Temporal changes in the trot between the first and third horse inspections at a CCI*** 3-day event

Kinematic parameters were measured from horses competing in a CCI*** 3-day event. The horses were filmed during the first and third horse inspection. This provided a repeat sample on 16 horses. The horses were filmed using a panning lateral S-VHS video camera (50 Hz). Spatial measurements were taken for mean +/- s.d. 5.66 +/- 0.92 strides for the first inspection and 5.05 +/- 1.27 for the third inspection. Within the calibration zone, data of the horses accelerating and obtaining a constant velocity were collected. The horses trotted with a higher mean velocity during the third inspection (0.26 +/- 0.05 m/s, P < 0.001). During the third inspection the horses trotted with a shorter stride length (0.193 +/- 0.03 m, P < 0.001) and stride duration (31 +/- 42 m/s, P < 0.001). The third inspection was characterised by a decrease in retraction percentage for both the forelimbs (3.69 +/- 2.39%, P < 0.001) and the hindlimbs (2.48 +/- 2.16%, P < 0.001). However, no significant difference was found between the 2 inspections for other temporal parameters when measured as a percentage of stride. It is proposed that the event horses trot with a decreased stride length and duration during the third horse inspection but maintain a consistent temporal relationship.