Article

Human dynamic models have been used to estimate joint kinetics during various
activities. Kinetics estimation is in demand in sports and clinical applications
where data on external forces, such as the ground reaction force (GRF), are not
available. The purpose of this study was to estimate the GRF during gait by
utilizing distance- and velocity-dependent force models between the foot and
ground in an inverse-dynamics-based optimization. Ten males were tested as they
walked at four different speeds on a force plate-embedded treadmill system. The
full-GRF model whose foot-ground reaction elements were dynamically adjusted
according to vertical displacement and anterior-posterior speed between the foot
and ground was implemented in a full-body skeletal model. The model estimated the
vertical and shear forces of the GRF from body kinematics. The shear-GRF model
with dynamically adjustable shear reaction elements according to the input
vertical force was also implemented in the foot of a full-body skeletal model.
Shear forces of the GRF were estimated from body kinematics, vertical GRF, and
center of pressure. The estimated full GRF had the lowest root mean square (RMS)
errors at the slow walking speed (1.0m/s) with 4.2, 1.3, and 5.7% BW for
anterior-posterior, medial-lateral, and vertical forces, respectively. The
estimated shear forces were not significantly different between the full-GRF and
shear-GRF models, but the RMS errors of the estimated knee joint kinetics were
significantly lower for the shear-GRF model. Providing COP and vertical GRF with
sensors, such as an insole-type pressure mat, can help estimate shear forces of
the GRF and increase accuracy for estimation of joint kinetics.
CI - Copyright (c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS