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NEUROENDOCRINOLOGY
LETTERS
including
Psychoneuroimmunology, Neuropsychopharmacology,
Reproductive Medicine, Chronobiology
and Human Ethology, ISSN 0172–780X
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NEL
Vol.24 No.1/2, Feb-Apr 2003
INVITED
RESEARCH PAPER
Mechanical
reaction of the frontal abdominal wall to the impact load during
gravidity
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2003;
24:15–20
pii: NEL241203A02
PMID: 12743526
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Mechanical
reaction of the frontal abdominal wall to the impact load
during gravidity
by
Karel Jelen & Antonín Dolezal
Department of Anatomy and Biomechanics, Faculty of Physical
Education and Sport, Charles University in Prague, CZECH REPUBLIC.
the Head: Prof. Ing. S. Otáhal
*1st
Medical Faculty, Clinic of Gynaecology and Obstretics, General
Teaching Hospital in Prague, Charles University in Prague;
Head: Prof., MD J. Živný. CZECH REPUBLIC.
Submitted:
October 20, 2002 Accepted: November 9, 2002
Key
words:
gravidity, impact load, vibration, cinematographic method,
tensometric method
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Abstract
The
Aim of the Study: Selected parameters of mechanical characteristics
of the gravid abdomen under impact load. Type of the Study:
Experimental biomechanical study carried out in a human in
vivo.
Method:
Damped vibration of the gravid abdomen was detected after
a defined impact load using speed cinematographic recording
of 103 pictures/sec. A women in 32nd week of gestation, performing
toe stand and fall down to the heel, the drop was 0.08 m.
The recording was digitalized and the values mathematically
analysed. The method used was PAM (polynomial approximation
method) of approximation of discrete coordinates. The umbilikus'
trajectory in reaction to the impact load was described analytically
and interpreted graphically. Parameters of abdomen vibration
were detected in horizontal profile by tensometric belt. Impact
in interaction of soles with the underlay was detected with
the help of tensometric platform Kistler. Ultimate strength
point of myometrium was set by tearing experiment in 12 samples.
Results:
Calculation of characteristics of damped, aperiodic vibration
of hydro-viscous elastic system as the outside behaviour of
the gravid abdomen. Parameters in vertical direction of umbilicus:
impulse in abdominal area - 2,72 Ns, T-period - 0.1299 s,
amplitude - 0,009 m, frequency - 7,7 Hz, functional damping
- from -6 to +12 Nsm-1. In horizontal direction: frequency
5,4 Hz, damping 123 Nsm-1. Impact in soles' sphere 40 Ns with
maximum value 1511 N, which represents level 2,2 G. Ultimate
strength point of myometrium is 0,1 - 1,1 MPa.
Conclusion: The results show one of the possible critical,
risky frequencies of the gravid abdomen, that is, in this
concrete case, the frequency of the vibrating system of cca
7,7 Hz in vertical direction and cca 5,4 Hz horizontally.
This implies that e.g. this frequency is dangerous (possible
abruptio placentae) and is necessary to be avoided e.g. when
travelling by means of public transportation. The applied
analytic methods and presented parameters will be used for
e.g. modelling the examined gravid system under impact load
of a general character - locomotion, work-load, car accidents,
etc.
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__________________________________________________________
Copyright © Neuroendocrinology Letters 2003
Society of Integrated Sciences
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