Effects of High Intensity Interval-Based Inspiratory Muscle Training on Respiratory Muscle Strength, Respiratory Function, Walking Ability and Endurance in Chronic Stroke Patients

Objective: This study aimed to evaluate the effects of high-intensity interval inspiratory muscle training (H-IMT) on respiratory muscle strength, pulmonary function, Gait Speed, Dynamic Balance, and endurance in patients with chronic stroke. Design: A two group pre-post test design Methods: Thirty patients with chronic stroke (onset＞6 months) were randomly assigned to either an experimental group receiving high-intensity interval inspiratory muscle training (H-IMT) or a control group receiving conventional inspiratory muscle training (IMT). Both groups completed 30-minute training sessions three times per week for 8 weeks, alongside standard physiotherapy. Outcome measures included maximal inspiratory pressure (MIP), Maximal Expiratory Pressure (MEP), Forced Vital Capacity (FVC), Forced Expiratory Volume in One second (FEV1), Peak Expiratory Flow (PEF), Six-Minute Walk Test (6MWT), 10-meter walk test (10MWT), and Timed Up and Go test (TUG). Results: The H-IMT group showed significantly greater improvements in MIP (p<0.05), FVC, FEV1, and PEF (p<0.05 for all) compared to the control group. MEP increased significantly only in the H-IMT group. Both groups increased 6MWT distance from baseline, and the H-IMT group achieved a greater improvement than the IMT group (p<0.05). No significant changes were found in gait speed (10MWT), dynamic balance (TUG) in either group. Conclusions: H-IMT effectively improved respiratory muscle strength, pulmonary function, and endurance in chronic stroke patients. However, it had no significant effect on gait speed (10MWT) or dynamic balance (TUG). These findings support its use as a cardiopulmonary intervention; however, further research is required to assess long-term and functional outcomes.