The Powerbreathe is an inspiratory muscle trainer promoted as improving inspiratory muscle strength (and consequently exercise performance) in athletes and @entity1 with @entity1576 . No published evidence supports its efficacy. We performed a prospective randomized controlled study in which 12 normal subjects received either Powerbreathe training or sham training for a 6-week period. The primary outcome measure was diaphragm strength evaluated as twitch transdiaphragmatic pressure (Tw @entity18035 ) but secondary outcome measures were provided by full respiratory muscle assessment and cardiopulmonary exercise testing. An advantage to training was observed when outcome was assessed by maximal static @entity551 (mean advantage 14.5 cm @entity2507 , 95% CI 2.2-26.9 cm @entity2507 , P=0.025). However. no significant difference was observed between the groups in any other parameter. In particular the deltaTw @entity18035 was not different between groups (mean 'advantage' 0.7 cm @entity2507 , 95% CI- 7.0+/-5.5 cm @entity2507 , P=0.8). The continued sale and use of the Powerbreathe device is not justified by our data. A sample size calculation showed that 234 subjects would need to be randomized to definitively refute the hypothesis that Powerbreathe improves Tw @entity18035 and we argue that such a study is required.

Evaluation of an inspiratory muscle trainer in healthy XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity18035 :: ('5034', 'Gene') :: ['Pdi'] @entity2507 :: ('CHEBI:33813', 'Chemical') :: ['H2O'] @entity1576 :: ('MESH:D012131', 'Disease') :: ['respiratory disease'] @entity551 :: ('MESH:D007022', 'Disease') :: ['inspiratory mouth pressure']
@entity1 :: (9606,Species) :: ['humans']
