title: A simple method for equine kinematic gait event detection.
abstract: BACKGROUND
  Previous studies have validated methods for determining kinematic gait events using threshold-based techniques. However, a simple method that can be successfully applied to walk, trot and canter is yet to be identified.
  
  
  OBJECTIVE
  To develop a simple kinematic method to identify the timing of hoof contact (hoof-on), peak vertical force and lift off (hoof-off), which can be applied in walk, trot and canter.
  
  
  METHODS
  In vivo method authentication study.
  
  
  METHODS
  Horses (n = 3) were ridden in walk, trot and canter down a runway on which four force plates were arranged linearly. Three-dimensional forces were recorded at a sampling rate of 960 Hz and were synchronised with a 10-camera motion analysis system sampling at 120 Hz. Events identified from vertical ground reaction force (GRFz) data were hoof-on (GRFz>50N), peak vertical force (GRFzpeak) and hoof-off (GRFz<50N). Kinematic identification of hoof-on and hoof-off events was based on sagittal planar angles of the fore- and hindlimbs. Peak metacarpophalangeal (MCP)/metatarsophalangeal (MTP) joint extension was used to assess the time of GRFzpeak. The accuracy (mean) and precision (s.d.) of time differences between kinetic and kinematic events were calculated for fore- and hindlimbs at each gait.
  
  
  RESULTS
  Hoof-off was determined with better accuracy (range: -3.94 to 8.33 ms) and precision (range: 5.43-11.39 ms) than hoof-on across all gaits. Peak MCP angle (range: 5.83-19.65 ms) was a more precise representation of GRFzpeakthan peak MTP angle (range: 11.49-67.75 ms).
  
  
  CONCLUSIONS
  The sample size was small and therefore further validation is required. The proposed method was tested on a single surface.
  
  
  CONCLUSIONS
  This study proposes a simple kinematic method of detecting hoof-on, hoof-off and GRFzpeakat walk, trot and canter. Further work should focus on validating the methodology in a larger number of horses and should extend the method for use on surfaces with varying levels of compliance.
authors.affiliation: Department of Research, Myerscough College, Preston, UK.
authors.forename: D
authors.identifier: http://orcid.org/0000-0003-0179-9515
authors.initials: D
authors.lastname: Holt
authors.affiliation: Centre for Applied Sport and Exercise Sciences, University of Central Lancashire, Preston, UK.
authors.forename: L B
authors.initials: LB
authors.lastname: St George
authors.affiliation: Sport Horse Science, Mason, Michigan, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Clayton
authors.affiliation: Centre for Applied Sport and Exercise Sciences, University of Central Lancashire, Preston, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Hobbs
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005552:Forelimb; D005684:Gait / Q000502:physiology*; D006614:Hindlimb; D006724:Hoof and Claw / Q000502:physiology; D006736:Horses / Q000502:physiology*; D016138:Walking
keywords: 3D analysis; biomechanics; gait event; ground reaction force; horse; kinematics; ridden horse