Inspiratory Muscle Training in Patients With Inflammatory Myopathy

The Effect of Inspiratory Muscle Training on the Functional Status of Patients With Inflammatory Myopathy

Inflammatory myopathies are rare autoimmune diseases leading to progressive muscle weakness, often including the respiratory muscles. This study aims to investigate whether inspiratory muscle training (IMT) using a threshold device can improve functional status in patients with inflammatory myopathy. Thirty-three patients will undergo a 3-month home-based IMT program with progressive resistance. Functional capacity, inspiratory muscle strength, lung function, diaphragmatic mobility, fatigue, and quality of life will be assessed at baseline and during follow-up. The primary hypothesis is that IMT will enhance inspiratory muscle strength and translate into better functional performance and quality of life.

Study Overview

• Status: Recruiting
• Conditions: Inflammatory Myopathies
• Intervention / Treatment: Behavioral: Inspiratory Muscle Training (IMT)

Detailed Description

Idiopathic inflammatory myopathies (IIM) are rare autoimmune disorders characterized by progressive, symmetrical proximal muscle weakness, frequently affecting the respiratory muscles. Diaphragmatic dysfunction and reduced inspiratory muscle strength contribute to impaired ventilation, fatigue, and reduced exercise tolerance. While exercise training has proven beneficial in patients with various neuromuscular conditions, evidence regarding inspiratory muscle training (IMT) in IIM is lacking.

This pilot interventional study will prospectively evaluate the impact of a 3-month IMT program on respiratory and functional outcomes in patients with IIM. The intervention consists of daily inspiratory resistance training (30 breaths/day, 7 days/week) using the Threshold IMT device (Philips Respironics, USA). Training intensity is set at 30% of maximal inspiratory pressure (MIP) and adjusted progressively based on patient-reported exertion. Participants receive individualized instruction, follow-up phone consultations every 2 weeks, and record adherence in exercise diaries.

Assessments include inspiratory muscle strength (measured with Powerbreathe KH2), spirometry (Forced Expiratory Volume in 1 Second, Forced Vital Capacity, Forced Inspiratory Vital Capacity, Inspiratory Reserve Volume), diaphragm ultrasound (mobility and thickness fraction), six-minute walk test (6MWT), fatigue assessment (Borg Rating of Perceived Exertion Scale, Fatigue Severity Scale), and quality of life (36-Item Short Form Health Survey). Outcomes will be measured 3 months before training, at baseline, after 3 months of training, and during extended follow-up (up to 6-12 months). The primary endpoint is change in MIP. Secondary endpoints include pulmonary function parameters, diaphragmatic function, exercise tolerance, fatigue, and health-related quality of life.

The study will be conducted in the Neurology Clinic of the Medical University of Warsaw (WUM). A total of 33 patients with IIM, diagnosed according to European Alliance of Associations for Rheumatology / American College of Rheumatology criteria, will be recruited. Inclusion requires age ≥18 and written informed consent. Exclusion criteria include cognitive impairment, acute respiratory infection, prior respiratory training, pneumothorax, pulmonary hypertension, or contraindications to IMT. This trial is expected to provide the first structured evidence on the role of IMT in improving functional status in patients with inflammatory myopathy, potentially guiding individualized rehabilitation strategies for this patient population.

• Study Type: Interventional
• Enrollment (Estimated): 33
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jan Sznajder, PhD; Phone Number: +48696994812; Email: jan.sznajder@awf.edu.pl
• Study Contact Backup: Name: Agnieszka Lewińska, PhD; Phone Number: +48790013404; Email: agnieszka.lewinska@awf.edu.pl

Study Locations

• Poland
  • Warsaw, Poland, 02-097
    • Recruiting
    • University Clinical Center of the Medical University of Warsaw
    • Contact: Jan Sznajder, PhD; Phone Number: +48696994812; Email: jan.sznajder@awf.edu.pl
    • Contact: Agnieszka Lewińska, PhD; Phone Number: +48790013404; Email: agnieszka.lewinska@awf.edu.pl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of inflammatory myopathy according to European Alliance of Associations for Rheumatology / American College of Rheumatology criteria
• Age ≥ 18 years
• Stable clinical condition allowing participation in physical activity
• Ability to understand and follow instructions
• Written informed consent to participate in the study

Exclusion Criteria:

• Cognitive impairment preventing proper exercise performance
• Current respiratory tract infection
• Previous respiratory muscle training within the last 12 months
• History of spontaneous pneumothorax
• Pulmonary hypertension
• Tympanic membrane rupture or other middle ear pathology
• Lack of voluntary and informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Inspiratory Muscle Training (IMT); Patients with inflammatory myopathy will perform a 3-month inspiratory muscle training (IMT) program using a threshold device (Philips Respironics Threshold IMT). Training will be home-based, preceded by individual instruction, and monitored through exercise diaries and follow-up phone consultations. Assessments will be performed before training, after 3 months, and during follow-up visits.

Behavioral: Inspiratory Muscle Training (IMT); Inspiratory muscle training performed with a threshold loading device (Threshold IMT, Philips Respironics). Participants perform 30 breaths once daily, 7 days per week, for 3 months. The training load is set at 30% of maximal inspiratory pressure (MIP) and increased by 10% if the perceived exertion decreases on two consecutive training days. Participants receive individualized instruction and regular follow-up consultations (every 2 weeks) to adjust load and verify adherence.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in maximal inspiratory pressure (MIP)	Maximal inspiratory pressure (MIP) measured at the mouth using Powerbreathe KH2 devices. Results are expressed in cmH₂O. Higher values indicate greater inspiratory muscle strength.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Forced Vital Capacity (FVC)	Forced Vital Capacity (FVC) assessed by spirometry using the EasyOne spirometer (NDD Medical Technologies). Results are expressed in liters (L) and as percent of predicted values (% predicted). Higher values indicate better pulmonary function.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in Forced Expiratory Volume in 1 Second (FEV1)	Forced Expiratory Volume in 1 Second (FEV1) assessed by spirometry using the EasyOne spirometer (NDD Medical Technologies). Results are expressed in liters (L) and as percent of predicted values (% predicted). Higher values indicate better pulmonary function.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in diaphragm thickness	Diaphragm thickness assessed by ultrasound using a Philips Lumify linear probe. Thickness is measured in millimeters (mm) at end-expiration and end-inspiration. Diaphragm thickening fraction (%) may be calculated from inspiratory and expiratory thickness measurements.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in 6-Minute Walk Distance (6-Minute Walk Test)	Functional exercise capacity assessed by the 6-Minute Walk Test (6MWT), conducted on a 30 m corridor. The total distance walked in 6 minutes is recorded in meters. Greater distance indicates better functional exercise capacity.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in perceived exertion (Borg Rating of Perceived Exertion)	Perceived exertion assessed using the Borg Rating of Perceived Exertion Scale (modified 0-10 scale). The scale ranges from 0 (no exertion) to 10 (maximal exertion), with higher scores indicating greater perceived exertion and fatigue.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in fatigue severity (Fatigue Severity Scale)	Fatigue assessed using the Fatigue Severity Scale (FSS), a 9-item questionnaire in which each item is scored from 1 (strongly disagree) to 7 (strongly agree). The total score is calculated as the mean of the 9 items (range 1-7), with higher scores indicating greater fatigue severity.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in quality of life (36-Item Short Form Health Survey)	Health-related quality of life assessed using the 36-Item Short Form Health Survey (SF-36). The questionnaire includes eight domains scored from 0 to 100, with higher scores indicating better health status and quality of life.	3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months

Collaborators and Investigators

• Sponsor: Józef Piłsudski University of Physical Education

Publications and helpful links

General Publications

• Van Thillo A, Vulsteke JB, Van Assche D, Verschueren P, De Langhe E. Physical therapy in adult inflammatory myopathy patients: a systematic review. Clin Rheumatol. 2019 Aug;38(8):2039-2051. doi: 10.1007/s10067-019-04571-9. Epub 2019 May 21.
• Ashton C, Paramalingam S, Stevenson B, Brusch A, Needham M. Idiopathic inflammatory myopathies: a review. Intern Med J. 2021 Jun;51(6):845-852. doi: 10.1111/imj.15358.
• Lundberg IE, Miller FW, Tjarnlund A, Bottai M. Diagnosis and classification of idiopathic inflammatory myopathies. J Intern Med. 2016 Jul;280(1):39-51. doi: 10.1111/joim.12524.

Helpful Links

• Academy of Physical Education in Warsaw - institutional website

Study record dates

Study Major Dates

• Study Start (Actual): August 12, 2024
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: November 27, 2025
• First Submitted That Met QC Criteria: November 27, 2025
• First Posted (Actual): December 10, 2025

Study Record Updates

• Last Update Posted (Actual): February 25, 2026
• Last Update Submitted That Met QC Criteria: February 23, 2026
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Inspiratory muscle training; Exercise tolerance; Diaphragm ultrasound; Respiratory muscle strength
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Neuromuscular Diseases; Myositis
• Other Study ID Numbers: KB/91/2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared because the study involves a small sample of clinical patients and contains potentially identifiable medical information. Summary results will be made available through scientific publications and presentations.

Drug and device information, study documents

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