Effect of Beetroot Extract Supplementation on the Athletic Performance of Trained Rugby Athletes
Phase: NA
Conditions: Athletic Performance
Sponsor: Universidad Nacional de Colombia

 
 
Effect of Beetroot Extract Supplementation on the 
Athletic Performance of Trained Rugby Athletes  
 
 
NCT07106489 
 
 
Last version: January 15, 2025 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Effect of Beetroot Extract Supplementation on the Athletic Performance of 
Trained Rugby Athletes. 
Study Protocol: 
- 
Objective: 
To evaluate the effect of nitrate supplementation, based on the consumption of beetroot 
juice, on athletic performance in rugby players. 
- 
Design: 
The research use a quasi-experimental design, using a non-randomized, crossover 
controlled trial, with the aim of minimizing the effects associated with each athlete's 
individual performance patterns, given that each participant acted as their own control. A 
double-blind protocol was implemented. Participants were divided into two groups 
(Beetroot-Placebo and Placebo-Beetroot); the researcher prepared waffles containing 
both beetroot (a source of nitrates) and placebo. A person external to the study was 
responsible for administering the compounds to each group, ensuring the corresponding 
crossover was performed in the second phase of data collection, so that all participants 
received both the placebo and nitrate supplementation at the end of the study. 
- 
Methods 
Beetroot and placebo (Waffles): 
These are given to participants on the third day before the physical tests, to be consumed 
from that day onward, the following day, and on the day of the physical tests. To ensure 
consumption of the compounds two hours before physical activity, participants must send 
a photo of their consumption with their sports practice schedule, and two hours before 
their appointment for the physical tests. 
There is then a 3-day washout period, during which participants are not given any 
compounds and cannot consume foods rich in nitrates (they are given a list of these 
foods). The process is repeated with the crossover compound (those who received 
placebo receive beetroot, while those who received the placebo receive beetroot). 
- 
Physical Tests: 
The protocol implemented by Sella, F. et al. (2023) is followed, with the 40 meters 
sprint being the first test. Prior to performing the sprints, participants completed a 10-
minute standardized warm-up comprising jogging, dynamic stretches, running drills, 
and three stride-outs at increasing intensity. The physical tests are then performed, 
beginning with a 40-meter sprint. After an adequate 10-minute rest period, the Bronco 
test is performed. After 20 minutes, strength tests are performed, starting with the 
squat and then the bench press, and ending with the Borg scale. 

This protocol is followed on both testing days; participants perform tests on the 
same day of the following week, at the same time 
 
- 
Background 
Specifically, in the case of nitrates in rugby, the evidence is scarce. There are some 
studies, such as the one conducted by Esen et al. (2023), which evaluated the effect 
of beetroot supplementation on trained male rugby players. They were given an 
average of 12.8 mmol of nitrates and a placebo with less than 0.08 mmol of nitrates, 
ingested 3 hours before physical tests. These studies revealed no improvement in the 
yo-yo endurance test or the countermovement jump. 
 
On the other hand, there is the study conducted by López-Samanes et al. (2022) on 
semi-professional female rugby players, which studied the influence of beetroot on 
neuromuscular performance. Providing similar amounts of nitrates to the 
aforementioned study yielded a positive response in the countermovement jump 
exercise; however, there were no differences in speed, agility, strength, and 
endurance tests. Thus, despite the dose, differences are found depending on the 
protocol used. 
 
However, while specific studies on rugby are limited, there is research in sports or 
activities with similar characteristics. An example of this is the study by Domínguez et 
al. (2018), who evaluated the effect of beetroot supplementation on high-intensity 
intermittent exercise. Their research observed an improvement in performance when 
rest periods between efforts were short. These improvements were primarily attributed 
to increased resynthesis of phosphocreatine, which contributes to delaying its 
depletion. Increases in muscle power and speed were also reported, as well as a 
possible reduction in muscle fatigue, although the specific physiological pathway 
through which this response occurs is not yet fully understood. 
 
In his study, Fernandes (2021) conducted a literature search on nutritional 
supplements that improve performance in elite soccer players, revealing the use of 
various supplements such as creatine, caffeine, sodium bicarbonate, beta-alanine, 
nitrates (from beetroot), among others. The results, focused on nitrates, reveal that 6 
mmol of NO3, used for at least 5 days, consumed 2 hours before training, improves 
soccer players' performance. Furthermore, they emphasize the importance of 
doubling the dose on game day. This study, compared to those presented initially, 

highlights the need to find an appropriate protocol, including dosage and application 
time, for each specific sport. Although the trend for ball sports, according to these 
studies, implies the need for chronic, not just acute, intake, reflecting the need for 
further research in the field. 
 
Delleli et al. (2023) conducted a systematic review of randomized controlled clinical 
trials evaluating the effect of beetroot supplementation on combat sports performance. 
They concluded that there was an improvement in different aspects of athletic 
performance, both with a single supplementation and multiple doses, in different 
combat sports; mainly oxidative metabolism in isometric and isokinetic exercises; 
however, there is variability in the results, associated with both individual factors and 
the characteristics of each individual sport. There are also other systematic reviews 
(Murphy et al. 2022 and Tan et al. 2022) that reflect the study of nitrates in sports, 
including team sports, with variability in their results. Therefore, the need for further 
research on the subject is evident, mainly in Colombia, where no results on the study 
of nitrates in rugby are found. 
In addition, this supplement is endorsed by the Australian Institute of Sport (AIS) for 
use by classifying it in category A, due to its safety and level of scientific evidence 
(2022). 
- 
Human subjects protection review board 
Initially, the study was considered experimental and approved by the committee of the 
Faculty of Medicine of the National University of Colombia in minutes B.FM. 1. 002-CE-
043-24. However, as the necessary sample of volunteers for randomization was not 
obtained (44 people were required, but 10 were obtained), the study was changed from 
experimental to quasi-experimental, and the changes were reviewed and approved by 
the same committee in minutes 2.FM. 1. 002- CE 105-25. 
 
Bibliographic references:  
1. Australian Institute of Sport [AIS]. (2022). Position statement: Supplements and 
sports 
foods 
in 
high 
performance 
sport.  
https://www.ais.gov.au/nutrition/supplements 
2. Delleli, S., Ouergui, I., Messaoudi, H., Trabelsi, K., Glenn, J. M., Ammar, A., & 
Chtourou, H. (2023). Does Beetroot Supplementation Improve Performance in 
Combat Sports Athletes? A Systematic Review of Randomized Controlled Trials. 
Nutrients, 15(2), e398. https://doi.org/10.3390/nu15020398 
3. Esen, O., Karayigit, R., & Peart, D. J. (2023). Acute beetroot juice supplementation 
did not enhance intermittent running performance in trained rugby players. 

European 
Journal 
of 
Sport 
Science, 
23(12), 
2321–2328. 
https://doi.org/10.1080/17461391.2023.2230942 
4. Fernandes, H. (2021). Dietary and Ergogenic Supplementation to Improve Elite 
Soccer Players’ Performance. Annals of Nutrition and Metabolism, 77(4), 197-203. 
https://doi.org/10.1159/000516397 
5. López-Samanes, Á., Ramos-Álvarez, J. J., Miguel-Tobal, F., Gaos, S., Jodra, P., 
Arranz-Muñoz, R., Domínguez, R., & Montoya, J. J. (2022). Influence of Beetroot 
Juice Ingestion on Neuromuscular Performance on Semi-Professional Female 
Rugby Players: A Randomized, Double-Blind, Placebo-Controlled Study. Foods, 
11(22), e3614. https://doi.org/10.3390/foods11223614 
6. Murphy, M. J., Rushing, B. R., Sumner, S. J., & Hackney, A. C. (2022). Dietary 
supplements for athletic performance in women: Beta-alanine, caffeine, and 
nitrate. International Journal of Sport Nutrition and Exercise Metabolism, 32(4), 
311-323. https://doi.org/10.1123/ijsnem.2021-0176 
7. Sella, F. S., Hopkins, W. G., Beaven, C. M., McMaster, D. T., Gill, N. D., & Hébert-
Losier, K. (2023). The associations between physical-test performance and match 
performance in women’s Rugby Sevens players. Biology of Sport, 40(3), 775–785. 
https://doi.org/10.5114/biolsport.2023.119985 
8. Tan, R., Cano, L., Lago-Rodríguez, Á., & Domínguez, R. (2022). The effects of 
dietary nitrate supplementation on explosive exercise performance: A systematic 
review. International Journal of Environmental Research and Public Health, 19(2), 
e762. https://doi.org/10.3390/ijerph19020762 
 
Statistical Analysis Plan (SAP): 
A descriptive and exploratory analysis was performed on the collected data using the R 
program. Univariate tests were performed for the mean (paired Student t-test) or Wilcoxon 
depending on the type of variable (continuous or ordinal) and compliance with the 
assumptions of normality with a confidence level of 95%.  
𝑑= 𝑑̅
𝑠𝑑
 
Where: 
𝑑̅ = mean of the differences (Beetroot − Placebo) 
𝑠𝑑= standard deviation of the differences 
 
Thus, for the Wilcoxon test, the following was used: 
𝑟= 𝑍
√𝑛 

Where: 
𝑍= Z statistics of the test 
𝑛= number of participants with data in both conditions