Abdominal muscle size and symmetry in normal subjects

Abstract

This study was undertaken to establish normal reference ranges for abdominal muscle size and symmetry and to examine the effects on these of gender and age. We studied 123 subjects, consisting of 55 men (aged 21-72 years) and 68 women (aged 20-64 years). Real-time ultrasound imaging of the abdominal muscles was performed. Thickness of internal and external oblique (IO, EO), transversus abdominis (TA), and rectus abdominis (RA), and cross-sectional area (CSA) of RA were measured, and absolute and relative muscle thickness (percent total muscle thickness), order of thickness, and symmetry (percent difference between sides) were determined. Males had significantly larger muscles than females and size was poorly correlated with age. The pattern of relative muscle thickness was RA > IO > EO > TA. Symmetry for total absolute thickness of all three lateral muscles was 8%-9% (mean) but for individual muscles there was asymmetry of absolute size (13%-24%), whereas relative thickness was symmetrical for all muscles. These findings provide robust reference data for the abdominal muscles in normal males and females in order to enable comparison with clinical groups to assess abnormalities and establish sensitivity for evaluating the effectiveness of interventions.

The effect of food consumption on the thickness of abdominal muscles, employing ultrasound measurements

“…The level of stomach fullness was not considered as a possible source of measurement error in this study that might affect the results. In studies performed in the aim of finding the relation among muscle thickness and some demographic characteristics of healthy subjects, divergent results have been reported [20,27,29]; respecting obtained results from current study, it can be assumed that absence of subjects matching regarding food consumption might be a potential reason for mentioned discrepancies. Besides, post manipulative [26] post Pilate exercise [5] and post upper limb exercise [21] evaluation of TrA muscle thickness did show improvement in thickness and strength of muscles.…”

“…Transducer was positioned in transverse plane and measurement of muscle thickness was made at the center point of the image using caliper of the machine [27]. To prevent feedback effects, subjects could not view the scanner screen.…”

“…(1) A point 25 mm anteromedial at the midpoint between the inferior rib and the iliac crest to the midaxillary line [16]. (2) A point immediately under the ribcage in direct vertical alignment with the anterior superior iliac spine (ASIS) [27]. We marked the transducer positions at the pre food consumption measurements and used the same position at the after food consumption measurements.…”

“…Ultrasonic waves have been utilized in measurements of abdominal muscle thickness [27]. Several studies have reported good reliability for measurement of individual abdominal muscle thicknesses at rest or in contracted state [10,11,18,30].…”

The importance of body mass normalisation for ultrasound measurements of the morphology of oblique abdominis muscles: the effect of age, gender, and sport practice

“…Some studies have tried to find some connection between OE, OI, and TrA morphology and conditions, such as low back pain and scoliosis [3,5,11,16,25]. To better understand lateral abdominal wall morphology, some studies have also examined the effect of age, gender, physical activity, as well as anthropometric measurements on the OE, OI, and TrA thickness in adult and adolescent healthy populations [13,17,18,22,27]. These works have shown that body mass is highly correlated with all lateral abdominal muscle thicknesses [14,17,18,22].…”