Changes in deep abdominal muscle thickness during common trunk-strengthening exercises using ultrasound imaging.

Teyhen DS, Rieger JL, Westrick RB, Miller AC, Molloy JM, Childs JD

The objective of this study ws to characterize changes in muscle thickness in the transversus abdominis (TrA) and internal oblique (IO) muscles during common trunk-strengthening exercises, and to determine whether these changes differ based on age. Six commonly prescribed trunk-strengthening exercises were performed by 120 subjects. Ultrasound imaging was used to measure the thickness of the TrA and IO during the resting and contracted state of each exercise. For both muscles, the trunk exercise-by-age interaction effect and the main effect for age were not significant. A significant main effect for trunk exercise for both muscles was found. The horizontal side-support and the abdominal crunch exercises resulted in the greatest change in muscle thickness for both muscles. The abdominal drawing-in maneuver and quadruped opposite upper and lower extremity lift exercises resulted in changes in TrA muscle thickness with minimal changes in IO muscle thickness.

Changes in TrA and IO muscle thickness differed across 6 commonly prescribed trunk-strengthening exercises among healthy subjects without LBP. These differences did not vary by age. This information may be useful for informing exercise prescription.

Journal of Orthopaedic and Sports Physical Therapy, 2008, 38(10), 596-605

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