Functional Inspiratory Muscle Training for Gait Recovery in Patients With Chronic Stroke

Stroke is a leading cause of long-term disability worldwide and is frequently associated with persistent impairments in walking ability. Patients with chronic stroke commonly demonstrate reduced gait speed, shorter stride length, impaired gait symmetry, prolonged double-support time, and decreased functional mobility. These gait abnormalities are associated with impaired trunk control, respiratory muscle weakness, reduced exercise tolerance, and diminished quality of life. Although conventional rehabilitation improves motor function, many patients continue to experience limitations in walking performance.

Inspiratory muscle training (IMT) has been shown to improve inspiratory muscle strength, pulmonary function, exercise capacity, and trunk stability in individuals with neurological disorders. Functional inspiratory muscle training (F-IMT) integrates inspiratory muscle training with functional rehabilitation exercises, allowing simultaneous activation of respiratory and postural muscles during task-oriented activities. This integrated approach may enhance motor control and walking performance beyond conventional IMT alone.

This study is a prospective, single-center, randomized controlled trial involving 60 participants with chronic stroke. Eligible participants will be randomly allocated in a 1:1 ratio to one of two intervention groups. The intervention group will receive functional inspiratory muscle training using a Threshold IMT device integrated with functional rehabilitation exercises at an intensity of 50% of maximal inspiratory pressure (MIP), five sessions per week for 8 weeks. The control group will receive conventional inspiratory muscle training using the same device, training intensity, frequency, and duration without integration into functional activities. Both groups will receive an identical standardized conventional rehabilitation program throughout the intervention period.

The primary outcome will be changes in spatiotemporal gait parameters measured using the STEADYS gait assessment system, including gait speed, cadence, stance time, swing time, double-support time, and stride length. Secondary outcomes will include functional exercise capacity measured using the Six-Minute Walk Test (6MWT) and health-related quality of life measured using the EuroQol Five-Dimension (EQ-5D) questionnaire. Outcome assessments will be performed at baseline and after completion of the 8-week intervention.

The findings of this trial will provide evidence regarding the effectiveness of functional inspiratory muscle training as an adjunct to conventional rehabilitation for improving gait performance, exercise capacity, and quality of life in individuals with chronic stroke.

Inclusion criteria

• Patients aged between 55 and 65 years.
• Both male and female participants.
• Chronic stroke patients (>6 months after stroke onset), including ischemic or hemorrhagic stroke confirmed by neuroimaging.
• Moderate gait impairment with gait speed ranging from 0.4 to 0.8 m/s.
• Ability to understand instructions and communicate sufficiently to participate in the study procedures.
• Breathing spontaneously without ventilatory support.
• No thoracic or abdominal surgery within the previous 6 months.
• No facial palsy, or mild facial palsy without limitation of labial occlusion.
• Ability to walk independently for at least 10 meters with or without an assistive device.
• Willingness to participate and provide written informed consent.

Exclusion criteria

• Unstable cardiovascular disease (e.g., recent myocardial infarction, uncontrolled hypertension, decompensated heart failure).
• Uncontrolled metabolic disease or poorly controlled diabetes mellitus.
• Severe pulmonary disease or respiratory impairment (e.g., severe COPD, hypoxemia, chronic cough, or sputum retention).
• Active malignancy.
• Presence of nasal feeding tube, tracheostomy tube, or any condition preventing implementation of the study procedures.
• Severe musculoskeletal disorders affecting gait performance (e.g., lower limb fracture, severe osteoarthritis, or amputation).
• Significant cognitive or communication impairment preventing reliable participation.
• Severe spasticity (Modified Ashworth Scale >3) or fixed contractures.
• Other neurological disorders affecting gait (e.g., Parkinson's disease, multiple sclerosis, spinal cord injury).
• Severe obesity (BMI ≥35 kg/m²) that may interfere with gait assessment or exercise performance.
• Previous participation in inspiratory muscle training programs.