Inspiratory Muscle Training on The Severity of Exercise-Induced Bronchoconstriction and Time-Trial Performance (IMT_EIB)

NCT06336681 | Completed Results FDA Device

• 1 other identifier: #12966
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

Due to the lack of studies examining the impact of inspiratory muscle training (IMT) on the severity of exercise-induced bronchoconstriction (EIB) and exercise performance, the specific aim of this study is to assess the efficacy of flow-resistive IMT on EIB severity and symptoms, short-acting beta-2-agonist medication use, operating lung volumes, respiratory and limb locomotor muscle deoxygenation during constant-load cycling exercise, exertional dyspnea, and cycling time-trial performance.

Conditions

Exercise Induced Bronchospasm; Exercise Induced Asthma

Outcome Measures

Primary Outcomes (6)

• Exercise-Induced Bronchoconstriction (EIB) Severity

  More specifically, the pre- and post-values of the percentage drop in forced expiratory volume in 1 second (FEV1) from the eucapnic voluntary hyperpnea (EVH) test before and after IMT will be measured. Percentage drop in forced expiratory volume in 1 second (FEV1) will be reported in percentages.

  8 weeks

• Maximum Inspiratory Pressure

  More specifically, the pre- to post-values of maximum inspiratory pressure (reported as cmH2O) before and after IMT will be measured.

  8 weeks

• Sustained Maximum Inspiratory Pressure

  More specifically, the pre- to post-values of sustained maximum inspiratory pressure (reported as pressure time units) before and after IMT will be measured.

  8 weeks

• 16-km Cycling Time-Trial Time to Completion

  More specifically, differences in 16-km cycling time-trial completion time (seconds) before and after IMT.

  8 weeks

• 16-km Cycling Time-Trial Power Output

  More specifically, differences in 16-km cycling time-trial power output (watts) before and after IMT.

  8 weeks

• Constant Load 1 and 2 Speed

  More specifically, differences in constant load performance (i.e., speed) before and after IMT.

  8 weeks

Secondary Outcomes (8)

• Perception of Breathing Intensity, Unpleasantness, and Leg Fatigue During Constant Load 1

  8 weeks

• Perception of Breathing Intensity, Unpleasantness, and Leg Fatigue During Constant Load 2

  8 weeks

• Perception of Breathing Intensity, Unpleasantness, and Leg Fatigue During Time-Trial Cycling

  8 weeks

• Deoxygenation of the Respiratory and Limb Locomotor Muscles During Constant Load 1

  8 weeks

• Deoxygenation of the Respiratory and Limb Locomotor Muscles During Constant Load 2

  8 weeks

Study Arms (2)

Inspiratory Muscle Training (IMT) group

EXPERIMENTAL

The test protocol requires participants to inhale maximally (maximum inspiratory pressure, MIP) against 2mm diameter leak and sustain inhalation (sustained maximal inspiratory pressure, SMIP) until task failure. Participants will complete 3 SMIP maneuvers with each training session and use the best of the three for that day's training template (corresponding to about 80% SMIP for the IMT group) via the PrO2Fit software. Participants must match or exceed the SMIP template with each increasing level of the work-rest ratio. Work at each level consists of 6 breaths, 36 breaths total. If six breaths are completed, the next level starts. Rest intervals will progressively shorten as training continues from 40-seconds to 5-seconds. The session will be terminated if participants are unable to match at least 90% of the training template for two consecutive breaths or have completed all 36 breaths. Training will be done 3 times a week, and over 8-weeks.

Device: PrO2Fit Device

Sham Inspiratory Muscle Training (Sham-IMT) group

SHAM COMPARATOR

Similar to the IMT group protocol, participants will be required to complete 3 SMIP maneuvers with each training session. Participants will use the best of the three for that day's training template (corresponding to about 30% SMIP for the Sham-IMT group) via the PrO2Fit software. Participants must match or exceed the SMIP template with each increasing level of the work-rest ratio. Work at each level consists of 6 breaths, 36 breaths total. If six breaths are completed, the next level starts. Rest intervals will progressively shorten as training continues from 40-seconds to 30-, 20-, 15-, 10-, and 5-seconds. The training session will be terminated if participants are unable to match at least 90% of the training template for two consecutive breaths or have completed all 36 breaths. Training will be done 3 times a week, and over 8-weeks.

Device: PrO2Fit Device

Interventions

PrO2Fit Device DEVICE

The flow-resistive protocol using the device requires participants to maximally inhale as hard as they can and as long as they can against a small leak (2mm diameter hole) until task failure. This records maximum inspiratory pressure (MIP) and sustained maximal inspiratory pressure (SMIP) values which will be recorded and the best is chosen for the software template by the participant to continue their training session (previously described in arm/group description). The use of the device occurs three times a week, and used for 6-8 weeks.

Also known as: Flow-resistive inspiratory muscle training, Sham-Flow-resistive inspiratory muscle training

Inspiratory Muscle Training (IMT) group; Sham Inspiratory Muscle Training (Sham-IMT) group

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Male and female, between the ages of 18 to 35 years.
• Required to be a competitive recreational or college athlete and have at least 1-2 years of cycling or biking experience.
• Body Mass Index (BMI) of 18.5 to 28 kg/m\^2
• Considered "moderately to highly active" by the International Physical Activity Questionnaire (IPAQ).
• Have clinically treated mild to moderate persistent asthma and/or exercise-induced bronchoconstriction (EIB), with a resting forced expiratory volume in 1 second (FEV1) \> 65% of predicted.
• A ≥ 10% drop in FEV1 after eucapnic voluntary hyperpnea (EVH).
• Prescribed short-acting β2-agonists (SABAs) by a physician.
• Comfortable not taking SABA before experimental visits.

You may not qualify if:

• History of smoking or recreational smoking, cardiovascular disease, renal disease, neurological disease, and metabolic disease.
• Currently taking asthma maintenance medications (e.g., corticosteroids and leukotriene modifiers)
• Any injuries in the past 6 months.
• Taking selective serotonin reuptake inhibitors (SSRI)'s (antidepressants and anxiety medication), attention-deficit hyperactivity disorder (ADHD) medication, and chronically consume pain medication (Aleve, Tylenol, cannabidiol (CBD), etc.).
• Has had or is positive for COVID-19.
• Resting blood pressure of \> 130 mmHg systolic or 90 mmHg diastolic.
• Resting Pulse rate of \> 100 bpm.
• Regularly consuming fish oil supplements or eating more then one fish meal per week

Sponsors & Collaborators

• Indiana University: lead

Study Sites (1)

School of Public Health-Bloomington

Bloomington, Indiana, 47405, United States

Location

MeSH Terms

Conditions

Asthma, Exercise-Induced

Condition Hierarchy (Ancestors)

Asthma; Bronchial Diseases; Respiratory Tract Diseases; Respiratory Hypersensitivity; Exercise-Induced Allergies; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases

Limitations and Caveats

Key limitations include a small, imbalanced sample (particularly Sham-IMT), increasing risk of Type II error and unstable interaction estimates. Baseline fitness differences may have biased performance outcomes. EIB variability, unsupervised training, and fixed resistance may have reduced treatment precision. Mechanistic measures were not assessed. Learning effects and methodological variability may have influenced kinetics data. Findings may not generalize beyond recreationally active people.

Results Point of Contact

• Title: Dr. Timothy D Mickleborough
• Organization: Indiana University

tmickleb@iu.edu

812-855-0753

Study Officials

• Tim Mickleborough, Ph.D.

  Indiana University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: March 7, 2024
• First Posted: March 29, 2024
• Study Start: February 10, 2022
• Primary Completion: April 30, 2025
• Study Completion: April 30, 2025
• Last Updated: May 12, 2026
• Results First Posted: May 12, 2026

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)