An Australian researcher reported he’s found a reliable way for trainers to monitor Thoroughbred racehorse fitness using global positioning system (GPS) technology measurements of velocity and heart rate during normal fast gallop training routines. David Evans, BVSc, PhD, associate professor in the Faculty of Veterinary Science at the University of Sydney, presented his research at the 51st Annual Convention of the American Association of Equine Practitioners, held Dec. 3-7, 2005, in Seattle, Wash.

“The three fundamental measurements during exercise that are used in the assessment of fitness are maximum oxygen uptake (VO₂max; which training aims to increase), blood lactate, and heart rates,” Evans said. “Measuring VO₂max is the gold standard for aerobic fitness, but this involves putting a mask on the horse’s face and exercising at high speeds on a suitable horse treadmill, so this technique has been limited to research in laboratories.” He said measuring blood lactate concentrations during and after exercise is an excellent approach, and decreases in blood lactate during submaximal exercise reflect improved aerobic fitness. However, this method has also been mostly limited to the treadmill lab because the procedure is invasive, and exercise protocols are difficult to standardize in field fitness tests, especially in Thoroughbreds.

Evans was searching for an assessment method that was non-invasive, readily acceptable by jockeys and trainers, rugged, reliable, and able to produce repeatable numbers. He applied GPS, a validated technology that can measure velocity and position at frequent time intervals, in a study of 10 Thoroughbreds that had already completed six weeks of slow training and one week of fast-gallop work under the same trainer.

The horses wore heart rate monitors and their jockeys wore GPS receivers in their skull caps during their fast gallop workouts, with batteries and GPS data loggers on board. Measurements were taken before, during, and after four weeks of commercial training for racing. The equipment gathered five-second averages of heart rate and velocity