Whole-body exposure to vibrations results mainly in mechanical effects on the living organism, which may include relative displacements, deformations or movement in or between different parts of the body. The response of the living organism is of the reflex action type. The musculature counteracts vibrations and stabilizes the body by an increase in muscle tone, especially under resonance-producing conditions when both striated and smooth muscles are affected. The most interesting phenomenon encountered when determining the biomechanical effects of vibrations on the human body is transmission. This study used a unique holographic technique by means of which the effects of vibrations on soft tissues and bones can be evaluated. The aim of the study was to investigate the manner in which the muscles of the back and vertebral column are affected by vibrations applied to the human buttocks in the sitting position. The subject was exposed to vibrations at two frequencies: 40 and SO Hz (vertical Z axis). Transmission of the vibrations along the subject’s back was recorded by means of double-pulse holography and electromyography. Evaluation of the vibration pattern showed that the vibrations are transmitted along the back all the way up to the neck and head. The pattern of vibration in the muscles of the back and vertebral column showed that the greatest effect was exerted on the lumbar region of the back and the area of transition between the thoracic and cervical regions.

1.
Bastek
,
R.
,
Buchholz
,
Ch
,
Denisov
,
E.I.
,
Enderlein
,
G.
,
Kramer
,
H.
,
Malinskaja
,
N.N.
,
Meister
,
A.
,
Metz
,
A.-M.
,
Mucke
,
R.
,
Rhein
,
A.
,
Rothe
,
R.
,
Seidel
,
H.
and
Sroka
,
Ch.
,
1977
.
Comparison of the effects of sinusoidal and stochastic octave-band-wide vibrationsa multi-disciplinary study Part I:ExDerimental arrangement and physical aspects Part II:Physiological aspects Part III Psychological investigations
.
International Archives of Occupational and Environmental Health
,
39
,
143
180
.
2.
Berthoz
,
A.
,
Wisner
A.
, (
1968
)
Striated muscles activity and biomecnanica effects in man submitted to low frequency vibrations
.
Electromyography
I
(
8
):
101
109
3.
Carlsöö
,
S.
,
Vibrationers inverkan pä skelett, leder och muskier
.
ARBETE OCH HÄLSA
,
1980
:
15
.
4.
Christ
,
W.
,
Dupuis
,
H.
,
Uber die Beanspruchung der Wirbelsäule unter dem Einfluss sinusförmiger und stochastischer Schwingungen
.
Int Z Ang Physiol
22
:
258
278
,
1966
5.
Guignard
,
J.C.
,
1965
, Vibration. In
A Textbook of Aviation Physiology
(Ed.
Gillies
J.A.
) (
New York
:
Pergamon Press
). Pp
813
894
6.
Hagberg
,
M.
,
On Evaluation of Local Muscular Load and Fatigue by Electromyography in ARBETE OCH HÄLSA, Vetenskaplig skriftserie
1981
:
24
7.
Sassor
,
H-J.
,
Krause
,
H.
, (
1966
)
Auswirkungen mechanischer Schwingungen auf den Menschen.
RKW-Serie Arbeitsphsiologie Arbeitspsychologie, Beuth
,
Berlin
, pp
3
87
8.
Schäfer
,
N.
, (
1977
)
Untersuchungen zur ergonomischen Beurteilung von Fahrzeugsitzen unter besonderer Berücksichtigung des Schwingungsubertragungsverhaltens
.
Thesis, Technical University
,
Darmstadt
, pp
1
147
9.
Svensson
,
B.M.
,
Methodological Study of Holographic Measurements of Vibrations Applied to the Back of the Human Body
.
Sixth International Congress on Application on Laser and Electro-optics
. November 8-12,
1987
.
San Diego, USA
.
This content is only available via PDF.
You do not currently have access to this content.