How The Hoof Meets The Road

By Paul Roberson
©Voice, June 2007

How do you go about adapting equipment and computers designed for human gait studies for use in gait studies of horses? That was the first question that researchers interested in the running walk had to answer. The obvious pitfalls of size and the number of legs were not the most difficult to overcome. In human studies the person being studied is simply asked to stand still while dozens of reflective markers are attached all over their body. They understand that the glue used to hold the markers in place will come off. The horse as you can imagine, is a bit different. Many of the horses took some time becoming comfortable with the glue and markers on their skin. Once all the markers were applied, the horse was placed in the middle of six infrared video cameras. Each camera recorded the horse as it stood perfectly still, not an easy task for some horses. Some of the markers could be taken off now because they are just used to show where the joints are located. The computer combined the video of the markers from each camera and made a three-dimensional (3-D) movie of the horse standing still. Now the horse can be ridden through the six cameras. Next, the 3-D movie of the horse standing and the 3-D movie of the horse being ridden at the running walk were combined. By combining the two movies all the markers could be seen, even the ones that had been removed earlier. There was now a complete 3-D movie of the running walk.