Validation and standardisation of a two dimensional motion analysis technique to measure normal conformation and gait in Arabian horses.

Abstract

The development of standardised two dimensional motion analysis techniques to obtain baseline measures would provide the equine industry with a consistent method for analysing equine conformation and gait. The use of these methods to define breed specific conformation and gait could be utilised by the industry for conformation and gait assessment. This study focussed on validating and standardising such methods to define normal conformation and gait for the Arabian horse. Validation involved comparing the accuracy of two 2D motion analysis software programmes; Quintic© and HU-M-AN (TM). Static and dynamic linear and angular validation was performed by comparing known values to values calculated by the software programmes. Higher variation was established for Quintic© measurements; the margin of error was up to 20mm for static measurements and 3.36° for angular measurements. When using Quintic©, angles of different size were measured with varying amounts of accuracy; these differences were significant (P<0.001). The pattern of these differences was similar to a sine wave. It was concluded that Quintic° was not compatible with a normal video camera recording at a 4:3 aspect ratio which may have related to calibration or angle measurement algorithms. HUMAN(TM) was used for all further analysis due to the smaller margin of error established during validation. Intra-horse variation in conformation and stride characteristics (stride length and RUM) were measured in a group of three horses over five consecutive days. Stride length was consistently longer on day one than subsequent days for all horses (P<0.001), and positively correlated to velocity. Variation in stride length between days varied for each horse; some horses had more stable gait characteristics than others. Little variation was established for ROM data between days; few joints demonstrated ROM that was significantly different between days for individual horses. Providing stance of the horse, marker placement and velocity are closely regulated, baseline data can be obtained on one occasion. The standardised method previously validated was used to define normal gait for Arabian horses. Conformation and stride characteristics were assessed for a group of six purebred Arabian horses (mean age 27± 10.56 months). There was no significant difference in ROM between any of the horses measured (P>0.05); the horses had breedspecific gait patterns which allowed normal gait to be defined for a distinct breed. A database of normal gait for the Arabian horse was created for use by Arab horse owners or breeders in the UK.