Caffeine Supplementation and Strength Endurance in Brazilian Jiu-jitsu Athletes

NCT07479875 | Completed

• 1 other identifier: 8.062.851
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Muscle Strength; Physical Endurance; Exercise

Keywords

Caffeine; Ergogenic Aid; Brazilian Jiu-Jitsu; Combat Sports; Muscular Endurance; Grip Strength; Athletes; Randomized Crossover Trial; Double-Blind

Outcome Measures

Primary Outcomes (2)

• 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.

  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.

  During each experimental session, following intervention administration (two sessions, approximately 7 days apart).

Secondary Outcomes (4)

• Interindividual Response Variability

  At study completion, after the second experimental session (two sessions approximately 7 days apart).

• Rating of perceived exertion (Borg CR10 scale)

  During each experimental session, at the end of testing following intervention administration (two sessions, approximately 7 days apart).

• Bang blinding index

  At the end of each experimental visit following intervention administration (two visits, approximately 7 days apart).

• Acute Adverse Effects

  Within 24 hours after each experimental session following intervention administration (two sessions, approximately 7 days apart).

Study Arms (2)

Placebo

PLACEBO COMPARATOR

Capsule containing 400 mg of starch (placebo), ingested 30 minutes before testing.

Other: Placebo

Caffeine

EXPERIMENTAL

Capsule containing 400 mg of anhydrous caffeine, ingested 30 minutes before testing.

Dietary Supplement: Caffeine

Interventions

Caffeine DIETARY_SUPPLEMENT

Capsule containing 400 mg of anhydrous caffeine ingested 30 minutes before performance testing.

Also known as: caf

Caffeine

Placebo OTHER

Capsule containing 400 mg of cornstarch used as placebo, ingested 30 minutes before performance testing.

Placebo

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Federal University of Minas Gerais: lead
• Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.: collaborator

Study Sites (1)

Universidade Federal de Minas Gerais (UFMG), Laboratory of Nutrition and Exercise Training (LAN-UFMG), Belo Horizonte, MG, Brazil

Belo Horizonte, Minas Gerais, 31275000, Brazil

Location

MeSH Terms

Conditions

Motor Activity

Interventions

Caffeine

Condition Hierarchy (Ancestors)

Behavior

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Caffeine and placebo capsules were identical in color, size, shape, and taste. Randomization was performed by a researcher not involved in data collection. Neither the participants nor the assessors were aware of which substance was administered in each session. The allocation code was revealed only after the completion of the data analysis.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: 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.

Study Record Dates

• First Submitted: November 20, 2025
• First Posted: March 18, 2026
• Study Start: December 12, 2025
• Primary Completion: January 15, 2026
• Study Completion: January 15, 2026
• Last Updated: March 18, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

BR (1)