COMPARISON OF THE STRIDE KINEMATICS OF THE COLLECTED, WORKING, MEDIUMAND EXTENDED TROT IN HORSES

Highly-trained dressage horses were studied to test the hypothesis tha t stride length is altered independently of stride duration in the tra nsitions between the collected, working, medium and extended trot. Six well-trained dressage horses were filmed at a frame rate of 150 frame s/s performing the collected, working, medium and extended trots in a sand arena. Temporal, linear and angular data were extracted from the films, with 4 strides being analysed for each horse and gait type. The re were no significant asymmetries between the left and rights limbs o r diagonals when data from the whole group were pooled, but 3 horses s howed asymmetries in one or more variables (P<0.01). Analysis of varia nce and post-hoc tests indicated that the speed increased significantl y (P<0.01) from the collected (3.20 m/s) to the working (3.61 m/s) to the medium (4.47 m/s) to the extended (4.93 m/s) trot. The increases i n speed were associated with a significant increase in stride length f rom 250 cm in the collected trot, to 273 cm in the working trot, 326 c m in the medium trot and 355 cm in the extended trot (P<0.01). The len gthening of the stride was a result of increases between each gait typ e in the over-reach distance, whereas the diagonal distance was signif icantly longer in the extended than the collected trot only (P<0.01). The stride duration tended to decrease as speed increased, and the dif ference became significant between the collected and extended trots (P <0.01).