Biomedical Engineering Reference
In-Depth Information
unexpected and inconsistent motor task. On the other hand in a stable system, the
same motor command leads to similar moves by controlling small disturbances [
9
].
This means that the resulting motion can be predicted and planned.
1.1
General Framework
One way of studying the stability, in particular de joint stability is through
Biomechanics. In Biomechanics the study objective is the motor production of
living beings, constituted and based in knowledge of morphology, cybernetics and
mechanics, but it marks autonomy in relation to their biological and mechanical
sources [
10
]. Also according to this author, the biomechanic study of motor
behaviour is the non determinist production of the locomotor system, resulting from
the mechanical and biological external responses organized by the Kinematics and
dynamic point of view. So, the biomechanic, studies the movements and forces
that are the consequence of mechanical relationship established and controlled by
the performer. Biomechanics can be considered as a complementary method of
diagnosis, using in the experimental setups their direct data (obtained from the
records of the external forces acting in center of pressure (COP)), or indirect data,
that are obtained from the records of the images [
11
].
One method to access the postural stability is studying the behaviour of the COP,
and it can be obtained by Posturography. In this method, the determination of COP
is done using one or two force plates [
12
]. A disadvantage of this method is the lack
of parameters that have confidence to be used in evaluation of pathological changes
[
13
]. On the other hand, there is a large gap between the methods of research-based
laboratories and those used in the clinical field. Particularly in the biomechanic field,
the equipment used to study the gait and postural stability, is fixed to the ground and
are very expensive [
14
]. It is necessary to develop equipment that has portability
characteristics, with the ability to perform valid, reliable and safe tests for use in a
clinical setting. Taking this into account, as an alternative to the use of one or two
force plates, we propose in this study the use of plantar pressure plate to access de
COP characteristics.
The plantar pressure has been applied to access the study of COP behavior.
A recent study [
15
] investigated the influence of loading and positioning of school
supplies, on the distribution of plantar forces and COP trajectory in students with
Baropodometric data, obtained from a plantar pressure plate (Matscan Research,
Teckscan). In 2004, another study [
16
] attempted to verify the risk factors for ankle
sprain in students, through the study of the COP, also using a plantar pressure plate
(Footscan Pressure Plate RSSCAN International, 2.0 m
0.4 m, 16,384 sensors,
480 Hz). In 2002, to compare the plantar pressure distribution between hemiplegic
children and a healthy control group, some authors [
17
] used a system of pressure
insoles (Parotec, Paromed GmbH, D-8201, Neubeuern Markt, Germany). Another
study conducted in 2006 [
18
] used a system of insoles (F-scan system) to identify
characteristics in the distribution of plantar pressure foot deformities and to identify
