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The effect on conventional gait model kinematics and kinetics of hip joint centre equations in adult healthy gait

Leboeuf, FY; Reay, J; Jones, R; Sangeux, M


FY Leboeuf

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Mrs Julie Reay
Senior Lecturer & Foundation Year Lead

M Sangeux


The Conventional Gait Model (CGM) needs to benefit from large investigations on localization of the hip joint centre (HJC). Incorrect positions from the native equations were demonstrated (Sangeux et al., 2014; Harrington et al., 2007). More accurate equations were proposed but their impact on kinematics and kinetic CGM outputs was never evaluated. This short communication aims at examining if adoption of new HJC equations would alter standard CGM outputs. Sixteen able bodied participants underwent a full 3-D optoelectronic gait analysis followed by a 3-D ultrasound localization of their hips. Data were processed through the open source python package pyCGM2 replicating kinematic and kinetic processing of the native CGM. Compared with 3D ultrasound location, Hara equations improved the accuracy of sagittal plane kinematics (0.6°) and kinetics (0.02 N m kg−1) for the hip. The worst case participant exhibited Harrington’s equations reached a deviation of 3° for the sagittal kinematics. In the coronal plane, Hara and Harrington equations presented similar differences (1°) for the hip whilst Davis equations had the largest deviation for hip abduction (2.7°) and hip abductor moment (0.10 N m kg−1).

Both Harrington and Hara equations improved the CGM location of the HJC. Hara equations improved results in the sagittal plane, plus utilise a single anthropometrics measurement, leg length, that may be more robust. However, neither set of equations had significant effect on kinematics. We reported some effects on kinetics, particularly in the coronal plane, which warrant caution in interpreting outputs using different sets of equations.


Leboeuf, F., Reay, J., Jones, R., & Sangeux, M. (2019). The effect on conventional gait model kinematics and kinetics of hip joint centre equations in adult healthy gait. Journal of Biomechanics, 87(Apr 19), 167-171.

Journal Article Type Article
Acceptance Date Feb 14, 2019
Online Publication Date Feb 20, 2019
Publication Date Apr 18, 2019
Deposit Date Apr 26, 2019
Journal Journal of Biomechanics
Print ISSN 0021-9290
Publisher Elsevier
Volume 87
Issue Apr 19
Pages 167-171
Publisher URL
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Additional Information Projects : CGM2.i project