title: Measurement of superficial and deep abdominal muscle thickness: an ultrasonography study.
abstract: BACKGROUND
  Real-time ultrasound imaging is a valid method in the field of rehabilitation. The ultrasound imaging allows direct visualization for real-time study of the muscles as they contract over the time. Measuring of the size of each abdominal muscle in relation to the others provides useful information about the differences in structure, as well as data on trunk muscle activation patterns. The purpose of this study was to assess the size and symmetry of the abdominal muscles at rest in healthy adults and to provide a reference range of absolute abdominal muscle size in a relatively large population.
  
  
  METHODS
  A total 156 healthy subjects with the age range of 18-44 years were randomly recruited. The thickness of internal oblique, external oblique, transverse abdominis, and rectus abdominis muscles was measured at rest on both right and left sides using ultrasound. Independent t test was used to compare the mean thickness of each abdominal muscle between males and females. Differences on side-to-side thicknesses were assessed using paired t test. The association between abdominal muscle thicknesses with gender and anthropometric variables was examined using the Pearson correlation coefficient.
  
  
  RESULTS
  A normal pattern of increasing order of mean abdominal muscle thickness was found in both genders at both right and left sides: transverse abdominis < external oblique < internal oblique < rectus abdominis. There was a significant difference on the size of transverse abdominis, internal oblique, and external oblique muscles between right and left sides in both genders. Males had significantly thicker abdominal muscles than females. Age was significantly correlated with the thickness of internal oblique, external oblique, and rectus abdominis muscles. Body mass index was also positively correlated with muscle thickness of rectus abdominis and external oblique.
  
  
  CONCLUSIONS
  The results provide a normal reference range for the abdominal muscles in healthy subjects and may be used as an index to find out abnormalities and also to evaluate the effectiveness of different interventions.
authors.affiliation: Physiotherapy Research Center, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran. nahidta2431@Gmail.com.
authors.forename: Nahid
authors.initials: N
authors.lastname: Tahan
authors.affiliation: Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Khosro
authors.initials: K
authors.lastname: Khademi-Kalantari
authors.affiliation: Iranian Research Centre on Aging, Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Evin, Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Mohseni-Bandpei
authors.affiliation: Physiotherapy Research Center, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Mikaili
authors.affiliation: Physiotherapy Research Center, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza Akbarzadeh
authors.initials: AA
authors.lastname: Baghban
authors.affiliation: Faculty of Medicine, Nursing and Health Sciences, School of Primary Health Care, Monash University, Melbourne, Australia.
authors.forename: Shapour
authors.initials: S
authors.lastname: Jaberzadeh
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000375:Aging; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D012737:Sex Factors; D014463:Ultrasonography; D055815:Young Adult