Muscle StrengthCAF-BJJNCT07479875
Caffeine Supplementation and Strength Endurance in Brazilian Jiu-jitsu Athletes
A study testing Caffeine in people with Muscle Strength and Physical Endurance, run by Federal University of Minas Gerais at 1 site in Brazil.
Trial summary
This study investigated the acute effects of ingesting 400 mg of caffeine administered 30 minutes before Brazilian jiu-jitsu-specific strength endurance tests. Experienced athletes completed two conditions, placebo and caffeine, in a randomized, double-blind, crossover clinical trial. Read more about this study
- Who is it for?
- Ages 18 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Muscle Strength, Physical Endurance, Exercise
- What is being tested?
- Caffeine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 15 participants
- Where
- 1 siteBrazil
- Study dates
- 12 Dec 2025to 15 Feb 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adult men
- Brazilian Jiu-Jitsu athletes
- Minimum of 5 years of continuous practice
- Participation in competitions within the past 12 months
- Absence of upper-limb injuries
- No use of caffeine or stimulant substances within 48 hours prior to testing
- Availability to attend both experimental sessions
- Physical fitness to perform maximal strength tests
Who cannot join
- Recent musculoskeletal injuries
- Use of stimulant substances, pre-workout supplements, or thermogenic products
- Known hypersensitivity to caffeine
- Clinical conditions that could limit participation (cardiovascular, respiratory, or neurological)
- Failure to attend any experimental session
- Noncompliance with pre-test nutritional guidelines
Trial locations and contacts
1 site in 1 country.
Brazil1 site
Universidade Federal de Minas Gerais (UFMG), Laboratory of Nutrition and Exercise Training (LAN-UFMG), Belo Horizonte, MG, Brazil
Belo Horizonte, Minas Gerais, 31275000
About this study
This study investigated the acute effects of ingesting 400 mg of caffeine administered 30 minutes before Brazilian jiu-jitsu-specific strength endurance tests. Experienced athletes completed two conditions, placebo and caffeine, in a randomized, double-blind, crossover clinical trial. Performance was assessed using the dynamic component of the kimono grip strength test (maximum number of repetitions, MNR) and the isometric component (maximum static lift, MSL), both performed with a gi grip. Rating of perceived exertion, adverse effects, and blinding effectiveness were also evaluated.
Read the detailed description
Caffeine is a widely used ergogenic aid in combat sports due to its effects on alertness, strength, and muscular endurance. This study evaluated whether an absolute dose of 400 mg of caffeine, ingested 30 minutes before testing, improved performance in Brazilian jiu-jitsu-specific strength endurance tests performed with a gi grip.
Fifteen experienced athletes completed two experimental sessions separated by at least seven days in a randomized, double-blind, crossover design. In each session, participants performed three maximal sets of the dynamic component of the kimono grip strength test (maximum number of repetitions, MNR) and three trials of the isometric component (maximum static lift, MSL). Dietary intake was controlled during the 24 hours preceding each session, and athletes were instructed to avoid stimulant substances.
Adverse effects were monitored for 24 hours following each session, and blinding effectiveness was assessed using the Bang blinding index. The study also examined interindividual variability in response to caffeine supplementation.
- Conditions
- Muscle Strength, Physical Endurance, Exercise
- Being tested
- Caffeine, Placebo
- Keywords
- Caffeine, Ergogenic Aid, Brazilian Jiu-Jitsu, Combat Sports, Muscular Endurance, Grip Strength, Athletes, Randomized Crossover Trial, Double-Blind
- Medical subject headings
- Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CaffeineDietary supplement
Also called caf
Capsule containing 400 mg of anhydrous caffeine ingested 30 minutes before performance testing.
PlaceboOther
Capsule containing 400 mg of cornstarch used as placebo, ingested 30 minutes before performance testing.
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Capsule containing 400 mg of starch (placebo), ingested 30 minutes before testing. Receives: Other: Placebo |
| Caffeine | Experimental | Capsule containing 400 mg of anhydrous caffeine, ingested 30 minutes before testing. Receives: Dietary Supplement: Caffeine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Dynamic component of the Kimono Grip Strength Test (Maximum Number of Repetitions, MNR)
Brazilian jiu-jitsu-specific strength endurance test performed using a kimono grip on a pull-up bar. Participants completed three maximal sets of the dynamic component of the Kimono Grip Strength Test (maximum number of repetitions, MNR), and the total number of valid repetitions was recorded.
Measured: During each experimental session, following intervention administration (two sessions, approximately 7 days apart).
Isometric component of the Kimono Grip Strength Test (Maximum Static Lift, MSL)
Maximum isometric holding time (seconds) during the isometric component of the Kimono Grip Strength Test. Participants maintained an isometric position at approximately 90 degrees of elbow flexion using a kimono grip on a pull-up bar, and the maximal hold time was recorded.
Measured: During each experimental session, following intervention administration (two sessions, approximately 7 days apart).
Secondary outcomes (4)
Interindividual Response Variability
Performance difference between caffeine and placebo conditions (CAF - placebo). A responder was defined as an improvement of ≥1 repetition in the dynamic component of the Kimono Grip Strength Test (maximum number of repetitions, MNR) or ≥1 second in the isometric component (maximum static lift, MSL).
Measured: At study completion, after the second experimental session (two sessions approximately 7 days apart).
Rating of perceived exertion (Borg CR10 scale)
Global perceptual assessment of effort using the Borg Category-Ratio 10 Scale (CR10). The scale ranges from 0 to 10, where 0 indicates no exertion and 10 indicates maximal exertion. Higher scores represent greater perceived effort.
Measured: During each experimental session, at the end of testing following intervention administration (two sessions, approximately 7 days apart).
Bang blinding index
Blinding effectiveness assessed using the Bang blinding index. The index ranges from -1 to +1, where values near 0 indicate successful blinding, positive values indicate correct identification of the assigned intervention, and negative values indicate incorrect guesses.
Measured: At the end of each experimental visit following intervention administration (two visits, approximately 7 days apart).
Acute Adverse Effects
Self-reported symptom questionnaire completed 24 hours after each experimental session, including tremor, anxiety, nausea, headache, insomnia, and tachycardia.
Measured: Within 24 hours after each experimental session following intervention administration (two sessions, approximately 7 days apart).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Mar 2026
- Study start12 Dec 2025
- Primary completion15 Jan 2026
- Study completion15 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Muscle StrengthStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Brazilian Jiu-Jitsu athletes completed two experimental sessions in a randomized, double-blind, crossover design. In one session, participants ingested caffeine, and in the other, they ingested a placebo, with a minimum washout period of seven days. The order of the conditions was counterbalanced across participants, and all performance assessments were conducted under both conditions.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Lead sponsor
- Federal University of Minas Gerais
- Sponsor type
- University, hospital or other
- Collaborators
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.
- Responsible party
- Principal investigator, FRANCISCO DE PAULA VITOR FERREIRA, Federal University of Minas Gerais
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07479875
- Sponsor's protocol ID
- 8.062.851
- Acronym
- CAF-BJJ
- Status last verified
- Mar 2026
- First submitted
- 20 Nov 2025
- Last updated
- 4 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared due to ethical and confidentiality restrictions, as participants did not provide consent for public data sharing. Aggregated data are available in the published study reports.
Study at a glance
From the registry record, last updated by the sponsor on 4 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Caffeine Supplementation and Strength Endurance in Brazilian Jiu-jitsu Athletes
- ClinicalTrials.gov ID
- NCT07479875
- Acronym / sponsor ID
- CAF-BJJ / 8.062.851
- Conditions
- Muscle Strength, Physical Endurance, Exercise
- Keywords
- Caffeine, Ergogenic Aid, Brazilian Jiu-Jitsu, Combat Sports, Muscular Endurance, Grip Strength, Athletes, Randomized Crossover Trial
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 15 participants (actual)
- Lead sponsor
- Federal University of Minas GeraisUniversity, hospital or other
- Collaborators
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.
- Study start
- 12 Dec 2025 (actual)
- Primary completion
- 15 Jan 2026 (actual)
- Study completion
- 15 Feb 2026 (actual)
- First posted
- 18 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study investigated the acute effects of ingesting 400 mg of caffeine administered 30 minutes before Brazilian jiu-jitsu-specific strength endurance tests. Experienced athletes completed two conditions, placebo and caffeine, in a randomized, double-blind, crossover clinical trial. Performance was assessed using the dynamic component of the kimono grip strength test (maximum number of repetitions, MNR) and the isometric component (maximum static lift, MSL), both performed with a gi grip. Rating of perceived exertion, adverse effects, and blinding effectiveness were also evaluated.
Detailed description
Caffeine is a widely used ergogenic aid in combat sports due to its effects on alertness, strength, and muscular endurance. This study evaluated whether an absolute dose of 400 mg of caffeine, ingested 30 minutes before testing, improved performance in Brazilian jiu-jitsu-specific strength endurance tests performed with a gi grip.
Fifteen experienced athletes completed two experimental sessions separated by at least seven days in a randomized, double-blind, crossover design. In each session, participants performed three maximal sets of the dynamic component of the kimono grip strength test (maximum number of repetitions, MNR) and three trials of the isometric component (maximum static lift, MSL). Dietary intake was controlled during the 24 hours preceding each session, and athletes were instructed to avoid stimulant substances.
Adverse effects were monitored for 24 hours following each session, and blinding effectiveness was assessed using the Bang blinding index. The study also examined interindividual variability in response to caffeine supplementation.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Brazilian Jiu-Jitsu athletes completed two experimental sessions in a randomized, double-blind, crossover design. In one session, participants ingested caffeine, and in the other, they ingested a placebo, with a minimum washout period of seven days. The order of the conditions was counterbalanced across participants, and all performance assessments were conducted under both conditions.
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Other: PlaceboCapsule containing 400 mg of starch (placebo), ingested 30 minutes before testing. |
| Caffeine | Experimental | Dietary Supplement: CaffeineCapsule containing 400 mg of anhydrous caffeine, ingested 30 minutes before testing. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Adult men
- Brazilian Jiu-Jitsu athletes
- Minimum of 5 years of continuous practice
- Participation in competitions within the past 12 months
- Absence of upper-limb injuries
Key exclusion criteria (6 listed)
- Recent musculoskeletal injuries
- Use of stimulant substances, pre-workout supplements, or thermogenic products
- Known hypersensitivity to caffeine
- Clinical conditions that could limit participation (cardiovascular, respiratory, or neurological)
- Failure to attend any experimental session
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CaffeineAlso: cafCapsule containing 400 mg of anhydrous caffeine ingested 30 minutes before performance testing. | Dietary supplement | Caffeine |
| PlaceboCapsule containing 400 mg of cornstarch used as placebo, ingested 30 minutes before performance testing. | Other | Placebo |
Primary outcome
Dynamic component of the Kimono Grip Strength Test (Maximum Number of Repetitions, MNR)
Time frame: During each experimental session, following intervention administration (two sessions, approximately 7 days apart).
Brazilian jiu-jitsu-specific strength endurance test performed using a kimono grip on a pull-up bar. Participants completed three maximal sets of the dynamic component of the Kimono Grip Strength Test (maximum number of repetitions, MNR), and the total number of valid repetitions was recorded.
Isometric component of the Kimono Grip Strength Test (Maximum Static Lift, MSL)
Time frame: During each experimental session, following intervention administration (two sessions, approximately 7 days apart).
Maximum isometric holding time (seconds) during the isometric component of the Kimono Grip Strength Test. Participants maintained an isometric position at approximately 90 degrees of elbow flexion using a kimono grip on a pull-up bar, and the maximal hold time was recorded.
4 secondary outcomes
Interindividual Response Variability
Time frame: At study completion, after the second experimental session (two sessions approximately 7 days apart).
Rating of perceived exertion (Borg CR10 scale)
Time frame: During each experimental session, at the end of testing following intervention administration (two sessions, approximately 7 days apart).
Bang blinding index
Time frame: At the end of each experimental visit following intervention administration (two visits, approximately 7 days apart).
Acute Adverse Effects
Time frame: Within 24 hours after each experimental session following intervention administration (two sessions, approximately 7 days apart).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Sep 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared due to ethical and confidentiality restrictions, as participants did not provide consent for public data sharing. Aggregated data are available in the published study reports.
Related trials for Muscle Strength
Enrolling by invitation
Online Exercise Program for Transplant Patients: A Pilot Study
Kidney Transplantation, Physical Function
Not yet recruitingObservational study
Isokinetic Knee Strength, Bilateral Muscle Balance, and Anaerobic Performance in Adolescent Athletes
Isokinetic Knee Strength, Hamstring-to-Quadriceps Strength Ratio
Recruiting
Effects of Urolithin A Supplementation on Glucose Metabolism in Healthy Adults 55 >= Years Old: A Randomized Triple-Masked Controlled Clinical Trial
Healthy Volunteer
Recruiting
Recovery After Fatigue in Young Athletes: Comparison Between TECAR Therapy and Cycle Ergometer"
Muscle Fatigue, Healthy Adult
RecruitingObservational study
Physical Impairments in Premature Ventricular Complex
Premature Ventricular Complexes
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine in people with Muscle Strength and Physical Endurance, run by Federal University of Minas Gerais at 1 site in Brazil.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Dynamic component of the Kimono Grip Strength Test (Maximum Number of Repetitions, MNR) (time frame: During each experimental session, following intervention administration (two sessions, approximately 7 days apart).). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Sep 2026.