Measuring stride characteristics.
| Measuring stride characteristics It has long been stated that having a long stride is a prerequisite for a good racehorse. But is stride length that important? Do horses that walk with a long stride necessarily have long strides when galloping? And do successful racehorses have different stride characteristics at exercise than less successful ones? |  |
3D-motion analysis equipment can produce accurate measurements. But the equipment is expensive and time-consuming to set up. It is also limited in that, at most, only two or three strides can be captured on the video recording.
Accelerometers that record movement in three planes are now available. When combined with global positioning system (GPS) devices, they allow the horse's speed and stride length to be recorded while it is galloping.
At the Conference on Equine Sports Medicine and Science, held in Utrecht, the Netherlands, recently, Dr Jeremy Naylor, racehorse trainer and veterinarian, and Debbie Holmes of the Equine Sports Medicine Centre at Bristol Vet School, described their experience with a commercial accelerometer system ("Pegasus")*.
The system comprises an accelerometer mounted on the withers and a GPS module mounted on the jockey's hat. Information is downloaded to a computer, which calculates speed, stride frequency and stride length.
Debbie Holmes described the initial study to validate the use of the system. Six fit Thoroughbred racehorses were exercised at two speeds (11m/s and 16m/s) on a wood chip track. Data from the accelerometer were compared with manual readings. Stride length was determined by measuring the distance between each successive lead footfall over one furlong (1 furlong = 660 feet or 201.86 metres) in the middle of the gallop. The horses' speed was calculated using a stopwatch.
The accelerometer system proved to give accurate results. The researchers found no significant differences between the results obtained with the accelerometer system and the manual measurements.
Dr Naylor described a further study that compared three standard exercise tests to see which was the most appropriate for measuring stride characteristics. He found little difference between the three tests. However, the most repeatable results were obtained using a two step constant speed test. (Horses were recorded running first at a constant speed of 8m/s, followed by a second gallop at 17m/s)
There was a wide variation between horses. "We did find there to be considerable variation in the individual horse's characteristics in how they got different stride length and stride frequency to achieve different speed of exercise."
Having demonstrated that the system provides a reliable and practical method of recording stride data of horses travelling at speed, Dr Naylor plans to broaden the scope of the research. By involving other trainers he hopes to examine the relationship between stride characteristics and performance in racehorses.
Further research could also look at how training or fatigue affects stride characteristics, and the effect of the rider on the way the horse goes.
*Pegasus Stride System. European Technology for Business Ltd.
Reproduced with kind permission of Mark Andrews BVM&S CertEP MRCVS
© Copyright Mark Andrews - Equine Science Update 2008
Added on: 01/08/08.
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