Functional roles of abdominal and back muscles during isometric axial rotation of the trunk

Ng, Joseph K.-F., Parnianpour, Mohamad, Richardson, Carolyn A. and Kippers, Vaughan (2001) Functional roles of abdominal and back muscles during isometric axial rotation of the trunk. Journal of Orthopaedic Research, 19 3: 463-471. doi:10.1016/S0736-0266(00)90027-5

Author Ng, Joseph K.-F.
Parnianpour, Mohamad
Richardson, Carolyn A.
Kippers, Vaughan
Title Functional roles of abdominal and back muscles during isometric axial rotation of the trunk
Journal name Journal of Orthopaedic Research   Check publisher's open access policy
ISSN 0736-0266
Publication date 2001-05-01
Sub-type Article (original research)
DOI 10.1016/S0736-0266(00)90027-5
Volume 19
Issue 3
Start page 463
End page 471
Total pages 9
Editor J. A. Buckwater
T. M. Wright
Place of publication Amsterdam
Publisher Elsevier Science
Language eng
Subject C1
321402 Biomechanics
780105 Biological sciences
Abstract Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In addition, there is no information on the coupling torque at different exertion levels during axial rotation. The aim of the study was to investigate the functional roles of rectus abdominis. external oblique. internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus during isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions (MVC) in a standing position. The coupling torques in sagittal and coronal planes were measured during axial rotation to examine the coupling nature of torque at different levels of exertions. Results showed that the coupled sagittal torque switches from nil to flexion at maximum exertion of axial rotation. Generally, higher EMG activities were shown at higher exertion levels for all the trunk muscles. Significant differences in activity between the right and left axial rotation exertions were demonstrated in external oblique, internal oblique, latissimus dorsi and iliocostalis lumborum while no difference was shown in rectus abdominis and multifidus. These results demonstrated the different functional roles of trunk muscles during axial rotation. This is important considering that the abdominal and back muscles not only produce torque but also maintain the spinal posture and stability during axial rotation exertions. The changing coupling torque direction in the sagittal plane when submaximal to maximal exertions were compared may indicate the complex nature of the kinetic coupling of trunk muscles. (C) 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Keyword Orthopedics
Lumbar Spine
Myoelectric Activity
Torso Flexion
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Human Movement and Nutrition Sciences Publications
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Created: Wed, 15 Aug 2007, 02:33:00 EST