Article

We investigated the accuracy of a linear soft tissue artefact (STA) model in
human movement analysis. Simultaneously recorded bone-mounted pin and skin marker
data for the thigh and shank during walking, cutting and hopping were used to
measure and model the motion of the skin marker clusters within anatomical
reference frames (ARFs). This linear model allows skin marker movements relative
to the underlying bone contrary to a rigid-body assumption. The linear model
parameters were computed through a principal component analysis, which revealed
that 95% of the variance of the STA motion for the thigh was contained in the
first four principal components for all three tasks and all subjects. For the
shank, 95% of the variance was contained in the first four principal components
during walking and cutting and first five during hopping. For the thigh, the
maximum residual artefact was reduced from 27.0mm to 5.1mm (walking), 22.7 mm to
3.0mm (cutting) and 16.2mm to 3.5mm (hopping) compared to a rigid-body
assumption. Similar reductions were observed for the shank: 24.2mm to 1.9 mm
(walking), 20.3mm to 1.9 mm (cutting) and 14.7 mm to 1.8mm (hopping). A geometric
analysis of the first four principal components revealed that, within the ARFs,
marker cluster STA is governed by rigid-body translations and rotations rather
than deformations. The challenge remains, however, in finding the linear model
parameters without bone pin data, but this investigation shows that relatively
few parameters in a linear model are required to model the vast majority of the STA movements.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS