A randomized placebo-controlled study investigating the efficacy of inspiratory muscle training in the treatment of children with bronchial asthma

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 (IP_max) for 20 min/session, thrice/week, over 12 consecutive weeks (IMT group; n = 17) or placebo IMT at 5% of IP_max (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 (EP_max), and asthma control test (ACT). Results: At a significance level adjusted to P<.008, there were significant post-treatment differences between the IMT and placebo groups in FEV₁ (P=.003), FVC (P=.001), FEV₁/FVC (P=.004), IP_max (P=.002), EP_max (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.