Kinematic analysis of the locomotion symmetry of sound horses at a slow trot.

This research is a detailed study into the locomotion symmetry of sound horses at a trot, utilizing kinematic analysis via a 3D data collection system to determine standard symmetry indices for various joint movements.

Research Methodology

• This study observed the trotting patterns of 13 clinically nonlame horses to establish a standard symmetry index.
• Using a 3D data collection system, researchers recorded the kinematics or the study of motion from the limb joints of the horses while trotting.
• The horses were trotting in usual conditions akin to a clinical lameness examination
• Data on the vertical displacement-time and joint angle-time for left and right joints of the horse were collected.
• An indexing system was created for the symmetry analysis based on an inter-correlation method.

Calculating the Index

• For every horse, an average symmetry index for each joint was calculated over five trials.
• The mean of these average symmetry indices were then collated for each joint from across the horses.
• Both intra- and inter-individual variabilities of these symmetry indices were evaluated to determine the repeatability of the locomotion symmetry.

Results and Observations

• It was noted that the symmetry levels from markers of the trunk were generally lower than those from the limbs.
• Across the five trials, while levels of symmetry varied considerably, mean values remained strikingly similar across horses.
• The trunks showed a higher degree of freedom in their movements than the limbs, indicating a higher intra-individual variability. This suggested that multiple trials are necessary to accurately quantify a trotting horse’s locomotion symmetry.
• Comparatively, the hindlimbs displayed a lower level of symmetry than the forelimbs, as evidenced by their lower symmetry indices. This is thought to be due to the propulsive function of the hindlimbs as opposed to the supporting role of the forelimbs.