Disease-specific changes in equine ground reaction force data documented by use of principal component analysis.
OBJECTIVE
To assess the force plate as a diagnostic aid in equine locomotor abnormalities, particularly for abnormalities such as navicular disease that do not have specific diagnostic criteria.


METHODS
17 Thoroughbreds without observable locomotor abnormalities (group A), 6 Thoroughbreds with superficial digital flexor tendon injury (group B), and 8 Thoroughbreds with navicular disease (group C).


METHODS
Using a force plate, ground reaction force patterns were recorded at the trot. Peak limb vertical force and force/time curve parameters were derived from 4 identifiable points at the beginning and end of vertical and craniocaudal horizontal plots. Principal component analysis (PCA) of group-A data was undertaken on beginning and end of stride data, and the first 2 components were represented graphically. The PCA rotation matrices were applied to equivalent data for horses of groups B and C.


RESULTS
Asymmetry of peak vertical force (PVF) could not be differentiated among groups A, B, and C. Values for group-B horses, however, were significantly outside mean group-A values on the PCA plot for beginning of stride phase variables. Group-B data were within the group-A range for end of stride phase variables. Values for group-C horses were significantly outside the group-A range for beginning of stride phase variables and were outside mean group-A values for end of stride phase variables.


CONCLUSIONS
PCA of force/time data provides a sensitive method to evaluate the force/time curve associated with 2 specific injury/disease processes.


CONCLUSIONS
Horses alter weight-bearing in biomechanically distinct ways, thus creating potential for the force plate to become an important diagnostic and prognostic tool.
D000818:Animals; D001696:Biomechanical Phenomena; D004282:Documentation; D005684:Gait / Q000502:physiology*; D006734:Horse Diseases / Q000503:physiopathology*; D006736:Horses; D007794:Lameness, Animal / Q000503:physiopathology*; D008124:Locomotion / Q000502:physiology*; D012016:Reference Values; D013708:Tendon Injuries / Q000503:physiopathology / Q000662:veterinary*; D016474:Weight-Bearing