The Use of Pressure Plates for Static Center of Pressure Analysis in Horses

Stabilographic analysis allows the quantification of balance by tracking center of pressure (COP) displacements in the horizontal plane during quiet standing. The aim of this study was to use pressure plates to measure descriptive stabilographic variables in Puro Sangue Lusitano horses. Center of pressure data were measured in seven horses during quiet standing using two synchronized pressures plates. For each horse, three sets of five 8-second trials were recorded with 15-minute intervals between data sets. The exported COP coordinates were converted into global coordinates defined in a global reference frame from which stabilographic variables, namely craniocaudal (CC) and mediolateral (ML) COP amplitudes and velocities, resultant COP velocity, and total path length, were calculated. The results showed no significant differences between variables for the left and right limbs. Compared with the forelimbs, the hind limbs have significantly greater values for COP ML amplitude (forelimbs: 3.2 ± 1.1mm; hind limbs: 2.5 ± 0.5mm), COP CC velocity (forelimbs: 1.2 ± 0.2mm/s; hind limbs: 2.1 ± 1.0mm/s), COP ML velocity (4.3 ± 0.9mm/s; hind limbs: 6.5 ± 2.3mm/s), and path length (forelimbs: 49.8 ± 8.5mm; hind limbs: 80.3 ± 31.4mm). The greater stability in the forelimbs may be related to their strut-like function in controlling body movements, whereas the hind limbs show a more dynamic postural response. The pressure plates used in this study, which are relatively inexpensive and more portable than force plates, are a promising tool for performing stabilographic analysis in the field.