Biomedical Engineering Reference
In-Depth Information
Table 3.2
Mean and S.D. per decade for gait variables for men and women
Age (year)
Gender
Walking speed
Stride freq.
Stride length
m/s
Hz
m
Male
1.59 (0.13)
0.97 (0.06)
1.65 (0.12)
20-29
Female
1.54 (0.12)
1.03 (0.06)
1.49 (0.10)
Male
1.54 (0.12)
0.98 (0.06)
1.57 (0.11)
30-39
Female
1.56 (0.11)
1.04 (0.06)
1.50 (0.09)
Male
1.63 (0.15)
1.00 (0.06)
1.64 (0.15)
40-49
Female
1.50 (0.10)
1.06 (0.04)
1.42 (0.08)
Male
1.42 (0.08)
0.96 (0.05)
1.49 (0.07)
50-59
Female
1.48 (0.12)
1.05 (0.08)
1.41 (0.07)
Male
1.47(0.11)
0.96 (0.04)
1.53 (0.09)
60-69
Female
1.35 (0.09)
1.03 (0.04)
1.32 (0.08)
Male
1.32 (0.12)
0.95 (0.06)
1.38 (0.08)
>70
Female
1.26 (0.19)
1.00 (0.08)
1.25 (0.15)
Adapted from [
6
]
Table 3.3
Correlations between step frequency SF (steps per minute) and four gait parameters
Parameters
Units
Correlation coefficient
Regression equation
Stride length
m
0.81
0
.
0088 SF
+
0
.
58
m
·
s
−
1
Velocity
0.95
0
.
021 SF
−
0
.
79
Stance phase duration
% cycle
−
0
.
68
−
0
.
073 SF
+
67
.
0
Double support time
% cycle
−
0
.
57
−
0
.
058 SF
+
15
.
6
Adapted from [
34
]
3.2.1.2 Nonlinear Walking
All of the above results have generally been obtained for straight line walking. For
curved paths that involve rotations, the problem is more complex. Definitions of
step length and width in such nonlinear walking are still being discussed. A modern
definition is given in Fig.
3.1
[
30
].
In both linear and non-linear walking the foot placement on the floor seems to
be constrained in order to minimize the risk of falling, to maximize the possibility
of fast change of directions, and to ensure continuity of the walking trajectory [
50
].
When turning, two main strategies [
24
] arise for the feet placement. In the “step-
turn” strategy, the change of direction is opposite to the contact foot (such as turning
left while the right foot is in contact with the ground). This strategy is very similar
to the one used in straight line walking and tends to enlarge the base of support
(area delimited with the border of the two feet), which minimizes the risk of falling.
In the “spin-turn” strategy, the change of direction and the contact foot are in the
same size (such as turning left during a left contact phase). This strategy decreases
the size of the base of support leading to more unstable, but also faster rotational
displacements. Some authors have shown a high preference for using the “step turn”
strategy compared to the “spin turn” strategy [
23
].
