Biomedical Engineering Reference
In-Depth Information
The increase in peak values for the plantar flexion angle,
plantar flexion moment and the positive power at the ankle
with age are consistent with the results described in the
literature [CHE 06, OEF 97].
With regard to using this database for clinical
applications, establishing reference curves (i.e. averaged) per
age category does not seem feasible, because of the effect of
walking speed and the combined effect of age and walking
speed on the different biomechanical parameters. It was
therefore decided to propose zones of reference values or
“targets to reach” instead, which can be estimated for each
subject and trial (knowing the age, length of the lower limb
and walking speed) and allows the deviations to be
visualized on the curve of a biomechanical parameter
compared to the healthy reference.
Regressions for the biomechanical parameters (peaks and
times of occurrence of peaks) according to age and walking
speed have been developed from this database, to act as a
reference for the healthy population. The regression model
chosen is written as a function of two factors and their
product, according to the formula:
∗∗∗∗
with:
-
: output variable (peaks and times of occurrence of
peaks);
-
Age
,
Speed
: input factors;
-
a
,
b
,
c
,
d
: regression parameters. These parameters are
calculated using the Ordinary Least Squares Method;
model error.
-
ε :
For each regression model, the coefficient of
determination from the regression (
R
²) and the Student's
