ponses
This
showed
before
ce was
1erapy,
ft knee
hat the
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le case
sponse
sorbed
3.3 Spectral Analysis by 1/f on Standing
When the physical and mental stress is given, the response of
stress appeared. After 15 minutes running and going up stairs
were given as physical stress, and standing on the balcony of
second floor were given as a mental stress of a fear of heights.
The fluctuations of COG were measured by gyro sensor and
those of pulse were measured by pulse sensor (Figure 8). By
receiving stress, the influence from a problematic part of the
lower limb transmits to the whole body (Figure 9).
Figure 8. Measurement ot Standing Balance
Using gyro sensor & Pulse Sensor
emi RE ins
Figure 9. Influence of a Problematic Part of the Lower Limb
beat
130 a: rest
b:balcony
«after going up stairs
d':after running
130
H0 ni
90 | A
b
70 nimmt eS lS
a
500 1 2 3 4 5 sec
Figure 10. The Fluctuations of Pulse
Resnonse from Stress
After stress was given, the subjects had a high pulse rate as a
result of stress, and became had a usual rate gradually (Figure
10). The Iff fluctuation of the COG movement, i.e., an index
to stable movement appeared in a rest condition (Figure 11).
But the power spectrum of COG fluctuations of roll, pitch and
yaw angles didn’t have //f fluctuation after receiving stress. It
disappeared and became be unstable (Figure 12).
In the case of pulse, the subjects maintained //f fluctuations.
It was observed that the movement of COG was influenced by
physical and mental stress.
log PS
29 e
*e Lf?
7:4 * eo
9o,
0 t
0 2 6
ub.
2
3 frequency (cycle/unit time) -log(I/f)
Figure 11. Power Spectrum of COG while Standing
Normal Condition
log PS
m roll
o .
Lj e e
© 9 ee umm JO
0
0 2 4 6
=!
2
=3 frequency (cycle/unit time) -log(1/f)
log PS
2] pitch
1,9
0 | e
0 e / 4 6
=] e e
| eeg c?
23
-3 frequency (cycle/unit time) -log(1/f)
log PS
2 | yaw
; ® So,
| (21)
Of
0 2 4 6
po
-2
-3 frequency (cycle/unit time) -log( 1/f)
Figure 12. Power Spectrum of COG while Standing
Physical Fatigue Condition
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