Inspiratory Muscle Training in Amateur CrossFit® Athletes

NCT06807957 | Recruiting DMC

• 1 other identifier: 81443024.9.0000.5108
• Study Type: interventional
• Target: 94
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of this randomized controlled trial is to investigate the effectiveness of inspiratory muscle training (IMT) on the performance of athletes in CrossFit® activities, respiratory muscle strength, and perceived post-training fatigue. This study follows a two-arm randomized controlled trial protocol. Ninety-four volunteers aged between 18 and 60 years, enrolled in CrossFit® training, will be randomly allocated to the IMT Group, which involves respiratory training using a linear load device (Powerbreathe®) in conjunction with CrossFit® training; or the Non-IMT Group, which undergoes the same training as the intervention group but uses a device without a valve that ensures resistance. The primary outcome is to investigate the effectiveness of IMT: on maximum inspiratory pressure and maximum expiratory pressure. The secondary outcomes include performance in the six-minute walk test, Pistol, Burpee, Sit-up, Box Jump, Thruster, and Single-Under, burning 25 calories on the "Air Bike" measured by the time taken to reach the 25-calorie mark on this equipment, as well as the assessment of subjective fatigue perception. All outcomes of interest will be collected at baseline and reassessed: mid-term (8 weeks after allocation); and long-term (12 weeks after allocation), the IMT and MEP will be reassessed. Analyses will follow the intention-to-treat principle. Treatment effects will be assessed using Linear Mixed Models. The results of this study may help clarify the effects of IMT on CrossFit® athletes.

Conditions

Healthy

Keywords

Sport; Athlete; Respiratory muscles; CrossFit

Outcome Measures

Primary Outcomes (2)

• Respiratory muscle strength (Maximum inspiratory pressure (MIP)

  Respiratory muscle strength (Maximum inspiratory pressure (MIP) Description: The assessment of the strength of the resistant muscles will be performed using a vacuum manometer with an operating range of ± 300 cmH2O. To measure the MIP, the participant must exhale until reaching their Residual Volume (RV), immediately connecting the mouthpiece to the oral tract and making a maximum inspiratory effort against the occluded airway, holding for at least one second.

  at 8 weeks and 12 weeks

• Respiratory muscle strength (Maximum expiratory pressure (MEP))

  The assessment of the strength of the resistant muscles will be performed using a manovacuometer with an operating range of ± 300 cmH2O. To measure MEP, the participant must inhale until reaching their Total Lung Capacity and then, inserting the mouthpiece into the oral cavity, perform a maximum expiratory effort against the occluded airway, which must be maintained for at least one second.

  at 8 and 12 weeks

Secondary Outcomes (9)

• Subjective perception of effort

  at 8 weeks

• 6-minute walk test (6MWT)

  at 8 weeks

• Box Jump

  at 8 weeks

• Sit Up

  at 8 weeks

• Burpee

  at 8 weeks

Study Arms (2)

Group with IMT

EXPERIMENTAL

CrossFit® Training: ParticipaIMT: The intervention will utilize the POWERbreathe® device. Participants will be provided with the device for home training. The model selected for this study is the POWERbreathe® Classic Medium Resistance (Fitness). The load will be set at 50% of each participant's MIP, as determined during the assessment phase using a vacuum manometer. IMT will be performed in two sets of 30 breaths through a mouthpiece connected to the POWERbreathe®, with a one-minute rest between sets. Participants will complete the training five days per week at home over the course of eight weeks. Additionally, participants will monitor their adherence by completing a log sheet to mark training days. To ensure proper use and management of the device, each participant will receive individual training after randomization. At the end of the eight weeks, participants will return the equipment to the research team for cleaning and redistribution to another participant in the same group.

Device: Group with IMT; Behavioral: CrossFit® Training

Group without IMT

PLACEBO COMPARATOR

Group without IMT Participants allocated to the "No IMT Group" will receive the same interventions as the "IMT Group," except for respiratory training. These participants will continue attending CrossFit® training sessions at the gym. They will also perform a simulated IMT, using a device without the valve that generates resistance to the respiratory muscles.

Behavioral: CrossFit® Training

Interventions

Group with IMT DEVICE

Group with IMT + CrossFit training

Group with IMT

CrossFit® Training BEHAVIORAL

The training routine will occur seven days a week, with participants encouraged and motivated to attend at least five training sessions. CrossFit® classes will include: warm-up exercises, strength training (with a focus on Olympic weightlifting and free weights), strength endurance (body weight and external loads), aerobic capacity (across multiple domains), maximal aerobic power (across multiple domains), anaerobic capacity (across multiple domains), cool-down activities, and mobility exercises. Each training session will be designed and supervised by a team of certified physical educators.

Group with IMT; Group without IMT

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age between 18 and 60 years;
• Be enrolled in a CrossFit® program;
• Be available to perform TMI at home 5 days a week.

You may not qualify if:

• Have any musculoskeletal, cardiovascular and/or neurological condition that prevents CrossFit® and/or IMT from being performed;
• Be a smoker;
• Not sign the Termo de Consentimento Livre Esclarecido (TCLE);
• Be performing or have performed IMT using linear load equipment in the last month.

Sponsors & Collaborators

• Federal University of the Valleys of Jequitinhonha and Mucuri: lead

Study Sites (1)

Academia Compasso - Kapura

Sete Lagoas, Minas Gerais, 35700-007, Brazil

RECRUITING

Central Study Contacts

Diego M Xavier, PhD student

CONTACT

+55 31 997106999; diegomendesxav@gmail.com

Murilo X Oliveira, Pdh

CONTACT

+55 38 9996-0002; murilo.xavier@ufvjm.edu.br

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: SUPPORTIVE CARE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: The randomization sequence for the experimental and control groups, with a 1:1 allocation ratio, will be generated by computer software by one of the researchers who will not be involved in participant recruitment. The groups will be coded, and the allocation will be transferred to a series of sequentially numbered, sealed, opaque envelopes.

Study Record Dates

• First Submitted: January 17, 2025
• First Posted: February 4, 2025
• Study Start: January 1, 2026
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): March 30, 2027
• Last Updated: January 27, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL
• Time Frame: Unending (Starting after publication with no end date)
• Access Criteria: Researchers in the area who are interested

Locations

BR (1)