Many studies have tested intermittent fasting (IF) in athletes, but its effects on female CrossFit athletes remain relatively unexplored in the existing literature. The aim of this study was to evaluate and compare the effects of 24-h IF on the physical performance of female CrossFit practitioners. Eleven female CrossFit athletes (age: 30.91 ± 3.42, weight: 65.26 ± 7.55 kg, height: 1.66 ± 0.05 m) participated in the study. The study used a crossover design with fasting and eating conditions. Participants completed an exercise test, standing long jump, and handgrip strength assessment. Hydration status, heart rate, blood lactate, blood glucose, rates of perceived exertion, and hunger were measured. Results showed significant differences in blood lactate concentration (F = 5.435, p = 0.042, η2p = 0.352). Resting blood lactate concentration was significantly lower in the fasting trial than in the eating trial (p < 0.001), but post-exercise blood lactate concentrations were higher in the fasting trial than in the eating trial (p < 0.001). No differences were found in performance times (p > 0.05). In conclusion, this pilot study of females suggests that 24-h fasting does not impair exercise performance or negatively affect physiological parameters in CrossFit athletes.

Beetroot juice (BJ), a nitrate-rich supplement, may enhance exercise performance, but its acute effects on anaerobic power and muscle oxygenation in football players are unclear. This study investigated these effects during a Wingate test in trained male footballers. In a randomized, crossover, double-blind, placebo-controlled design, 16 male football players (age: 18.2 ± 0.4 years, weight: 69.6 ± 6.5 kg, height: 177.5 ± 5.5 cm) consumed 140 mL of BJ (12.8 mmol nitrate) or a placebo (blackcurrant juice (< 0.1 mmol nitrate)). After 2.5 h, a 30-s Wingate test was performed. Muscle oxygenation, heart rate, blood pressure, and blood lactate were assessed. BJ supplementation increased peak power (placebo: 720.33 ± 107.78 W; BJ: 803.50 ± 127.23 W, p = 0.002) and mean power (placebo: 541.23 ± 62.05 W; BJ: 581.42 ± 80.09 W, p = 0.001), and reduced the time to peak power (placebo: 7.32 ± 0.84 s; BJ: 8.10 ± 0.94 s, p = 0.032) compared to placebo. Muscle oxygenation did not differ during exercise ( p > 0.05); however, post-exercise muscle oxygen saturation was higher (∼10%, p = 0.017) and deoxygenated haemoglobin was lower (∼13%, p = 0.019) with BJ. Post-exercise blood lactate levels were higher in BJ compared to placebo ( p < 0.05). Blood pressure at all time points and heart rate during exercise did not differ between conditions ( p > 0.05). Acute BJ supplementation increases anaerobic power output and post-exercise muscle oxygenation in football players, without affecting heart rate or blood pressure. Trial registration The randomized controlled trial was registered on 03/07/2025 at ClinicalTrials.gov, under the registration number NCT07048912.

Sleep is essential for physical recovery and performance in athletes, and diet is one of the major factors influencing sleep. However, the relationship between dietary nutrients and sleep in elite athletes is not well understood. This study aims to examine the association between nutrient intake and sleep quality in elite athletes. A total of 115 elite athletes (75.3% (n=78) males; mean age: 68.70±10.91 years) from five sports (swimming, canoeing, archery, volleyball and taekwondo) were included in the study. All athletes were at national/professional competitive level. Sleep quality was measured using the Richard-Campbell Sleep Scale (RCSQ). Food consumption was recorded over 24 hours and the data were analysed using nutritional software (Nutrition Information Systems (BeBiS version 8.1)). The daily sleep duration of the participants was 7.50 ± 0.92 hours. The RCSQ score was 62.54 ± 22.49 and 28.6% of the participants had poor sleep quality. The good sleeper group had higher intakes of energy (kcal), protein (g/kg and g) and tryptophan (g/kg and g) (p < 0.05). Nutrient intakes in elite athletes are associated with sleep and may play a role in sleep disorders. Research should investigate causal relationships between nutrient intake and sleep, and the efficacy of dietary interventions to improve sleep in elite athletes with nutrient deficiencies.

Background/Objectives: Beetroot juice (BRJ), a dietary nitrate source, may enhance high-intensity intermittent exercise, but its effects on single- and repeated-sprint performance remain unclear. This systematic review and meta-analysis aimed to evaluate the effects of BRJ supplementation on sprint-related performance and neuromuscular, perceptual, and physiological outcomes. Methods: PubMed, Scopus, and Web of Science were searched for trials published from 2014 to June 2026. Eligible studies compared BRJ with placebo or control in healthy adults aged 18–40 years. The review followed PRISMA guidelines. Methodological quality and risk of bias were assessed using the PEDro scale and Cochrane RoB 2 tool. Evidence certainty was assessed using GRADE. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. Results: Twenty-three randomized trials involving 401 participants were included, and 21 contributed to the meta-analysis. BRJ improved time to peak power in four Wingate-based studies (SMD = −0.92, 95% CI: −1.29 to −0.54, p < 0.001) and handgrip strength (SMD = 0.40, 95% CI: 0.05 to 0.74, p = 0.027). No significant effects were observed for countermovement jump, peak or mean power, 10 m or 20 m sprint performance, perceived exertion, heart rate, or blood lactate. Sex did not significantly moderate the effects, although female data were limited. Certainty was low for most outcomes and very low for 20 m sprint performance and blood lactate. Conclusions: BRJ may improve time to peak power and handgrip strength; however, low- to very-low-certainty evidence does not support its routine use to enhance short-distance or repeated-sprint performance.

Despite well‐established guidelines for carbohydrate (CHO) intake to support endurance performance, many athletes fail to meet these targets, and in‐race intake is often estimated based on planned consumption rather than measured intake. We aimed to quantify actual CHO intake during endurance races and explore behavioral and psychological predictors. Sixty Tier 2 endurance athletes (38 marathoners and 22 cyclists) participated in two official races. Athletes' planned, perceived, and actual CHO intake 24 h before and during the race were assessed using food diary analysis, and pre‐ and post‐race weighing of sports products containing CHO. Sleep behavior (ASBQ), pre‐race anxiety (CSAI‐2R), and gastrointestinal symptoms were also evaluated using validated questionnaires. Across the cohort, actual CHO intake (31.7 ± 23.5 g/hr) was lower than planned (38.0 ± 27.3 g/hr; p < 0.001). The absolute planned‐actual gap was larger in cyclists (58.9 → 49.1 g/hr; Δ = 10.3 g/hr) than in marathoners (25.9 → 21.7 g/hr; Δ = 4.2 g/hr); proportionally, the shortfall was similar (∼16%–17%) in both groups. Cyclists planned substantially higher CHO intakes and achieved higher actual intakes than marathoners. Regression analysis showed that race type, better sleep behavior, and lower cognitive anxiety predicted higher actual intake ( R ² = 0.41, p < 0.05). Despite similar intentions, marathoners consumed less CHO than cyclists and overestimated their CHO intake, highlighting behavioral gaps. Sleep and psychological readiness played key roles in fueling success. Findings support the importance of measuring actual intake and considering individual behavioral factors to optimize endurance nutrition strategies.