A methematical model analysing the motion of the calcaneus
from pressure plate measurements
F. Hagman
Download thesis (17 MB)
Project description:
The use of two legs to move about is a quality of humans. After an
extensive period
of evolution, walking and running are the most natural forms of human
locomotion.
Other forms of human locomotion do exist: some are developmental in
nature such as
crawling in case of very young children, others are situational such as
stair climbing
and hurdling. In this thesis, we focus primarily on gait, that is
walking, with an
occasional side step to running.
Though natural, these two forms of locomotion are by no means
infallible. Deficiencies to the locomotion system make up an important
part of the injuries sustained
in our present day society. Besides injuries, the locomotion system is
susceptive to
deceases. Both injuries and deceases change our gait pattern from its
natural, "normal
state", to a sometimes painful, or gait.
Since the problems accompanying gait disorders have a great impact on
both the
individual (for example restraint mobility) and society (for example
loss of working
hours), the professional community involved in gait analysis is
numerous. This area
of study draws the attention of both the medical and the scientific
world. These communities are constantly trying to better understand the
underlying processes of gait.
The knowledge acquired is used to medically treat gait disorders, and
to scientifically
indicate intrinsic factors that may lead to the development of future
individual gait
problems.
To analyse gait, a variety of measurement devices are used. An
important measuring device is the video-based or
cinematographical-based motion analysis system.
Such a system analyses the kinematic part of locomotion, i.e., the
determination of
positions of human body segments during gait. Classically, a force
plate system is used
together with a motion analysis system in order to assess the dynamical
characteristics
of locomotion. More specifically, the force plate measures the
resultant forces of the
foot during foot unroll.
A more recently used measuring device in gait analysis is the pressure
plate system. This system measures the distribution of pressure
perpendicular to the plate in a
two-dimensional grid underneath the foot during foot unroll. It allows
insight into the
local loading of the foot during the foot-to-ground contact phase. In
the remainder of
this thesis, we will refer to this phase as the stance phase.
The topic of this thesis is the analysis of foot mechanics. In gait
analysis, historically the foot has taken up an import role, see
Section 1.1. However, only in the last
decennia thorough analyses of the foot as a three-dimensional segment
have been possible because of the improvement of measurement devices
such as the pressure plate.
In this thesis, we will combine measurements from all three previously
described measurement devices. A four-segment foot model will be
measured using a motion analysis
system. These measurements will be synchronised with the measurements
from the
force platform and the plantar pressure plate for an overview of the
measurement set-up. With all these measurements, we will introduce a
description of
new characteristics of foot mechanics. Furthermore, we will present a
model of foot
motion based on the introduced characteristics. The main feature of
this foot model
is that it uses pressure plate data only to simulate foot kinematics.
Therefore, the
functionality of the pressure plate system is extended to the
simulation of foot kinematics. At present, foot kinematics are analysed
with motion analysis systems only.
This thesis gives impulse to using a pressure plate accompanied with
the proposed
model as an alternative to analyse foot kinematics.
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