An interventional study of Placebo and Beetroot juice supplementation in Nitrate and Placebo - Control, sponsored by Universidad Pontificia Comillas. Enrolling by invitation at 1 site in Spain. Open to female participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-03.
Sponsored by Universidad Pontificia Comillas · Not applicable, Interventional, and Treatment
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A randomized, double-blind, placebo-controlled study investigates the effects of 5 days of nitrate-rich beetroot juice supplementation (70 mL·day-¹; 6.4 mmol NO₃-·day-¹) on physical performance in female basketball players. Performance will be evaluated using jump, 30-m sprint, agility, and isometric mid-thigh pull (IMTP) tests, while RPE and potential side effects will be assessed through questionnaires. The study aims to address the limited evidence regarding the ergogenic effects of beetroot juice supplementation in female team-sport athletes.
Although beetroot juice supplementation, primarily due to its high inorganic nitrate (NO₃-) content, has been associated with improvements in endurance and high-intensity intermittent exercise performance, its potential ergogenic effects in team sports remain unclear, particularly in female athletes. This knowledge gap is especially relevant in basketball, a sport characterized by repeated bouts of sprinting, jumping, accelerating, decelerating, and changing direction. Therefore, this randomized, double-blind, placebo-controlled study aimed to investigate the effects of 5 consecutive days of nitrate-rich beetroot juice supplementation (70 mL·day-¹, providing 6.4 mmol NO₃-·day-¹) on physical performance in female basketball players. Following the supplementation period, performance was assessed through jumping performance, 30-m sprint, agility, and isometric mid-thigh pull (IMTP) tests. Additionally, rating of perceived exertion (RPE) and potential side effects associated with beetroot juice supplementation were assessed using questionnaires.
Universidad Pontificia Comillas is the lead sponsor of 19 studies on the registry; 4 are open to participants now.
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Exclusion Criteria:
Participants consumed one serving of 70 mL of nitrate-rich BJ (6.4 mmol of NO₃-; Beet-It-Pro Elite Shot, James White Drinks Ltd., Ipswich, UK) was administered daily for 5 consecutive days. On the final supplementation day, the placebo was consumed 3 h before the testing session
Dietary Supplement: Beetroot juice supplementation
Participants consumed one 70-mL serving of nitrate-depleted beetroot juice placebo (0.04 mmol of NO₃-; Beet-It-Pro Elite Shot, James White Drinks Ltd., Ipswich, UK) daily for 5 consecutive days. On the final supplementation day, the placebo was consumed 3 h before the testing session.
Other: Placebo
Participants consumed one 70-mL serving of nitrate-depleted beetroot juice placebo (0.04 mmol of NO₃-; Beet-It-Pro Elite Shot, James White Drinks Ltd., Ipswich, UK) daily for 5 consecutive days.
Participants consumed one 70-mL serving of nitrate-rich BJ (6.4 mmol of NO₃-; Beet-It-Pro Elite Shot, James White Drinks Ltd., Ipswich, UK) daily for 5 consecutive days. On the final supplementation day, BJ was consumed 3 h before the testing session.
Changes in maximal isometric handgrip strength (N)
Isometric Mid-Thigh Pull (IMTP): Lower-body maximal isometric strength will be assessed using the isometric mid-thigh pull (IMTP) performed on VALD ForceDecks force platforms (VALD Performance, Brisbane, Australia). Participants will adopt a standardized mid-thigh pull position with the knees and hips slightly flexed and will be instructed to pull against an immovable bar as hard and as fast as possible. Ground reaction force will be recorded by the force platforms throughout each maximal effort. Peak force will be expressed both as absolute force (N) and relative to body mass (N·kg-¹). Participants will perform maximal trials separated by an appropriate recovery period, and the best trial will be retained for analysis.
Time frame: 1-week
Changes in maximal jump height (cm)
Maximal Jump Height: Lower-body explosive performance will be assessed using the squat jump (SJ), countermovement jump (CMJ), and countermovement jump with arm swing (CMJ-AS). Jump performance will be measured using an OptoJump Next system (Microgate, Bolzano, Italy). Participants will perform maximal-effort trials for each jump condition following standardized instructions. Maximal jump height (cm) will be recorded for each jump type, and the best performance will be retained for analysis. Changes in maximal jump height following 5 days of supplementation will be compared between the nitrate-rich beetroot juice and placebo conditions.
Time frame: 1-week
Changes in sprint time (s)
Sprint performance will be assessed by measuring the time required to complete 10-m, 20-m, and 30-m sprints using Microgate photocell timing gates (Microgate, Bolzano, Italy). Participants will be instructed to sprint as fast as possible over the 30-m distance, with split times recorded at 10 m, 20 m, and 30 m. Sprint time will be recorded in seconds (s). Participants will perform maximal trials separated by an appropriate recovery period, and the best performance will be retained for analysis.
Time frame: 1-week
Changes in agility test (s)
Modified T-Test Performance: Change-of-direction performance will be assessed using the modified T-test, with completion time measured using Microgate photocell timing gates (Microgate, Bolzano, Italy). Participants will be instructed to complete the standardized course as quickly as possible, incorporating forward sprinting, lateral shuffling, and backward running. Completion time will be recorded in seconds (s). Participants will perform maximal trials separated by an appropriate recovery period, and the best performance will be retained for analysis.
Time frame: 1-week
Saliva NO3- and NO2- Measurements
Saliva samples were collected 150 min after BJ or the placebo ingestion and were stored at -20°C for four months until subsequent analysis. To confirm the effectiveness of BJ supplementation on nitrate (NO3-) and nitrite (NO2-) levels, saliva concentrations were measured using a nitric oxide assay kit (EMSNO K195325, Thermo Fisher Scientific, Roskilde, Denmark) according to the manufacturer's instructions and as reported in previous literature (Richard et al., 2018). All samples and standards were measured in duplicate and averaged.
Time frame: 1-week
Rating of percevied exertion (RPE) (measured using scale 6-20 points)
Immediately after each physical performance battery, participants were asked for providing her RPE using a Borg scale from 6 to 20 points
Time frame: 1-week
Side Effects Associated With Beetroot Juice Supplementation
The morning after the supplementation and testing session, participants will complete a questionnaire assessing potential side effects associated with beetroot juice or placebo ingestion. The questionnaire includes gastrointestinal upset, red urine, gastric reflux, mild nausea, muscle pain, headache, increased urine excretion, increased fatigue, and nervousness. Each side effect will be assessed using a dichotomous Yes/No response scale (No = 0; Yes = 1). The incidence of each side effect will be reported as the number and percentage of participants reporting the symptom.
Time frame: 1-week
Plan to share: No — Individual participant data (IPD) will not be publicly shared to protect participant confidentiality and privacy. The study involves a relatively small and specific sample of competitive female basketball players, which could increase the potential risk of participant identification. Aggregated and anonymized study results will be reported in scientific publications and presentations.
Ran from Sep 2026 to primary completion in Oct 2026, 1 month.
Completion moved once since we started tracking on Sep 25, 2026: Oct 2026 → Nov 2026, on Nov 3, 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Universidad Pontificia Comillas