The Accuracy and Precision of an Equine In-Shoe Pressure Measurement System as a Tool for Gait Analysis

Normal horses with no clinical lameness were studied to test the hypothesis that Equine F-Scan sensors (EFS) would produce vertical force data that correlated highly with vertical force data from a force platform. Six horses were trotted across a force platform while wearing the EFS. Vertical force measurements were recorded from each system with data analyzed from hoof strikes that occurred simultaneously on both systems. Coefficients of variation (CV) were evaluated to test precision of the systems. The CV of the EFS was 10.2%, compared with 6.6% for the force platform. The accuracy of the pressure measurement system was tested by measuring agreement and a paired t test. The test for measuring agreement showed large differences between measuring devices, indicating an overall lack of agreement between measurements from the two systems, with differences ranging from 9 Newtons (N) to 1,200 N. Results from a paired t test, however, showed no significant difference between measurements from the two devices as noted by a P-value of .294, indicating a lack of significant differences because of assessment of averaged data. Because of the inability of the EFS to provide precise measurements of vertical ground reaction force as noted by high coefficients of variation and an overall lack of agreement between measurements from the two systems, this system should not be used to objectively measure vertical force in horses in its current format.