The influence of speed and height at the withers on the kinematics of sound horses at the hand-led trot.

The influence of speed and height at the withers on some biokinematic stride parameters (linear, temporal and angular) was measured in 15 Spanish Thoroughbreds (Andalusian Purebred) trotted hand-led along a track; analysis was made of the correlation between speed and height at the withers and of some biokinematic parameters of equine locomotion. Both height at the withers and speed were positively and significantly correlated to the linear parameters examined. Temporal parameters did not reveal a significant correlation with the height at the withers. The correlations with the angular parameters were variable, often being significant for both height at withers and speed, although in most cases the coefficient was relatively low, probably owing to the narrow ranges of speed and height at the withers and their low variability. It was concluded that horses at the hand-led trot tend to have low variability in speed during successive trials, although the speed at which they move does have a significant influence on both linear and temporal stride parameters, and also on several angular parameters, while height at the withers has a major effect on linear parameters but less on angular parameters, and does not affect the temporal parameters.