Article

Activity of the extrinsic ankle-foot muscles is typically described for the whole
foot. This study determines if this muscle activity is also confirmed for
individual foot segments defined in multi-segment foot models used for clinical
gait analysis. Analysis of the individual bone motion can identify functional
complexes within the foot and evaluates the influence of an altered foot position
on muscle activity. A custom designed and built gait simulator incorporating
pneumatic actuators is used to control the muscle force of six muscle groups in
cadaveric feet. Measurements were performed in three static postures in which
individual muscle force was incrementally changed. The motion of four bone
embedded LED-clusters was measured using a Krypton motion capture system and
resulting motion of calcaneus, talus, navicular and cuboid was calculated.
Results indicate that primary muscle activity at bone level corresponds with that
described for the whole foot. Secondary activity is not always coherent for bones
within one segment: decoupling of the movement of medial and lateral foot bones
is documented. Furthermore, secondary muscle activity can alter according to foot
position. The observed medio-lateral decoupling of the foot bones dictates the
need to extend some of the multi-segment foot models currently used in clinical
gait analysis.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS