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Volume 25, Issue 3, March 2007, Pages 440-452 |
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doi:10.1016/j.gaitpost.2006.05.018
Copyright © 2006 Elsevier B.V. All rights reserved.
On the expression of joint moments during gait
Anthony G. Schache and Richard Baker
Hugh Williamson Gait Laboratory, Royal Children's Hospital, Parkville, Vic., Australia
Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Vic., Australia
Received 15 May 2006; accepted 15 May 2006. Available online 29 September 2006.
Abstract
The purpose of the current study was to examine the effect of different reference frames on lower limb joint moments during gait with a view to identifying a recommended convention for clinical purposes. Data were collected from 10 subjects (nine able-bodied adults and one child with diplegic cerebral palsy) whilst walking at a self-selected speed. Calculations utilised a three-dimensional inverse dynamics model. For each joint, moments were expressed in four different reference frames. Three of the frames were orthogonal: laboratory frame; anatomical frame of proximal segment; anatomical frame of distal segment. The fourth reference frame was a non-orthogonal joint coordinate system (JCS). Significant differences in the joint moment profiles during gait were found with alternative references frames. This was apparent primarily for the transverse plane joint moments for able-bodied adult gait. For the pathological gait pattern presented, there were also marked differences in the frontal plane joint moments and more subtle ones in the sagittal plane. Whilst it is recognised that all possible reference frames for the expression of the net moment vector are mathematically valid, a decision needs to be made as to which one is more clinically useful. It is proposed that the non-orthogonal JCS is most logical on the basis of what, biomechanically, the joint moment actually represents.
Keywords: Gait analysis; Inverse dynamics; Lower limb; Joint coordinate system
Article Outline
1. Introduction
2.1. Subjects
2.2. Instrumentation
2.3. Frame definitions
2.4. Procedures
2.5. Data analysis
3. Results
3.3. Effect of different reference frame
4. Discussion
Volume 25, Issue 3, March 2007, Pages 440-452 |
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