Journal of the International Society of Sports Nutrition

Background: Sports practice, particularly eccentric exercises, induces significant muscular changes, including muscle fiber injuries, strength loss, pain, and increased permeability of the muscle membrane. The duration of muscle recovery depends on factors such as exercise intensity and the specific muscle groups engaged. The inflammatory response plays a crucial role in muscle regeneration, involving various cell types. Curcumin, especially when its stability is enhanced through encapsulation, exhibits potent antioxidant and anti-inflammatory properties. Supplementing with curcumin can reduce muscle damage and inflammation caused by eccentric exercise, making it a potential remedy for athletes. Objective: The objective of this systematic review is to assess the scientific evidence supporting the efficacy of curcumin in reducing muscle damage caused by sports. Methods: A structured search in SCOPUS, Medline, and Web of Science databases was conducted in March 2023, including all available articles. The strategy involved selecting English articles without time constraints, using the search terms "curcumin" AND "Exercise-Induced Muscle Damage" (ALL(curcumin AND "Exercise-Induced Muscle Damage")). Titles and abstracts were screened to assess eligibility. Studies were chosen based on PICOS criteria, and quality was evaluated using the reliable PEDro scale. The eligibility criteria included adults without any diagnosed diseases who regularly exercise (at least three times per week) and follow a consistent pattern of curcumin intake before, during, or after exercise. Results: The comprehensive search identified 11 relevant studies investigating the effects of curcumin supplementation in sport-simulated interventions. These studies suggest that curcumin intake may help reduce muscle symptoms associated with eccentric exercises, thereby improving pain perception. Effective use of curcumin depends on factors such as dosage, bioavailability, and timing, with post-exercise ingestion appearing to be more beneficial. Conclusions: Curcumin demonstrates a significant potential to relieve muscle-related symptoms, especially delayed-onset muscle soreness (DOMS) that arises from eccentric exercises, thus potentially improving the well-being of those who are trained. It also appears to have the capability to lower biomarkers associated with inflammation and boost antioxidant levels. Nevertheless, for future studies, the bioavailability of curcumin must be considered, as it is a key factor in its efficacy.

Rationale: Firefighters are at risk for cardiovascular disease due to occupational-related inflammation, oxidative stress, and lifestyle practices. Astaxanthin (AX) possesses anti-inflammatory/antioxidant and purported ergogenic properties. This study examined the impact of supplementing the diet with 12 mg/d AX for four weeks on markers of inflammation, oxidative stress, cardiometabolic health, exercise capacity, and occupation-related performance in career firefighters. Methods: In a randomized, double-blinded, placebo-controlled, crossover fashion, 15 male career firefighters (34.5 ± 7.4 years; 177.7 ± 7.0 cm; 95.6 ± 12.0 kg; 30.1 ± 2.9 kg/m2; 11.03 ± 6.85 years of service) ingested 12 mg/d of AX (AstaReal®, AstaReal AB, Nacka, SWE) or placebo (PLA) for four weeks while following a standardized resistance training program. After each treatment, testing sessions were completed to assess inflammatory markers, oxidative stress markers, cardiopulmonary exercise capacity, and performance to a fire ground test (FGT) consisting of nine fire suppressive activities. Data were analyzed using general linear model (GLM) analysis with repeated measures. Clinical significance was assessed via mean changes from baseline with 95% confidence intervals. Results: Analysis of mean percent changes from baseline revealed that AX supplementation lessened the inflammatory response to to performing an incremental maximal exercise test and attenuated increases in interleukin-1β, cortisol, and uric acid in response to performing fire suppressive activities compared to when they ingested PLA. However, most of these effects were within groups rather than between groups. Additionally, there was evidence that AX ingestion increased the ventilatory anaerobic threshold. Four weeks of AX supplementation did not significantly affect fasting markers of oxidative stress, blood lipids, performance during the FGT, general clinical chemistry panels, or self-reported side effects. Conclusions: Results provide some evidence that AX supplementation may help mediate occupation-related inflammation in response to high-intensity, short-duration exercise in firefighters. More research is warranted to determine if long-term supplementation can improve cardiometabolic risk in this population. Clinical trial registration: ISRCTN10901752.

Background This study aimed to investigate the impact of Urolithin A (UA) on muscle endurance, muscle strength, inflammatory levels, oxidative stress, and protein metabolism status in resistance-trained male athletes. Method An 8-week randomized, double-blind, placebo-controlled study was conducted with twenty resistance-trained male athletes. Participants were supplemented with 1 g of UA daily. Muscle strength and muscle endurance measures were assessed, and fasting venous blood samples and morning urine samples were collected to evaluate their oxidative stress levels, inflammatory markers, and protein metabolism status. Results There were no significant differences observed in terms of dietary energy intake and composition between the two assessments conducted within a 24-hour period. After 8 weeks of UA supplementation, compared to baseline measurements, the UA group exhibited increases in 1RM bench press and squat, although these changes were not statistically significant (Δ = 3.00 ± 0.17 kg, p = 0.051, Δ = 1.35 ± 2.73 kg, p = 0.499). However, significant improvements were noted in Maximum Voluntary Isometric Contraction (MVIC) and repetitions to failure (RTF) performance (Δ = 36.10 ± 0.62 NM, p = 0.000; Δ = 2.00 ± 0.56, p = 0.001). When compared to the placebo group, the UA supplementation for 8 weeks led to an increase in 1RM bench press and squat, although statistical significance was not reached (Δ = 3.50 ± 0.79 kg, p = 0.462; Δ = 2.55 ± 1.36 kg, p = 0.710). Furthermore, the group receiving UA supplementation, compared to the placebo group, showed significant improvements in MVIC and RTF (Δ = 43.50 ± 0.77 NM, p = 0.048; Δ = 2.00 ± 1.22, p = 0.011), indicating that the UA group exhibited superior performance enhancements in these metrics compared to the placebo group. After 8 weeks of UA supplementation, the UA group showed a significant decrease in 3-methylhistidine (3-MH) compared to baseline measurement (Δ=-2.38 ± 1.96 μmol/L, p = 0.049). Additionally, the UA group exhibited a significant increase in C-reactive protein (CRP) compared to baseline (Δ = 0.71 ± 0.21 mg/L, p = 0.001). However, there was no significant changes observed in Interleukin-6 (IL-6) (Δ=-1.00 ± 1.01 pg/mL, p = 0.076), or superoxide dismutase (SOD) (Δ=-0.004 ± 0.72 U/mL, p = 0.996) compared to baseline in the UA group. When compared to the placebo group, there was no significant difference observed in 3-MH in the UA group (Δ=-3.20 ± 0.31 μmol/L, p = 0.36). In terms of inflammation markers, the UA group exhibited a significant decrease in CRP (Δ=-0.79 ± 0.38 mg/L, p = 0.032) compared to the placebo group, whereas there was a decrease in IL-6 without statistical significance (Δ=-1.75 ± 0.45 pg/mL, p = 0.215). Furthermore, the UA group showed a significant decrease in SOD compared to the placebo group (Δ=-4.32 ± 0.90 U/mL, p = 0.041). Conclusions After 8 weeks of UA supplementation at 1 g/day, resistance-trained male athletes showed improvements in muscle strength and endurance. Additionally, UA supplementation was also associated with reduced oxidative stress levels and a decrease in inflammation response levels.

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.

Background: There is growing interest in the potential of alternative modes of caffeine administration for enhancing sports performance. Given that alternative modes may evoke improved physical performance via distinct mechanisms, effects may not be comparable and studies directly comparing the erogenicity of alternative modes of caffeine administration are lacking. To address this knowledge gap, the present study evaluated the effect of 3 mg·kg-1 caffeine delivered in anhydrous form via capsule ingestion, chewing gum or mouth rinsing on measures of muscular strength, power, and strength endurance in male Rugby Union players. Methods: Twenty-seven participants completed the study (Mean ± SD: Age 20 ± 2 yrs; daily caffeine consumption 188 ± 88 mg). Following assessments and reassessment of chest press (CP), shoulder press (SP), Deadlift (DL), and Squat (SQ) 1-repetition maximum (1RM) and familiarization to the experimental procedures, participants completed six experimental trials where they were administered 3 mg.kg-1 caffeine (Caff) or placebo (Plac) capsule(CAP), chewing gum(GUM) or mouth rinse(RINSE) in a randomized, double-blind and counterbalanced fashion prior to force platform assessment of countermovement jump, drop jump and isometric mid-thigh pull performance. Strength endurance was measured across two sets of CP, SP, DL, and SQ at 70% 1RM until failure. Pre-exercise perceptions of motivation and arousal were also determined. Results: Caffeine increased perceived readiness to invest mental effort (p = .038; ηp2=.156), countermovement jump height (p = .035; ηp2=.160) and SQ repetitions until failure in the first set (p < .001; d = .481), but there was no effect of delivery mode (p > .687; ηp2<.015). Readiness to invest physical effort, felt arousal, drop jump height, countermovement jump, drop jump and isometric mid-thigh pull ground reaction force-time characteristics and repetitions until failure in CP, SP and DL were not affected by caffeine administration or mode of caffeine delivery (p > .0.052; ηp2< .136). Conclusion: 3 mg.kg-1 caffeine administered via capsule, gum or mouth rinse had limited effects on muscular strength, power, and strength endurance. Small effects of caffeine on CMJ height could not be explained by changes in specific ground reaction force-time characteristics and were not transferable to DJ performance, and effects specific to the SQ RTP exercise underpin the complexity in understanding effects of caffeine on muscular function. Novel modes of caffeine administration proposed to evoke benefits via distinct mechanisms did not offer unique effects, and the small number of effects demonstrated may have little translation to a single performance trial when data examining direct comparison of each caffeine vehicle compared against a mode matched placebo is considered.

Background Exercise-induced bronchoconstriction (EIB) is highly prevalent in athletes. The objective of this study was to assess the therapeutic efficacy of daily tangeretin combined with whey protein supplementation over a period of 4 weeks in professional athletes with EIB. Methods Using a placebo-controlled, double-blind, paired, randomized trial design, a cohort of 30 professional athletes with EIB, consisting of 14 females and 16 males, was divided into two groups: the tangeretin combined with whey protein intervention group (TIG), and the placebo control group (PCG). Both the TIG and PCG underwent exercise challenge tests (ECT) and VO2max tests before (ECT1, V1) and after (ECT2, V2) the intervention. Blood (eosinophils, neutrophils, and basophils) and serum (interleukin-5, IL-5; interleukin-8, IL-8; Clara cell secretory protein-16, CC16; immunoglobulin E, IgE) levels were measured early in the morning of ECT1 and ECT2, respectively. Lung function was assessed immediately before and post-ECT immediately. Results Tangeretin combined with whey protein use for 4 weeks attenuated the decrease in forced expiratory volume in 1 s (FEV1) post trials (∆FEV1(ECT1-ECT2): mean (SD) TIG −7.51(6.9)% vs. PCG −2.33(11.49)%, p = 0.013). Tangeretin also substantially attenuated IL-5 concentration (∆IL-5(T1-T5): Tangeretin −19.4% vs Placebo + 8.37%, p = 0.022); IL-8 concentration (∆IL-8(T1-T5): Tangeretin −17.28% vs Placebo + 6.1%, p = 0.012); CC16 concentration (∆CC16(T1-T5): Tangeretin −11.77% vs Placebo + 24.19%); and IgE concentration in the serum (∆IgE(T1-T5): Tangeretin −24.1% vs Placebo −3.9%), and significantly decreased neutrophil count (∆N(T1-T5): Tangeretin −11.34% vs Placebo + 0.3%) and eosinophil count in blood (∆N(T1-T5): Tangeretin −38.5% vs Placebo + 4.35%). Compared with V1, VO2max (p = 0.042) and TLim (p = 0.05) of V2 were significantly increased in the TIG, and there was no significant change in the PCG. Meanwhile, six athletes in the TIG and 0 athletes in the PCG became EIB-negative at ECT2; the overall negative conversion rate of EIB was 40.00% in TCG. Additionally, the number of cough symptoms decreased from 9 to 3 and dyspnea from 4 to 2 in the TIG. Conclusion After high-intensity exercise, athletes with EIB achieved significant improvements in lung function and blood inflammatory factors by combining tangeretin and whey protein supplementation. EIB athletes also showed longer exercise endurance and VO2max at 4 weeks after TI. In addition, some patient symptoms disappeared after combination supplementation. The effect of this treatment on professional athletes with EIB was beneficial.

Background: Prolonged exercise usually leads to exercise fatigue, which has a negative short-term impact on exercise performance and metabolic rate; thus, fatigue needs to be resolved. Okara is a protein-rich residue of soy processing. Enzyme hydrolysis is known to increase the content of branched-chain amino acids (BCAAs), which have been reported to confer benefits for exercise. The purpose of this study was to investigate the antifatigue effect of okara protein hydrolysate (OPH) on cycling exercise. Methods: A total of 16 male participants who habitually exercised (2 times or more per week and without participation in athletic contests) were instructed to receive 11.74 g of OPH once a day. They then completed two intense cycling exercise challenges before and after four weeks of supplementation. Exercise time and blood markers related to fatigue and energy metabolism were measured. Results: The results showed that the time to exhaustion significantly increased after the treatment. The levels of lactate during exercise and at the end of exercise were significantly lower after treatment than before. Additionally, postexercise insulin sensitivity was increased after treatment. Conclusions: This study showed that OPH supplementation can promote endurance in exercise by decreasing the accumulation of fatigue-related metabolites during exercise and can promote energy recovery by increasing insulin function. These findings suggest that OPH has an antifatigue property.

Background: There is growing interest in the use of nutrition and dietary supplements to optimize training and time-trial (TT) performance in cyclists. Separately, quercetin (QCT) and citrulline (CIT) have been used as ergogenic aids to improve oxygen (VO2) kinetics, perceived effort, and cycling TT performance. However, whether the combination of QCT and CIT can provide additive benefits and further enhance cycling performance production is currently unknown. Methods: We examined 28-days of QCT + CIT supplementation on TT performance and several performance measures (i.e. mean power, VO2, respiratory exchange ratio (RER), and rate of perceived exertion (RPE)). Forty-eight highly trained cyclists were assigned to one of four supplementation groups: (1) QCT + CIT (QCT: 500 mg, CIT: 3000 g), (2) QCT (500 mg), (3) CIT (3000 mg), or (4) placebo (3500 mg of a zero-calorie flavored crystal light package). Supplements were consumed two times per day for 28 consecutive days. Participants performed a 20-km cycling time-trial race, pre- and post-supplementation to determine the impact of the combined effects of QCT + CIT. Results: There were no potential benefits of QCT +CIT supplementation on TT performance and several performance measures. However, there was an improvement in VO2 from pre-to-post-supplementation in QCT (p = 0.05) and CIT (p = 0.04) groups, but not in the QCT+CIT and PL groups. Conclusions: QCT + CIT does not seem beneficial for 20-km TT performance; further exploration with a focus on an increase in cycling duration or QCT+CIT combined with additional polyphenols may amplify any perceived bioactive or metabolic effects on cycling performance. The efficacy of QCT + CIT supplementation to improve cycling performance remains ambiguous.

Background: This study investigated the effects of caffeinated chewing gum on fatigue index and 400-meter performance in trained sprinters. Methods: Nineteen participants (age: 20.9 ± 1.0 years; height: 175.6 ± 4.9 cm; mass: 66.5 ± 5.6 kg; training age: 7.9 ± 1.0 years) were randomly assigned to either a caffeine trial (CAF) or a placebo trial (PL) using a double-blind, randomized crossover design. The participants in the CAF trial chewed a gum containing 3 mg/kg of caffeine for a period of 10 minutes, while those in the PL trial chewed a gum containing a placebo with no caffeine. Following a 15-minute period of rest, the fatigue index was tested by six maximal 35-meter sprints with a 10-second rest between efforts. After this, at least 30 minutes of rest was permitted, during which time the participants engaged in brief warm-up activities prior to the commencement of the 400-meter sprint test. Saliva samples were collected before chewing gum, before the fatigue test and before 400-meters sprinting. Results: The fatigue index was significantly lower in the CAF trial compared to the PL trial (CAF: 8.1 ± 2.5%; PL: 9.6 ± 4.8%; p = 0.046, Cohen's d = 039). The CAF trial demonstrated significantly lower sprint time for the 300-400 meter segment (CAF: 14.73 ± 1.35 seconds; PL: 15.23 ± 1.30 seconds; p = 0.019, Cohen's d = 0.37) and total sprint time compared to the PL trial (CAF: 53.87 ± 2.88 seconds; PL: 54.68 ± 3.37 seconds; p = 0.003, Cohen's d = 0.27). Saliva caffeine and α-amylase concentration were significantly higher in the CAF trial compared to the PL trial (p < 0.05). Conclusion: The present study demonstrated that caffeine gum supplementation prior to exercise significantly reduced the fatigue index and increased the capacity to maintain speed, particularly in the final 300 to 400 meters, as well as enhancing 400-meter sprint performance.

An increasing number of people, including recreational trained individuals, choose not to consume animal products and follow a vegan diet. Young women in particular are switching to a vegan diet. Studies have shown no difference in performance and muscle adaptations between a balanced vegan and an omnivorous diet. However, there are hardly any studies on the transition phase from an omnivorous to a vegan diet and the potential difficulties. Therefore, this study aimed to investigate the influence of a vegan dietary transition and its effects on body composition, physical performance, and menstrual cycle in young, recreationally trained women. Methods Ten young healthy women (23.8 ± 2.0 years, 173.0 ± 5.8 cm) were recruited to participate in this 12-week controlled study (4-week omnivorous phase, 8-week vegan intervention). At the beginning and before the vegan phase, all participants were informed about a balanced diet for fitness-oriented individuals and a vegan lifestyle. They were supervised by a sports dietitian for the entire 12 weeks. Explicit instructions and regular checks on macronutrient distribution were not carried out but had to be implemented independently. The diet was documented using FDDB Extender. The training habits were not explicitly specified, but should not be changed over the entire period. At baseline (T0) and 4-week intervals (T1, T2, T3), body composition (body weight, skeletal muscle mass, fat mass) and performance (squat, countermovement jump) were tested. In addition, the menstrual cycle was examined every two days using saliva samples and a cycle diary. Results Between treatments, there was a significant decrease in absolute (T0: 94.44 ± 20.37 kcal; T3: 71.67 ± 27.64 kcal; p < 0.001) and in relative protein intake (T0: 1.39 ± 0.28 g/kg BW; T3: 1.06 ± 0.37 g/kg BW; p < 0.05). In carbohydrate consumption, a significant increase was observed (T0: 240.11 ± 53.15 kcal; T3: 266.89 ± 49.01 kcal; p < 0.001). During the vegan phase, a significant decrease in body weight (T0: 68.19 ± 6.47 kg, T3: 67.73 ± 6.07 kg; p < 0.001) and skeletal muscle mass (T0: 29.40 ± 2.23 kg; T3: 28.74 ± 2.55 kg; p < 0.001) was observed. No changes were noted in squat performance. The countermovement jump showed a significant decrease in the vegan phase (T0: 26.08 ± 3.44 cm; T3: 23,62 ± 1,00 p < 0.05), but also a significant time effect starting in the omnivorous phase (p < 0.001). No effects were found on hormone concentrations of individual menstrual cycles. Conclusion The dietary change resulted in a shift in overall macronutrient distribution. Relative protein intake was significantly lower during the vegan phase than during the omnivore phase. This was also observed in a slight decrease in skeletal muscle mass. No clear effects on performance and menstrual cycle were observed during the first eight weeks. The results suggest that despite the knowledge of a balanced diet and in particular the recommendations for a vegan diet, the implementation of a vegan diet in everyday life could be associated with a number of difficulties for recreationally trained women. However, it should be noted that the vegan phase was only conducted for eight weeks and no statement can be made about the long-term effects or on well-trained female athletes.

Introduction Rugby league is a physically demanding sport that necessitates considerable nutritional intake, focusing on quality and type, in order to optimize training and competition demands. However, rugby league athletes are reported to have inadequate nutrition intake to match these demands. Some factors that may determine an athlete’s nutrition intake have been reported in other sports, including (but not limited to, knowledge, time, cooking skills, food costs, income, belief in the importance of nutrition, body composition goals, and family/cultural support). However, these potential factors are relatively unexplored in rugby league, where a range of personal (age, body composition) or social (ancestry) influences could affect nutritional intake. Further exploration of these factors is warranted to understand the knowledge, attitudes and behavior underlying rugby league athletes’ nutritional intake that can provide practitioners with a more detailed understanding of how to approach nutrition behaviors and attitudes in rugby league athletes. Objectives The primary aim was to describe the nutrition behaviors and knowledge of rugby league athletes. A secondary aim was to compare nutrition knowledge and behavior based on age, body composition and self-identified ancestry. Methods Fifty professional rugby league athletes anonymously completed a seventy-six-question online survey. The survey consisted of three sections : 1) sports nutrition knowledge, 2) attitudes toward nutrition on performance , and 3) nutrition behaviors. All participants completed the online survey without assistance using their own personal device, with data entered via REDCap during pre-season. Nutrition knowledge was compared based on age (years), body composition (body fat percentage (%)) and ancestral groups (Pasifika, Aboriginal and/or Torres Strait Islander (ATSI) and Anglo- European). Pearson correlation was used for the relationship between nutrition knowledge, age and body composition. An Analysis of Covariance (ANCOVA) was used to determine nutrition knowledge differences between ancestral groups with age and body composition as covariates. Attitudes and behaviors were compared based on age groups (<20, 20–24 and >25 y), ancestry and body composition. Attitudes and behaviors were analyzed by Pearson correlation for body composition, one-way ANOVA for age groups and ANCOVA for ancestry with covariates age and body composition. Results Overall athletes’ nutrition knowledge score was reported as 40 ± 12% (overall rating “poor”). Nutritional behaviors were significant for body composition, as those with lower body fat percentage had higher intakes of vegetables and dairy products (p = 0.046, p = 0.009), and ate more in the afternoon (lunch p = 0.048, afternoon snack p = 0.036). For ancestry, after adjustment for both age and body composition, Pasifika athletes were more inclined to miss breakfast and lunch compared to their Anglo-European (p = 0.037, p = 0.012) and ATSI (p = 0.022, p = 0.006) counterparts and ate more fruit than Anglo-Europeans (p = 0.006, p = 0.016). After adjustment for body composition, ATSI athletes also viewed the impact of nutrition on mental health and well-being significantly lower than Pasifika (p = 0.044). Conclusion These findings suggest differences exist within rugby league athletes based on ancestral backgrounds and body composition for nutrition attitudes, behaviors and knowledge. Such outcomes could be used when designing nutrition education interventions, with consideration given to these factors to optimize long-term positive behavior change.

Purpose: The effects of coffee ingestion on skeletal muscle microvascular function are not well understood. This study aimed to investigate the acute effects of coffee intake with varying levels of caffeine on skeletal muscle microvascular reactivity at rest and oxygen extraction during maximal incremental exercise in physically active individuals. Methods: Twenty healthy young male participants were administered coffee with low caffeine (3 mg/kg body weight; LC), high caffeine (6 mg/kg body weight; HC), and placebo (decaf) in different sessions. Skeletal muscle reactivity indexes, including tissue saturation index 10s slope (TSI10) and TSI half time recovery (TSI ½) following 5-minute ischemia were measured at rest and were measured at baseline and post-coffee consumption using near-infrared spectroscopy (NIRS). Post-coffee intake, NIRS was also used to measure microvascular oxygen extraction during exercise via maximal incremental exercise. Peak oxygen consumption and peak power output (Wpeak) were simultaneously evaluated. Results: Post-coffee consumption, TSI10 was significantly higher in the LC condition compared to placebo (p = 0.001) and significantly higher in the HC condition compared to placebo (p < 0.001). However, no difference was detected between LC and HC conditions (p = 0.527). HC condition also showed significant less TSI ½ compared to placebo (p = 0.005). However, no difference was detected for microvascular oxygen extraction during exercise, despite the greater Wpeak found for HC condition (p < 0.001) compared to placebo. Conclusion: Coffee ingestion with high caffeine level (6 mg/kg body weight) significantly enhanced skeletal muscle reactivity at rest. However, the improvement of exercise performance with coffee intake is not accompanied by alterations in muscle oxygen extraction.

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: Green tea (GT) is a common component of supplements known as fat burners. It has gained popularity as an ergogenic aid for weight reduction to assist with obesity management. This systematic review and meta-analysis aim to explore the effect of green tea ingestion coupled with exercise training (EX) on body composition and lipid profile in overweight and obese individuals. Methods: Two independent researchers systematically searched the electronic databases of PubMed, Web of Science, and Scopus. Studies with a randomized-controlled design to compare the effect of green tea in conjunction with exercise training (EX+GT) versus exercise training alone (EX+P) in overweight or obese participants were included. Results: Of the 1,015 retrieved studies, 24 were identified to undergo full-text review, out of which 10 randomized trials met the inclusion criteria. EX+GT versus EX+P had a small and consistent effect on weight [Standardized mean difference (SMD) = -0.30, CI: -0.53 to -0.07], BMI [SMD = -0.33 CI: -0.64 to -0.02] and fat reduction [SMD = -0.29, CI: -0.57 to -0.01] and there was no evidence of heterogeneity across the trials. When compared to EX+P, EX+GT had no greater effect on lipid profile improvement [triglyceride: SMD = -0.92, CI: -1.30 to 0.49; LDL: SMD = -1.44, CI: -0.73 to 0.82; HDL: SMD = 0.56, CI -0.71 to 0.46; and total cholesterol SMD = -0.54, CI -0.85 to 0.13]. Conclusions: Current evidence suggests that green tea could have quite minimal additive benefit over exercise-induced weight loss. However, incorporation of green tea into exercise training does not seem to exert additional benefits on lipid profile and it warrants further investigations in the future.

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 (V.O2max) was performed on the graded cycling. The prolonged exercise was set at 60% V.O2max 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 V.O2max, 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.

Background: Scuba diving is an increasingly popular activity that involves the use of specialized equipment and compressed air to breathe underwater. Scuba divers are subject to the physiological consequences of being immersed in a high-pressure environment, including, but not limited to, increased work of breathing and kinetic energy expenditure, decreased fluid absorption, and alteration of metabolism. Individual response to these environmental stressors may result in a differential risk of decompression sickness, a condition thought to result from excess nitrogen bubbles forming in a diver’s tissues. While the mechanisms of decompression sickness are still largely unknown, it has been postulated that this response may further be influenced by the diver’s health status. Nutritional intake has direct relevancy to inflammation status and oxidative stress resistance, both of which have been associated with increased decompression stress. While nutritional recommendations have been determined for saturation divers, these recommendations are likely overly robust for recreational divers, considering that the differences in time spent under pressure and the maximum depth could result nonequivalent energetic demands. Specific recommendations for recreational divers remain largely undefined. Methods: This narrative review will summarize existing nutritional recommendations and their justification for recreational divers, as well as identify gaps in research regarding connections between nutritional intake and the health and safety of divers. Results: Following recommendations made by the Institute of Medicine and the Naval Medical Research Institute of Bethesda, recreational divers are advised to consume ~170– 210 kJ/kg (40–50 kcal/kg) body mass, depending on their workload underwater, in a day consisting of 3hours’ worth of diving above 46 msw. Recommendations for macronutrient distribution for divers are to derive 50% of joules from carbohydrates and less than 30% of joules from fat. Protein consumption is recommended to reach a minimum of 1 g of protein/kg of body mass a day to mitigate loss of appetite while meeting energetic requirements. All divers should take special care to hydrate themselves with an absolute minimum of 500ml of fluid per hour for any dive longer than 3hours, with more recent studies finding 0.69 liters of water two hours prior to diving is most effective to minimize bubble loads. While there is evidence that specialized diets may have specific applications in commercial or military diving, they are not advisable for the general recreational diving population considering the often extreme nature of these diets, and the lack of research on their effectiveness on a recreational diving population. Conclusions: Established recommendations do not account for changes in temperature, scuba equipment, depth, dive time, work of breathing, breathing gas mix, or individual variation in metabolism. Individual recommendations may be more accurate when accounting for basal metabolic rate and physical activity outside of diving. However, more research is needed to validate these estimates against variation in dive profile and diver demographics.

Background: This study was conducted to investigate the nutritional knowledge of elite athletes undergoing weight loss and to identify differences in weight-loss strategies according to nutritional knowledge. Methods: The participants included 22 coaches and 88 elite athletes registered under the same affiliation. The survey involved translating the General Nutrition Knowledge Questionnaire (GNKQ), and interviews were used to confirm the diet and weight loss patterns of the athletes. The coaches and athletes were divided into high-rank (12 coaches and 57 athletes) and low-rank (10 coaches and 31 athletes) groups based on GNKQ scores. Paired t-tests, correlation analysis, and logistic regression analysis were performed. Results: GNKQ results showed significant differences between high-ranking and low-ranking coaches (p < 0.001). Furthermore, a significant difference in nutrition knowledge scores was also noticed between athletes with high-ranking and low-ranking coaches (p < 0.001). A strong correlation was observed between the GNKQ scores of coaches and athletes (r = 0.369; p < 0.001). The nutritional knowledge of coaches was also correlated with weight-loss strategies (weight loss attempt frequency; r = -0.235; p = 0.027; weight loss duration; r = -0.268; p = 0.012). Additionally, differences were observed in the intake of all nutrients (carbohydrates, proteins, and fat) in the diets of athletes (p < 0.001). Conclusion: Our study suggests that the nutritional knowledge of coaches indirectly affects athletes. Coaches have significant influence over athletes and possess experience with diet and weight-loss patterns. This insight should be effectively utilized to enhance the training and performance of athletes and coaches.

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.