title: Correlation Between Abdominal Muscle Thickness and Maximal Expiratory Pressure.
abstract: OBJECTIVE
  The activity of abdominal muscles mainly produces high expiratory pressure. These include the rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles. The purpose of this study was to determine whether maximal expiratory pressure is associated with each abdominal muscle thickness at rest.
  
  
  METHODS
  Thirty-nine healthy male volunteers (mean age ± SD, 20.7 ± 2.7 years) participated in the study. The thickness of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles was measured by B-mode sonography in the supine position. The maximal expiratory pressure was obtained with a spirometer in the sitting position. The correlations between each abdominal muscle thickness and maximal expiratory pressure were determined by the Pearson correlation coefficient.
  
  
  RESULTS
  The correlation coefficient between the rectus abdominis muscle and maximal expiratory pressure was 0.571 (P< .001). Correlation coefficients between the external oblique, internal oblique, and transverse abdominis muscles and maximal expiratory pressure were 0.297 (P = .066), 0.267 (P = .100), and 0.022 (P = .894), respectively.
  
  
  CONCLUSIONS
  Our results indicate that the rectus abdominis muscle thickness might be more highly correlated with expiratory pressure production than the external oblique, internal oblique, and transverse abdominis muscle thickness.
authors.affiliation: Department of Rehabilitation (H.I., T.S., C.K., S.W.) and Master's Program in Rehabilitation (K.O.), Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan ishida@mw.kawasaki-m.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishida
authors.affiliation: Department of Rehabilitation (H.I., T.S., C.K., S.W.) and Master's Program in Rehabilitation (K.O.), Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors.forename: Tadanobu
authors.initials: T
authors.lastname: Suehiro
authors.affiliation: Department of Rehabilitation (H.I., T.S., C.K., S.W.) and Master's Program in Rehabilitation (K.O.), Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Kurozumi
authors.affiliation: Department of Rehabilitation (H.I., T.S., C.K., S.W.) and Master's Program in Rehabilitation (K.O.), Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ono
authors.affiliation: Department of Rehabilitation (H.I., T.S., C.K., S.W.) and Master's Program in Rehabilitation (K.O.), Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging* / Q000502:physiology*; D045853:Exhalation / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D009929:Organ Size / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult
keywords: abdominal muscle thickness; expiration; musculoskeletal ultrasound; sonography