Effects of inspiratory muscle training on pulmonary function, diaphragmatic thickness, balance and exercise capacity in people after stroke: a systematic review and meta-analysis.

Abstract

To examine the effects of inspiratory muscle training (IMT) on pulmonary and diaphragmatic function, exercise capacity, balance and quality of life (QOL), in post-stroke individuals. A literature search was conducted using MEDLINE, CINAHL, EMBASE, PubMed, PEDro, Web of Science and China Biological Medicine databases. Randomized controlled trials (RCTs) with a PEDro score ≥6 focusing on the effects of IMT were included. The GRADE system was used to determine the certainty of evidence for each outcome. Nine studies (255 participants) were included. IMT significantly increased forced expiratory volume in one second (FEV₁) (4 studies, 112 participants, mean difference (MD)=0.18 litre, 95% confidence interval (CI): 0.14-0.23); maximal inspiratory pressure (MIP) (8 studies, 226 participants, MD = 6.37 cm H₂O, 95% CI: 1.26-11.49); and diaphragm thickness fraction (DTf) on both sides (MD of affected side vs. unaffected side: 51 vs. 37%). The evidence certainty for diaphragmatic function was moderate. No significant change was observed in forced vital capacity (FVC), balance function, exercise capacity and QOL. This review reveals moderate evidence certainty in support of IMT improving diaphragmatic function. It appears that a training intensity between 30 and 50% MIP results in a significantly improved MIP.