Effects of inspiratory muscle training on walking capacity of individuals after stroke: A double-blind randomized trial

Abstract

Objectives: Identify the effects of inspiratory muscle training (IMT) on walking capacity, strength and inspiratory muscle endurance, activities of daily living, and quality of life poststroke. Design: Double-blind randomized trial. Setting: The Sarah Network of Rehabilitation Hospitals. Subjects: Adult poststroke inpatients with inspiratory muscle weakness. Interventions: The Experimental Group (EG) (n = 23) underwent IMT for 30 minutes/day, five times/week over six weeks. The Control Group (CG) (n = 27) performed sham IMT. Both groups underwent standard rehabilitation. Main measures: Primary outcome was post-intervention six-minute walking test (6MWT) distance. We also measured maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), inspiratory muscle endurance, activities of daily living (functional independence measure – FIM), and quality of life at baseline and post-intervention. Three months after intervention, we measured MIP, walking capacity and quality of life. Results: Baseline characteristics were similar, with mean age 53 ± 11 years and FIM 74 ± 10p. Both groups similarly increased the walking capacity at six weeks (63 vs 67 m, P = 0.803). Compared to the CG, the EG increased the inspiratory endurance (22 vs 7 cmH2O, P = 0.034) but there was no variation in MEP (14 vs 5 cmH2O, P = 0.102), MIP (27 vs 19 cmH2O, P = 0.164), FIM (6 vs 6, P = 0.966) or quality of life (0 vs 0.19, P = 0.493). Gains in both groups were sustained at three months. Conclusion: Adding IMT to a rehabilitation program improves inspiratory muscle endurance, but does not further improve MIP, 6-MWT distance, activities of daily living or quality of life of individuals after stroke beyond rehabilitation alone. Registered in Clinical Trials, NCT03171272.