Abstract
Objective To investigate the efficacy of inspiratory muscle training (IMT) on respiratory functions, respiratory muscle strength, and asthma symptoms in asthmatic children. Methods In a randomized placebo-controlled assessor-blinded study, 34 children with asthma were randomized to receive either the IMT at 40% of the maximal inspiratory pressure (IPmax) for 20 min/session, thrice/week, over 12 consecutive weeks (IMT group;n = 17) or placebo IMT at 5% of IPmax(placebo group;n = 17). Additionally, both groups received the conventional respiratory rehabilitation (CRR) program. Outcome measurements performed pre- and post-treatment, included respiratory functions [forced expiratory volume at the first second (FEV1), forced vital capacity (FEV), and FEV1/FVC], respiratory muscle strength [represented by IP(max)and maximal expiratory pressure (EPmax), and asthma control test (ACT). Results At a significance level adjusted toP<.008, there were significant post-treatment differences between the IMT and placebo groups in FEV1(P=.003), FVC (P=.001), FEV1/FVC (P=.004), IPmax(P=.002), EPmax(P=.004), and ACT (P=.001) adjusted to the pretreatment values, in favor of the IMT group. Conclusion Incorporation of IMT in the CRR program for children with asthma can improve respiratory function, enhance respiratory muscle strength, and improve children's perception of asthma symptoms.