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Analysis of the tonic vibration reflex: influence of vibration variables on motor unit synchronization and fatigue.

Authors
Martin-BJ; Park-HS
Source
Eur J Appl Physiol Occup Physiol 1997 May; 75(6):504-511
NIOSHTIC No.
20031025
Abstract
The influence of vibration frequency (40, 80, 100, 120, 150, or 200 Hz) at selected displacement amplitudes (0.2, 0.3 mm) on tonic vibration reflex (TVR) characteristics was investigated. The degree of synchronization of motor unit activity with vibratory stimuli in ten humans was determined using the electromyographic (EMG) activity of the finger and wrist flexor muscles when vibration was applied to the distal tendons of the hand flexor muscles. The EMG spectral analysis indicates that harmonic and subharmonic motor unit synchronization mechanisms contribute to the modulation of the amplitude of the TVR as the vibration frequency increases. Harmonic synchronization decreases while subharmonic synchronization increases as vibration frequency increases. It is suggested that the synchronization process influences muscle fatigue, since it forces the driving of motor units, leading to a decrease in contraction efficiency. This phenomenon most probably results from an impairment of excitation-contraction coupling. High-frequency vibration (> 150 Hz) tends to induce less motor unit synchronization in a frequency range beyond the known mechanical resonance of biological tissues. The findings of this study may be applied to the design of hand-held power tools, since their vibration triggers the TVR in active muscles.
Keywords
Vibration; Vibration-effects; Fatigue; Fatigue-properties; Muscles; Physiology; Vibration-disease; Visual-motor-performance; Sensory-motor-system; Sensory-perceptual-processes
CODEN
EJAPCK
Publication Date
19970501
Document Type
Journal Article
Funding Amount
189066
Funding Type
Grant
Fiscal Year
1997
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-002967
Issue of Publication
6
ISSN
0301-5548
Source Name
European Journal of Applied Physiology and Occupational Physiology
State
MI
Performing Organization
University of Michigan at Ann Arbor, Ann Arbor, MI
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