title: Breathing exercises: influence on breathing patterns and thoracoabdominal motion in healthy subjects.
abstract: BACKGROUND
  The mechanisms underlying breathing exercises have not been fully elucidated.
  
  
  OBJECTIVE
  To evaluate the impact of four on breathing exercises (diaphragmatic breathing, inspiratory sighs, sustained maximal inspiration and intercostal exercise) the on breathing pattern and thoracoabdominal motion in healthy subjects.
  
  
  METHODS
  Fifteen subjects of both sexes, aged 23 ± 1.5 years old and with normal pulmonary function tests, participated in the study. The subjects were evaluated using the optoelectronic plethysmography system in a supine position with a trunk inclination of 45° during quiet breathing and the breathing exercises. The order of the breathing exercises was randomized. Statistical analysis was performed by the Friedman test and an ANOVA for repeated measures with one factor (breathing exercises), followed by preplanned contrasts and Bonferroni correction. A p<0.005 value was considered significant.
  
  
  RESULTS
  All breathing exercises significantly increased the tidal volume of the chest wall (V(cw)) and reduced the respiratory rate (RR) in comparison to quiet breathing. The diaphragmatic breathing exercise was responsible for the lowest V(cw), the lowest contribution of the rib cage, and the highest contribution of the abdomen. The sustained maximal inspiration exercise promoted greater reduction in RR compared to the diaphragmatic and intercostal exercises. Inspiratory sighs and intercostal exercises were responsible for the highest values of minute ventilation. Thoracoabdominal asynchrony variables increased significantly during diaphragmatic breathing.
  
  
  CONCLUSIONS
  The results showed that the breathing exercises investigated in this study produced modifications in the breathing pattern (e.g., increase in tidal volume and decrease in RR) as well as in thoracoabdominal motion (e.g., increase in abdominal contribution during diaphragmatic breathing), among others.
authors.affiliation: Universidade Federal de Santa Catarina (UFSC), Araranguá, SC, Brazil.
authors.forename: Danielle S R
authors.initials: DS
authors.lastname: Vieira
authors.affiliation: Departamento de Fisioterapia, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
authors.forename: Liliane P S
authors.initials: LP
authors.lastname: Mendes
authors.affiliation: Hospital das Clínicas, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Nathália S
authors.initials: NS
authors.lastname: Elmiro
authors.affiliation: Departamento de Fisioterapia, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Velloso
authors.affiliation: Departamento de Fisioterapia, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Raquel R
authors.initials: RR
authors.lastname: Britto
authors.affiliation: Departamento de Fisioterapia, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Verônica F
authors.initials: VF
authors.lastname: Parreira
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000328:Adult; D001945:Breathing Exercises; D003430:Cross-Sectional Studies; D003964:Diaphragm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D055815:Young Adult