title: Determinants of inspiratory muscle strength in healthy humans.
abstract: We investigated (1) the relationship between the baseline and inspiratory muscle training (IMT) induced increase in maximal inspiratory pressure (P(I,max)) and (2) the relative contributions of the inspiratory chest wall muscles and the diaphragm (P(oes)/P(di)) to P(I,max) prior to and following-IMT. Experiment 1: P(I,max) was assessed during a Müeller manoeuvre before and after 4-wk IMT (n=30). Experiment 2: P(I,max) and the relative contribution of the inspiratory chest wall muscles to the diaphragm (P(oes)/P(di)) were assessed during a Müeller manoeuvre before and after 4-wk IMT (n=20). Experiment 1: P(I,max) increased 19% (P<0.01) post-IMT and was correlated with baseline P(I,max) (r=-0.373, P<0.05). Experiment 2: baseline P(I,max) was correlated with P(oe)/P(di) (r=0.582, P<0.05) and after IMT PI,max increased 22% and Poe/Pdi increased 5% (P<0.05). In conclusion, baseline P(I,max) and the contribution of the chest wall inspiratory muscles relative to the diaphragm affect, in part, baseline and IMT-induced P(I,max). Great care should be taken when designing future IMT studies to ensure parity in the between-subject baseline P(I,max).
authors.affiliation: English Institute of Sport, Loughborough, UK. Electronic address: peter.brown@eis2win.co.uk.
authors.forename: Peter I
authors.initials: PI
authors.lastname: Brown
authors.affiliation: School of Science and Technology, Nottingham Trent University, Nottingham, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Johnson
authors.affiliation: School of Science and Technology, Nottingham Trent University, Nottingham, UK.
authors.forename: Graham R
authors.initials: GR
authors.lastname: Sharpe
mesh_terms: D000328:Adult; D001945:Breathing Exercises; D003964:Diaphragm / Q000502:physiology*; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D007366:Intercostal Muscles / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D011312:Pressure; D035441:Thoracic Wall / Q000502:physiology; D055815:Young Adult
keywords: Chest wall; Diaphragm; Inspiratory muscle training; Respiratory muscles