Effects of inspiratory muscle training on respiratory function and balance in stroke survivors: a randomized controlled trial

Abstract

After a stroke, patients with hemiparesis and / or hemiplegia will present a notable asymmetry of the trunk and pelvis, and decreased postural stability and balance, affecting, consequently, respiratory function. The objective of this study is to analyze the effects of inspiratory muscle training (IMT) on lung function, inspiratory muscle strength, postural and trunk control and balance in stroke survivors in the subacute phase. 16 survivors of stroke in the subacute phase participated in RCT (experimental = 8; placebo = 8). The experimental group received IMT program, 5 days a week, once a day, for 8 weeks, with a progressive intensity from 15% to 60% of the PImax. The placebo group performed the same program, but with a fixed load of 7cmH20. Inspiratory muscle strength (PImax), lung function (FVC, FEV1, PEF, VMV), trunk control (TCT), and postural control and balance (PASS and Berg Scale) were evaluated. Experimental and placebo groups showed significant increases in PImax, with a difference between groups. There was a moderate and negative correlation between the initial PImax value and the percentage change (?PImax) (r = -0.572; p = 0.021). Significant increases in VMV (l/m) were observed in the experimental group, and increases in PASS in both groups, but without significant differences between groups. Inspiratory muscle training, although low intensity, is effective in improving inspiratory muscle strength in stroke survivors. However, the effects on postural control and balance remain uncertain.