title: Reversal time of postprandial changes of the thickness of abdominal muscles employing ultrasound measurements.
abstract: OBJECTIVE
  Low thickness of Transversus Abdominis, Internal Oblique and External Oblique muscles may play a role in development of low back pain. Ultrasonography is increasingly utilized to measure the thickness of these muscles. Prandial state has recently been proposed as a confounding factor in such measurements. We aimed to compare the reversal time of the postprandial thickness of these muscles with preprandial values. The measurement errors of ultrasonographic values were also assessed in both immediate preprandial and postprandial states.
  
  
  METHODS
  Interventional cross-sectional study.
  
  
  METHODS
  The ultrasonographic thickness of lateral abdominal muscles was measured at rest and during abdominal drawing-in maneuver in 20 healthy participants before and after consumption of a specific meal. Postprandial ultrasound measurements continued every 15 min until their thickness reached 95% of their preprandial values.
  
  
  RESULTS
  There was a statistically significant reduction in postprandial thickness of these muscles (all p-values <0.001 on both sides). The reversal times were 1.5, 1.3 and 1.2 h for Transversus Abdominis, Internal Oblique, and External Oblique muscles, respectively. Standard Error of Measurement and Smallest Detectable Change were in the range of 0.007-0.013 mm and 0.020-0.035 mm, respectively.
  
  
  CONCLUSIONS
  To limit the effects of prandial state on the sonographic thickness of lateral abdominal muscles, we recommend measuring these values at least 1.5-2 h after food consumption. For the future studies, controlling the participants according to their prandial state is recommended.
authors.affiliation: Sports Medicine Research Center, Tehran University of Medical Sciences, No 7, Al-e Ahmad St., Tehran, Iran; Department of Sports and Exercise Medicine, School of Medicine, Tehran University of Medical Sciences, Imam Khomeini Hospital, Bagher Khan St., Chamran Highway, Tehran, Iran.
authors.forename: Pardis
authors.initials: P
authors.lastname: Noormohammadpour
authors.affiliation: Sports Medicine Research Center, Tehran University of Medical Sciences, No 7, Al-e Ahmad St., Tehran, Iran; Spine Division, Noorafshar Rehabilitation & Sports Medicine Hospital, 17th St., Khodaverdi St., Niavaran, Tehran, Iran.
authors.forename: Majid
authors.initials: M
authors.lastname: Ansari
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Poursina St., Shanzdah-e Azar St., Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Mansournia
authors.affiliation: Sports Medicine Research Center, Tehran University of Medical Sciences, No 7, Al-e Ahmad St., Tehran, Iran; Spine Division, Noorafshar Rehabilitation & Sports Medicine Hospital, 17th St., Khodaverdi St., Niavaran, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Rostami
authors.affiliation: Sports Medicine Research Center, Tehran University of Medical Sciences, No 7, Al-e Ahmad St., Tehran, Iran; Spine Division, Noorafshar Rehabilitation & Sports Medicine Hospital, 17th St., Khodaverdi St., Niavaran, Tehran, Iran.
authors.forename: Ruhollah
authors.initials: R
authors.lastname: Nourian
authors.affiliation: Sports Medicine Research Center, Tehran University of Medical Sciences, No 7, Al-e Ahmad St., Tehran, Iran; Spine Division, Noorafshar Rehabilitation & Sports Medicine Hospital, 17th St., Khodaverdi St., Niavaran, Tehran, Iran. Electronic address: ramin_kordi@tums.ac.ir.
authors.forename: Ramin
authors.initials: R
authors.lastname: Kordi
mesh_terms: D000009:Abdominal Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D019518:Postprandial Period
keywords: Confounding factor; Food intake; Internal oblique; Outcome measurement errors; Transversus Abdominis; Ultrasonography