History
# Registration date Revision Id
2 2026-04-02, 1405/01/13 374250
1 2025-05-22, 1404/03/01 341070
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  • Protocol summary

    A crossover, placebo-controlled, double-blind, randomized, phase 3 clinical trial on 16 judo athletes. The RAND function of Excel software will be used for randomization.
    A crossover, placebo-controlled, double-blind, randomized, phase 3 clinical trial on 34 judo athletes. The RAND function of Excel software will be used for randomization.
    کارآزمایی بالینی متقاطع، کنترل شده با دارونما، دو سویه کور ، تصادفی شده، فاز 3 بر روی 16 جودوکار. برای تصادفی سازی از فانکشن RAND نرم افزار اکسل استفاده خواهد شد.
    کارآزمایی بالینی متقاطع، کنترل شده با دارونما، دو سویه کور ، تصادفی شده، فاز 3 بر روی 34 جودوکار. برای تصادفی سازی از فانکشن RAND نرم افزار اکسل استفاده خواهد شد.
    Participants will perform two sessions of SJFT after beetroot or placebo supplementation. The number of throws (TT), heart rate (HR) immediately at the end of SJFT (HR0) and 1 minute after SJFT (HR1), SJFT index and rate of perceived exertion (RPE) will be measured. This study will use a double-blind method (participants and researchers). The study will take place in Ankara, Turkey.
    Participants will perform two sessions of SJFT after beetroot or placebo supplementation. The number of throws (TT), heart rate (HR) immediately at the end of SJFT (HR0) and 1 minute after SJFT (HR1), SJFT index, rate of perceived exertion (RPE), muscle oxygenation, and plasma nitrate, nitrite and lactate levels will be measured. This study will use a double-blind method (participants and researchers). The study will take place in Ankara, Turkey.
    شرکت‌کنندگان دو جلسه SJFT را پس از مصرف مکمل چغندر یا دارونما انجام خواهند داد. تعداد پرتاب‌ها (TT)، ضربان قلب (HR) بلافاصله در پایان SJFT (HR0) و 1 دقیقه پس از SJFT (HR1)، شاخص SJFT و میزان درک فشار (RPE) اندازه‌گیری خواهد شد. این مطالعه از روش دوسوکور (شرکت‌کنندگان و محققان) استفاده خواهد کرد. این مطالعه در آنکارا، ترکیه انجام خواهد شد.
    شرکت‌کنندگان دو جلسه SJFT را پس از مصرف مکمل چغندر یا دارونما انجام خواهند داد. تعداد پرتاب‌ها (TT)، ضربان قلب (HR) بلافاصله در پایان SJFT (HR0) و 1 دقیقه پس از SJFT (HR1)، شاخص SJFT، میزان درک فشار (RPE)، اکسیژن رسانی عضلانی، و مقدار نیترات، نیتریت و لاکتات پلاسمایی اندازه‌گیری خواهد شد. این مطالعه از روش دوسوکور (شرکت‌کنندگان و محققان) استفاده خواهد کرد. این مطالعه در آنکارا، ترکیه انجام خواهد شد.
    Consuming beetroot juice supplement (140 ml) or placebo (140 ml of water with red food coloring) 120 minutes before exercise sessions
    Consuming beetroot juice supplement (140 ml) or placebo (140 ml of nitrate-depleted beetroot juice) 120 minutes before exercise sessions
    مصرف مکمل آب چغندر (140 میلی لیتر) یا دارونما (140 میلی لیتر آب با رنگ خوراکی قرمز) 120 دقیقه قبل از جلسات ورزشی
    مصرف مکمل آب چغندر (140 میلی لیتر) یا دارونما (140 میلی لیتر آب چغندر فاقد نیترات) 120 دقیقه قبل از جلسات ورزشی
  • General information

    16
    34
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    Adding some secondary variables to evaluate possible mechanisms; Adding subjects number to enhance statistical analysis power; Using nitrate-depleted beetroot juice as a placebo to enhancing blinding effect.
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    افزودن برخی متغیرهای ثانویه برای اندازه گیری سازوکارهای احتمالی؛ اضافه کردن تعداد آزمودنی ها برای افزایش توان تحلیل های آماری؛ استفاده از مکمل آب چغندر فاقد نیترات بعنوان دارونما برای افزایش اثر کورسازی.
  • Secondary outcomes

    #1
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    Plasma nitrate concentration
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    غلظت نیترات پلاسمایی
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    At baseline, pre-test, and post-test (5 minutes after exercise)
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    در حالت پایه، پیش آزمون و پس آزمون (5 دقیقه بعد از ورزش)
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    By high‑performance liquid chromatography method (ENO‑20; EiCom, Kyoto, Japan)
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    با روش کروماتوگرافی مایع عملکرد بالا (ENO‑20; EiCom، کیوتو، ژاپن)
    #2
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    Plasma nitrite concentration
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    غلظت نیتریت پلاسمایی
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    At baseline, pre-test, and post-test (5 minutes after exercise)
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    در حالت پایه، پیش آزمون و پس آزمون (5 دقیقه بعد از ورزش)
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    By high‑performance liquid chromatography method (ENO‑20; EiCom, Kyoto, Japan)
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    با روش کروماتوگرافی مایع عملکرد بالا (ENO‑20; EiCom، کیوتو، ژاپن)
    #3
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    Plasmalactate
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    لاکتات پلاسمایی
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    At baseline, pre-test, and post-test (5 minutes after exercise)
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    در حالت پایه، پیش آزمون و پس آزمون (5 دقیقه بعد از ورزش)
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    Using a lactate ELISA kit
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    با استفاده از کیت الایزای لاکتات
    #4
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    Muscle oxygenation
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    اکسیژن رسانی عضلانی
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    During the SJFT
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    در طول SJFT
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    Near-infrared spectroscopy
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    طیف سنجی اشعه مادون قرمز-نزدیک
  • Intervention groups

    #1
    Placebo (140 ml) will be consumed 2 hours before exercise in opaque bottles. Placebo will be prepared by adding flavor and red food color (McCormick red food color; FD&C reds 40 and 3) to water.
    Placebo (140 ml) will be consumed 2 hours before exercise in opaque bottles. Commercial nitrate-depleted beetroot juice supplement (NO₃⁻-depleted BJ, Beet It Sport®, James White Drinks Ltd., UK) will be used in this study.
    گروه کنترل: دارونما (140 میلی لیتر) 2 ساعت قبل از ورزش در بطری های مات 2 ساعت قبل از ورزش مصرف خواهد شد. دارونما از طریق اضافه کردن طعم دهنده و رنگ خوراکی قرمز (McCormick red food color; FD&C reds 40 and 3) به آب تهیه خواهد شد.
    گروه کنترل: دارونما (140 میلی لیتر) 2 ساعت قبل از ورزش در بطری های مات 2 ساعت قبل از ورزش مصرف خواهد شد. از مکمل آب چغندر فاقد نیترات تجاری (NO₃⁻-depleted BJ, Beet It Sport®, James White Drinks Ltd., UK) در این مطالعه استفاده خواهد شد.

Protocol summary

Study aim
This study aims to evaluate the effect of training status on the Special Judo Fitness Test (SJFT) performance following beetroot juice ingestion.
Design
A crossover, placebo-controlled, double-blind, randomized, phase 3 clinical trial on 34 judo athletes. The RAND function of Excel software will be used for randomization.
Settings and conduct
Participants will perform two sessions of SJFT after beetroot or placebo supplementation. The number of throws (TT), heart rate (HR) immediately at the end of SJFT (HR0) and 1 minute after SJFT (HR1), SJFT index, rate of perceived exertion (RPE), muscle oxygenation, and plasma nitrate, nitrite and lactate levels will be measured. This study will use a double-blind method (participants and researchers). The study will take place in Ankara, Turkey.
Participants/Inclusion and exclusion criteria
Inclusion criteria: Having at least a Purple Belt in Judo Free from neuromuscular and musculoskeletal disorders Non-smokers Non-alcoholic Not consumers of medicine Exclusion criteria: Having any injuries or pain Inability to perform tests Non-adherence to recommendations
Intervention groups
Consuming beetroot juice supplement (140 ml) or placebo (140 ml of nitrate-depleted beetroot juice) 120 minutes before exercise sessions
Main outcome variables
Number of throws; Heart rate immediately after SJFT; Heart rate one minute after SJFT; SJFT index; Rate of perceived exertion

General information

Reason for update
Adding some secondary variables to evaluate possible mechanisms; Adding subjects number to enhance statistical analysis power; Using nitrate-depleted beetroot juice as a placebo to enhancing blinding effect.
Acronym
IRCT registration information
IRCT registration number: IRCT20231004059615N3
Registration date: 2025-05-22, 1404/03/01
Registration timing: registered_while_recruiting

Last update: 2026-04-07, 1405/01/18
Update count: 1
Registration date
2025-05-22, 1404/03/01
Registrant information
Name
Davar Khodadadi
Name of organization / entity
Country
Iran (Islamic Republic of)
Phone
+98 21 2263 3583
Email address
davar.khodadadi@yahoo.com
Recruitment status
Recruitment complete
Funding source
Expected recruitment start date
2025-05-22, 1404/03/01
Expected recruitment end date
2025-05-31, 1404/03/10
Actual recruitment start date
empty
Actual recruitment end date
empty
Trial completion date
empty
Scientific title
Acute effects of beetroot juice supplementation on the Special Judo Fitness Test performance in judokas: a randomized double-blinded crossover trial
Public title
Acute effects of beetroot juice supplementation on judo performance
Purpose
Other
Inclusion/Exclusion criteria
Inclusion criteria:
Having at least a Purple Belt in Judo Free from neuromuscular and musculoskeletal disorders Non-smokers Non-alcoholic Not consumers of medicine
Exclusion criteria:
Having any injuries or pain Inability to perform tests
Age
From 20 years old to 30 years old
Gender
Both
Phase
3
Groups that have been masked
  • Participant
  • Investigator
  • Outcome assessor
  • Data analyser
Sample size
Target sample size: 34
Randomization (investigator's opinion)
Randomized
Randomization description
The names of the subjects will be entered in one column of Excel; in another column, a number will be randomly assigned to each subject using the RAND function (=RAND()); then, the numbers will be sorted from smallest to largest; 50% of the subjects (from rows 1 to 8) will receive the supplement and the other 50% (from rows 9 to 16) will receive the placebo. In the second experimental session, the subjects will be switched (subjects who received the supplement in the first session will receive the placebo in the second session and vice versa).
Blinding (investigator's opinion)
Double blinded
Blinding description
The order of beetroot juice supplement or placebo intake will be determined randomly by a person outside the study, and participants and researchers will not be informed of it until after data analysis. Also, subjects will receive the supplement and placebo in an opaque container with a similar appearance. In addition, the color and taste of the placebo will be similar to the beetroot juice through the addition of food coloring and flavoring.
Placebo
Used
Assignment
Crossover
Other design features

Secondary Ids

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Ethics committees

1

Ethics committee
Name of ethics committee
Ethics Committee of the International Science and Technology University
Street address
Tunahan Mah. Dumlupinar 30 Agustos Cad. No:2, Metromal Business F Blok Office
City
Ankara
Postal code
21,06824
Approval date
2025-05-14, 1404/02/24
Ethics committee reference number
202505-03

Health conditions studied

1

Description of health condition studied
Improve exercise performance
ICD-10 code
ICD-10 code description

Primary outcomes

1

Description
SJFT index
Timepoint
َAfter SJFT
Method of measurement
Using the following formula: SJFT index = HR0 + HR1 / total number of throws

Secondary outcomes

1

Description
Rate of perceived exertion
Timepoint
Following SJFT
Method of measurement
Using the Borg scale

2

Description
Number of throws
Timepoint
During the SJFT
Method of measurement
Counting the number

3

Description
Heart rate
Timepoint
Immediately at the end of SJFT and 1 minute after SJFT
Method of measurement
Using a Polar heart rate monitor

4

Description
Plasma nitrate concentration
Timepoint
At baseline, pre-test, and post-test (5 minutes after exercise)
Method of measurement
By high‑performance liquid chromatography method (ENO‑20; EiCom, Kyoto, Japan)

5

Description
Plasma nitrite concentration
Timepoint
At baseline, pre-test, and post-test (5 minutes after exercise)
Method of measurement
By high‑performance liquid chromatography method (ENO‑20; EiCom, Kyoto, Japan)

6

Description
Plasmalactate
Timepoint
At baseline, pre-test, and post-test (5 minutes after exercise)
Method of measurement
Using a lactate ELISA kit

7

Description
Muscle oxygenation
Timepoint
During the SJFT
Method of measurement
Near-infrared spectroscopy

Intervention groups

1

Description
Intervention group: Beetroot juice supplement (140 ml, containing approximately 12.8 mmol nitrate) in opaque bottles will be consumed 2 hours before exercise. Commercial beetroot juice supplement (BEET It Sport®; James White Drinks Ltd., Ipswich, UK) will be used in this study.
Category
Rehabilitation

2

Description
Placebo (140 ml) will be consumed 2 hours before exercise in opaque bottles. Commercial nitrate-depleted beetroot juice supplement (NO₃⁻-depleted BJ, Beet It Sport®, James White Drinks Ltd., UK) will be used in this study.
Category
Rehabilitation

Recruitment centers

1

Recruitment center
Name of recruitment center
INTERNATIONAL SCIENCE AND TECHNOLOGY UNIVERSITY
Full name of responsible person
Heidar Sajedi
Street address
Tunahan Mah. Dumlupinar 30 Agustos Cad. No:2, Metromal Business F Blok Office
City
Ankara
Postal code
21,06824
Phone
+90 312 475 76 15
Email
heidar.sajedi@istu.edu.pl

Sponsors / Funding sources

1

Sponsor
Name of organization / entity
INTERNATIONAL SCIENCE AND TECHNOLOGY UNIVERSITY
Full name of responsible person
Erdal Dursun
Street address
Tunahan Mah., Dumlupinar 30 Agustos Cad. No. 2, Metromal Business F Blok Office
City
Ankara
Postal code
21,06824
Phone
+90 312 475 76 15
Email
heidar.sajedi@istu.edu.pl
Grant name
Grant code / Reference number
Is the source of funding the same sponsor organization/entity?
Yes
Title of funding source
INTERNATIONAL SCIENCE AND TECHNOLOGY UNIVERSITY
Proportion provided by this source
100
Public or private sector
Private
Domestic or foreign origin
Foreign
Category of foreign source of funding
Sponsor: country of origin
Country of origin
Ir
Type of organization providing the funding
Persons

Person responsible for general inquiries

Contact
Name of organization / entity
Islamic Azad University
Full name of responsible person
Davar Khodadadi
Position
Assistant professor
Latest degree
Ph.D.
Other areas of specialty/work
Physiology
Street address
Faculty of Physical Education and Sports Sciences, Velayat University Complex, Shahid Sohani St., Sohank
City
Tehran
Province
Tehran
Postal code
1955847781
Phone
+98 21 2263 3583
Fax
Email
davar.khodadadi@yahoo.com

Person responsible for scientific inquiries

Contact
Name of organization / entity
Islamic Azad University
Full name of responsible person
Davar Khodadadi
Position
Assistant professor
Latest degree
Ph.D.
Other areas of specialty/work
Physiology
Street address
Faculty of Physical Education and Sports Sciences, Velayat University Complex, Shahid Sohani St., Sohank
City
Tehran
Province
Tehran
Postal code
1955847781
Phone
+98 21 2263 3583
Fax
Email
davar.khodadadi@yahoo.com

Person responsible for updating data

Contact
Name of organization / entity
Islamic Azad University
Full name of responsible person
Davar Khodadadi
Position
Assistant professor
Latest degree
Ph.D.
Other areas of specialty/work
Physiology
Street address
Faculty of Physical Education and Sports Sciences, Velayat University Complex, Shahid Sohani St., Sohank
City
Tehran
Province
Tehran
Postal code
1955847781
Phone
+98 21 2263 3583
Fax
Email
davar.khodadadi@yahoo.com

Sharing plan

Deidentified Individual Participant Data Set (IPD)
Yes - There is a plan to make this available
Study Protocol
Yes - There is a plan to make this available
Statistical Analysis Plan
Undecided - It is not yet known if there will be a plan to make this available
Informed Consent Form
Undecided - It is not yet known if there will be a plan to make this available
Clinical Study Report
Not applicable
Analytic Code
Not applicable
Data Dictionary
Not applicable
Title and more details about the data/document
All data collected during the study will be shareable after de-identifying the subjects.
When the data will become available and for how long
The data will be published after the extracted articles are accepted.
To whom data/document is available
All people
Under which criteria data/document could be used
All data collected during the study will be shareable after de-identifying the subjects. The requester will only be permitted to use the data for meta-analysis reviews.
From where data/document is obtainable
Corresponding author: Davar Khodadadi, Faculty of Physical Education and Sports Sciences, Islamic Azad University Central Tehran Branch, Tehran, Iran Email: davar.khodadadi@yahoo.com
What processes are involved for a request to access data/document
Sending an email request to the corresponding author: Davar Khodadadi Email: davar.khodadadi@yahoo.com
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