Biomedical Engineering Reference
In-Depth Information
the values themselves. In this particular experiment, one clear conclusion
is that inserting the rest period into the exercise regime does not result in
a proportional decrease in bone gain. On the contrary, the bone gain in the
2 × 5 and 3 × 5 loading schemes is similar: 8.4% versus 9.1% (only 8.3% dif-
ference) in the simulation and 9.8% versus 10.4% (only 6.1% difference) in the
experiment. It is much higher than the 1 × 5 loading scheme, which is 6.1% in
the simulation and 7.6% in the experiment.
In another two experiments [12], the right ulnas of 26 adult female rats
were subjected to 360 load cycles/day, delivered in a haversine waveform at
17 N peak force, 2 Hz, 3 days/week for 16 weeks. Half of the rats (13) were
administered all 360 daily cycles in a single uninterrupted bout (360 × 1); the
other half were administered 90 cycles four times per day (90 × 4), with 3 h
rest time between bouts. At the end of the intervention, the BMC and BFE
were measured for each rat, statistically analyzed, and compared with the
nonloaded baseline control group. The simulation results and experimental
results presented in Qin and Wang [2] are plotted in Figures 7.4 and 7.5.
0.0018
0.0016
600
NO
PGE 2
0.0014
500
0.0012
400
0.0010
OBA
OCA
OBP
0.0008
300
0.0006
200
0.0004
100
0.0002
0
0
20
40
60
Time [days)
(a)
80
100
0
20
40
60
Time [days)
(b)
80
100
0.0018
1.2
360*1
90*4
0.0016
1.0
0.0014
0.8
0.0012
0.6
0.0010
0.4
0.0008
360*1
90*4
0.2
0.0006
0
20
40
60
Time [days)
(c)
80
100
0
20
40
60
Time [days)
(d)
80
100
FIGURE 7.4
Simulation results of the right ulnas of 26 adult female rats subjected to 360 load cycles/
day. (a):  OBA,  OCA,  and  OBP cell population dynamics during the loading period (360 ×  1).
(b):  Messengers NO and PGE 2 population dynamics during the loading period (360 × 1).
(c): Bone turnover (OBA + OCA) dynamics. (d): OCA/OBA during the loading period.
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