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

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.