The McPhail Chair Report #4 Published in Dressage and CT, September 1998   The Value of Video   Video is a marvelous tool for evaluating horses and riders. Part of its value lies in the fact that we can replay the tape to observe the same movement repeatedly. This is allows us to detect things that would normally be missed due to our inability to take in everything in a single pass. Typically, by focusing on one aspect of the horse or rider, we fail to see something else that’s happening at the same time. The other great advantage of video over the human eye is that we can replay the tapes in slow motion to detect things that normally occur too quickly for our eyes to perceive them. With this in mind, let’s hope it’s a long time before our judges have access to instant video replays complete with all the bobbles they missed on the first viewing! The applications of video in equestrian sports are numerous and range from pure enjoyment to sophisticated scientific analysis. It’s a great tool for riders to evaluate their own performance and for trainers to help their students relate what they feel with how it looks. At the scientific end of the spectrum, video evaluation is one of the most informative aspects of locomotion analysis. In the McPhail Dressage Laboratory, almost all our studies incorporate some aspect of video evaluation. In order to extract useful scientific data from the tapes, however, we must set up our cameras in a precise manner and calibrate the space in which the recording is made. Figure 1 shows a horse and rider, complete with reflective markers, taking part in a study. This particular study was designed to compare the walk strides of horses in hand and with a rider. Figure 1. Three-time Dutch Olympic rider Tineke Bartels and Olympic Courage (above) - and (right) on screen, where the image is being analyzed by computer. For scientific analysis of videos we use a computerized gait analysis system. The reflective markers on the horse and rider are located automatically by the computer and used to measure the tempo, rhythm, step length, and the angles of the horse’s joints at different stages of the stride. In effect, we’re measuring the things we see when a horse moves, converting a qualitative observation into a quantitative measurement. Although this type of precision analysis is only possible in a gait laboratory, the same principles can be applied to get more information using your home video system. This column will give you tips for improving the quality of your videos for this type of evaluation, and next month we’ll look at some specific situations in which video tapes can provide useful information. Making Good Movies Videography is a form of photography and you should observe the same general rules in making videos as you would in taking still photographs. When recording outdoors, the flat light that occurs on a cloudy day is better than bright sunlight that creates distracting shadows. For indoor recordings use artificial lights but try to avoid back lighting, for example through leaving doors open. Many camcorders have a back light compensation feature that helps to overcome this problem. When you watch a video tape, it’s very distracting if the picture jiggles around. Avoid this by supporting the camcorder on a tripod or monopod, which give it some stability as you move around. Choose your recording area carefully so that you can minimize panning and zooming (or take motion sickness pills before replay). And tell the rider or handler of the horse not to come too close to the camera – it’s helpful to lay out some rails or pylons as a guide. Position the lens at the height of the primary area of interest to minimize distortion (parallax error). Unfortunately, this is not always the height that’s most comfortable for you. For example, to get a good view of how the hoof hits the ground, the camcorder should be at ground level - otherwise you get an oblique view of the hoof wall from above rather than seeing the interface of the hoof with the ground. Use the high speed shutter to avoid blurring of the limbs in fast-moving horses. The fastest moving part of the horse’s body is the hoof ; during the swing phase it reaches a speed about three times as fast as the horse’s overall speed, and this must be taken into account in determining the shutter factor. Usually, a setting of 1/500 second is adequate, but 1/1000 second may be needed for horses moving at high speed. Be aware, however, that faster shutter speeds require more light, which is not always possible indoors. Choose a background that gives good contrast with the horse and avoid ‘noisy’ backgrounds. Trees and shrubs may look nice on a sale video but the background clutter makes it more difficult to follow the movements of the horse. Use tape or wraps to facilitate visualization of the parts of the horse you’re interested in. Each time you make a video, label the tape clearly and, if you plan to make a lot of tapes, keep a log book for easy retrieval. To get the most out of your tapes, invest in a VCR that gives crystal clear slow motion replay, freeze frame and single frame advance. These features make a huge difference in what you can learn from the tapes. Figure 2. Video taping at home, you can use a fenceline as a horizontal reference. Outlining the hooves with white tape improves their contrast with the ground. Next month I’ll give you some examples of situations in which video evaluation can be a useful technique for improving your appreciation of a horse’s movement or for diagnosing problems in a horse’s way of going.   Published with permission from Dressage & CT magazine.