Ergonutrition Supplementation and Recovery in Water Polo: A Systematic Review

BACKGROUND

Water polo (WP) is a high-intensity team sport that requires a combination of physical endurance, muscular strength, speed, and specific technical skills. Due to the demanding and prolonged nature of this sport, adequate and balanced nutrition plays a fundamental role in athletes' performance, recovery, and overall health maintenance.

OBJECTIVES

We aimed to compile all available information on the importance of ergonutrition and supplementation in the recovery of WP players. This will help in understanding this sport's specific challenges and requirements, enabling players and coaches to design more effective recovery plans to optimize performance, achieve goals, and successfully cope with intense training and competition.

METHOD

English-language publications were searched in databases such as Web of Science, Scopus, SciELO Citation Index, Medline (PubMed), KCI Korean Journal Database, and Current Contents Connect using a series of keywords such as WP, nutrition, recovery, and ergogenic aids individually or in combination.

RESULTS

In the field of ergonutritional recovery in WP, certain supplements such as whey protein, beta-alanine, L-arginine, spirulina, and copper can be beneficial for improving performance and recovery. In some cases, WP athletes may consider using ergogenic supplements to further improve their performance and recovery process. However, it is important to bear in mind that any supplement should be carefully evaluated under the supervision of a health professional or a sports nutritionist, as some supplements may present side effects or unwanted interactions.

CONCLUSIONS

Adequate ergogenic nutrition adapted to the needs of WP players is essential not only to optimize their athletic performance but also to ensure effective recovery and maintain their long-term health and general well-being. The application of these strategies should be evidence-based and tailored to the individual needs of the players and the specific demands of the sport. Future experimental research that can confirm our results is essential.

The effect of eight weeks beetroot juice supplement on aerobic, anaerobic power, and field performance of soccer players

The purpose of the study investigated the effect of eight weeks of soccer training with beetroot juice supplement on aerobic power, anaerobic power, and field performance of soccer players. This is experimental research, by the control group in pre and post-test. The statistical population was male soccer players. Forty subjects were randomly divided into four groups including the exercise group (EX) the exercise group with beetroot juice supplement (EX&BRJS) the beetroot juice supplement group (BRJS), and the control group (C). Aerobic power, anaerobic threshold, and respiratory exchange ratio, measured by the gas analyser (Cosmed), anaerobic power (peak, mean power), and fatigue index, by Wingate cycle test (Monark, 839), and field performance by (Bangsbo, field test performance). The statistical methods include the Kolmogorov-Smirnov, Levin, covariance (ANCOVA), and pair comparison with Bonferroni test. The results showed eight weeks' of soccer training with beetroot juice supplement, significantly changed aerobic power, respiratory exchange ratio, anaerobic threshold, anaerobic power, field performance, and fatigue index (P ≤ 0.05). Additionally, in all variables, the paired comparison showed that the EX&BRJS group progressed more than all other condition groups. The soccer athletes may use beetroot juice supplements along with soccer exercises to improve aerobic and anaerobic power and field performance.

Beetroot juice ingestion does not improve neuromuscular performance and match-play demands in elite female hockey players: a randomized, double-blind, placebo-controlled study

PURPOSE

Beetroot juice is a dietary supplement that contains high levels of inorganic nitrate (NO_3-) and that its intake has proven effective at increasing blood nitric oxide (NO) concentrations improving endurance performance. However, the effect of this supplement in team sport performance, especially in female athletes, has been barely studied. This study aimed to compare the acute effects of beetroot juice supplementation on neuromuscular performance and match-play demands in elite female field hockey players.

METHODS

Eleven elite female hockey players (22.8 ± 5.1 years) belonging to a bronze team medal in Eurohockey Club Champions Cup participated in this study. Participants were randomly divided into two groups undergoing a test battery with beetroot juice (70 mL, 6.4 mmol NO₃^-) or placebo (70 mL, 0.04 mmol NO₃^-) in two different days with one week between protocols. The neuromuscular test battery consisted of a countermovement jump, isometric handgrip strength (i.e., dominant hand), 20 m-sprint and repeated sprint ability test (RSA). Afterward, a simulated hockey match play (2 × 12.5 min) was performed and recorded by Global Positioning System (GPS).

RESULTS

No statistically significant improvements were observed in any physical parameters analysed comparing beetroot juice compared to placebo ingestion, countermovement jump (p = 0.776, ES = 0.16), isometric handgrip strength (p = 0.829; ES = - 0.08), 20 m sprint test (p = 0.227; ES = - 0.23), mean repeated sprint ability (p = 0.955, ES = 0.03) and in any physical match demands measured by GPS (p = 0.243-1.000; ES = 0.02-0.47).

CONCLUSION

Acute beetroot juice supplementation did not produce any statistically significant improvement in neuromuscular performance or match-play demands in elite female field hockey players.

TRIAL REGISTRATION

The study was registered in ClinicalTrials.gov with the following ID: NCT05209139. The study was retrospectively registered by 26 January 2022.

Ergogenic Aids to Improve Physical Performance in Female Athletes: A Systematic Review with Meta-Analysis

Most intervention studies investigating the effects of ergogenic aids (EAs) on sports performance have been carried out in the male population. Thus, the aim of this systematic review and meta-analysis was to summarize the effects in the existing literature of EAs used by female athletes on performance. A literature research was conducted, and a descriptive analysis of the articles included in the systematic review was carried out. Meta-analyses could be performed on 32 of the included articles, evaluating performance in strength, sprint, and cardiovascular capacity. A random-effects model and the standardized mean differences (SMD) ± 95% confidence intervals (CI) were reported. The results showed that caffeine helped to improve jumping performance, isometric strength values, and the number of repetitions until failure. Caffeine and sodium phosphate helped to improve sprint performance. Aerobic tests could be improved with the use of taurine, caffeine, and beta-alanine. No conclusive effects of beetroot juice, polyphenols, or creatine in improving aerobic performance were shown. In terms of anaerobic variables, both caffeine and sodium phosphate could help to improve repeated sprint ability. More studies are needed in female athletes that measure the effects of different EAs on sports performance, such as beetroot juice, beta-alanine or sodium phosphate, as the studies to date are scarce and there are many types of EA that need to be further considered in this population, such as creatine and taurine.

Influence of Beetroot Juice Ingestion on Neuromuscular Performance on Semi-Professional Female Rugby Players: A Randomized, Double-Blind, Placebo-Controlled Study

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.

Effectiveness of Nitrate Intake on Recovery from Exercise-Related Fatigue: A Systematic Review

BACKGROUND

Recovery between efforts is critical to achieving optimal physical and sports performance. In this sense, many nutritional supplements that have been proven to improve recovery and physical and physiological performance are widely used. Supplements such as nitrates (NO₃^-), including organic foods such as beets, promote muscle recovery and relieve fatigue. This study aimed to comprehensively summarise the available literature on the effect of NO₃^- consumption on exercise-related fatigue and muscle damage.

METHODS

A systematic search was carried out based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) using electronic databases (e.g., PubMed, Scopus, and Web of Science). From a total of 1634 studies identified, 15 studies were included in this review.

RESULTS

Based on the review, NO₃^- intake provokes physiological and metabolic responses that could potentially boost exercise-related recovery. NO₃^- could improve recovery indicators related to strength, pain, inflammation, and muscle damage.

CONCLUSIONS

Despite the relative proven effectiveness of NO₃^- on recovery after aerobic and anaerobic efforts, based on the heterogeneity of the procedures (e.g., dosage, chronic vs. acute intake, participants' characteristics, variables and outcomes), it could be premature to suggest its extended use in sports.

Recovery in water polo: how much do we have to know? A systematic review

Water polo (WP) is a high-intensity intermittent aquatic sport, with a predominance of swimming skills and nonswimming activities and incomplete recovery periods. Consequently, recovery after exercise is a fundamental part of sports performance. The main purpose of this systematic review was to evaluate the effects of different recovery strategies in WP performance. The studies were found by searching in the databases of PubMed, Web of Science, and Scopus. Methodological quality and risk of bias were assessed in accordance with the Cochrane Collaboration Guidelines samples. A summary of results including five studies was followed. The results show that supplementation with cherry juice before training does not imply improvements in recovery; the full-body photobiomodulation therapy reduces muscle damage; reducing training load during the season increased the natural logarithm of the root mean square of successive differences and perceived state of recovery, and the heart rate variability stabilizes and could progressively increase at the end of a tournament; and when an increase in internal training load is less than 60%–70% autonomic cardiac disturbances during preseason training do not occur. Recovery in WP is a very limited field of study that needs future research in active recovery, hydrotherapy, massage, rest and sleep to help coaches formulate recommendations.

Dietary Supplements for Athletic Performance in Women: Beta-Alanine, Caffeine, and Nitrate

Beta-alanine, caffeine, and nitrate are dietary supplements generally recognized by the sport and exercise science community as evidence-based ergogenic performance aids. Evidence supporting the efficacy of these supplements, however, is greatly skewed due to research being conducted primarily in men. The physiological differences between men and women, most notably in sex hormones and menstrual cycle fluctuations, make generalizing male data to the female athlete inappropriate, and potentially harmful to women. This narrative review outlines the studies conducted in women regarding the efficacy of beta-alanine, caffeine, and nitrate supplementation for performance enhancement. Only nine studies on beta-alanine, 15 on caffeine, and 10 on nitrate in healthy women under the age of 40 years conducted in normoxia conditions were identified as relevant to this research question. Evidence suggests that beta-alanine may lower the rate of perceived exertion and extend training bouts in women, leading to greater functional adaptations. Studies of caffeine in women suggest the physiological responder status and caffeine habituation may contribute to caffeine's efficacy, with a potential plateau in the dose-response relationship of performance enhancement. Nitrate appears to vary in influence based on activity type and primary muscle group examined. However, the results summarized in the limited literature for each of these three supplements provide no consensus on dosage, timing, or efficacy for women. Furthermore, the literature lacks considerations for hormonal status and its role in metabolism. This gap in sex-based knowledge necessitates further research on these ergogenic supplements in women with greater considerations for the effects of hormonal status.

Role of nitric oxide in convective and diffusive skeletal microvascular oxygen kinetics

Progress in understanding physiological mechanisms often consists of discrete discoveries made across different models and species. Accordingly, understanding the mechanistic bases for how altering nitric oxide (NO) bioavailability impacts exercise tolerance (or not) depends on integrating information from cellular energetics and contractile regulation through microvascular/vascular control of O₂ transport and pulmonary gas exchange. This review adopts state-of-the-art concepts including the intramyocyte power grid, the Wagner conflation of perfusive and diffusive O₂ conductances, and the Critical Power/Critical Speed model of exercise tolerance to address how altered NO bioavailability may, or may not, affect physical performance. This question is germane from the elite athlete to the recreational exerciser and particularly the burgeoning heart failure (and other clinical) populations for whom elevating O₂ transport and/or exercise capacity translates directly to improved life quality and reduced morbidity and mortality. The dearth of studies in females is also highlighted, and areas of uncertainty and questions for future research are identified.

Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Increasing nitric oxide bioavailability may induce physiological effects that enhance endurance exercise performance. This review sought to evaluate the performance effects of consuming foods containing compounds that may promote nitric oxide bioavailability.

METHODS

Scopus, Web of Science, Ovid Medline, EMBASE and SportDiscus were searched, with included studies assessing endurance performance following consumption of foods containing nitrate, L-arginine, L-citrulline or polyphenols. Random effects meta-analysis was conducted, with subgroup analyses performed based on food sources, sex, fitness, performance test type and supplementation protocol (e.g. duration).

RESULTS

One hundred and eighteen studies were included in the meta-analysis, which encompassed 59 polyphenol studies, 56 nitrate studies and three L-citrulline studies. No effect on exercise performance following consumption of foods rich in L-citrulline was identified (SMD=-0.03, p=0.24). Trivial but significant benefits were demonstrated for consumption of nitrate and polyphenol-rich foods (SMD=0.15 and 0.17, respectively, p<0.001), including performance in time-trial, time-to-exhaustion and intermittent-type tests, and following both acute and multiple-day supplementation, but no effect of nitrate or polyphenol consumption was found in females. Among nitrate-rich foods, beneficial effects were seen for beetroot, but not red spinach or Swiss chard and rhubarb. For polyphenol-rich foods, benefits were found for grape, (nitrate-depleted) beetroot, French maritime pine, Montmorency cherry and pomegranate, while no significant effects were evident for New Zealand blackcurrant, cocoa, ginseng, green tea or raisins. Considerable heterogeneity between polyphenol studies may reflect food-specific effects or differences in study designs and subject characteristics. Well-trained males (V̇O2max ≥65 ml.kg.min-1) exhibited small, significant benefits following polyphenol, but not nitrate consumption.

CONCLUSION

Foods rich in polyphenols and nitrate provide trivial benefits for endurance exercise performance, although these effects may be food dependent. Highly trained endurance athletes do not appear to benefit from consuming nitrate-rich foods but may benefit from polyphenol consumption. Further research into food sources, dosage and supplementation duration to optimise the ergogenic response to polyphenol consumption is warranted. Further studies should evaluate whether differential sex-based responses to nitrate and polyphenol consumption are attributable to physiological differences or sample size limitations.

OTHER

The review protocol was registered on the Open Science Framework ( https://osf.io/u7nsj ) and no funding was provided.

Beetroot as a functional food with huge health benefits: Antioxidant, antitumor, physical function, and chronic metabolomics activity

Previously, beetroot is mainly consumed as a food additive. In recent years, the beetroot, especially the betalains (betanin) and nitrates it contains, now has received increasing attention for their effective biological activity. Betalains have been proven to eliminate oxidative and nitrative stress by scavenging DPPH, preventing DNA damage, and reducing LDL. It also has been found to exert antitumor activity by inhibiting cell proliferation, angiogenesis, inducing cell apoptosis, and autophagy. In some chronic diseases, nitrate is the main component for lowing blood lipids, glucose, and pressure, while its role in treating hypertension and hyperglycemia has not been clearly stated. Moreover, the intake of nitrate-rich beetroot could enhance athletic performance and attenuate muscle soreness in certain types of exercise. The objective of this review is to provide sufficient evidence for the clarification of health benefits of beetroot, especially in the aspect of biooxidation, neoplastic diseases, some chronic diseases, and energy supplementation.

Acceptability and Feasibility of a 13-Week Pilot Randomised Controlled Trial Testing the Effects of Incremental Doses of Beetroot Juice in Overweight and Obese Older Adults

Nitrate-rich food can increase nitric oxide production and improve vascular and brain functions. This study examines the feasibility of a randomised controlled trial (RCT) testing the effects of prolonged consumption of different doses of dietary nitrate (NO3-) in the form of beetroot juice (BJ) in overweight and obese older participants. A single-blind, four-arm parallel pilot RCT was conducted in 62 overweight and obese (30.4 ± 4 kg/m2) older participants (mean ± standard deviation (SD), 66 ± 4 years). Participants were randomized to: (1) high-NO3- (HN: 2 × 70 mL BJ/day) (2) medium-NO3- (MN: 70 mL BJ/day), (3) low-NO3- (LN: 70 mL BJ on alternate days) or (4) Placebo (PL: 70 mL of NO3--depleted BJ on alternate days), for 13 weeks. Compliance was checked by a daily log of consumed BJ, NO3- intake, and by measuring NO3- and NO2- concentrations in plasma, saliva, and urine samples. Fifty participants completed the study. Self-reported compliance to the interventions was >90%. There were significant positive linear relationships between NO3- dose and the increase in plasma and urinary NO3- concentration (R2 = 0.71, P < 0.001 and R2 = 0.46 P < 0.001, respectively), but relationships between NO3- dose and changes in salivary NO3- and NO2- were non-linear (R2 = 0.35, P = 0.002 and R2 = 0.23, P = 0.007, respectively). The results confirm the feasibility of prolonged BJ supplementation in older overweight and obese adults.

Dietary Nitrate and Nitric Oxide Metabolism: Mouth, Circulation, Skeletal Muscle, and Exercise Performance

Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in myriad physiological processes, including the regulation of vascular tone, neurotransmission, mitochondrial respiration, and skeletal muscle contractile function. NO may be produced via the canonical NO synthase-catalyzed oxidation of l-arginine and also by the sequential reduction of nitrate to nitrite and then NO. The body's nitrate stores can be augmented by the ingestion of nitrate-rich foods (primarily green leafy vegetables). NO bioavailability is greatly enhanced by the activity of bacteria residing in the mouth, which reduce nitrate to nitrite, thereby increasing the concentration of circulating nitrite, which can be reduced further to NO in regions of low oxygen availability. Recent investigations have focused on promoting this nitrate-nitrite-NO pathway to positively affect indices of cardiovascular health and exercise tolerance. It has been reported that dietary nitrate supplementation with beetroot juice lowers blood pressure in hypertensive patients, and sodium nitrite supplementation improves vascular endothelial function and reduces the stiffening of large elastic arteries in older humans. Nitrate supplementation has also been shown to enhance skeletal muscle function and to improve exercise performance in some circumstances. Recently, it has been established that nitrate concentration in skeletal muscle is much higher than that in blood and that muscle nitrate stores are exquisitely sensitive to dietary nitrate supplementation and deprivation. In this review, we consider the possibility that nitrate represents an essential storage form of NO and discuss the integrated function of the oral microbiome, circulation, and skeletal muscle in nitrate-nitrite-NO metabolism, as well as the practical relevance for health and performance.

Dietary Nitrate Supplementation and Exercise-Related Performance

Over the last decade, there has been a growing interest in the utility of nitrate (NO3^-) supplementation to improve exercise-related performance. After consumption, dietary NO3^- can be reduced to nitric oxide, a free radical gas involved in numerous physiological actions including blood vessel vasodilation, mitochondrial respiration, and skeletal muscle contractile function. Emerging evidence indicates that dietary NO3^- supplementation has a small but nevertheless significant beneficial effect on endurance performance through the combined effects of enhanced tissue oxygenation and metabolic efficiency in active skeletal muscle. There is further evidence to suggest that dietary NO3^- exerts a direct influence on contractile mechanisms within the skeletal muscle through alterations in calcium availability and sensitivity. Response heterogeneity and sizeable variability in the nitrate content of beetroot juice products influence the effectiveness of dietary NO3^- for exercise performance, and so dosing and product quality, as well as training history, sex, and individual-specific characteristics, should be considered.

Oral nitrate reduction is not impaired after training in chlorinated swimming pool water in elite swimmers

This study tested the hypothesis that exposure to chlorine-sterilised pool water would impair oral nitrate reduction (ONR). ONR was assessed in elite swimmers before and after morning and afternoon pool-based training. Nonswimmers were only assessed in the morning. ONR was similar in swimmers and nonswimmers (P = 1.000) and unchanged before and after morning and afternoon training (P ≥ 0.341). Therefore, exposure to chlorinated pool water does not interfere with ONR. Novelty Exposure to chlorine-sterilised pool water does not impair oral nitrate reduction in elite swimmers.

Ingestion of Carbohydrate Prior to and during Maximal, Sprint Interval Cycling Has No Ergogenic Effect: A Randomized, Double-Blind, Placebo Controlled, Crossover Study

Carbohydrate (CHO) ingestion may improve intermittent sprint performance in repeated sprint efforts ≤15 s. Yet, evidence for its efficacy on sprint interval durations ~30 s is lacking. The purpose of this study was to investigate the effects of CHO ingestion on maximal sprint interval exercise. Fifteen (n = 15) recreational athletes (13/2 males/females, age 22 ± 2 years; height 176 ± 11 cm; mass 76.8 ± 11.3 kg) volunteered for this randomised, double-blind, placebo-controlled, crossover design. Participants completed two experimental trials (performed 10-days apart) involving the ingestion of an 8% CHO solution or a flavour and appearance-matched placebo (PLA) solution (5 mL/kg/bw), immediately before exercise, and preceding the second interval of four × 30 s bouts of repeated maximal sprint efforts (separated by 3.5 min of passive recovery). Peak and mean power (W) output progressively decreased during the repeated sprints (main effect of time, p < 0.0001), but there were no differences between CHO and PLA during any of the sprints (p > 0.05 for condition main effect and condition × time interaction). Physiological responses (blood lactate, heart rate, oxygen consumption, respiratory exchange ratio and RPE) were also unaltered by CHO ingestion. In conclusion, CHO ingestion does not enhance performance or modulate physiological responses during intermittent maximal, sprint cycling.

Effectiveness of beetroot juice derived nitrates supplementation on fatigue resistance during repeated-sprints: a systematic review

In recent decades, the search for non-doping substances that enhance sports performance has increased. Ergogenic aids such as beetroot juice (BRJ) and BRJ rich in nitrates (NO₃^-) are widely used to cause physiological benefits that may lead to physical improvements. Therefore, the purpose of this systematic review was to explore the knowledge reported to date on the NO₃^- derived from BRJ intake effect on fatigue resistance during repeated sprints. A digital search was conducted following systematic review guidelines, and 18 studies met inclusion criteria from a total of 209 articles. In a third of the selected studies, the consumption of beet juice rich in NO₃^- contributes to an increase in nitrites in plasma that led to the rise in peak power, mean power, number of sprint repetitions, total work and time to task failure, and causes a decrease in fatigue index and sprints times. Some different dose has been proposed for both chronic and acute protocols. It seems that a chronic intake of ∼5-6 mmol of NO₃^- in 70 ml of BRJ, twice a day, for a minimum of 3-6 days could lead to a fatigue resistance improvement during repeated sprints. Besides, acute intake of NO₃^- 2.5-3 h before physical exertion or a dose of 250 ml/d to 500 ml/d of BRJ could lead to similar effective results. This systematic review presents some improvements (1.2-5.38%) in fatigue resistance during repeated sprints when consuming BRJ derived NO₃^-. The in-field practical meaning of these results should be explored.

The impact of beetroot juice supplementation on muscular endurance, maximal strength and countermovement jump performance

Purpose: Dietary nitrate has been shown to enhance muscle contractile function and has, therefore, been linked to increased muscle power and sprint exercise performance. However, the impact of dietary nitrate supplementation on maximal strength, performance and muscular endurance remains to be established. Methods: Fifteen recreationally active males (25 ± 4 y, BMI 24 ± 3 kg/m²) participated in a randomized double-blinded cross-over study comprising two 6-d supplementation periods; 140 mL/d nitrate-rich (BR; 985 mg/d) and nitrate-depleted (PLA; 0.37 mg/d) beetroot juice. Three hours following the last supplement, we assessed countermovement jump (CMJ) performance, maximal strength and power of the upper leg by voluntary isometric (30° and 60° angle) and isokinetic contractions (60, 120, 180 and 300°·s^-1), and muscular endurance (total workload) by 30 reciprocal isokinetic voluntary contractions at 180°·s^-1. Results: Despite differences in plasma nitrate (BR: 879 ± 239 vs. PLA: 33 ± 13 μmol/L, P < 0.001) and nitrite (BR: 463 ± 217 vs. PLA: 176 ± 50 nmol/L, P < 0.001) concentrations prior to exercise testing, CMJ height (BR: 39.3 ± 6.3 vs. PLA: 39.6 ± 6.3 cm; P = 0.39) and muscular endurance (BR: 3.93 ± 0.69 vs. PLA: 3.90 ± 0.66 kJ; P = 0.74) were not different between treatments. In line, isometric strength (P > 0.50 for both angles) and isokinetic knee extension power (P > 0.33 for all velocities) did not differ between treatments. Isokinetic knee flexion power was significantly higher following BR compared with PLA ingestion at 60°·s^-1 (P = 0.001), but not at 120°·s^-1 (P = 0.24), 180°·s^-1 (P = 0.066), and 300°·s^-1 (P = 0.36). Conclusion: Nitrate supplementation does not improve maximal strength, countermovement jump performance and muscular endurance in healthy, active males.

The benefits and risks of beetroot juice consumption: a systematic review

Beetroot juice (BRJ) has become increasingly popular amongst athletes aiming to improve sport performances. BRJ contains high concentrations of nitrate, which can be converted into nitric oxide (NO) after consumption. NO has various functions in the human body, including a vasodilatory effect, which reduces blood pressure and increases oxygen- and nutrient delivery to various organs. These effects indicate that BRJ may have relevant applications in prevention and treatment of cardiovascular disease. Furthermore, the consumption of BRJ also has an impact on oxygen delivery to skeletal muscles, muscle efficiency, tolerance and endurance and may thus have a positive impact on sports performances. Aside from the beneficial aspects of BRJ consumption, there may also be potential health risks. Drinking BRJ may easily increase nitrate intake above the acceptable daily intake, which is known to stimulate the endogenous formation of N-nitroso compounds (NOC's), a class of compounds that is known to be carcinogenic and that may also induce several other adverse effects. Compared to studies on the beneficial effects, the amount of data and literature on the negative effects of BRJ is rather limited, and should be increased in order to perform a balanced risk assessment.

Does Acute Beetroot Juice Supplementation Improve Neuromuscular Performance and Match Activity in Young Basketball Players? A Randomized, Placebo-Controlled Study

Whereas beetroot juice (BJ) supplementation is shown to increase physical performance in endurance activities, its benefits in team sports has been barely studied. In this randomized placebo-controlled study, we investigated the effects of BJ acute supplementation in improving neuromuscular performance and physical match activity in basketball. Ten young male competitive basketball players aged 15–16 years received 140 mL of BJ or placebo (PLA) on two separated days in a balanced cross-over design. Testing sessions comprised a neuromuscular test battery consisting of a countermovement jump (CMJ), isometric handgrip strength, 10-m/20-m sprint and agility T-test, followed by a 40-minute simulated basketball match. Physical match activity (distances, speeds, accelerations, and decelerations) was monitored using an inertial tracking system (Wimu Pro^TM) Results revealed no significant effects of BJ on CMJ (p = 0.304, ES = 0.13), isometric handgrip strength (p = 0.777, ES = 0.06), 10-m (p = 0.820, ES = 0.10), and 20-m sprint (p = 0.540, ES = 0.13), agility T-test (p = 0.979, ES ≤ 0.01) and any physical match demands (p > 0.151, ES = 0.13–0.48). Acute moderate doses of BJ (12.8 mmol of NO₃⁻) was not effective in improving neuromuscular performance (jump height, isometric handgrip strength, sprint, and agility) or physical match requirements in young trained basketball players the day of the competition.

No Effect of Beetroot Juice Supplementation on 100-m and 200-m Swimming Performance in Moderately Trained Swimmers

Purpose: Dietary nitrate supplementation has been reported to improve performance in kayaking and rowing exercise, which mandate significant recruitment of the upper-body musculature. Because the effect of dietary nitrate supplementation on swimming performance is unclear, the purpose of this study was to assess the effect of dietary nitrate supplementation on 100-m and 200-m swimming freestyle time-trial (TT) performance. Methods: In a double-blind, randomized crossover design, 10 moderately trained swimmers underwent 2 separate 3-d supplementation periods, with a daily dose of either 140 mL nitrate-rich (∼800 mg/d nitrate) or nitrate-depleted (PLA) beetroot juice (BRJ). After blood sampling on day 3, the swimmers performed both 200-m and 100-m freestyle swimming TTs, with 30 min recovery between trials. Results: Plasma nitrite concentration was greater after BRJ relative to PLA consumption (432 [203] nmol/L, 111 [56] nmol/L, respectively, P = .001). Systolic blood pressure was lowered after BRJ compared with PLA supplementation (114 [10], 120 [10] mm Hg, respectively P = .001), but time to complete the 200-m (BRJ 152.6 [14.1] s, PLA 152.5 [14.1] s) and 100-m (BRJ 69.5 [7.2] s, PLA 69.4 [7.4] s) freestyle swimming TTs was not different between BRJ and PLA (P > .05). Conclusions: Although 3 d of BRJ supplementation increased plasma nitrite concentration and lowered blood pressure, it did not improve 100-m and 200-m swimming TT performance. These results do not support an ergogenic effect of nitrate supplementation in moderately trained swimmers, at least for 100-m and 200-m freestyle swimming performance.