title: A neuromuscular strategy to prevent spinal torsion: backward perturbation alters asymmetry of transversus abdominis muscle thickness into symmetry.
abstract: Symmetric co-contraction of the transversus abdominis (TrA) muscle is beneficial in terms of increasing trunk stability. The aim of this study was to investigate the symmetry of lateral abdominal muscle thickness during static and dynamic conditions. Fifteen male subjects (27.13 ± 5.51 years old) were instructed to sit on a chair and maintain upright posture. Every individual subject wore a jacket harness that could be backwardly attached to a 9-kg weight through a pulley system. An unexpected drop of the weight induced the transition from static to dynamic condition. The thickness of external oblique, internal oblique, and TrA muscles was measured with ultrasonography. Our results revealed more symmetry of TrA thickness during the dynamic condition (21% vs. 13%, p = 0.019) compared with the static. The symmetric muscle thickness of TrA during the dynamic condition is considered a result of more contraction on the non-dominant side. This phenomenon could be a possible strategy of deep abdominal muscles to prevent spinal torsion during sudden trunk perturbation.
authors.affiliation: Department of Physical Therapy, College of Health Sciences, Korea University, Seoul, Republic of Korea.
authors.forename: Yushin
authors.initials: Y
authors.lastname: Kim
authors.forename: Jae Kun
authors.initials: JK
authors.lastname: Shim
authors.forename: Jaebum
authors.initials: J
authors.lastname: Son
authors.forename: Hyo Young
authors.initials: HY
authors.lastname: Pyeon
authors.forename: Bumchul
authors.initials: B
authors.lastname: Yoon
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging / Q000502:physiology*; D000328:Adult; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D013131:Spine / Q000502:physiology*; D054159:Torsion, Mechanical; D060726:Torso / Q000502:physiology*; D014463:Ultrasonography; D055815:Young Adult