Abstract
Objective—To assess the reliability of the center-ofpressure (COP) values obtained from a force platform for analysis of postural sway in horses.
Animals—Six 2-year-old horses that were free from lameness and neurologic disease.
Procedure—Horses stood stationary with all 4 hooves on a force platform; COP data were collected at 1,000 Hz and 3-dimensional kinematics collected at 60 Hz for 10 seconds. Five trials were recorded at each of 3 time periods (15-minute intervals) or at 1 time period on 3 separate days. Mean values for each set of 5 trials and actual, normalized, and relative COP variables were calculated. The reliability was quantified by use of agreement boundary.
Results—The COP results within and across days were similar and provided small agreement boundary limits (eg, across days, in order of least relative reliability: area, ± 62 mm2; mediolateral range, ± 8 mm; radius, ± 2 mm; craniocaudal range, ± 4 mm; and velocity, ± 3 mm/s). Head height possessed the greatest relative intraday reliability (12%) but a high agreement boundary limit (± 0.15 m).
Conclusions and Clinical Relevance—The use of a force platform to analyze postural sway in a group of young healthy horses was found to produce reliable results and may provide a simple and sensitive measure for assessing balance deficiencies in horses. Agreement boundaries provide 95% confidence intervals for use as limits of error and variability in measurements that, if exceeded, may signify meaningful effects. (Am J Vet Res 2003;64:1354–1359)
