Hilary M Clayton1, David E Bialski, Joel L Lanovaz, David R Mullineaux. 1. Mary Anne McPhail Equine Performance Center, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824-1314, USA.
Abstract
OBJECTIVE: To assess the reliability of the center-of-pressure (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.
OBJECTIVE: To assess the reliability of the center-of-pressure (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.