Document Detail

Electromyographic and kinematic indicators of fatigue in horses: a pilot study.
MedLine Citation:
PMID:  11721578     Owner:  NLM     Status:  MEDLINE    
Muscle fatigue can be quantified using Fourier analysis of the recorded EMG signal. Median frequency is the frequency at which the Fourier profile is bisected, and this measure typically shifts to smaller values during fatigue. This technique was combined with kinematic analysis to describe the time course of fatigue in horses galloping on an inclined treadmill. It was hypothesised that EMG median frequency would decrease in tandem with changes in kinematic variables through the exercise test. Three fit Thoroughbred horses had retroreflective markers placed on their hooves and withers. Surface electrodes were attached to the skin over the forelimb deltoid muscle. After warm-up at walk and trot, each horse galloped at 110% VO2max on a treadmill inclined to 7.5% until fatigue onset. Kinematic data were recorded at 200 Hz for 5 s at 30 s intervals, and raw EMG data were recorded at 1024 Hz for 3 s at 15 s intervals. Fatigue onset was the point in time when the horse could not keep up with the treadmill speed with minimal encouragement. One horse performed the entire exercise test on the same lead, while the other 2 horses changed leads periodically, interrupting the changes in both the EMG and kinematic measurements. Overall, through the course of the trials, mean stride length increased by 0.34 m and stride duration increased by 0.03 s. Vertical excursion of the trunk marker increased by 0.03 m. For the horse that did not change lead, median frequency of the EMG signal decreased by 36%. In the other 2 horses, lead changes were interspersed between smaller decreases in median frequency, whereupon median frequency recovered to starting levels immediately following a lead change. The median frequency decreased by 12-20% between lead changes. Kinematic changes are more global indicators of fatigue, while the EMG indicators are dependent upon lead changes.
G R Colborne; D M Birtles; I C Cacchione
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Equine veterinary journal. Supplement     Volume:  -     ISSN:  -     ISO Abbreviation:  Equine Vet J Suppl     Publication Date:  2001 Apr 
Date Detail:
Created Date:  2001-11-27     Completed Date:  2002-01-03     Revised Date:  2007-05-18    
Medline Journal Info:
Nlm Unique ID:  9614088     Medline TA:  Equine Vet J Suppl     Country:  England    
Other Details:
Languages:  eng     Pagination:  89-93     Citation Subset:  IM    
Jim Joel Equine Sports Medicine Centre, Department of Anatomy, University of Bristol, Langford, N. Somerset BS40 5DU, UK.
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MeSH Terms
Electromyography / veterinary
Exercise Test / veterinary
Forelimb / physiology
Horses / physiology*
Locomotion / physiology*
Muscle Fatigue / physiology*
Muscle, Skeletal / physiology*
Pilot Projects
Regression Analysis

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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