title: Electromyographic activity of the palatinus and palatopharyngeus muscles in exercising horses.
abstract: BACKGROUND
  Determining the respiratory related activity of the palatinus and palatopharyngeus muscles in exercising horses is relevant because dysfunction of these muscles has been implicated in the pathogenesis of dorsal displacement of the soft palate.
  
  
  OBJECTIVE
  To determine if the palatinus and palatopharyngeus muscles have respiratory activity that increases with intensity in exercising horses.
  
  
  METHODS
  Electromyographic activity was measured in the palatinus and palatopharyngeus muscles using bipolar fine-wire electrodes while the horses completed an incremental exercise treadmill protocol.
  
  
  RESULTS
  Both muscles displayed synchronous expiratory activity that increased significantly (P < 0.05) with exercise intensity. Phasic expiratory activity of the palatinus increased 390 +/- 98%, whereas phasic expiratory activity of the palatopharyngeus increased by 198 +/- 30% as the treadmill speed increased from 6 to 12 m/s.
  
  
  CONCLUSIONS
  The palatinus and palatopharyngeus muscles may be important respiratory muscles, functioning to stabilise the position of the soft palate during intense exercise.
  
  
  CONCLUSIONS
  The predominant expiratory activity of these muscles may be associated with specific muscle function related to exercise or distinct upper airway phenomena of an obligate nasal breather, such as the horse.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48624, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Holcombe
authors.forename: F J
authors.initials: FJ
authors.lastname: Derksen
authors.forename: N E
authors.initials: NE
authors.lastname: Robinson
mesh_terms: D000818:Animals; D004576:Electromyography / Q000379:methods / Q000662:veterinary; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006736:Horses / Q000502:physiology*; D007821:Laryngeal Muscles / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010156:Palatal Muscles / Q000502:physiology*; D010609:Pharyngeal Muscles / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*; D012420:Running / Q000502:physiology