supplementation regimen of AG1^Ⓡ vs. placebo (PL). Fifteen men and 15 women provided stool samples for microbiome analysis, questionnaires for digestive quality of life (DQLQ), and completed visual analog scales (VAS) and Bristol stool charts to assess stool consistency and bowel frequency before and after the 4-week intervention. Participant's blood work (CBC, CMP, and lipid panel) was also assessed before and after the 4-week intervention. Alpha diversity was determined by Shannon and Chao1 index scores and evaluated by a two-way ANOVA, beta diversity in taxonomic abundances and functional pathways was visualized using partial least squares-discriminant analyses and statistically evaluated by PERMANOVA. To identify key biomarkers, specific feature differences in taxonomic relative abundance and normalized functional pathway counts were analyzed by linear discriminant analysis (LDA) effect size (LEfSe). Questionnaires, clinical safety markers, and hemodynamics were evaluated by mixed factorial ANOVAs with repeated measures. This study was registered on clinicaltrials.gov (NCT06181214).

Results: AG1^Ⓡ supplementation enriched two probiotic taxa (Lactobacillus acidophilus and Bifidobacterium bifidum) that likely stem from the probiotics species that exist in the product, as well as L. lactis CH_LC01 and Acetatifactor sp900066565 ASM1486575v1 while reducing Clostridium sp000435835. Regarding community function, AG1^Ⓡ showed an enrichment of two functional pathways while diminishing none. Alternatively, the PL enriched six, but diminished five functional pathways. Neither treatment negatively impacted the digestive quality of life via DQLQ, bowel frequency via VAS, or stool consistency via VAS and Bristol. However, there may have been a greater improvement in the DQLQ score (+62.5%, p = 0.058, d = 0.73) after four weeks of AG1^Ⓡ supplementation compared to a reduction (-50%) in PL. Furthermore, AG1^Ⓡ did not significantly alter clinical safety markers following supplementation providing evidence for its safety profile.

Conclusions: AG1^Ⓡ can be consumed safely by healthy adults over four weeks with a potential beneficial impact in their digestive symptom quality of life.

Background: Vitamin D is associated with vascular function; however, the impact of different vitamin D levels on vascular elasticity following prolonged exercise remains uncertain. The primary objective of this study was to investigate the association of vitamin D levels with changes in peripheral pulse wave velocity (pPWV) and the magnitude of acute post-exercise hypotension (PEH) following prolonged endurance exercise in healthy young men.

Methods: All the participants were divided into two groups: the 25-hydroxyvitamin D (25(OH)D) sufficiency group (25(OH)D ≧50 nmol/L) and the deficiency group (25(OH)D < 50 nmol/L). A cardiopulmonary exercise test for maximal oxygen uptake ($\stackrel{.}{V}$O_2max) was performed on the graded cycling. The prolonged exercise was set at 60% $\stackrel{.}{V}$O_2max for 120 min of continuous riding on a stationary bicycle. The pPWV and blood pressure were measured at baseline and 0, 15, 30, 45, 60 min after prolonged endurance exercise.

Results: Post hoc analysis revealed that the vitamin D sufficient group had a greater magnitude of PEH than the deficiency group at post-45 min. Multiple linear regression analyses showed a significant correlation between 25(OH)D and both pPWV (p = 0.036) and PEH (p = 0.007), after adjusting for $\stackrel{.}{V}$O_2max, weight, height, and physical activity. In addition, the 25(OH)D deficiency group also had higher pPWV at post-15 min (5.41 ± 0.93 vs 4.84 ± 0.75 m/s), post-30 min (5.30 ± 0.77 vs 4.87 ± 0.50 m/s), post-45 min (5.56 ± 0.93 vs 5.05 ± 0.68 m/s) than the sufficiency group.

Conclusions: There was a positive correlation between 25(OH)D levels and systolic PEH following prolonged endurance exercise. Individuals with sufficient 25(OH)D status may have better vascular elasticity and more efficient blood pressure regulation during exercise.

The aim of this study was to examine the acute effects of a non-caloric energy drink (C4E) compared to a traditional sugar-containing energy drink (MED) and non-caloric placebo (PLA) on exercise performance and cardiovascular safety. Thirty healthy, physically active males (25 ± 4 y) completed three experimental visits under semi-fasted conditions (5-10 h) and in randomized order, during which they consumed C4E, MED, or PLA matched for volume, appearance, taste, and mouthfeel. One hour after drink consumption, participants completed a maximal, graded exercise test (GXT) with measurement of pulmonary gases, an isometric leg extension fatigue test (ISO_FTG), and had their cardiac electrical activity (ECG), leg blood flow (LBF), and blood pressure (BP) measured throughout the visit. Neither MED nor C4E had an ergogenic effect on maximal oxygen consumption, time to exhaustion, or peak power during the GXT (p > 0.05). Compared to PLA, MED reduced fat oxidation (respiratory exchange ratio (RER) +0.030 ± 0.01; p = 0.026) during the GXT and did not influence ISO_FTG performance. Compared to PLA, C4E did not alter RER (p = 0.94) and improved impulse during the ISO_FTG (+0.658 ± 0.25 V·s; p = 0.032). Relative to MED, C4E did not significantly improve gas exchange threshold (p = 0.05-0.07). Both MED and C4E increased systolic BP at rest (+7.1 ± 1.2 mmHg; p < 0.001 and + 5.7 ± 1.0 mmHg; p < 0.001, respectively), C4E increased SBP post-GXT (+13.3 ± 3.8 mmHg; p < 0.001), and MED increased SBP during recovery (+3.2 ± 1.1 mmHg; p < 0.001). Neither MED nor C4E influenced ECG measures (p ≥ 0.08) or LBF (p = 0.37) compared to PLA. C4E may be more efficacious for improving performance in resistance-type tasks without altering fat oxidation under semi-fasted conditions during fatiguing exercise bouts, but promotes similar changes in BP and HR to MED.

Background: Despite the robust evidence demonstrating positive effects from creatine supplementation (primarily when associated with resistance training) on measures of body composition, there is a lack of a comprehensive evaluation regarding the influence of creatine protocol parameters (including dose and form) on body mass and estimates of fat-free and fat mass.

Methods: Randomized controlled trials (RCTs) evaluating the effect of creatine supplementation on body composition were included. Electronic databases, including PubMed, Web of Science, and Scopus were searched up to July 2023. Heterogeneity tests were performed. Random effect models were assessed based on the heterogeneity tests, and pooled data were examined to determine the weighted mean difference (WMD) with a 95% confidence interval (CI).

Results: From 4831 initial records, a total of 143 studies met the inclusion criteria. Creatine supplementation increased body mass (WMD: 0.86 kg; 95% CI: 0.76 to 0.96, I² = 0%) and fat-free mass (WMD: 0.82 kg; 95% CI: 0.57 to 1.06, I² = 0%) while reducing body fat percentage (WMD: -0.28 %; 95% CI: -0.47 to -0.09; I² = 0%). Studies that incorporated a maintenance dose of creatine or performed resistance training in conjunction with supplementation had greater effects on body composition.

Conclusion: Creatine supplementation has a small effect on body mass and estimates of fat-free mass and body fat percentage. These findings were more robust when combined with resistance training.

Background: The estimation of body fat percentage (BF%) in wrestling is used to determine the minimum wrestling weight (MWW) and lowest allowable weight class (MWC) in which wrestlers are eligible to compete. A 12% minimum threshold is currently used for women wrestlers, yet a potential increase for safety has been discussed. Because of the novelty of collegiate women's wrestling, there is a paucity of literature available on the body composition norms of this population. The purpose of this study was to provide a descriptive summary of BF% and MWW values of female wrestlers and how MWW values would change with the use of different BF% thresholds.

Methods: Data from the 2022-2023 collegiate season were retrospectively analyzed resulting in a sample of 1,683 collegiate women wrestlers from the National Association of Intercollegiate Athletics (NAIA, n = 868) and the National Collegiate Athletics Association (NCAA, n = 815). All wrestlers completed skinfold assessments for weight certification at the start of the competition season. The skinfold values were used to estimate BF% using the Slaughter skinfold prediction equation. Frequency statistics and descriptive analysis were performed to compute normative MWW and BF% profiles. BF% thresholds of 12% (12MWW) and the BF% value defined as the lowest 5th percentile, which would be considered unusually lean, were used to determine the resulting MWW and MWC for each method. The lowest recorded weight and weight class division throughout the season was also recorded for each wrestler.

Results: There was a positively skewed (0.94) and platykurtic (1.86) distribution of MWW values. The median ± interquartile range BF% for all wrestlers was 27.4 ± 10.22%, with 17% BF representing the 5th percentile. Only 354 out of 1,579 (22.4%) wrestlers competed in their lowest allowable weight class, based on the 12MWW. Of these 354 wrestlers, the mean BF% was 21.3 ± 5.2% at weight certification with only n = 17 being at or below 12% body fat and an average weight loss of 11.1 ± 8.8 lbs. from the time of weight certification. Throughout the season, wrestlers competed at weights that were, on average (mean ± SD), 19.4 ± 16.9 lbs. higher than their 12MWW (95% CI: 18.6, 20.2 lbs. p < 0.001; effect size [ES] = 1.1), 13.4 ± 19.0 lbs. higher than the 17MWW (p < 0.001; ES = 0.70), and 8.7 ± 8.3 lbs. lower than their weight at the certification (95% CI: 8.3, 9.1 lbs. p < 0.001; ES = 1.1).

Conclusions: Nearly all BF% values were well above the 12% threshold used to determine MWW. Increasing the minimum BF% threshold from 12% to 17% would affect a small percentage of wrestlers, likely reduce the need for excessive weight cutting, and minimize the deleterious health effects of an athlete at such a low BF%.

Background: Caffeine is one of the most popular ergogenic aids consumed by athletes. Caffeine's ergogenic effect has been generally explained by its ability to bind to adenosine receptors, thus modulating pain and reducing perceived exertion. Another pharmacological agent that may improve performance due to its analgesic proprieties is paracetamol. This study aimed to explore the effects of caffeine, paracetamol, and caffeine + paracetamol consumption on muscular endurance, strength, power, anaerobic endurance, and jumping performance.

Methods: In this randomized, crossover, double-blind study, 29 resistance-trained participants (11 men and 18 women) ingested either a placebo, caffeine (3 mg/kg), paracetamol (1500 mg) or caffeine + paracetamol 45 min before the testing sessions. The testing sessions included performing the bench press exercise with 75% of one-repetition maximum to momentary muscular failure, isokinetic knee extension and flexion at angular velocities of 60°/sec and 180°/sec, Wingate, and countermovement jump (CMJ) tests.

Results: Compared to placebo, isolated caffeine ingestion increased the number of repetitions performed in the bench press (p = 0.005; d = 0.42). Compared to placebo, isolated caffeine ingestion and/or caffeine + paracetamol consumption was ergogenic for strength (torque), muscular endurance (total work), or power in the isokinetic assessment, particularly at slower angular velocities (p = 0.027 to 0.002; d = 0.16 to 0.26). No significant differences between the conditions were observed for outcomes related to the Wingate and CMJ tests.

Conclusion: This study provided novel evidence into the effectiveness of caffeine, paracetamol, and their combination on exercise performance. We found improvements in muscular endurance, strength, or power only when caffeine was consumed in isolation, or in combination with paracetamol. Isolated paracetamol consumption did not improve performance for any of the analyzed outcomes, thus calling into question its ergogenic potential.

Background: The aim of this research is to explore the interrelationships between different psychological issues and the potential role of eating behavior and physical activity among nursing students.

Methods: Undergraduate nursing students (n = 892) from some medical universities in China were recruited through convenience and snowball sampling methods using online platforms. Participants completed measures on demographics, fear of negative evaluation (FNE), social avoidance and distress (SAD), psychological distress (DASS), disordered eating behavior (TFEQ) and physical activity. The relationship models among the aforementioned variables were established using Process 3.5.

Results: A total of 290 males and 602 females were included in this study. The average FNE score of students was (39.44 ± 8.78), SAD was (13.83 ± 7.06), DASS was (22.45 ± 20.47), and TFEQ was (56.09 ± 12.57), respectively. TFEQ and SAD independently and jointly acted as mediators in the relationship between FNE and DASS. Physical activity played a moderating role, with the interaction effect between FNE and groups Q2, Q3, and Q4 determined to be 0.407 (95%CI 0.136 to 0.678), 0.328 (95%CI 0.061 to 0.596) and 0.332 (95%CI 0.073 to 0.591), respectively.

Conclusions: This study supports that disordered eating behaviors have a negative impact on mechanisms of psychological changes, and enhancing physical activity is an effective prevention strategy for psychological distress and disordered eating behaviors among nursing students.