Purpose: the aim of the present study was to analyse the pattern of dietary supplements (DS) consumption on federated rugby players, including the analysis of differences based on the sex and competitive level (professional vs. amateurs). Material and methods: 144 rugby players (83 male and 61 female), of whom 69 were professionals and 75 amateurs, were recruited for the study. All the participants filled out a specific questionnaire about DS consumption including questions related to the consumption of DS and their effects on sport performance and health status. Results: 65.3% of participants declared consuming at least one DS, with a higher prevalence in males than females (77.1% vs. 49.2%) and in professionals thanin amateur players (79.7% vs. 52.0%). The main reason for consumption was to enhance sport performance (62.3%) with differences only based on sex (74.3% males vs. 43.2% females). The most common purchase sites were the Internet (45.6%) and specialised stores (39.8%). As to the moment of ingestion, professionals did this most frequently during competition and training (56.4% vs. 28.2%), whereas amateur players did so only during competition (20.5% vs. 3.6%). Moreover, professional player intake most frequently in post-exercise (65.5% vs. 35.9%), whereas amateur during pre-exercise (30.8% vs. 5.5%). The DS most consumed included whey protein (44%), caffeine (42%), sports drinks (38%), energy bars (34%) and creatine monohydrate (31%), with a higher prevalence in male and professional players of whey protein and creatine monohydrate. Conclusions: The main reason for DS consumption is for enhancing sports performance). Professional players more frequently purchase them on the Internet and consume DS during training and competition period and in the post-exercise, whereas amateur players consume during competition and pre-exercise. Related to the main form of DS consumption, it is observed that a moderate consumption of DS could be considered ergogenic, such as whey protein, sport bar and creatine, while an absence of other DS could be considered ergogenic.

Objective: The aim of this study was to investigate the effects of caffeine supplementation on: (i) psychological responses of subjective vitality and mood; (ii) performance through a Wingate test; and (iii) rate of perceived exertion (RPE) reported after a Wingate test. Methods: Fifteen male participants (22.60 ± 2.16 years) ingested 6 mg·kg-1 of caffeine or placebo (sucrose) supplementation in two experimental sessions. After 60 min from supplement intake, participants fulfilled two questionnaires, which measured subjective vitality and mood state, respectively. Subsequently, participants’ performance was assessed through a Wingate test, which was followed by measurements of RPE at general, muscular, or cardiovascular level. Results: Caffeine supplementation increased some components of mood, as assessed by profile of mood states (POMS) (tension and vigor dimensions) and subjective vitality profiles, which were followed by a greater maximum power, average power, and lower time needed to reach maximum power during the Wingate test. Moreover, lower RPE, both at muscular and general levels were reported by participants after the Wingate test. Conclusions: These results suggest that caffeine supplementation exerts positive effects both in psychological and physical domains in trained subjects.

Purpose: Beetroot juice (BRJ) is considered an ergogenic aid with good to strong evidence for improving human performance in sport modalities with similar demands to rugby. However, most of the studies were realized in male athletes with limited evidence in female athletes. Thus, the aim of this study was to explore the acute ingestion of BRJ in female rugby players. Methods: Fourteen semi-professional female rugby players (25.0 ± 3.7 years) belonging to a team from the First Spanish Female Rugby Division participated in this study. Participants were randomly divided into two groups that realized a neuromuscular battery after BRJ (140mL, 12.8 mmol NO₃⁻) or placebo (PLAC, 140 mL, 0.08 mmol NO₃⁻) ingestion on two different days separated by one week between protocols. The neuromuscular test battery consisted of a countermovement jump (CMJ), isometric handgrip strength (i.e., dominant), 10-m and 30-m sprint, agility t-test and Bronco test. Afterwards, participants reported a rate of perception scale (6–20 points) and side effects questionnaire associated with BRJ or PLAC ingestion. Results: Statistically significant improvements were observed in CMJ (7.7%; p = 0.029; ES = 0.62), while no differences were reported in dominant isometric handgrip strength (−1.7%; p = 0.274; ES = −0.20); 10-m and 30-m sprint (0.5–0.8%; p = 0.441–0.588; ES = 0.03–0.18); modified agility t-test (−0.6%; p = 0.503; ES = −0.12) and Bronco test (1.94%; p = 0.459; ES = 0.16). Conclusions: BRJ ingestion could improve neuromuscular performance in the CMJ test, while no differences in sprint (10-m and 30-m sprint test), agility, isometric handgrip strength and endurance performance (i.e., Bronco test) were reported

Dietary nitrate (NO₃⁻) supplementation, which can enhance performance in exercise settings involving repeated high-intensity efforts, has been linked to improved skeletal muscle contractile function. Although muscular strength is an important component of explosive movements and sport-specific skills, few studies have quantified indices of muscular strength following NO₃⁻ supplementation, particularly isokinetic assessments at different angular velocities. We performed a systematic review and meta-analysis to determine whether dietary NO₃⁻ supplementation improves peak torque, as assessed by the gold standard method of isokinetic dynamometry, and if this effect was linked to the angular velocity imposed during the assessment. Dialnet, Directory of Open Access Journals, MEDLINE, PubMed, SciELO, Scopus, and SPORTDiscus were searched for articles using the following search strategy: (nitrate OR beet*) AND (supplement* OR nutr* OR diet*) AND (isokinetic OR strength OR “resistance exercise” OR “resistance training” OR “muscular power”). The meta-analysis of data from 5 studies with 60 participants revealed an overall effect size of −0.01 for the effect of nitrate supplementation on isokinetic peak torque, whereas trivial effect sizes ranging from −0.11 to 0.16 were observed for independent velocity-specific (90°/s, 180°/s, 270°/s, and 360°/s) isokinetic peak torque. Four of the five studies indicated that dietary NO₃⁻ supplementation is not likely to influence voluntary knee extensor isokinetic torque across a variety of angular velocities. These results suggest that NO₃⁻ supplementation does not influence isokinetic peak torque, but further work is required to elucidate the potential of NO₃⁻ supplementation to influence other indices of muscular strength, given the dearth of experimental evidence on this topic.

Different rugby positions make different demands on players. It therefore follows that optimum body composition may vary according to the position played. Using anthropometry and bioimpedance analysis (BIA) to assess body composition, the present study aimed to compare the effect of sex and position on body composition variables using anthropometry and BIA methods. A total of 100 competitive rugby players (35 women and 65 men) competing in the First Spanish National League were recruited voluntarily and for convenience for this study. In the laboratory, body composition was assessed by anthropometry, following the recommendations established by the International Society for the Advancement of Kinanthropometry (ISAK), and by direct segmental multi-frequency BIA, following the guidelines established by the Spanish Group of Kinanthropometry (GREC) of the Spanish Federation of Sports Medicine (FEMEDE). We found sex-related differences in height, weight, body mass index and body fat (%) by anthropometry and in body lean mass (%) by DSM-BIA, in 4 of the 6 skinfolds assessed (p < 0.05). We also observed position-related differences in all the variables assessed (p < 0.05) except for lean body mass, as measured by both methods of determining body composition, and front thigh skinfold. Body composition and ∑6skinfolds differs according to sex and playing position, backs (16.6 ± 3.8% and 92.3 ± 33.9 mm,) vs. forwards (20.0 ± 6.7 and 115.3 ± 37.6 mm), and the muscle-adipose (meso-endomorphic somatotype) development predominated in both sexes. Thus, forwards of both sexes are taller, heavier and fatter, possibly due to the specific demands of this position. In addition, body composition measurements vary according to the method used (DSM-BIA vs. anthropometry), indicating that anthropometry is probably the best body composition assessment method.

Background: Nutritional biomarkers are essential for assessing the impact of dietary interventions on health. Amino Acids (AA) serve as potential biomarkers due to their role in metabolic pathways, although the influence of combining macronutrients on AA metabolism remains unclear. Objective: This study aims to evaluate the effects of combining macronutrients (fat, protein, and fiber) on AA metabolism. Methods: A dietary intervention was conducted with 41 participants who were assigned to two groups: the Protein Fat (PF) group and the Protein Fat and Fiber (PFF) group. AA concentration was measured using LC-MS/MS. Results: Our findings indicated that combining macronutrients reduced plasma levels of AA with statistically significant differences between the two diets (p < 0.05 for EAA and BCAA; p < 0,01 for NEAA and AAA). Metabolic profile analysis showed differences between the groups, especially at 55 days (55 D) (R2X: 0.749; R2Y: 0.589; Q2: 0.582, p < 0.001) and 98 days (98 D) (R2X: 0.886; R2Y: 0.7; Q2: 0.605, p < 0.001). Five metabolites (leucine, asparagine, alanine, cysteine, and creatine) were the most influential factors in group differentiation (VIP score), with values ranging between 1.04 and 1.75. Conclusions: The combination of macronutrients led to a significant reduction in plasma amino acids and amines in the PFF group, with recovery post-intervention. These findings highlight the possibility that these metabolites are related to different health statuses.