Article

Force platforms (FPs) are used in human movement analysis to measure the ground
reaction force and the center of pressure (COP), and calculate derived kinetic
and energetic quantities. We propose a re-calibration method that compensates for
the FP non-linearity induced by top plate bending under loading. The method
develops a previous solution that was proposed for a linear re-calibration and
proved suitable for both local and global error compensation (Cedraro et al.,
2008). The new method was experimentally tested on 4 commercial FPs by estimating
the non-linear re-calibration matrix in a first training trial and by using it to
assess the three force components and the COP in a validation trial, comparing
the new method to the previously proposed solution for global, linear
re-calibration. The average COP accuracy (mm) in the training trial was
(mean+/-std): 2.3+/-1.4, 2.6+/-1.5, 11.8+/-4.3, 14.0+/-2.5 for the 4 FPs before
re-calibration, and 0.7+/-0.4, 0.6+/-0.2, 0.5+/-0.2, 2.3+/-1.3 after non-linear
re-calibration. In the validation trial, for one of the 4 tested FPs, mean errors
for the three force components (N) and COP (mm) were: 3.6+/-2.3 (F(X)), 3.0+/-0.7
(F(Y)), 5.0+/-2.5 (F(Z)), 1.2+/-0.68 (COP) after linear re-calibration, and
2.5+/-0.7 (F(X)), 2.6+/-0.5 (F(Y)), 3.9+/-1.2 (F(Z)), 0.6+/-0.3 (COP) after
non-linear re-calibration. The proposed global, non-linear method performed
equally well as the local, linear re-calibration method, proving well-suited to
compensate for the mild non-linear behavior of FP with the advantage of
estimating a single re-calibration matrix.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS