Document Detail

Myoelectric reactions to ultra-low frequency and low-frequency whole body vibration.
MedLine Citation:
PMID:  3396572     Owner:  NLM     Status:  MEDLINE    
5 healthy males were exposed to vertical sinusoidal whole body vibration (WBV) at 5 frequencies (F1 = 0.315 Hz, F2 = 0.63 Hz, F3 = 1.25 Hz, F4 = 2.5 Hz, F5 = 5.0 Hz) and 2 intensities (I1 = 1.2 ms-2 rms, F1-F5; I2 = 2.0 ms-2 rms, F2-F5). Erector spinae EMGs were derived at the levels of the first thoracic (T1) and third lumbar (L3) spinous processes, rectified and synchronously averaged, as were the accelerations of the seat and the head. WBV induced vibration-synchronous EMG activity (T1 and L3) which exceeded the activity without WBV during enhanced gravitation and decreased during lowered gravitation from F1 to F3. At F4 and F5, these phase relations changed drastically, thus suggesting a different trigger mechanism. The extreme average EMG-amplitudes remained nearly constant at F1 to F3 and increased at higher frequencies. Maximum EMG activity was higher at I2 than at I1. WBV from F1 to F3 is supposed to cause tonic muscular activity triggered by the otoliths; at higher frequencies, stretch reflexes probably gain additional importance. The results hint at an increasing sensory conflict with decreasing frequency of WBV and are interpreted within the theoretical framework of different modes of motor control. Relations between transmissibility and muscle activity suggest the usefulness of including time-variant spring-characteristics into biomechanical models.
H Seidel
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of applied physiology and occupational physiology     Volume:  57     ISSN:  0301-5548     ISO Abbreviation:  Eur J Appl Physiol Occup Physiol     Publication Date:  1988  
Date Detail:
Created Date:  1988-08-26     Completed Date:  1988-08-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0410266     Medline TA:  Eur J Appl Physiol Occup Physiol     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  558-62     Citation Subset:  IM    
Central Institute for Occupational Medicine, Department for Occupational Hygiene, Berlin, German Democratic Republic.
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MeSH Terms
Muscles / physiology*

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