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Joseph A. McQuillan, Julia R. Casadio, Deborah K. Dulson, Paul B. Laursen and Andrew E. Kilding

Athletes commonly use dietary supplements in an effort to enhance athletic performance. Recently, consumption of NO 3 − by way of either nitrate salt ( NaNO 3 − ) or beetroot juice has been found to improve both economy and performance, 1 potentially due to improved efficiency of mitochondrial

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Matthew W. Hoon, Andrew M. Jones, Nathan A. Johnson, Jamie R. Blackwell, Elizabeth M. Broad, Bronwen Lundy, Anthony J. Rice and Louise M. Burke

Context:

Beetroot juice is a naturally rich source of inorganic nitrate (NO3 ), a compound hypothesized to enhance endurance performance by improving exercise efficiency.

Purpose:

To investigate the effect of different doses of beetroot juice on 2000-m ergometer-rowing performance in highly trained athletes.

Methods:

Ten highly trained male rowers volunteered to participate in a placebo-controlled, double-blinded crossover study. Two hours before undertaking a 2000-m rowing-ergometer test, subjects consumed beetroot juice containing 0 mmol (placebo), 4.2 mmol (SINGLE), or 8.4 mmol (DOUBLE) NO3 . Blood samples were taken before supplement ingestion and immediately before the rowing test for analysis of plasma [NO3 ] and [nitrite (NO2 )].

Results:

The SINGLE dose demonstrated a trivial effect on time to complete 2000 m compared with placebo (mean difference: 0.2 ± 2.5 s). A possibly beneficial effect was found with DOUBLE compared with SINGLE (mean difference –1.8 ± 2.1 s) and with placebo (–1.6 ± 1.6 s). Plasma [NO2 ] and [NO3 ] demonstrated a dose-response effect, with greater amounts of ingested nitrate leading to substantially higher concentrations (DOUBLE > SINGLE > placebo). There was a moderate but insignificant correlation (r = –.593, P = .055) between change in plasma [NO2 ] and performance time.

Conclusion:

Compared with nitratedepleted beetroot juice, a high (8.4 mmol NO3 ) but not moderate (4.2 mmol NO3 ) dose of NO3 in beetroot juice, consumed 2 h before exercise, may improve 2000-m rowing performance in highly trained athletes.

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Ozcan Esen, Ceri Nicholas, Mike Morris and Stephen J. Bailey

Dietary supplementation with inorganic nitrate (NO 3 − ) has emerged as a popular nutritional intervention to enhance exercise performance. After ingestion, NO 3 − is chemically reduced to nitrite (NO 2 − ), via anaerobic bacteria that populate the oral cavity, and subsequently to nitric oxide (NO

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Peter Peeling, Martyn J. Binnie, Paul S.R. Goods, Marc Sim and Louise M. Burke

, when accepted CM supplementation protocols are followed, the expected increase in intramuscular creatine stores are likely to enhance lean mass, maximal power/strength, and the performance of single and repeated bouts of short-term, high-intensity exercise. Nitrate Dietary nitrate (NO 3 – ) is a

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Peter Peeling, Linda M. Castell, Wim Derave, Olivier de Hon and Louise M. Burke

). Indeed, there has been lengthy but unclear speculation that the independently achieved performance benefits of creatine supplementation might be negated by caffeine supplementation ( Trexler & Smith-Ryan, 2015 ). Nitrate Nitrate enhances NO bioavailability via the NO 3 − –nitrite–NO pathway, which plays

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Ronald J. Maughan, Louise M. Burke, Jiri Dvorak, D. Enette Larson-Meyer, Peter Peeling, Stuart M. Phillips, Eric S. Rawson, Neil P. Walsh, Ina Garthe, Hans Geyer, Romain Meeusen, Luc van Loon, Susan M. Shirreffs, Lawrence L. Spriet, Mark Stuart, Alan Vernec, Kevin Currell, Vidya M. Ali, Richard G.M. Budgett, Arne Ljungqvist, Margo Mountjoy, Yannis Pitsiladis, Torbjørn Soligard, Uğur Erdener and Lars Engebretsen

. These supplements include: caffeine, creatine (in the form of creatine monohydrate), nitrate, sodium bicarbonate, and possibly also β-alanine. The mechanisms of action, typical dose, potential performance benefits, and known side-effects of each of these supplements are summarized in Table  3

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Louise M. Burke, Asker E. Jeukendrup, Andrew M. Jones and Martin Mooses

of performance supplements marketed to athletes have a strong evidence base. Peeling et al. ( 2019 ) have separately reviewed these products (caffeine, nitrate, creatine, β-alanine, and bicarbonate) and their mechanisms of action in relation to Athletics, identifying only the first two of this group

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Louise M. Burke, Linda M. Castell, Douglas J. Casa, Graeme L. Close, Ricardo J. S. Costa, Ben Desbrow, Shona L. Halson, Dana M. Lis, Anna K. Melin, Peter Peeling, Philo U. Saunders, Gary J. Slater, Jennifer Sygo, Oliver C. Witard, Stéphane Bermon and Trent Stellingwerff

-based performance supplements (caffeine, creatine, nitrate/beetroot juice, beta-alanine, and bicarbonate) may contribute to performance gains, according to the event, the specific scenario of use and the individual Athlete’s goals and responsiveness (Table  5 ). Specific challenges include developing protocols to

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David J. Muggeridge, Christopher C. F. Howe, Owen Spendiff, Charles Pedlar, Philip E. James and Chris Easton

The aim of the current study was to determine the effects of dietary nitrate ingestion on parameters of submaximal and supramaximal exercise and time trial (TT) performance in trained kayakers. Eight male kayakers completed four exercise trials consisting of an initial discontinuous graded exercise test to exhaustion and three performance trials using a kayak ergometer. The performance trials were composed of 15 min of paddling at 60% of maximum work rate, five 10-s all-out sprints, and a 1 km TT. The second and third trials were preceded by ingestion of either 70 ml nitrate-rich concentrated beetroot juice (BR) or tomato juice (placebo [PLA]) 3 hr before exercise using a randomized crossover design. Plasma nitrate (PLA: 33.8 ± 1.9 μM, BR: 152 ± 3.5 μM) and nitrite (PLA: 519.8 ± 25.8, BR: 687.9 ± 20 nM) were higher following ingestion of BR compared with PLA (both p < .001). VO2 during steady-state exercise was lower in the BR trial than in the PLA trial (p = .010). There was no difference in either peak power in the sprints (p = .590) or TT performance between conditions (PLA: 277 ± 5 s, BR: 276 ± 5 s, p = .539). Despite a reduction in VO2, BR ingestion appears to have no effect on repeated supramaximal sprint or 1 km TT kayaking performance. A smaller elevation in plasma nitrite following a single dose of nitrate and the individual variability in this response may partly account for these findings.

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Raul Bescós, Carlos Gonzalez-Haro, Pere Pujol, Franchek Drobnic, Eulalia Alonso, Maria Luisa Santolaria, Olga Ruiz, Marc Esteve and Pedro Galilea

To assess the effect of diet enrichment with L-arginine or supplementation at high doses on physiological adaptation during exercise, 9 athletes followed 3 different diets, each over 3 consecutive days, with a wash-out period of 4 d between training sessions: control diet (CD), 5.5 ± 0.3 g/d of L-arginine; Diet 1 (rich in L-arginine food), 9.0 ± 1.1 g/d of L-arginine; and Diet 2 (the same as CD but including an oral supplement of 15 g/d), 20.5 ± 0.3 g/d of L-arginine. Plasma nitrate levels of each participant were determined on the day after each treatment. Participants performed a submaximal treadmill test (initial speed 10–11 km/hr, work increments 1 km/hr every 4 min until 85–90% VO2max, and passive recovery periods of 2 min). Oxygen uptake and heart rate were monitored throughout the test. Blood lactate concentration ([La]b) was determined at the end of each stage. Repeated-measures ANOVA and paired Student’s t tests were used to compare the various physiological parameters between diets. The level of significance was set at p < .05. [La]b showed a significant effect at the 5-min time point between CD and Diet 2 (CD 3.0 ± 0.5 mM, Diet 2 2.5 ± 0.5 mM, p = .03), but this tendency was not found at higher exercise intensities. No significant differences were observed in any of the cardiorespiratory or plasma nitrate levels. In conclusion, dietary L-arginine intake on the days preceding the test does not improve physiological parameters during exercise.