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Effects of beetroot juice supplementation on intermittent high-intensity exercise efforts

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Beetroot juice contains high levels of inorganic nitrate (NO3−) and its intake has proved effective at increasing blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of investigations have sought to assess the effects of this supplement on performance at high-intensity exercise. Here we review the few studies that have addressed this issue. The databases Dialnet, Elsevier, Medline, Pubmed and Web of Science were searched for articles in English, Portuguese and Spanish published from 2010 to March 31 to 2017 using the keywords: beet or beetroot or nitrate or nitrite and supplement or supplementation or nutrition or “sport nutrition” and exercise or sport or “physical activity” or effort or athlete. Nine articles fulfilling the inclusion criteria were identified. Results indicate that beetroot juice given as a single dose or over a few days may improve performance at intermittent, high-intensity efforts with short rest periods. The improvements observed were attributed to faster phosphocreatine resynthesis which could delay its depletion during repetitive exercise efforts. In addition, beetroot juice supplementation could improve muscle power output via a mechanism involving a faster muscle shortening velocity. The findings of some studies also suggested improved indicators of muscular fatigue, though the mechanism involved in this effect remains unclear.
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R E V I E W Open Access
Effects of beetroot juice supplementation
on intermittent high-intensity exercise
efforts
Raúl Domínguez
1*
, José Luis Maté-Muñoz
1
, Eduardo Cuenca
2
, Pablo García-Fernández
1
, Fernando Mata-Ordoñez
3
,
María Carmen Lozano-Estevan
1
, Pablo Veiga-Herreros
1
, Sandro Fernandes da Silva
4
and
Manuel Vicente Garnacho-Castaño
2
Abstract: Beetroot juice contains high levels of inorganic nitrate (NO
3
) and its intake has proved effective at increasing
blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial
impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on
exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of
investigations have sought to assess the effects of this supplement on performance at high-intensity exercise. Here we
review the few studies that have addressed this issue. The databases Dialnet, Elsevier,Medline,PubmedandWebof
Science were searched for articles in English, Portuguese and Spanish published from 2010 to March 31 to 2017 using
the keywords: beet or beetroot or nitrate or nitrite and supplement or supplementation or nutrition or sport nutrition
and exercise or sport or physical activityor effort or athlete. Nine articles fulfilling the inclusion criteria were identified.
Resultsindicatethatbeetrootjuicegivenasasingledoseoroverafewdaysmayimproveperformanceatintermittent,
high-intensity efforts with short rest periods. The improvements observed were attributed to faster phosphocreatine
resynthesis which could delay its depletion during repetitive exercise efforts. In addition, beetroot juice supplementation
could improve muscle power output via a mechanism involving a faster muscle shortening velocity. The findings of
some studies also suggested improved indicators of muscular fatigue, though the mechanism involved in this effect
remains unclear.
Keywords: Beet, Ergogenic aids, Exercise, Sport supplement
Background
Because of the increase in competitive equality in high level
sport, a 0.6% performance improvement is today consid-
ered sufficient to make a difference [1]. In this setting of
high competition, athletes often look to nutritional supple-
ments to boost their performance [2]. However, most state-
ments about the potential effects on sport performance or
health that appear on the labels of many products are not
backed by clear scientific evidence [2]. Because of this,
institutions such as the Australian Institute of Sport (AIS)
have created a system to classify supplements according to
their effects on performance based on confirmed scientific
evidence [3]. Thus, dietary supplements assigned to class A
have been proven with a high level of evidence to improve
exercise performance in certain modalities when taken in
appropriate amounts. The only substances in this class are
β-alanine, sodium bicarbonate, caffeine, creatine and beet-
root juice [4]. However, it is thought that the effect of a
given supplement on performance besides the recom-
mended dose may be specific to each sportsmodality[5].
This, in turn, will depend on the energy and/or mechanical
requirements of each form of exercise such that some
supplements will have an ergogenic effect on some types of
exercise efforts and have no effects on other types.
The relationship between exercise intensity and time to
exhaustion is hyperbolic [6] as it is directly linked to the
prevailing energy producing systems during exercise [7].
Thus, depending on their bioenergetics, the different exer-
cise efforts can be classified according to exercise duration.
This means we can differentiate between explosive efforts,
* Correspondence: rdomiher@uax.es
1
Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El
Sabio University, Madrid, Spain
Full list of author information is available at the end of the article
© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Domínguez et al. Journal of the International Society of Sports Nutrition
(2018) 15:2
DOI 10.1186/s12970-017-0204-9
high-intensity efforts and endurance-intensive efforts [8].
Explosive efforts are those lasting under 6 s in which the
main energy metabolism pathway is the high-energy
phosphagen system and there is some participation also of
glycolysis [9, 10], which gradually contributes more energy
until 50% at 6 s [9]. High-intensity efforts are those of dur-
ationlongerthan6sandshorterthan1min[11].These
efforts are characterized by a major contribution of
glycolytic metabolism and smaller contribution of high-
energy phosphagens and oxidative phosphorylation [8]. Fi-
nally, intensive endurance efforts are those lasting longer
than 60 s and whose main energy producing system is
oxidative phosphorylation [8].
Beetroot juice is used as a supplement because it may
serve as a precursor of nitric oxide (NO) [12]. The mech-
anism of NO synthesis is thought to be via the catabolism
of arginine by the enzyme NO synthase [13]. Effectively,
arginine supplementation has been shown to increase NO
levels [14]. An alternative mechanism of NO genesis is
mediated by inorganic nitrate (NO
3
). This means that the
high amounts of NO
3
present in beetroot juice are able to
increase NO levels in the organism.
In the mouth, some 25% of dietary NO
3
is reduced by
NO
3
reductase produced by microorganisms [15] to ni-
trite (NO
2
) [16]. This NO
2
is then partially reduced to
NO through the actions of stomach acids which is later
absorbed in the gut [17]. Some of this NO
2
enters the
bloodstream, and, in conditions of low oxygen levels,
will be converted into NO [18] (Fig. 1).
Nitrous oxide has numerous physiological functions in-
cluding haemodynamic and metabolic actions [19, 20].
Mediated by guanylyl cyclase [21], NO has an effect on
smooth muscle fibres causing blood vessel dilation [22].
This vasodilation effect increases blood flow to muscle fi-
bres [23] promoting gas exchange [24]. NO also induces
gene expression [25], enhancing biogenesis [26] and mito-
chondrial efficiency [27]. All these effects can favour an
oxidative energy metabolism. In effect, though not all [28
31], numerous investigations have noted that beetroot juice
supplementation boosts performance in exercise modalities
involving intensive endurance efforts in which the domin-
ant type of energy metabolism is oxidative [24, 27, 3245].
To date, several reviews of the literature have assessed
the effects of beetroot juice supplements on physical exer-
cise [12, 4649]. In addition, given that NO can potentiate
the factors that limit performance when executing actions
in which the predominant metabolism is oxidative, two re-
cent reviews have explored the positive effects of this form
of supplementation on endurance exercise [50, 51]. Thus,
the different studies showed that beetroot juice supple-
mentation was effective at: lowering VO
2
by 6% during a
swimming test conducted at an intensity equivalent to the
Fig. 1 Conversion of NO
3
in beetroot juice to NO. The diagram shows how ingested NO
3
is transformed by bacteria in the mouth containing
nitrite reductase to NO
2
. Once in the gut, NO
2
enters the bloodstream and, under conditions of hypoxia, is used to generate NO
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 2 of 12
ventilatory threshold (VT) [27]; lowering VO
2
by 3%
during a kayaking test conducted at 60% VO
2max
[38] and
during a cycle ergometry test conducted by recreation
sport athletes [45] and cyclists [34] at 4570% VO
2max
;in-
creasing performance by 1217% in cycle ergometry tests
until exhaustion conducted at intensities of 60 to 90%
VO
2max
by recreation sport athletes [37, 42], and by 22%
when conducted at a 70% intensity between VT and
VO
2max
[36]; and finally, improving times by 2.8% in
trained cyclists conducting cycle ergometery tests of 4 km
[33], 10 km (1.2%) [34], 16 km (2.7%) [33] and 50 miles
(0.8%) [35]. However, besides the effects of NO mentioned
above, other impacts need to be considered. Accordingly,
it has been described that the effect of increased blood
flow induced by NO is specific to type II muscle fibres
[20]. Moreover, in type II muscle fibres, beetroot juice in-
take has been found to improve the release and later re-
uptake of calcium from the sarcoplasmic reticulum [52].
This could translate to an increased capacity for muscle
strength production of these type II muscle fibres. Such
effects of NO could mean a physiological advantage for ef-
forts involving the recruitment of type II muscle fibres,
such as intermittent, high-intensity efforts. Hence, given
the scarce yet growing number of studies that have ad-
dressed the effects of beetroot juice supplementation on
this type of intermittent, high-intensity effort [38, 5360],
here we review the results of experimental studies that
have specifically examined in adults (whether athletes or
not) the effects of beetroot juice supplementation on
intermittent, high-intensity efforts.
Methodology
We identified all studies that have assessed the effects of
BJ supplementation on intermittent, high-intensity efforts
by searching the databases Dialnet, Elsevier, Medline,
Pubmed and Web of Science published up until March
31, 2017 using the keywords: beet OR beetroot OR nitrate
OR nitrite (concept 1) AND supplement OR supplementa-
tion OR nutrition OR sport nutrition(concept 2) AND
exercise OR sport OR physical activityOR effort OR
athlete (concept 3).
Two of the present authors (E.C and P.G-F) first elimi-
nated duplicate articles and then removed descriptions of
studies that were not experimental, were not written in
English or Spanish, or were published before 2010. This
meant that all the studies reviewed were published over
the period January 1, 2010 to March 31, 2017. Next, these
two same authors applied a set of exclusion criteria to
ensure the selection only of studies specifically designed to
assess the effects of BJ supplementation on intermittent,
high-intensity efforts:
Studies performed in non-adults (samples including
subjects aged <18 or >65 years).
Studies conducted in vitro or in animals.
Studies in which the direct effects of BJ were not
determined.
Studies in which impacts were examined on
exercises that did not comply with the
characteristics of intermittent, high-intensity efforts.
If there was disagreement about whether a given study
met the inclusion/exclusion criteria, the opinion of a
third researcher (F.M-O) was sought.
Results
Study selection
Of 738 studies identified in the search, 359 were left
after eliminating repeated records. Once, the titles and
abstract of these 359 publications were reviewed, 212 full
text articles were indentified and retrieved for assess-
ment, of which 9 articles met the elegibility criteria
(Fig. 2).
Study characteristics
The nine studies selected for our review included a total
of 120 subjects, 107 of whom were men and 13 women.
In five of these studies [38, 53, 54, 57, 59], the effects of a
single beetroot juice supplement (acute effects) were
assessed. The supplement was taken 120 min before exercise
inonestudy[53],150minbeforeexerciseintwo[57,59]
and 180 min before exercise in the remaining two [38, 54].
In the remaining four studies, the effects of chronic beet-
root juice supplementation were examined [55, 56, 58, 60].
The supplementation periods were 5 days in one study [60],
6 days in two [55, 58] and 7 days in the fourth study [56].
Doses of NO
3
ingested ranged from ~5 mmol [38] to
~11.4 mmol [57]. In addition, one study examined the
efficacy of beetroot juice taken separately or in combin-
ation with sodium phosphate [55].
In four of the nine studies reviewed, participants were
competition athletes [38, 55, 57, 59] and in the other five
they were recreation sport or low-level competition ath-
letes [53, 54, 56, 58, 60]. Only one of the study popula-
tions included athletes of individual sports modalities
[38], the rest of the studies were conducted in players of
team sports [5360].
The tests used to assess performance were a 30-s dur-
ation cycle ergometer test in one [59] and high-intensity,
intermittent exercises in the remaining studies with
work intervals ranging from 6 s [58] to 60 s [60] and rest
periods from 14 s [56] to 4 min [60]. The types of tests
employed were running at maximum speed in three
studies [5557], cycle ergometry in four [53, 54, 59, 60],
one of which was an isokinetic test [59], a kayak ergom-
eter test in one [38] and bench press strength training in
the remaining study [58].
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 3 of 12
The beetroot juice intervention led to significantly im-
proved performance in four of the studies [54, 56, 58,
60], while in another four no such effects were observed
[38, 55, 57, 59]. In the remaining study, an ergolytic, or
reduced performance, effect was noted in relation to the
placebo treatment.
Study results
InTable1wesummarizetheresultsoftheninestudies
reviewed and provide details on the participants, experi-
mental conditions, supplement regimens, and performance
tests employed.
Discussion
Effects of chronic supplementation with beetroot juice on
intermittent, high-intensity exercise efforts
Four of the studies reviewed tested the effects of taking
beetroot juice supplements for 5 to 7 days on intermittent,
high-intensity efforts [55, 56, 60] or on a resistance training
session [58]. Three of these studies detected a significant
effect of beetroot juice supplementation [56, 58, 60] while
in the remaining study, no significant difference compared
with the placebo was noted [55].
Effects of chronic supplementation with beetroot juice on
resistance training
Resistance training is used to improve muscular hyper-
trophy, strength, power and muscular endurance [61].
Training sessions targeting muscle hypertrophy include
workloads of around 7085% 1 RM and 812 repetitions,
while those aiming to improve muscular endurance include
loads of around 50% 1 RM and some 1525 repetitions
[62]. Such exercise sessions are largely dependent on glyco-
lytic metabolism; the lactate threshold in resistance training
exercises such as half squat is detected at ~25% 1 RM [63,
64]. To determine the effects of 6 days of beetroot juice
supplementation (6.4 mmol NO
3
) on resistance training
sessions designed to improve local muscular hypertrophy
and endurance, in the study by Mosher et al. reviewed here
[58], the number of bench press repetitions accomplished
in three sets using loads equivalent to 60% 1 RM was re-
corded. Results indicated that supplementation increased
the number of repetitions in the three exercise sets improv-
ing session performance by 18.9%.
In an earlier investigation, the effects of sodium bicar-
bonate supplements were assessed in a similar study to the
onebyMosheretal.[58].Subjectsperformed3setsuntil
exhaustion with loads of 1012 RM in three exercises
Fig. 2 Article selection
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 4 of 12
targeting the lower limbs [65]. Results indicated that, like
the beetroot juice, sodium bicarbonate supplementation
led to more repetitions in the session [65]. However, in par-
allel with the increasing number of repetitions, blood lac-
tate concentrations also rose (~2.5 mmol) [65]. This was
not observed in Moshers study [58].
If we consider the nature of resistance training, the ath-
lete passes from a resting condition to a situation demand-
ing high energy levels during the first repetitions of a set.
Because the phosphagen system is the main energy path-
way in rest-exercise transitions [66], phosphocreatine re-
serves may be depleted in response to a resistance training
Table 1 Summary of the results obtained in studies examining the impacts of beetroot juice supplements on intermittent high
intensity exercise performance
Reference Subjects Study design Dose Exercise test Results
Muggeridge et al. [38] Trained kayakers
(male, n=8)
(VO
2peak
49.0
± 6.1 ml·kg·min
1
)
Single-blind,
randomized,
cross-over
5 mmol NO
3
(180 min before)
Kayak ergometer:
5 × 10 s sprint-rest
50 s
+4% average power
(420 ± 23 vs 404 ± 24 W)
Martin
et al. [53]
Recreation team
sport players (male,
n= 16) (VO
2peak
47.2 ± 8.5 ml·kg·min
1
)
Double-blind,
randomized,
cross-over
6.4 mmol NO
3
(120 min before)
Cycle ergometer:
sets until exhaustion
of 8 srest 30 s
13% reps (13 ± 5 vs 15 ± 6)
and 17% total work (49.2 ±
24.2 vs 57.8 ±34.0 kJ)
Aucouturier et al. [54] Recreation team sport
players (male, n= 12)
(VO
2peak
46.6 ± 3.4
ml·kg·min
1
)
Single-blind,
randomized,
cross-over
10.9 mmol NO
3
(180 min before)
Cycle ergometer:
sets until exhaustion
of 15 s at 170%
MAPrest 30 s
+20% reps
*
(26.1 ± 10.7 vs
21.8 ± 8.0) and 18% total
workload
*
(168.2 ± 60.2 vs
142.0 ± 46.8 kJ)
Buck
et al. [55]
Amateur team sport
players (female, n= 13)
(VO
2peak
not specified)
Double-blind,
randomized,
Latin-square
BJ: 6.4 mmol NO
3
(6 days) BJ + SP:
6.4 mmol NO
3
+
50 mg·kg lean
mass SP (6 days)
PRE, MID and POST
simulation team
sport matches: 6×(20
m sprint + rest 25 s)
BJ: 0.2% total sprint time
per set (69.8 ± 4.9 vs 69.97
± 4.2) BJ + SP: 2% total
sprint time per set (68.9 ±
5.1 vs 69.97 ± 4.2)
Thompson et al. [56] Recreation team sport
players (male, n= 16)
(VO
2peak
50 ± 7
ml·kg·min
1
)
Double-blind,
randomized,
cross-over
12.8 mmol
NO
3
(7 days)
MID and POST simulated
team-sport matches:
2×[5×(6 s cycle ergometry
sprint + rest 14 s)]
5% work volume at MID
*
(63 ± 20 vs 60 ± 18 kJ),
2% POST (60 ± 17 vs 59
± 16 kJ) and 4% whole
session
*
(123 ± 19 vs
119 ± 17 kJ)
Clifford
et al. [57]
Competition team
sport players (male,
n= 20) (VO
2peak
not specified)
Double-blind,
independent
groups design
11.4 mmol NO
3
(150 min before)
2xRST: 20×(30 m
sprintrest 30 s)
-1% average sprint time
RST1 (4.65 ± 0.3 vs 4.7 ±
0.2 s) and 2% RST2
(4.66 ± 0.2 vs 4.77 ± 0.2 s)
and 2% fastest sprint RST1
(4.41 ± 0.2 vs 4.48 ± 0.1 s)
and 3%RST2 (4.38 ± 0.2
vs 4.53 ± 0.2 s)
Mosher
et al. [58]
Recreation sport
players (male,
n= 12) (VO
2peak
not specified)
Double-blind,
randomized,
cross-over
6.4 mmol
NO
3
(6 days)
Bench press: 3×
(maximum number
reps at 60% 1 RM)
+ 19% weight lifted in
session and improved
no. of reps S1
*,
S2
*,
S3
*
and whole session.
*
improvements not
specified
Rimer
et al. [59]
Competition sport
players (male, n= 13)
(VO
2peak
not specified)
Double-blind,
randomized,
cross-over
11.2 mmol NO
3
(150 min before)
Isokinetic cycle
ergometer: Wingate
30-s test
-1% peak power (1173
± 255 vs 1185 ± 249 W)
and 1% total work
(22.8 ± 4.8 vs 23 ± 4.8 W)
Wylie et al. [60] Recreation team sport
players (male, n= 10)
(VO
2peak
58 ± 8
ml·kg·min
1
)
Double-blind,
randomized,
cross-over design
8.4 mmol
NO
3
(5 days)
Cycle ergometer: 24 x
(6 s sprintrest 24 s)
Cycle ergometer: 7 x
(30 s sprintrest 4 min)
Cycle ergometer: 6 x
(60 s sprintrest 60 s)
+5% mean average power
*
(568 ± 136 vs 539 ± 136 W)
and +1% mean peak power
(792 ± 159 vs 782 ± 154 W)
in 24 x (6 s sprintrest 24 s);
1% mean average power
(558 ± 95 vs 562 ± 94 W) and
1% mean peak power (768
± 157 vs 776 ± 142 W) in 7 x
(30 s sprintrest 4 min)
BJ Beetroot juice, MID Half-time simulation match, nSample size; no Number, NO
3
nitrate concentration in the drink, MAP Maximum aerobic power, POST End
simulation match, PRE Before simulation match, Rep Repetition, RST Repeated sprint test, SP Sodium phosphate, VO
2peak
Peak oxygen consumption,
*
statistically
significant differences
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 5 of 12
exercise set. Recovering these reserves takes some 3
5 min [67]. Given that phosphocreatine resynthesis is
dependent on oxidative metabolism [68] and that beetroot
juice has an ergogenic effect on exercise modalities with a
major oxidative metabolism component [50], it could be
that this supplement accelerated this recovery during the
rest period in Moshers study (2 min) and thus avoided
progressive phosphocreatine depletion throughout the ses-
sion. In turn, this faster rate of resynthesis would attenuate
the increasing levels of adenosine diphosphate (ADP) and
inorganic phosphates [68]. Both these metabolites have
been associated with the appearance of muscular fatigue
[69]. Hence, by delaying the build-up of critical levels of
these metabolites, the appearance of fatigue will be delayed
and this will allow for more repetitions in sets until ex-
haustion [58]. NO
3
supplementation could also improve
muscle efficiency and contractile capacity by promoting
the release of calcium from the sarcoplasmic reticulum in
the muscle cells and its reuptake [52, 69]. Thus, a train of
action potentials leading to an increased supply of calcium
to the muscle fibre will increase the strength of muscle
contraction [13].
Effects of chronic supplementation with beetroot juice on
intermittent high-intensity exercise efforts
Some sport modalities such as team, racket or combat
sports require bursts of high-intensity efforts followed
by rest periods. Thus, in team sports, high-intensity ef-
forts (~34 s) are interspersed with variable active rest
periods [70]. In racket sports like tennis, efforts last 7
10 s and rest periods 1016 s (between points) and/or
6090 s (side changes) [71]. Finally, in combat sports
more intense efforts are 1530 s long and active rest pe-
riods are 510 s long every 5 min [72]. In all these
sports modalities, the capacity to repeat high-intensity
efforts with only short recovery periods is considered a
performance indicator [73]. This means that higher level
athletes are able to maintain performance in successive
high-intensity intervals over a long time period [74].
To find out if beetroot juice supplementation would im-
prove this ability to repeat high-intensity efforts during a
team sport match, Thompson et al. [56] administered
beetroot juice over 7 days to a group of athletes
(12.8 mmol NO
3
). The performance test consisted of two
blocks of five 6-s sets of sprints on a cycle ergometer with
14-s active recovery periods in the middle and end of a
simulated match lasting 2 × 40 min [56]. The results of
this study indicated a total work volume improved by
3.5% in the whole session, though this improvement was
greater at the end of the first half (at half time).
If we again consider the nature of this type of exercise, it
has been established that it involves the recruitment of
type II muscle fibres [75, 76], which are more powerful
though show more fatigue than type I units [77]. This
lesser resistance to fatigue has been related to reduced
blood flow and myoglobin concentrations in these muscle
fibres compared to type I. Hence, type II muscle fibres are
designed to promote non oxidative pathways and have
shown a greater creatine storage capacity [78] for an en-
hanced metabolism of phosphocreatine [79] and proteins
with a buffering effect at the intracellular level such as
carnosine [80], favouring a glycolytic type metabolism.
Animal studies have shown that increased blood flow in
response to NO
3
supplementation is greater in type II com-
pared to type I muscle fibres [20]. This greater irrigation
and oxygen availability in the recovery period along with a
greater creatine storage capacity of motor type II units [78]
(promoting phosphocreatine resynthesis [79]) means that
during an exercise effort followed by a short rest period
(14 s), beetroot juice supplementation could delay
phosphocreatine depletion during successive sprints and
explain the improvements noted by Thompson et al. [56].
Despite such greater effects of NO
3
supplementation
on type II versus type I muscle fibres, animal studies
have also shown that effects on calcium release and re-
uptake in the muscle cell sarcoplasmic reticulum is
greater in type II than type I muscle fibres [52]. Accord-
ingly, because of the important role of type II muscle fi-
bres during sprints [75, 76], supplementation could have
led to an improved capacity to generate muscle power
and thus explain the significant improvements in per-
formance observed by Thompsons group.
Buck et al. [55] examined the effects of 6 days of sup-
plementation with beetroot juice (6.4 mmol NO
3
) or so-
dium phosphate (50 mg·kg lean mass) on performance
in a test consisting of repeated sprints as 6 sets of 20 m
and 25-s of rest between sets in the middle and end of a
simulated match lasting 60 min. The beetroot juice
intervention did not improve performance at these
sprints, yet did do so when taken along with sodium
phosphate (2%) compared with placebo, though this im-
provement was of lesser magnitude than when the sub-
jects only took sodium phosphate supplements (5%).
These findings suggest that, unlike beetroot juice, so-
dium phosphate intake may have an ergogenic effect in
this protocol. If we compare the tests used by Buck et al.
[55] and Thompson et al. [56], work periods were
shorter (23 vs 6 s), while rest periods were longer (25
vs 14 s). Therefore it could be that 23 s efforts lead to
a significantly lower reduction of phosphocreatine re-
serves at the end of these efforts. Further, the 25 s of rest
approaching the 30 s in which the recovery of 50% of
phosphocreatine stores takes place [67], may have been
sufficient to stabilize reserves of phosphocreatine and
therefore avoid the appearance of fatigue [81].
Another study investigated the effects of longer term
supplementation (5 days) with beetroot juice (8.4 mmol
NO
3
), this time on performance in a repeated high-
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 6 of 12
intensity test [60]. These authors sought to determine
supplementation effects on different exercise protocols.
Subjects performed a session consisting of twenty four
6-s sets of work and 24 s of rest between sets, a second
session of two 30-s sets of work and 2 min of rest be-
tween sets and a third session of six 6-s sets and 60 s of
rest between sets. As did Thompson et al. [56], Wylie et
al. [60] selected 6-s exercise sets in the first session
though rest intervals were longer (24 vs 14 s). Another
difference was that the participants had not first under-
gone fatigue (in the simulated team sport match) before
the performance test. Notwithstanding, results were
similar in that mean power generated in the sets over a
whole session improved by ~7%. However, improve-
ments across the 24 × 624 protocol were not compar-
able to those recorded in the other two tests, in which
no significant improvements were recorded.
In the test protocols including 30-s and 60-s work ef-
forts, beetroot juice supplementation resulted in no im-
provements in any indicators of performance [60]. These
protocols consisting of longer duration work intervals
mainly involve a glycolytic type metabolism and in smaller
measure elicit the high-energy phosphagen system. An in-
crease in glycolysis leads to increased H
+
production, low-
ering pH [82]. To avoid increasing acidosis, a series of
responses targeted at reducing phosphofructokinase take
place including diminished glycolysis [83] and phospho-
creatine resynthesis [84], and muscle contractibility modi-
fications [85]. Such responses manifest as reduced non
aerobic metabolism or a reduced capacity for muscle
power and strength, in other words, fatigue [86]. Supple-
ments such as β-alanine (which increases muscle carno-
sine concentrations [87], a protein that acts as a buffer
inside the cell [88]) and sodium bicarbonate [89] (main
extracellular buffering agent) have shown ergogenic effects
on performance at high-intensity efforts involving the pre-
dominance of glycolytic metabolism [90]. The combined
effect of these supplements is greater than the impact of
each supplement on its own [91].
Although beetroot juice supplementation induces vaso-
dilation and increased blood flow (in type II muscle fibres,
recruited mainly in exercise bouts of 30 to 60 s duration),
increasing available oxygen in the muscles, rather than be-
ing activated because of a lack of oxygen (anaerobiosis),
non-oxygen dependent pathways are activated because of a
greater demand for energy production via oxidative phos-
phorylation. Thus, these effects, although they potentiate
oxidative phosphorylation, have no repercussions on glyco-
lytic energy metabolism. Hence, as beetroot juice has no al-
kalizing effect supplementation with this product is unable
to reduce acidosis, as the main factor limiting performance
at efforts lasting 3060 s. However, potentiating effects on
aerobic metabolism increases the speed of phosphocreatine
resynthesis, dependent on oxidative phosphorylation. This
means it may be effective for repeated high-intensity efforts
whose duration is close to 610 s, in which high energy
phosphagens contribute mainly to the metabolism [92] and
the work volume is sufficient to cause significant depletion,
which when faced with short rest intervals leads to pro-
gressive depletion and consequently to fatigue. Accord-
ingly, beetroot juice supplements can have an ergogenic
effect when exercise efforts are intermittent, maximum in-
tensity, short-duration (610 s) and interspersed with brief
recovery periods (<30 s).
Effects of acute beetroot juice supplementation on
intermittent high-intensity efforts
Five of the studies reviewed here were designed to analyze
the effects of a single beetroot juice supplement on inter-
mittent high-intensity exercise efforts [38, 53, 54, 57, 59].
Aucouturier et al. [54] administered the supplement
(~10.9 mmol NO
3
) to a group of recreation athletes
180 min before performing sets until exhaustion consist-
ing of 15 s of pedalling at 170% VO
2max
followed by 30-s
rest periods. The authors reported that the beetroot sup-
plement gave rise to improvements close to 20% in the
number of repetitions performed and the total work com-
pleted in the session [54]. Besides the number of sets com-
pleted and the work accomplished, these authors
measured red blood cell concentrations at the micro-
vascular level. The beetroot juice, apart from improving
performance, was found to increase microvascularization.
Such improvements are considered a beneficial effect on
oxygen exchange in the muscle [93]. Accordingly, these
oxygen availability improvements produced at the muscu-
lar level could have potentiated oxidative phosphorylation
during rest periods, and, given their brief duration, could
have increased phosphocreatine resynthesis when subjects
took the supplement rather than the placebo. Thus, sup-
plementation would have delayed the depletion of
phosphocreatine reserves and this effect was likely the
cause of the improvements observed in the repeated sets
of intermittent sprints [94, 95].
As did Aucouturier et al. [54], Muggeridge et al. [38] ex-
amined the effect of beetroot juice (5 mmol NO
3
)taken
180 min before an intermittent effort consisting of 5 sets
of 10 s in a kayak ergometer with 50-s interset rest periods.
In this study, though supplementation seemed to have a
greater effect on the power generated in the last two sets,
the improvement noted lacked significance. However, if we
compare this study with the study by Aucouturier et al.
[54], work periods in the Muggeridge study [38] were
shorter (10 vs 15 s) and rest periods were much longer (50
vs 30 s). Ten second maximum intensity intervals have a
significantly reduced capacity compared with 15s intervals
to deplete phosphocreatine reserves. Moreover, the rate of
phosphocreatine replacement has a first phase in which up
to 50% of these reserves can be replenished in 30 s and
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 7 of 12
100% in 35 min [67]. Also if we consider that the main
effect of beetroot juice supplements is linked to an im-
proved rate of phosphocreatine resynthesis, it is possible
that as there is less depletion and a rest period in which
there is almost complete recovery of phosphocreatine re-
serves, supplementation could not have exerted any bene-
ficial effect in the study by Muggeridge et al. [38].
However, despite the short work periods and relatively
long recovery periods and the fact that the power devel-
oped in the last sets showed an improved trend following
supplementation, it is possible that lengthening intervals
in a set until exhaustion would have been beneficial and
given rise to similar results to those observed by Aucou-
turier et al. [54].
Rimer et al. [59] assessed the effects of acute supplemen-
tation (150 min before exercise) with beetroot juice
(11.2 mmol NO
3
) on performance in a maximal intensity
3-s test on an isoinertial cycle ergometer and a 30-s test on
an isokinetic cycle ergometer. Supplementation was effect-
ive at improving pedalling cadence, and thus the power
generated, in the 3-s test. However, no such effect was ob-
served in the isokinetic test.
The improvements noted by Rimers group in the 3-s
test affected pedalling cadence. Because of the link be-
tween such improvements and an increase in muscle
shortening velocity [96] and the proposal that NO could
increase this velocity [97, 98], the authors suggested that
beetroot juice could have a beneficial effect on power
output [59]. This rationale was also used to explain the
lack of changes produced in the 30-s test in which ped-
alling cadence was fixed at 120 rpm. This means that
any improved power production in the isokinetic test
could only occur if there was an increase in power at a
constant shortening velocity [59], since power equals
force times velocity.
In a later investigation performed in CrossFit athletes, it
was reported that supplementation with NO
3
salts (8 mmol
NO
3
) rather than beetroot juice was able to improve per-
formance in a 30-s cycle ergometry test [99]. However, un-
like the 30-s test used by Rimer et al. [59], the test was
isoinertial. The difference between the 2 cycle ergometers
is that while in the isokinetic test pedalling cadence is pre-
fixed and improvements only in strength are possible, in
an isoinertial test the workload is fixed and any power im-
provements produced manifest as improvements in pedal-
ling cadence. Given that beetroot juice supplementation
could improve power development as a consequence of a
reduced muscle shortening velocity [59, 97, 98], the isokin-
etic cycle ergometer is perhaps not sufficiently sensitive to
assess the effects of this supplementation. Considering the
beneficial effects on cadence and power output observed
in the cycle ergometry 3-s [59] and 30-s [99] tests, it seems
that beetroot juice supplementation could have a beneficial
effect on this type of effort.
In a fourth study, Clifford et al. [57] assessed the ef-
fects of a single intake of beetroot juice on performance
in a test of 20 sets of 30 m sprints interspersed with 30-s
rest periods. These authors observed no ergogenic ef-
fects of the supplementation. However, if we look at the
characteristics of the test employed by the researchers,
we find that the work periods (close to 3 s) together with
the 30 s recovery periods could be sufficient for the sub-
jects to have recovered their phosphocreatine levels in
the rest intervals, minimizing the possible ergogenic ef-
fects of the supplementation.
A novel indicator used in this study by Clifford et al.
[57] was the counter-movement jump (CMJ) test per-
formed before the intermittent velocity test and in the
rest periods. Performance in this test is determined by
the contractile properties of muscle and by neuromuscu-
lar control of the entire musculoskeletal system [100].
Given that fatigue reflects the incapacity of the neuro-
muscular system to maintain the level of power required
[101], losses in CMJ height at the end of exercise are
taken as an indicator of muscular fatigue [102].
In the study by Cliffords group [57], it was observed
that the protocol of intermittent sprints gave rise to
muscular fatigue. This fatigue can be the outcome of de-
ficiencies in the muscles contractile mechanism [101,
103]. Alternatively, strong eccentric actions of the ham-
string muscles during sprints may produce muscle dam-
age [104] and therefore modify the structure of the
muscle fibres sarcomeres. Thus, any loss in CMJ height
could indicate muscle damage. While CMJ was moni-
tored after the protocol of 20 sets of 30 m with 30-s rest
periods, a greater recovery of CMJ height was observed
in the supplementation group. This suggests that beet-
root juice could help preserve muscle structure during
high-intensity efforts. Another explanation could be re-
lated to the vasodilation effect of beetroot juice [50] pos-
sibly helping muscle regeneration during early recovery.
In future work, biomarkers of muscle damage or inflam-
mation need to be examined.
In the fifth study, Martin et al. investigated the effects
of beetroot juice (6.4 mmol NO
3
) on repetitive sets
until exhaustion each consisting of 8 s of work followed
by 30 s of rest on a cycle ergometer [53]. No effects
were detected on power output in the different sets.
Moreover, a lower number of sets was accomplished in
the session for the supplementation group versus
placebo group. In effect, this was the only study to
describe an ergolytic effect of beetroot juice. The
authors argued that because of the scarce contribution
of oxidative phosphorylation to energy metabolism dur-
ing high-intensity efforts and that the ergogenic poten-
tial of this supplement is related to potentiating
oxidative pathways, no beneficial effects are produced
on this type of physical action.
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 8 of 12
The results of the investigation by Martin et al. [53]
conflict with those of others who did observe benefi-
cial effects on performance in similar tests [54, 56,
58, 60]. Beetroot juice was taken 120 min before ex-
ercise. This regimen is not appropriate, as peak NO
2
levels are produced 23 h after ingestion and it is
recommended that supplementation should be taken
at least 150 min180 min before the high-intensity
effort [32, 50]. Effectively, Aucouturier et al. [54] used
a test of similar characteristics but the beetroot sup-
plement was taken 180 min before the exercises, as
recommended.
Conclusions
To date, few studies have examined the effects of
supplementation with beetroot juice on short-duration
high-intensity exercise efforts [38, 5360] and obser-
vations so far will need confirmation in future
studies:
Supplementation with beetroot juice has been
shown to diminish the muscular fatigue associated
with high-intensity exercise efforts, though it is not
known if this is achieved by reducing fatigue and
muscle damage and/or promoting muscle regener-
ation postexercise.
When faced with exercise efforts that could
considerably deplete phosphocreatine reserves (sets
of resistance training or repetitive sprints of around
15 s interspersed with short rest periods) and given
that phosphocreatine resynthesis requires an
oxidative metabolism, beetroot juice could help the
recovery of phosphocreatine reserves and thus avoid
its depletion during repeated efforts. In parallel,
supplementation would limit the build-up of metab-
olites such as ADP and inorganic phosphates, which
are known to induce muscular fatigue.
Beetroot juice has been shown to improve the release
and reuptake of calcium at the sarcoplasmic reticulum.
Thiscouldhelpthepowerproductionassociatedwith
improvements in muscle shortening velocity. Non-
isokinetic ergometers (in which movement velocity is
not assessed) are sensitive to such improvements in
power generation.
Study limitations
The main limitation of our review is the scarcity of stud-
ies that have examined the effects of beetroot juice sup-
plementation on intermittent, high- intensity exercise.
This limitation is also magnified by the varied design of
the few studies available including different supplemen-
tation doses and regimens.
Future lines of research
As it has been proposed that beetroot juice
supplementation improves phosphocreatine
resynthesis during the brief rest periods included in
protocols of intermittent high-intensity exercise, future
studies are needed to confirm via a muscle biopsy
phosphocreatine levels during repeated high-intensity
efforts.
To examine the possible beneficial effect of
beetroot juice on muscle shortening velocity
reflected as improved pedalling cadence, future
studies need to assess the ergogenic effect of this
supplement in a single, constant-load test on an
inertial cycle ergometer.
To elucidate the mechanism whereby beetroot juice
diminishes muscular fatigue and improves recovery
from this fatigue, the effects of ingesting NO
3
on
biomarkers of inflammation and muscle damage
need to be addressed.
According to the results of the study in which an
ergolytic effect was produced in response to a single
dose of beetroot juice administered 120 min before
exercise, future investigations should determine the
most appropriate timing of supplementation to
optimize its ergogenic potential.
Finally, owing to the possible beneficial impacts of
beetroot juice, we will need to assess the
interactions of beetroot juice with other
supplements of proven ergogenic effects in this type
of exercise effort such as caffeine, creatine, β-alanine
and sodium bicarbonate.
Acknowledgements
Not applicable.
Funding
There were no sources of funding for this research.
Availability of data and materials
Data sharing not applicable to this article as no datasets were generated or
analysed during the current study.
Authorscontributions
R.D. and M.V.G.-G. conceived and designed the review; E.C., P.G.-F. and F.M.-
O. selected the articles included; E.C., M.C.L.-E. and P.V.-H. analyzed the
articles included; P.G.-F., F.M.-O. and P.V.-H. translated the manuscript into
English; R.D., J.L.M.-M., E.C., S.F.S. and M.V.G.-C. prepared the figures and
tables and drafted the manuscript; R.D., J.L.M.-M., E.C., P.G.-F., F.M.-O., M.C.L.-E.,
P.V.-H., S.F.S. and M.V.G.-C. edited and revised manuscript; R.D., J.L.M.-M., E.C.,
P.G.-F., F.M.-O., M.C.L.-E., P.V.-H., S.F.S. and M.V.G.-C. Approved the final version
of the manuscript.
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 9 of 12
PublishersNote
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
Author details
1
Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El
Sabio University, Madrid, Spain.
2
TecnoCampus. GRI-AFIRS, School of Health
Sciences, Pompeu Fabra University, Mataró, Barcelona, Spain.
3
NutriScience,
C/Paco León, 1, 14010 Córdoba, Spain.
4
Physical Activity and Sport Sciences,
Physical Education Departament, University of Lavras, Lavras, Brazil.
Received: 6 June 2017 Accepted: 7 December 2017
References
1. Paton CD, Hopkins WG. Variation in performance of elite cyclists from race
to race. Eur J Sport Sci. 2006;6:2531.
2. Koncic MZ, Tomczyk M. New insights into dietary supplements used in
sport: active substances, pharmacological and side effects. Curr Drug
Targets. 2013;14:107992.
3. Australian Institute of Sport. ABCD classification system. 2017. Available online: http://
www.ausport.gov.au/ais/nutrition/supplements/classification (Accessed on 11 Apr 2017).
4. Burke LM. Practical issues in evidence-based use of performance
supplements: supplement interactions, repeated use and individual
responses. Sports Med. 2017;47:79100.
5. Close GL, Hamilton L, Philps A, Burke L, Morton JP. New strategies in sport
nutrition to increase exercise performance. Free Radic Biol Med. 2016;5:307.
6. Burnley B, Jones AM. Oxygen uptake kinetics as a determinant of sports
performance. Eur J Sport Sci. 2007;7:6379.
7. Morton RH. The critical power and related whole-body bioenergetic
models. Europ J Appl Physiol. 2006;96:33954.
8. Chamari K, Padulo J. Aerobicand anaerobicterms used in exercise
physiology: a critical terminology reflection. Sports Med Open. 2015;1:9.
9. Gaitanos GC, Williams C, Boobis LH, Brooks S. Human muscle metabolism
during intermittent maximal exercise. J Appl Physiol. 1993;75:7129.
10. Chamari K, Ahmaidi S, Blum JY, Hue O, Temfemo A, Hertogh C, et al.
Venous blood lactate increase after vertical jumping in volleyball athletes.
Eur J Appl Physiol. 2001;85:1914.
11. Spencer MR, Gastin PB. Energy system contribution during 200- to 1500-m
running in highly trained athletes. Med Sci Sports Exerc. 2001;33:15762.
12. Jones AM. Influence of dietary nitrate on the physiological determinants of
exercise performance: a critical review. Appl Physiol Nutr Metab. 2014;39:101928.
13. Stamler JS, Meissner G. Physiology of nitric oxide in skeletal muscle. Physiol
Rev. 2009;81:20937.
14. Lundberg JO, Weitzberg E. NO-synthase independent NO generation in
mammals. Biochem Biophys Res Commun. 2010;396:3945.
15. Potter L, Angove H, Richardson D, Cole J. Nitrate reduction in the periplasm
of gram-negative bacteria. Adv Microb Physiol. 2001;45:51112.
16. Lundberg JO, Weitzberg E, Gladwin MT. The nitrate-nitrite-nitric oxide pathway
in physiology and therapeutics. Nat Rev Drug Discov. 2008;7:15667.
17. Raat NJ, Shiva S, Gladwin MT. Effects of nitrite on modulating ROS generation
following ischemia and reperfusion. Adv Drug Deliv. 2009;61:33950.
18. Lundberg JO, Govoni M. Inorganic nitrate is a possible source for systemic
generation of nitric oxide. Free Radic Biol Med. 2004;37:395400.
19. Larsen FJ, Ekblom B, Lundberg JO, Weitzberg E. Effects of dietary nitrate on
oxygen cost during exercise. Acta Physiol. 2007;191:5966.
20. Ferguson SK, Hirai DM, Copp SW, Holdsworth CT, Allen JD, Jones AM, et al.
Impact of dietary nitrate supplementation via beetroot juice on exercising
muscle vascular control in rats. J Physiol. 2013;591:54757.
21. Ignarro LJ, Adams JB, Horowitz PM. Activation of soluble guanylate cyclase by NO-
hemoproteins involves NO-heme exchange. J Biol Chem. 1986;261:49975002.
22. Furchgott R, Jothianandan D. Endothelium-dependent and -independent
vasodilation involving cyclic GMP: relaxation induced by nitric oxide, carbon
monoxide and light. Blood Vessels. 1991;28:5261.
23. Erzurum SC, Ghosh S, Janocha AJ, Xu W, Bauer S, Bryan NS, et al. Higher
blood flow and circulating NO products offset high-altitude hypoxia among
Tibetans. Proc Natl Acad Sci U S A. 2007;104:175938.
24. Puype J, Ramaekers M, Thienen R, Deldicque L, Hespel P. No effect of
dietary nitrate supplementation on endurance training in hypoxia. Scand J
Med Sci Sports. 2015;25:23441.
25. Tong L, Heim RA, Wu S. Nitric oxide: a regulator of eukaryotic initiation
factor 2, kinases. Free Radic Biol Med. 2011;50:171725.
26. Dejam A, Hunter C, Schechter A, Gladwin M. Emerging role of nitrite in
human biology. Blood Cells Mol Dis. 2004;32:4239.
27. Pinna M, Roberto S, Milia R, Maronquiu E, Olla S, Loi A. Effect of beetroot juice
supplementation on aerobic response during swimming. Nutrients. 2014;6:60515.
28. Handzlik L, Gleeson M. Likely additive Ergogenic effects of combined
Preexercise dietary nitrate and caffeine ingestion in trained cyclists. ISRN
Nutr. 2013:396581. https://doi.org/10.5402/2013/396581.
29. Boorsma RK, Whitfield SL. Beetroot juice supplementation does not improve
performance of elite 1500-m runners. Med Sci Sports Exerc. 2014;46:232634.
30. Arnold J, James L, Jones T, Wylie L, Macdonald J. Beetroot juice does not
enhance altitude running performance in well-trained athletes. Appl Physiol
Nutr Metab. 2015;40:5905.
31. MacLeod KE, Nugent SF, Barr S, Khoele MS, Sporer BC, Maclnnis MJ. Acute
beetroot juice supplementation does not improve cycling performance in
Normoxia or moderate hypoxia. Int J Sport Nutr Exerc Metab. 2015;25:35966.
32. Vanhatalo A, Bailey SJ, Blackwell JR, DiMenna FJ, Pavey TG, Wilkerson DP, et al.
Acute and chronic effects of dietary nitrate supplementation on blood pressure
and the physiological responses to moderate-intensity and incremental exercise.
Am J Physiol Regul Integr Comp Physiol. 2010;299:112131.
33. Lansley KE, Winyard PG, Bailey SJ, Vanhatalo A, Wilkerson DP, Blackwell JR, et
al. Acute dietary nitrate supplementation improves cycling time trial
performance. Med Sci Sports Exerc. 2011;43:112531.
34. Cermak N, Gibala M, Van Loon J. Nitrate Supplementations improvement of
10-km time-trial performance in trained cyclists. Int J Sport Nutr Exerc Metab.
2012;22:6471.
35. Wilkerson DP, Hayward GM, Bailey SJ, Vanhatalo A, Blackwell JR, Jones AM.
Influence of acute dietary nitrate supplementation on 50 mile time trial
performance in well-trained cyclists. Eur J Appl Physiol. 2012;112:412734.
36. Breese BC, McNarry MA, Marwood S, Blackwell JR, Bailey SJ, Jones AM. Beetroot
juice supplementation speeds O
2
uptake kinetics and improves exercise
tolerance during severe-intensity exercise initiated from an elevated metabolic
rate. Am J Physiol Regul Integr Comp Physiol. 2013;305:144150.
37. Kelly J, Vanhatalo A, Wilkerson D, Wylie L, Jones AM. Effects of nitrate on the
power-duration relationship for severe-intensity exercise. Med Sci Sports
Exerc. 2013;45:1798806.
38. Muggeridge DJ, Howe CF, Spendiff O, Pedlar C, James PE, Easton C. The
effects of a single dose of concentrated beetroot juice on performance in
trained Flatwater kayakers. Int J Sport Nutr Exerc Metab. 2013;23:498506.
39. Kelly J, Vanhatalo A, Bailey SJ, Wylie LJ, Tucker C, List S, et al. Dietary nitrate
supplementation: effects on plasma nitrite and pulmonary O
2
uptake
dynamics during exercise in hypoxia and normoxia. Am J Physiol Regul
Integr Comp Physiol. 2014;307:92030.
40. Lane S, Hawley J, Desbrow B, Jones AM, Blackwell J, Ross ML. Single and
combined effects of beetroot juice and caffeine supplementation on
cycling time trial performance. Appl Physiol Nutr Metab. 2014;39:10507.
41. Muggeridge DJ, Howe C, Spendiff O, Pedlar C, James P, Easton C. A single
dose of beetroot juice enhances cycling performance in simulated altitude.
Med Sci Sports Exerc. 2014;46:14350.
42. ThompsonK,TurnerbL,PrichardbJ,DoddbF,KennedybD,HaskellbC,etal.
Influence of dietary nitrate supplementation on physiological and cognitive
responses to incremental cycle exercise. Respir Physiol Neurobiol. 2014;193:1120.
43. Glaister M, Pattison JR, Muniz-Pumares D, Patterson SD, Foley P. Effects of
dietary nitrate, caffeine, and their combination on 20-km cycling time trial
performance. J Strength Cond Res. 2015;29:16574.
44. Peeling P, Cox G, Bullock N, Burke L. Beetroot juice improves on-water 500 M
time-trial performance, and laboratory-based paddling economy in national and
international-level kayak athletes. Int J Sport Nutr Exerc Metab. 2015;25:27884.
45. Whitfield J, Ludzki A, Heigenhauser G, Senden S, Verdijk L, Van L, et al.
Beetroot juice supplementation reduces whole body oxygen consumption
but does not improve indices of mitochondrial efficiency in human skeletal
muscle. J Physiol. 2016;594:42135.
46. Bescós R, Sureda A, Tur JA, Pons A. The effect of nitric-oxide-related supplements
on human performance. Sports Med. 2012;42:119.
47. Hoon MW, Johnson NA, Chap man PG, Burke LM. The effect of nitrate
supplementation on exercise performance in healthy individuals: a
systematic review and meta-analysis. Int J Sport Nutr Exerc Metab.
2013;23:52232.
48. Clements WT, Lee SR, Bloomer RJ. Nitrate ingestion: a review of the health
and physical performance effects. Nutrients. 2014;6:522464.
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 10 of 12
49. Pawlak-Chaouch M, Boissiere J, Gamelin FX, Cuvelier G, Berthoin S,
Aucouturier J. Effect of dietary nitrate supplementation on metabolic rate
during rest and exercise in human: a systematic review and a meta-analysis.
Nitric Oxide. 2016;53:6576.
50. Domínguez R, Cuenca E, Maté-Muñoz JL, García-Fernández P, Serra-Paya N,
Estevan MC, et al. Effects of beetroot juice supplementation on
cardiorespiratory endurance in athletes. A systematic review Nutrients. 2017;9:1.
51. McMahon NF, Leveritt MD, Pavey TG. The effect of dietary nitrate
supplementation on endurance exercise performance in healthy adults: a
systematic review and meta-analysis. Sports Med. 2017;47:73556.
52. Hernández A, Schiffer TA, Ivarsson N, Cheng AJ, Bruton JD, Lundberg JO, et
al. Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse
fasttwitch muscle. J Physiol. 2012;590:357583.
53. Martin K, Smee D, Thompson KG, Rattray B. No improvement of repeated-Sprint
performance with dietary nitrate. Int J Sports Physiol Perform. 2014;9:84550.
54. Aucouturier J, Boissiere J, Pawlak-Chaouch M, Cuvelier G, Gamelin FX. Effect
of dietary nitrate supplementation on tolerance to supramaximal intensity
intermittent exercise. Nitric Oxide. 2015;49:1625.
55. Buck CL, Henry T, Guelfi K, Dawson B, McNaughton LR, Wallman K. Effects of
sodium phosphate and beetroot juice supplementation on repeated-sprint
ability in females. Eur J Appl Physiol. 2015;115:220513.
56. Thompson C, Wylie LJ, Fulford J, Kelly J, Black MI, McDonagh STJ, et al.
Dietary nitrate improves sprint performance and cognitive function during
prolonged intermittent exercise. Eur J Appl Physiol. 2015;115:182534.
57. Clifford T, Berntzen B, Davison GW, West DJ, Howatson G, Stevenson EJ.
Effects of beetroot juice on recovery of muscle function and performance
between bouts of repeated Sprint exercise. Nutrients. 2016;8:506.
58. Mosher SL, Sparks SA, Williams EL, Bentley DJ, McNaughton LR. Ingestion of
a nitric oxide enhancing supplement improves resistance exercise
performance. J Strength Cond Res. 2016;30:35204.
59. Rimer EG, Peterson LR, Coggan AR, Martin JC. Increase in maximal cycling
power with acute dietary nitrate supplementation. Int J Sports Physiol
Perform. 2016;11:71520.
60. Wylie LJ, Mohr M, Krustrup P, Jackman SR, Ermιdis G, Kelly J, et al. Dietary
nitrate supplementation improves team sport-specific intense intermittent
exercise performance. Eur J Appl Physiol. 2013;113:167384.
61. Domínguez R, Garnacho-Castaño MV, Maté-Muñoz JL. Efectos del
entrenamiento contra resistencias o resistance training en diversas
patologías. Nutr Hosp. 2016;33:71933.
62. Ratamess NA, Albar BA, Evetoch TK, Housh TJ, Kibler WB, Kraemer WJ, et al.
Special communication. American College of Sports Medicine position
stand: progression models in resistance training for healthy adults. Med Sci
Sports Exerc. 2009;41:687708.
63. Garnacho-Castaño MV, Domínguez R, Maté-Muñoz JL. Understanding the
meaning of the lactate threshold in resistance exercises. Int J Sports Med.
2015;36:3717.
64. Garnacho-Castaño MV, Domínguez R, Ruiz-Solano P, Maté-Muñoz JL. Acute
physiological and mechanical responses during resistance exercise executed
at the lactate threshold workload. J Strength Cond Res. 2015;29:286773.
65. Carr BM, Webster MJ, Boyd JC, Hudson GM, Scheett TP. Sodium bicarbonate
supplementation improves hypertrophy-type resistance exercise
performance. Eur J Appl Physiol. 2013;113:74352.
66. Phillips SM. Nutritional supplements in support of resistance exercise to
counter age-related sarcopenia. Adv Nutr. 2015;6:45260.
67. Tomlin DL, Wenger HA. The relationship between aerobic fitness and
recovery from high intensity intermittent exercise. Sports Med. 2001;31:111.
68. Vanhatalo A, Fulford J, Bailey SJ, Blackwell JR, Winyard PG, Jones AM. Dietary
nitrate reduces muscle metabolic perturbation and improves exercise
tolerance in hypoxia. J Physiol. 2011;589:551728.
69. Bloomer JR, Farney TM, Trepanowski JF, McCarthy CG, Canale RE, Schilling
BK. Research article comparison of preworkout nitric oxide stimulating
dietary supplements on skeletal muscle oxygen saturation, blood nitrate/
nitrite, lipid peroxidation, and upper body exercise performance in
resistance trained men. J Int Soc Sports Nutr. 2010;7:115.
70. Spencer M, Bishop D, Dawson B, Goodman C. Physiological and metabolic
responses of repeated-sprint activities. Sports Med. 2005;35:102544.
71. ODonoghue P, Ingram B. A notational analysis of elite tennis strategy. J
Sport Sci. 2001;19:10715.
72. Felippe LC, Lopes-Silva JP, Bertuzzi R, McGinley C, Lima-Silva AE. Separate
and combined effects of caffeine and sodium-bicarbonate intake on judo
performance. Int J Sports Physiol Perform. 2016;11:2216.
73. Mujika I. Nutrition in team sports. Ann Nutr Metab. 2010;57:2635.
74. Fitzsimons M, Dawson BT, Ward D, Wilkinson A. Cycling and running tests
of repeated sprint ability. Aust J Sci Med Sport. 1993;25:827.
75. Krustrup P, Mohr M, Steensberg A, Bencke J, Kjaer M, Bangsbo J. Muscle and
blood metabolites during a soccer game: implications for sprint
performance. Med Sci Sports Exerc. 2006;38:116574.
76. Krustrup P, Söderlund K, Relu MU, Ferguson RA, Bangsbo J. Heterogeneous
recruitment of quadriceps muscle portions and fibre types during moderate
intensity knee-extensor exercise: effect of thigh occlusion. Scand J Med Sci
Sports. 2009;19:57684.
77. Lucía A, Sánchez O, Carvajal A, Chicharro JL. Analysis of the aerobic-anaerobic
transition in elite cyclists during incremental exercise with the use of
electromyography. Br J Sports Med. 1999;33:17885.
78. Syrotuik DG, Bell GJ. Acute creatine monohydrate supplementation: a
descriptive physiological profile of responders vs. nonresponders. J Strength
Cond Res. 2004;18:6107.
79. Volek JS, Kraemer WJ. Creatine supplementation: its effect on human muscular
performance and body composition. J Strength Cond Res. 1996;10:20010.
80. Kendrick IP, Kim HJ, Harris RC, Kim CK, Dang VH, Lam TQ, et al. The effect of
4 weeks b-alanine supplementation and isokinetic training on carnosine
concentrations in type I and II human skeletal muscle fibres. Eur J Appl
Physiol. 2009;106:1318.
81. Fulford J, Winyard PG, Vanhatalo A, Bailey SJ, Blackwell JR, Jones AM.
Influence of dietary nitrate supplementation on human skeletal muscle
metabolism and force production during maximum voluntary contractions.
Pflugers Arch. 2013;465:51728.
82. Wallimann T, Tokarska-Schlattner M, Schlattner U. The creatine kinase
system and pleiotropic effects of creatine. Amino Acids. 2011;40:127196.
83. Trivedi B, Daniforth WH. Effect of pH on the kinetics of frog muscle
phosphofructokinase. J Biol Chem. 1966;241:41102.
84. Sahlin K, Harris RC. The creatine kinase reaction: a simple reaction with
functional complexity. Amino Acids. 2011;40:13637.
85. Hobson RM, Saunders B, Ball G, Harris RC, Sale C. Effects of beta-alanine
supplementation on exercise performance: a review by meta-analysis.
Amino Acids. 2012;43:2537.
86. Messonier L, Kristensen M, Juel C, Denis C. Importance of pH regulation and
lactate/H+ transport capacity for work production during supramaximal
exercise in humans. J Appl Physiol. 2007;102:193644.
87. Sterlingwerff T, Decombaz J, Harris RC, Boesch C. Optimizing human in vivo
dosing and delivery of ß-alanine supplements for muscle carnosine
synthesis. Amino Acids. 2012;43:5765.
88. Harris RC, Tallon MJ, Dunnett M, Boobis L, Coakley J, Kim HJ, et al. The
absorption of orally supplied beta-alanine and its effect on muscle
carnosine synthesis in human vastus lateralis. Amino Acids. 2006;30:27989.
89. Requena B, Zabala M, Padial P, Feriche B. Sodium bicarbonate and sodium
citrate: ergogenic aids? J Strength Cond Res. 2005;19:21324.
90. Domínguez R, Lougedo JH, Maté-Muñoz JL, Garnacho-Castaño MV. Efectos
de la suplementación con β-alanina sobre el rendimiento deportivo. Nutr
Hosp. 2015;31:15569.
91. Tobias G, Benatti FB, De Salles V, Roschel H, Gualano B, Sale C, et al. Additive
effects of beta-alanine and sodium bicarbonate on upper-body intermittent
performance. Amino Acids. 2013;45:30917.
92. Gray SR, Söderlund K, Ferguson RA. ATP and phosphocreatine utilization in
single human muscle fibres during the development of maximal power
output at elevated muscle temperatures. J Sports Sci. 2008;26:7017.
93. Poole DS, Copp SW, Hirai DM, Musch TI. Dynamics of muscle microcirculatory
and blood-myocyte O(2) flux during contractions. Acta Physiol. 2011;202:293310.
94. Bogdanis GC, Nevill ME, Lakomy HK, Graham CM, Louis G. Effects of active
recovery on power output during repeated maximal sprint cycling. Eur J
Appl Physiol Occup Physiol. 1996;74:4619.
95 . Haseler LJ, Hogan MC, Richardson RS. Skeletal muscle phosphocreatine recovery in
exercise-trained humans is dependent on O2 availability. J Appl Physiol. 1999;86:20138.
96. Martin JC, Brown NA, Anderson FC, Spirduso WW. A governing relationship
for repetitive muscular contraction. J Biomech. 2000;33:96974.
97. Marechal G, Beckers-Bleukx G. Effect of nitric oxide on the maximal velocity
of shortening of a mouse skeletal muscle. Pflugers Arch. 1998;436:90613.
98. Marechal G, Gailly P. Effects of nitric oxide on the contraction of skeletal
muscle. Cell Mol Life Sci. 1999;55:1088102.
99. Kramer SJ, Baur DA, Spicer MT, Vukovich MD, Ormsbee MJ. The effect of six
days of dietary nitrate supplementation on performance in trained CrossFit
athletes. J Int Soc Sports Nutr. 2016;13:39.
Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 11 of 12
100. Bobbert MF, Van Soest AJ. Why do people jump the way they do? Exerc
Sport Sci Rev. 2001;29:95102.
101. Rodacki ALF, Fowler NE, Bennett SJ. Multi-segment coordination: fatigue
effects. Med Sci Sports Exerc. 2001;33:115767.
102. Sánchez-Medina L, González-Badillo JJ. Velocity loss as an indicator of
neuromuscular fatigue during resistance training. Med Sci Sports Exerc.
2011;43:172534.
103. Rodacki AL, Fowler NE, Bennett SJ. Vertical jump coordination: fatigue
effects. Med Sci Sports Exerc. 2002;34:10516.
104. Mosteiro-Muñoz F, Domínguez R. Effects of inertial overload resistance training
on muscle function. Rev Int Med Cienc Act Fís Deporte. 2017;In press.
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Domínguez et al. Journal of the International Society of Sports Nutrition (2018) 15:2 Page 12 of 12
... These include health-enhancing effects such as the regulation of blood flow and blood pressure, the maintenance of gastric integrity, and protection against ischemic tissue damage [17][18][19]. They have also been found to be related to improved performance in different types of disciplines and through different supplements, improving vasodilation and angiogenesis, causing an increase in mitochondrial respiration and biogenesis, positively impacting glucose uptake, optimizing oxygen regulation, and improving muscle contraction [20][21][22][23][24][25][26]. ...
... Considering the already known role of Cit in the synthesis and production of NO and the possible effects associated with this compound, the potential impact of its supplementation on physical performance and associated variables in different types of exercise and using different tests has been studied in recent years [59,65]. A positive impact on various training adaptations related to other NO pathway supplements has also been suggested [24,26]. However, studies examining such effects are scarce. ...
... In view of the promising results, further studies should be proposed that use a chronic supplementation methodology and at higher doses than the usual ones (6 g/min). This would make it possible to measure not only the acute effects on performance but also the possible physiological and metabolic adaptations already analyzed for other sup-plements [26]. Although this systematic review and meta-analysis has not been able to establish relationships in terms of the sample of studies, it may be of interest to analyze the difference in effects between participants of different levels, due to the differences already reported in similar supplements between elite and amateur athletes [24]. ...
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Supplementation with Citrulline (Cit) has been shown to have a positive impact on aerobic exercise performance and related outcomes such as lactate, oxygen uptake (VO2) kinetics, and the rate of perceived exertion (RPE), probably due to its relationship to endogenous nitric oxide production. However, current research has shown this to be controversial. The main objective of this systematic review and meta-analysis was to analyze and assess the effects of Cit supplementation on aerobic exercise performance and related outcomes, as well as to show the most suitable doses and timing of ingestion. A structured literature search was carried out by the PRISMA® (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and PICOS guidelines in the following databases: Pubmed/Medline, Scopus, and Web of Science (WOS). A total of 10 studies were included in the analysis, all of which exclusively compared the effects of Cit supplementation with those of a placebo group on aerobic performance, lactate, VO2, and the RPE. Those articles that used other supplements and measured other outcomes were excluded. The meta-analysis was carried out using Hedges’ g random effects model and pooled standardized mean differences (SMD). The results showed no positive effects of Cit supplementation on aerobic performance (pooled SMD = 0.15; 95% CI (−0.02 to 0.32); I2, 0%; p = 0.08), the RPE (pooled SMD = −0.03; 95% CI (−0.43 to 0.38); I2, 49%; p = 0.9), VO2 kinetics (pooled SMD = 0.01; 95% CI (−0.16 to 0.17); I2, 0%; p = 0.94), and lactate (pooled SMD = 0.25; 95% CI (−0.10 to 0.59); I2, 0%; p = 0.16). In conclusion, Cit supplementation did not prove to have any benefits for aerobic exercise performance and related outcomes. Where chronic protocols seemed to show a positive tendency, more studies in the field are needed to better understand the effects.
... There are three types of NOS in the muscle; (1) neural (nNOS or NOS-1), (2) cytokine-inducible (iNOS or NOS-2), and (3) endothelial (eNOS or NOS-3) [17]. NO is a signalling molecule responsible for vasodilation, glucose uptake, mitochondrial respiration, calcium handling, and muscle contractility [18][19][20]. All of these are associated with improvements in exercise performance [20][21][22][23]. ...
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Consumption of amino acids L-arginine (L-Arg) and L-citrulline (L-Cit) are purported to increase nitric oxide (NO) production and improve physical performance. Clinical trials have shown relatively more favorable outcomes than not after supplementing with L-Cit and combined L-Arg and L-Cit. However, in most studies, other active ingredients such as malate were included in the supplement. Therefore, the aim of this study was to determine the efficacy of consuming standalone L-Arg, L-Cit, and their combination (in the form of powder or beverage) on blood NO level and physical performance markers. A systematic review was undertaken following PRISMA 2020 guidelines (PROSPERO: CRD42021287530). Four electronic databases (PubMed, Ebscohost, Science Direct, and Google scholar) were used. An acute dose of 0.075 g/kg of L-Arg or 6 g L-Arg had no significant increase in NO biomarkers and physical performance markers (p > 0.05). Consumption of 2.4 to 6 g/day of L-Cit over 7 to 16 days significantly increased NO level and physical performance markers (p < 0.05). Combined L-Arg and L-Cit supplementation significantly increased circulating NO, improved performance, and reduced feelings of exertion (p < 0.05). Standalone L-Cit and combined L-Arg with L-Cit consumed over several days effectively increases circulating NO and improves physical performance and feelings of exertion in recreationally active and well-trained athletes.
... Beetroot juice has been studied primarily in endurance athletes because of nitrates' touted impact on oxygenation and skeletal muscles' cellular respiration. However, trained sprinters, kayakers, sprint cyclists, soccer players, and team sport athletes had increased average power, max power, and in-game distance covered during supplementation (49). ...
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Elite athletes often use nutritional supplements to improve performance and gain competitive advantage. The prevalence of nutrient supplementation ranges from 40% to 100% among trained athletes, yet few athletes have a trusted source of information for their supplement decisions and expected results. This critical analysis review evaluates systematic reviews, meta-analyses, randomized control trials, and crossover trials investigating commonly used supplements in sport: caffeine, creatine, beta-alanine (β-alanine), branched chain amino acids (BCAAs), and dietary nitrates. By reviewing these supplements' mechanisms, evidence relating directly to improving sports performance, and ideal dosing strategies, we provide a reference for athletes and medical staff to personalize supplementation strategies. Caffeine and creatine impact power and high-intensity athletes, β-alanine, and BCAA mitigate fatigue, and dietary nitrates improve endurance. With each athlete having different demands, goals to maximize their performance, athletes and medical staff should collaborate to personalize supplementation strategies based on scientific backing to set expectations and potentiate results.
... 7,63 BRJ is a dietary supplement rich in inorganic nitrate (NO 3 -), this being a precursor of nitric oxide (NO) through the NO 3 --nitrite (NO 2 -)-NO pathway. 18 NO 3 is considered biologically inert, but in the oral cavity NO 3 is reduced to NO 2 by the salivary glands and the facultative anaerobic bacteria nitrate reductase present on the dorsal surface of the tongue. 39,51 In the stomach, NO 2 is partially reduced to NO, resulting in increased levels of and NO in the systemic circulation. ...
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Background Beetroot juice (BRJ) is used as an ergogenic aid, but no previous study has analyzed the effect this supplement has on the production of explosive force and muscular endurance in physically active women. Hypothesis BRJ improves explosive force and muscular endurance in the lower limbs of physically active women. Study design Randomized double-blind crossover study. Level of evidence Level 3 Methods Fourteen physically active women performed a countermovement jump (CMJ) test, a back squat test for assessing velocity and power at 50% and 75% of one-repetition maximum (1RM), and the number of repetitions on a muscular endurance test consisting of 3 sets at 75% of 1RM in a resistance training protocol comprising 3 exercises (back squat, leg press, and leg extension). The participants performed the test in 2 sessions, 150 minutes after ingesting 70 mL of either BRJ (400 mg of nitrate) or a placebo (PLA). Results A greater maximum height was achieved in the CMJ after consuming BRJ compared with a PLA ( P = 0.04; effect size (ES) = 0.34). After a BRJ supplement at 50% 1RM, a higher mean velocity [+6.7%; P = 0.03; (ES) = 0.39 (–0.40 to 1.17)], peak velocity (+6%; P = 0.04; ES = 0.39 [−0.40 to 1.17]), mean power (+7.3%; P = 0.02; ES = 0.30 [−0.48 to 1.08]) and peak power (+6%; P = 0.04; ES = 0.20 [−0.59 to 0.98]) were attained in the back squat test. In the muscular endurance test, BRJ increased performance compared with the PLA ( P < 0.00; η p ² = 0.651). Conclusion BRJ supplements exert an ergogenic effect on the ability to produce explosive force and muscular endurance in the lower limbs in physically active women. Clinical relevance If physically active women took a BRJ supplement 120 minutes before resistance training their performance could be enhanced.
... Fresh beetroot or beet powder, or extracted pigments, are used to enhance red color of tomato pastes, sauces, jams, jellies, ice creams, desserts, & morning cereals. It is acknowledged to include antioxidants due to presence of nitrogen pigments termed betalains, which are mostly composed of red-violet colored betacyanins [1]. It [4]. ...
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beet root (Beta vulgaris L.), also acknowledged as chuk&er, is renowned due to its sweetness; it has higher sugar content but is low in calories. Beetroot is classified botanically as a herbaceous biennial of Chenopodiaceae family. Fresh beets provide a nutritional benefit in form of ir green tops, which are high in beta-carotene, iron, & calcium. It essentially refers to cool-season vegetable crops that are produced all over globe. Beetroot is rich in antioxidants & minerals such as potassium magnesium, betalaine, , vitamin C, & sodium, & comes in a variety of hues ranging from yellow to red in bulb. Beetroots with a deep red hue are most widespread for human consumption, both cooked & raw in salads & juices. Carotenoids, saponins, betacyanines, betanin, polyphenols, & flavonoids are active chemicals found in beets. As a result, beetroot consumption may be regarded a cancer-prevention strategy. Betacyanins & betaxanthins are most common betalains found in beetroot. Betalains are a dietary supplement used to prevent & cure hypertension & cardiovascular disease. y have antibacterial & antiviral properties, as well as ability to suppress cell growth in human carcinoma cells. Osmotic dehydration may also be used to make beetroot c&y, which can be used in bread goods, confectionery, & ice creams, among or things.
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Current sports nutrition guidelines recommend that athletes only take supplements following an evidence-based analysis of their value in supporting training outcomes or competition performance in their specific event. While there is sound evidence to support the use of a few performance supplements under specific scenarios (creatine, beta-alanine, bicarbonate, caffeine, nitrate/beetroot juice and, perhaps, phosphate), there is a lack of information around several issues needed to guide the practical use of these products in competitive sport. First, there is limited knowledge around the strategy of combining the intake of several products in events in which performance benefits are seen with each product in isolation. The range in findings from studies involving combined use of different combinations of two supplements makes it difficult to derive a general conclusion, with both the limitations of individual studies and the type of sporting event to which the supplements are applied influencing the potential for additive, neutral or counteractive outcomes. The repeated use of the same supplement in sports involving two or more events within a 24-h period is of additional interest, but has received even less attention. Finally, the potential for individual athletes to respond differently, in direction and magnitude, to the use of a supplement seems real, but is hard to distinguish from normal day to day variability in performance. Strategies that can be used in research or practice to identify whether individual differences are robust include repeat trials, and the collection of data on physiological or genetic mechanisms underpinning outcomes.
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Athletes use nutritional supplementation to enhance the effects of training and achieve improvements in their athletic performance. Beetroot juice increases levels of nitric oxide (NO), which serves multiple functions related to increased blood flow, gas exchange, mitochondrial biogenesis and efficiency, and strengthening of muscle contraction. These biomarker improvements indicate that supplementation with beetroot juice could have ergogenic effects on cardiorespiratory endurance that would benefit athletic performance. The aim of this literature review was to determine the effects of beetroot juice supplementation and the combination of beetroot juice with other supplements on cardiorespiratory endurance in athletes. A keyword search of DialNet, MedLine, PubMed, Scopus and Web of Science databases covered publications from 2010 to 2016. After excluding reviews/meta-analyses, animal studies, inaccessible full-text, and studies that did not supplement with beetroot juice and adequately assess cardiorespiratory endurance, 23 articles were selected for analysis. The available results suggest that supplementation with beetroot juice can improve cardiorespiratory endurance in athletes by increasing efficiency, which improves performance at various distances, increases time to exhaustion at submaximal intensities, and may improve the cardiorespiratory performance at anaerobic threshold intensities and maximum oxygen uptake (VO2max). Although the literature shows contradictory data, the findings of other studies lead us to hypothesize that supplementing with beetroot juice could mitigate the ergolytic effects of hypoxia on cardiorespiratory endurance in athletes. It cannot be stated that the combination of beetroot juice with other supplements has a positive or negative effect on cardiorespiratory endurance, but it is possible that the effects of supplementation with beetroot juice can be undermined by interaction with other supplements such as caffeine.
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Background While it is well established that dietary nitrate reduces the metabolic cost of exercise, recent evidence suggests this effect is maintained 24 h following the final nitrate dose when plasma nitrite levels have returned to baseline. In addition, acute dietary nitrate was recently reported to enhance peak power production. Our purpose was to examine whether chronic dietary nitrate supplementation enhanced peak power 24 h following the final dose and if this impacted performance in a heavily power-dependent sport. Methods In a double-blind, randomized, crossover design, maximal aerobic capacity, body composition, strength, maximal power (30 s Wingate), endurance (2 km rowing time trial), and CrossFit performance (Grace protocol) were assessed before and after six days of supplementation with nitrate (NO) (8 mmol·potassium nitrate·d⁻¹) or a non-caloric placebo (PL). A 10-day washout period divided treatment conditions. Paired t-tests were utilized to assess changes over time and to compare changes between treatments. Results Peak Wingate power increased significantly over time with NO (889.17 ± 179.69 W to 948.08 ± 186.80 W; p = 0.01) but not PL (898.08 ± 183.24 W to 905.00 ± 157.23 W; p = 0.75). However, CrossFit performance was unchanged, and there were no changes in any other performance parameters. Conclusion Consuming dietary nitrate in the potassium nitrate salt form improved peak power during a Wingate test, but did not improve elements of strength or endurance in male CrossFit athletes.
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Background Recent research into the use of dietary nitrates and their role in vascular function has led to it becoming progressively more popular amongst athletes attempting to enhance performance. Objective The objective of this review was to perform a systematic review and meta-analysis of the literature to evaluate the effect of dietary nitrate (NO3−) supplementation on endurance exercise performance. An additional aim was to determine whether the performance outcomes are affected by potential moderator variables. Data sourcesRelevant databases such as Cochrane Library, Embase, PubMed, Ovid, Scopus and Web of Science were searched for the following search terms ‘nitrates OR nitrate OR beetroot OR table beet OR garden beet OR red beet AND exercise AND performance’ from inception to October 2015. Study selectionStudies were included if a placebo versus dietary nitrate-only supplementation protocol was able to be compared, and if a quantifiable measure of exercise performance was ≥30 s (for a single bout of exercise or the combined total for multiple bouts). Study appraisal and synthesisThe literature search identified 1038 studies, with 47 (76 trials) meeting the inclusion criteria. Data from the 76 trials were extracted for inclusion in the meta-analysis. A fixed-effects meta-analysis was conducted for time trial (TT) (n = 28), time to exhaustion (TTE) (n = 22) and graded-exercise test (GXT) (n = 8) protocols. Univariate meta-regression was used to assess potential moderator variables (exercise type, dose duration, NO3− type, study quality, fitness level and percentage nitrite change). ResultsPooled analysis identified a trivial but non-significant effect in favour of dietary NO3− supplementation [effect size (ES) = −0.10, 95 % Cl = −0.27 to 0.06, p > 0.05]. TTE trials had a small to moderate statistically significant effect in favour of dietary NO3− supplementation (ES = 0.33, 95 % Cl = 0.15–0.50, p < 0.01). GXT trials had a small but non-significant effect in favour of dietary NO3− supplementation in GXT performance measures (ES = 0.25, 95 % Cl = −0.06 to 0.56, p > 0.05). No significant heterogeneity was detected in the meta-analysis. No statistically significant effects were observed from the meta-regression analysis. Conclusion Dietary NO3− supplementation is likely to elicit a positive outcome when testing endurance exercise capacity, whereas dietary NO3− supplementation is less likely to be effective for time-trial performance. Further work is needed to understand the optimal dosing strategies, which population is most likely to benefit, and under which conditions dietary nitrates are likely to be most effective for performance.
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This study examined the effects of beetroot juice (BTJ) on recovery between two repeated-sprint tests. In an independent groups design, 20 male, team-sports players were randomized to receive either BTJ or a placebo (PLA) (2 × 250 mL) for 3 days after an initial repeated sprint test (20 × 30 m; RST1) and after a second repeated sprint test (RST2), performed 72 h later. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), reactive strength index (RI), pressure-pain threshold (PPT), creatine kinase (CK), C-reactive protein (hs-CRP), protein carbonyls (PC), lipid hydroperoxides (LOOH) and the ascorbyl free radical (A(•-)) were measured before, after, and at set times between RST1 and RST2. CMJ and RI recovered quicker in BTJ compared to PLA after RST1: at 72 h post, CMJ and RI were 7.6% and 13.8% higher in BTJ vs. PLA, respectively (p < 0.05). PPT was 10.4% higher in BTJ compared to PLA 24 h post RST2 (p = 0.012) but similar at other time points. No group differences were detected for mean and fastest sprint time or fatigue index. MIVC, or the biochemical markers measured (p > 0.05). BTJ reduced the decrement in CMJ and RI following and RST but had no effect on sprint performance or oxidative stress.
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Resistance training should be included in all exercise programs that improve health and quality of life. These programs have been focusing on both concentric-eccentric contractions, however, a new type of resistance training based on eccentric contractions provided by inertial overload is being carried out. Therefore, the aim of the present study is to prove the effects of this kind of training based on eccentric contractions by inertial overload. Databases utilized to carry out information research were Web of Science, Pubmed, Medline, Dialnet and Scielo. Results would suggest that inertial training based on inertial overload produces maximal EMG and an earlier muscular hypertrophy compared to conventional resistance training, besides the fact it could be successful on muscle-tendon injuries.
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La fuerza infl uye directamente en el estado de salud y en la capacidad de fi tness, motivo por el que el entrenamiento contra resistencias o resistance training (RT) se incluye dentro de aquellos programas de ejercicio encaminados a mejorar la salud y calidad de vida. Debido a que muchas enfermedades cursan con alteración de la masa y funcionalidad muscular y a que el RT es la principal modalidad de ejercicio encaminada a mejorar la función muscular, el objetivo de la presente revisión bibliográfi ca ha sido exponer las evidencias actuales sobre las adaptaciones del RT, así como su posible aplicación en patologías como la obesidad, diabetes, dislipemia, hipertensión, cáncer, Parkinson, esclerosis múltiple o fibromialgia. El RT en estas enfermedades puede aumentar los niveles de masa muscular, disminuyendo los niveles de masa grasa, los niveles de ácidos grasos en sangre y la glucemia, incrementando la sensibilidad a la insulina, y disminuyendo los niveles de citokinas infl amatorias. El RT, además, mejora el gasto cardiaco y la funcionalidad endotelial, regulando la tensión arterial e incrementando el consumo de oxígeno. Las ganancias de fuerza muscular mejoran la funcionalidad y la calidad de vida, especialmente en población con una afectación neuromuscular grave, como pudieran ser los enfermos de esclerosis múltiple, fibromialgia o Parkinson. Por ello, el RT debe ser incorporado como parte del tratamiento en las personas que presentan determinado tipo de patologías.
Article
La fuerza infl uye directamente en el estado de salud y en la capacidad de fi tness, motivo por el que el entrenamiento contra resistencias o resistancetraining (RT) se incluye dentro de aquellos programas de ejercicio encaminados a mejorar la salud y calidad de vida. Debido a que muchasenfermedades cursan con alteración de la masa y funcionalidad muscular y a que el RT es la principal modalidad de ejercicio encaminada amejorar la función muscular, el objetivo de la presente revisión bibliográfi ca ha sido exponer las evidencias actuales sobre las adaptaciones delRT, así como su posible aplicación en patologías como la obesidad, diabetes, dislipemia, hipertensión, cáncer, Parkinson, esclerosis múltiple ofi bromialgia. El RT en estas enfermedades puede aumentar los niveles de masa muscular, disminuyendo los niveles de masa grasa, los nivelesde ácidos grasos en sangre y la glucemia, incrementando la sensibilidad a la insulina, y disminuyendo los niveles de citokinas infl amatorias. El RT,además, mejora el gasto cardiaco y la funcionalidad endotelial, regulando la tensión arterial e incrementando el consumo de oxígeno. Las gananciasde fuerza muscular mejoran la funcionalidad y la calidad de vida, especialmente en población con una afectación neuromuscular grave, comopudieran ser los enfermos de esclerosis múltiple, fi bromialgia o Parkinson. Por ello, el RT debe ser incorporado como parte del tratamiento enlas personas que presentan determinado tipo de patologías.
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