Through two seasons of racing and training, two and three year-old horses carried GPS units in their saddlebags and the jockeys' helmets were fitted with receiver antennae. A heart-monitor enabled the simultaneous analysis of heart-rate data with the measurements of speed and time collected by the GPS receivers.
The resulting information, of the speed and heart rate of a horse at any given moment, is a complementary tool by which trainers may identify peak fitness, or a state of over-training, says Dr Chris Rogers.
A senior researcher in the Institute of Veterinary and Animal Biomedical Sciences, Dr Rogers says trainers use heart rate, the time taken to run a furlong (200m), and visual assessment of the horse's rate of recovery to assess performance in training. "There is room for tightening in these methods, and it is the subtle changes to training that can ultimately have a big difference on performance," he says.
Whereas at peak fitness a horse's heart rate remains constant at its training galloping pace, the rate of an overtrained horse on the track will rise, or fluctuate. Dr Rogers says overtraining places stress and strain on a horse, on its limbs and general wellbeing. "Recovery and respiration rate indicate whether a horse has been pushed too far. A trainer can generally assess this, based on the animal's appearance and performance, but the methods are not scientific".
The equine research team is also applying GPS technology to the study of thoroughbred foals in the paddock to quantify their paddock activity. International interest in the high standards of health and strength of young New Zealand-raised racehorses has prompted collaborative research into raising and training methods, and a Dutch Masters student has been working with Dr Rogers on this project.
Dr Rogers says a Dutch study several years ago raised horses in three different ways. One group of foals were stabled continuously and another group was stabled with periods of exercise. The third group of foals was pasture-raised and later showed to be significantly stronger than others, in terms of cartilage strength in their legs. Dr Rogers says trainers in the Netherlands are increasingly adopting methods to encourage exercise, including shipping foals to Poland where they can be more easily kept at pasture.
Previous research conducted by the University's equine specialists shows that the biochemical composition of the cartilage matrix increases with exercise, and the number of cartilage cells is greater. Biochemical diversity and cell number are thought to protect against potential injury in later years of training and racing. By comparison, stabled horses' cartilage tends to be uniform in its composition.
Foals at pasture with their dam (mare) will race around the paddock, for the fun of it, and with particular enthusiasm at dawn and dusk. To measure the extent of this type, small GPS receivers were fitted to foals for an accurate assessment of their activity. The data collected showed that foals in their first month did twice as much exercise as in their second and third.
Dr Rogers says this situation compares with the previous research on exercise and cartilage growth. "That foals exercise the most, at their own will, in the first month, coincides with the sensitive period we found for cartilage development, which is the period where the cartilage cells can respond to varying stresses, and adapt in its growth and composition accordingly."
The data collected from the GPS trials will allow researchers to estimate an optimal exercise regime, and permit the definition of exercise guidelines for the development of stronger, sounder horses. Dr Rogers says the next step is to re-think the size and shapes of paddocks to encourage more exercise.
"A long skinny paddock seems to be preferable, and a gentle slope is good for building muscle. By putting a water trough at the top, and a feeding trough at the bottom of a sloping paddock, a dam and foal have to move between the two, and a foal will often tear ahead of its mother."