Gait analysis in jumping horses via computerkinematography

Abstract

With the newly developed method of computerkinematography we analysed more than 300 jumps of 5 horses across obstacles of heights between 1,00 and 1.60 m. The accelerations were measured at the metapodia. In the run-up, the usual frequency of the gallop was increased. In the last cycle before take-off the hindlimbs often touched down before the liftoff of the forelimbs, so that the suspension phase disappeared. The take-off seems to be a bipedal phase, but in fact the trailing limb touched down shortly before the leading limb, and its acceleration was higher. There was marked individual variation, in particular in the less thouroughly trained horses. Maximum accelerations were found at the hindlimbs, especially during touchdown before the take-off, and in the touchdown after the landing. Surprisingly, the accelerations of the forelimbs were lower in nearly all cases. The highest forelimb accelerations occured during the landing and in the following cycle. The latter was very short and fused to the former without time interval for a suspension phase. The temporal succession of the limbs determined the lead of the gallop after the landing. Three of the horses under investigation landed always on their left limbs, with the right limbs leading. When going counter-clockwise they corrected their gallop after three or four cycles. We found clear differences between jumping under the rider and free jumping, the controlling influence of the rider could thus be proved. The relation between the measured acceleration and the loads (that is, the ground-hoof-forces) is discussed.