title: Clinimetric properties of the pressure biofeedback unit method for estimating respiratory pressures.
abstract: OBJECTIVE
  The Pressure Biofeedback Unit (PBU) is used to assess the transversus abdominis muscle activity in order to determine the effectiveness of segmental stabilization, but not to verify its accuracy for measuring the pressure values of breathing from transversus abdominis activation. The objective of this study was to cross-validate the PBU pressure evaluated in transversus abdominis muscle activation with the respiratory pressure assessed through manovacuometry in order to verify the extent to which the PBU can be used to indirectly evaluate the strength of the respiratory muscle in both men and women and verify the reliability of the methods.
  
  
  METHODS
  A total of 39 healthy subjects.
  
  
  METHODS
  Manovacuometry and Pressure Biofeedback Unit tests were performed in three days each with three replications: 1) Maximal Inspiratory Pressure; 2) Maximal Expiratory Pressure; and 3) Pressure Biofeedback Unit.
  
  
  RESULTS
  Both tests showed good reliability and low correlation between the Pressure Biofeedback Unit and Maximal Inspiratory Pressure (r = 0.40; p = 0.01) and Maximal Expiratory Pressure (r = 0.33; p = 0.04). High differences were observed between pressures and wide limits of agreement in Bland-Altman analysis.
  
  
  CONCLUSIONS
  It seems that the Pressure Biofeedback Unit is not able to effectively predict the respiratory muscles' strength as routinely evaluated through the use of the manovacuometry presenting a low cross-validation and good reliability.
authors.affiliation: a Health Sciences Center, College of Physiotherapy , Federal University of Piauí , Parnaíba , PI , Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: da Silva
authors.affiliation: a Health Sciences Center, College of Physiotherapy , Federal University of Piauí , Parnaíba , PI , Brazil.
authors.forename: Rayele Pricila Moreira
authors.initials: RPM
authors.lastname: Dos Santos
authors.affiliation: a Health Sciences Center, College of Physiotherapy , Federal University of Piauí , Parnaíba , PI , Brazil.
authors.forename: Patrícia Chaves
authors.initials: PC
authors.lastname: Coertjens
authors.affiliation: a Health Sciences Center, College of Physiotherapy , Federal University of Piauí , Parnaíba , PI , Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Coertjens
mesh_terms: D000009:Abdominal Muscles / Q000294:innervation*; D000328:Adult; D001676:Biofeedback, Psychology / Q000295:instrumentation*; D003430:Cross-Sectional Studies; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D009119:Muscle Contraction; D011237:Predictive Value of Tests; D011312:Pressure; D015203:Reproducibility of Results; D012119:Respiration; D012132:Respiratory Muscles / Q000294:innervation*; D014160:Transducers, Pressure; D055815:Young Adult
keywords: Cross-validation; manovacuometry; reliability; transversus abdominis