Measurement of Lumbar Spine Loads and Motions During Rotational Mobilization
Received 9 March 2004
Abstract
Objectives
To measure the loads acting at the lumbar spine and the resulting motions during rotational mobilization.
Methods
Twenty healthy subjects were subjected to right rotational mobilization of different grades. The magnitude and frequency of mobilization loads were decided by an experienced manipulative therapist to be appropriate for each mobilization grade. Subjects were positioned on a specially constructed plinth capable of measuring forces and moments about 3 axes. The 3-dimensional movements of the lumbar spine were captured by an electromagnetic tracking device.
Results
In the starting positions, the lumbar spines were found to be flexed, axially rotated to the right, and laterally bent to the left. As the mobilization grade increased, the spine was axially rotated further into the range. Rotational mobilization was found to induce oscillatory moments and movements of the spine in all 3 anatomical planes. The twisting moment and movement were generally accompanied by lateral bending moment and movement in the opposite direction. The mean amplitudes of the moment and movement oscillations were small and found to be largest for grade III mobilization.
Conclusion
The mechanical effects of rotational mobilization are not restricted to axial rotation of the spine as the name may have suggested. Rotational mobilization may be able to restore lost movements of the lumbar spine in any of the 3 planes. The method developed in this study showed good reliability and may be considered to assess treatment outcome and changes in spinal stiffness after therapy.
aPhD Candidate, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong
bAdjunct Professor, School of Engineering Systems, Queensland University of Technology, Australia
cProfessor, Department of Mechanical Engineering, University of Science and Technology, Hong Kong
dAssociate Professor, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong
Submit requests for reprints to: Raymond Lee, PhD, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Yuk Choi Road, Hunghom, Hong Kong
Sources of support: Hong Kong Research Grant Council, Competitive Research Grant PolyU 5195/01E.
ABSTRACT