Document Detail


Examining the low, high and range measures of muscle activity amplitudes in symptomatic and asymptomatic computer users performing typing and mousing tasks.
MedLine Citation:
PMID:  19255772     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Past studies on work-related musculoskeletal disorders (WMSD) have reported increased median muscle activities in terms of 50th% of amplitude probability distribution function (APDF), and this was thought to be a manifestation of altered motor control--an important mechanism contributing to WMSD. The present study aimed to examine whether such altered motor control was also present in other parameters of APDF--the 10th and 90th% values, which can be considered indicators of the low and high measures of muscle activity. The difference between 10th and 90th% APDF can be considered an indicator of the variation in muscle activity amplitude (the "APDF range"). Surface electromyography was examined in female office workers as Case (n = 21) and Control (n = 18) subjects. The APDF variables were measured in cervical erector spinae (CES) and upper trapezius (UT) muscles during typing, mousing and type-and-mouse, for 20 min each. The Case Group had significantly higher CES activity in the 10th, 90th% and APDF range compared to Controls. The UT muscles showed similar trends but the between-group differences were not statistically significant. These results have demonstrated the robustness of the APDF variables as sensitive indicators of motor control variations in symptomatic subjects with musculoskeletal disorders.
Authors:
Grace P Y Szeto; Leon M Straker; Peter B O'Sullivan
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-03-03
Journal Detail:
Title:  European journal of applied physiology     Volume:  106     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-05-01     Completed Date:  2009-08-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  243-51     Citation Subset:  IM    
Affiliation:
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong. rsgszeto@inet.polyu.edu.hk
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MeSH Terms
Descriptor/Qualifier:
Biomechanics
Case-Control Studies
Computers
Electromyography
Female
Humans
Muscle Contraction / physiology
Muscle Fatigue / physiology
Muscle, Skeletal / physiopathology*
Musculoskeletal Diseases / physiopathology*
Neck Muscles / physiology
Neck Pain / physiopathology
Occupational Diseases / physiopathology*
Range of Motion, Articular / physiology

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