Respiratory Muscle Strength and Jiu-Jitsu-Specific Performance in Male Brazilian Jiu-Jitsu Athletes

Relationship of Maximal Inspiratory and Expiratory Pressures With Jiu-Jitsu-Specific Anaerobic Performance and Static Kimono Grip Endurance in Male Brazilian Jiu-Jitsu Athletes: A Cross-Sectional Study

Brazilian Jiu-Jitsu (BJJ) is an intermittent combat sport that requires repeated high-intensity efforts and sustained gripping. This analytical cross-sectional study will examine whether respiratory muscle strength is associated with BJJ-specific anaerobic performance and static kimono grip endurance in adult male BJJ athletes. Forty athletes will attend three assessment visits separated by 48 to 72 hours. Maximal inspiratory pressure, maximal expiratory pressure, and spirometric indices (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1], FEV1/FVC ratio, and peak expiratory flow [PEF]) will be measured at the first visit. The Jiu-Jitsu Anaerobic Performance Test and the Maximum Static Kimono Grip Test will be completed at the other two visits in randomized order. The primary analysis will examine the association between maximal inspiratory pressure and the total number of valid repetitions completed during the Jiu-Jitsu Anaerobic Performance Test. Spirometric indices will be evaluated as secondary outcomes.

Study Overview

• Status: Not yet recruiting
• Conditions: Athletic Performance

Detailed Description

This is an analytical cross-sectional observational study involving 40 male Brazilian Jiu-Jitsu athletes aged 18 to 40 years. Assessments will be completed during three visits separated by 48 to 72 hours. At Visit 1, eligibility will be assessed and written informed consent will be obtained. Demographic and sport-related information, including self-reported height, body weight, and Brazilian Jiu-Jitsu experience, will be recorded. Spirometry will be performed using acceptable and repeatable forced expiratory maneuvers in accordance with current ATS/ERS technical standards. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, and peak expiratory flow (PEF) will be recorded; percent-predicted and z-score values will also be documented when available. Respiratory muscle strength will be assessed as maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). Participants will perform at least five acceptable maneuvers for each pressure measurement, with up to eight attempts when necessary. The highest acceptable value meeting reproducibility criteria will be recorded in cmH2O. At Visits 2 and 3, participants will complete the Jiu-Jitsu Anaerobic Performance Test (JJAPT) and the Maximum Static Kimono Grip Test on separate days in randomized order. Before each performance test, participants will complete a standardized sport-specific warm-up. The JJAPT consists of five 60-second work bouts separated by 45 seconds of passive recovery. A partner whose body weight is within 5% of the participant's self-reported body weight will be used, and the total number of valid butterfly-guard lifting repetitions will be recorded. For the static kimono grip test, a kimono is wrapped around a horizontal bar and the participant maintains a suspended position with maximal elbow flexion for as long as possible; performance is recorded in seconds. The primary analysis will assess the relationship between MIP and JJAPT total valid repetitions. Secondary analyses will assess MEP in relation to JJAPT performance and MIP and MEP in relation to static kimono grip endurance. Spirometric indices will be summarized descriptively and examined in exploratory secondary analyses in relation to the performance outcomes. Self-reported body weight and Brazilian Jiu-Jitsu experience in months will be considered as prespecified covariates.

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye), 34337
    • Roger Gracie Academy Turkey
    • Contact: Omer Guliyev; Phone Number: +90 534 786 70 90; Email: omerguliyev@rgaistanbul.com
    • Principal Investigator: Muhammed Hüseyin Pekeren

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adult male Brazilian Jiu-Jitsu athletes who train regularly at clubs or academies in Istanbul, Türkiye, and meet the prespecified eligibility criteria. Participants will be recruited by non-probability sampling.

Description

Inclusion Criteria:

• Male sex
• Age 18 to 40 years
• At least 1 year of Brazilian Jiu-Jitsu experience
• Brazilian Jiu-Jitsu training on at least 2 days per week during the previous 3 months
• Familiarity with gi/kimono training and the butterfly-guard lifting movement
• Ability to safely and technically perform the Maximum Static Kimono Grip Test and the Jiu-Jitsu Anaerobic Performance Test
• Provision of written informed consent

Exclusion Criteria:

• Diagnosed cardiovascular, respiratory, neurological, metabolic, or musculoskeletal condition that may affect maximal testing or participant safety
• Active pain, acute injury, or relevant surgery during the previous 6 months
• Current regular use of cigarettes, electronic cigarettes, or inhaled nicotine products
• Medical advice to avoid maximal physical effort
• Regular use of medication that may materially affect study measurements

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Male Brazilian Jiu-Jitsu Athletes; Adult male Brazilian Jiu-Jitsu athletes who train regularly and complete spirometric pulmonary function, respiratory muscle strength, BJJ-specific anaerobic performance, and static kimono grip endurance assessments. No intervention will be assigned.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Jiu-Jitsu Anaerobic Performance Test Total Valid Repetitions	Total number of valid butterfly-guard lifting repetitions completed across five 60-second work bouts separated by 45 seconds of passive recovery. Higher values indicate better BJJ-specific anaerobic performance.	At Visit 2 or Visit 3, within 6 days after Visit 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal Inspiratory Pressure	The highest acceptable maximal inspiratory pressure meeting prespecified reproducibility criteria, recorded in centimeters of water (cmH2O). Higher values indicate greater inspiratory muscle strength.	At Visit 1
Maximal Expiratory Pressure	The highest acceptable maximal expiratory pressure meeting prespecified reproducibility criteria, recorded in centimeters of water (cmH2O). Higher values indicate greater expiratory muscle strength.	At Visit 1
Maximum Static Kimono Grip Test Time	Maximum time, in seconds, that the participant maintains a suspended position with maximal elbow flexion while gripping a kimono wrapped around a horizontal bar. Higher values indicate greater static kimono grip endurance.	At Visit 2 or Visit 3, within 6 days after Visit 1
Forced Vital Capacity (FVC)	Forced vital capacity measured by spirometry and recorded in liters (L). Percent-predicted and z-score values will also be documented when available. Higher values generally indicate greater ventilatory volume, with interpretation based on appropriate reference limits.	At Visit 1
Forced Expiratory Volume in 1 Second (FEV1)	Forced expiratory volume in the first second measured by spirometry and recorded in liters (L). Percent-predicted and z-score values will also be documented when available. Higher values generally indicate greater expiratory volume in the first second, interpreted using appropriate reference limits.	At Visit 1
FEV1/FVC Ratio	Ratio of forced expiratory volume in the first second to forced vital capacity, calculated from acceptable spirometry maneuvers and recorded as a ratio and percentage. The z-score and lower limit of normal will be documented when available; lower values may indicate airflow limitation.	At Visit 1
Peak Expiratory Flow (PEF)	Peak expiratory flow obtained during acceptable forced spirometry maneuvers and recorded in liters per second (L/s). The highest acceptable value will be recorded. Higher values indicate greater maximal expiratory flow.	At Visit 1

Collaborators and Investigators

• Sponsor: Halic University

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: August 25, 2026
• First Submitted That Met QC Criteria: August 26, 2026
• First Posted (Actual): August 31, 2026

Study Record Updates

• Last Update Posted (Actual): August 31, 2026
• Last Update Submitted That Met QC Criteria: August 26, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Pulmonary Function; Spirometry; Anaerobic Performance; Respiratory Muscle Strength; Maximal Inspiratory Pressure; Maximal Expiratory Pressure; Brazilian Jiu-Jitsu; Kimono Grip Endurance
• Other Study ID Numbers: HALICU-BJJ-2209-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No