Article

An investigation into the kinematic and kinetic predictions of two "inverted
pendulum" (IP) models of gait was undertaken. The first model consisted of a
single leg, with anthropometrically correct mass and moment of inertia, and a
point mass at the hip representing the rest of the body. A second model
incorporating the physiological extension of a head-arms-trunk (HAT) segment,
held upright by an actuated hip moment, was developed for comparison. Simulations
were performed, using both models, and quantitatively compared with empirical
gait data. There was little difference between the two models' predictions of
kinematics and ground reaction force (GRF). The models agreed well with empirical
data through mid-stance (20-40% of the gait cycle) suggesting that IP models
adequately simulate this phase (mean error less than one standard deviation). IP
models are not cyclic, however, and cannot adequately simulate double support and
step-to-step transition. This is because the forces under both legs augment each
other during double support to increase the vertical GRF. The incorporation of an
actuated hip joint was the most novel change and added a new dimension to the
classic IP model. The hip moment curve produced was similar to those measured
during experimental walking trials. As a result, it was interpreted that the
primary role of the hip musculature in stance is to keep the HAT upright. Careful
consideration of the differences between the models throws light on what the
different terms within the GRF equation truly represent.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS