Electromyographic amplitude and frequency changes in the iliocostalis lumborum and multifidus muscles during a trunk holding test.

Key Words: Back, Electromyography, Fourier analysis, Isometric contraction, Muscle fatigue.

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JK-F Ng, MPhtySt, is Assistant Professor, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong. He was a postgraduate student in the Department of Physiotherapy, The University of Queensland, at the time this study was completed.

CA Richardson, PhD, is Senior Lecturer, Department of Physiotherapy, The University of Queensland, Brisbane, Queensland, Australia 4072 ([e-mail]) Address all correspondence to Dr Richardson.

GA Jull, MPhty, FACP, is Reader, Department of Physiotherapy, The University of Queensland.

This study was approved by the Medical Research Ethics Committee of The University of Queensland.

Part of the results of this study was presented at the Ninth Biennial Conference of the Manipulative Physiotherapists Association of Australia; November 22-25, 1995; Cold Coast, Queensland, Australia.

This article was submitted December 14, 1995, and was accepted February 3, 1997